view hoareBinaryTree1.agda @ 871:043c698a261d default tip

...
author Shinji KONO <kono@ie.u-ryukyu.ac.jp>
date Sat, 06 Apr 2024 18:19:23 +0900
parents 315efbf0148f
children
line wrap: on
line source

module hoareBinaryTree1 where

open import Level hiding (suc ; zero ; _⊔_ )

open import Data.Nat hiding (compare)
open import Data.Nat.Properties as NatProp
open import Data.Maybe
-- open import Data.Maybe.Properties
open import Data.Empty
open import Data.List
open import Data.Product

open import Function as F hiding (const)

open import Relation.Binary
open import Relation.Binary.PropositionalEquality
open import Relation.Nullary
open import logic


--
--
--  no children , having left node , having right node , having both
--
data bt {n : Level} (A : Set n) : Set n where
  leaf : bt A
  node :  (key : ℕ) → (value : A) →
    (left : bt A ) → (right : bt A ) → bt A

node-key : {n : Level} {A : Set n} → bt A → Maybe ℕ
node-key (node key _ _ _) = just key
node-key _ = nothing

node-value : {n : Level} {A : Set n} → bt A → Maybe A
node-value (node _ value _ _) = just value
node-value _ = nothing

bt-depth : {n : Level} {A : Set n} → (tree : bt A ) → ℕ
bt-depth leaf = 0
bt-depth (node key value t t₁) = suc (bt-depth t  ⊔ bt-depth t₁ )

open import Data.Unit hiding ( _≟_ ) -- ;  _≤?_ ; _≤_)

tr< : {n : Level} {A : Set n} → (key : ℕ) → bt A → Set
tr< {_} {A} key leaf = ⊤
tr< {_} {A} key (node key₁ value tr tr₁) = (key₁ < key ) ∧ tr< key tr  ∧  tr< key tr₁

tr> : {n : Level} {A : Set n} → (key : ℕ) → bt A → Set
tr> {_} {A} key leaf = ⊤
tr> {_} {A} key (node key₁ value tr tr₁) = (key < key₁ ) ∧ tr> key tr  ∧  tr> key tr₁

--
--
data treeInvariant {n : Level} {A : Set n} : (tree : bt A) → Set n where
    t-leaf : treeInvariant leaf
    t-single : (key : ℕ) → (value : A) →  treeInvariant (node key value leaf leaf)
    t-right : (key key₁ : ℕ) → {value value₁ : A} → {t₁ t₂ : bt A} → key < key₁
       → tr> key t₁
       → tr> key t₂
       → treeInvariant (node key₁ value₁ t₁ t₂)
       → treeInvariant (node key value leaf (node key₁ value₁ t₁ t₂))
    t-left  : (key key₁ : ℕ) → {value value₁ : A} → {t₁ t₂ : bt A} → key < key₁
       → tr< key₁ t₁
       → tr< key₁ t₂
       → treeInvariant (node key value t₁ t₂)
       → treeInvariant (node key₁ value₁ (node key value t₁ t₂) leaf )
    t-node  : (key key₁ key₂ : ℕ) → {value value₁ value₂ : A} → {t₁ t₂ t₃ t₄ : bt A} → key < key₁ → key₁ < key₂
       → tr< key₁ t₁
       → tr< key₁ t₂
       → tr> key₁ t₃
       → tr> key₁ t₄
       → treeInvariant (node key value t₁ t₂)
       → treeInvariant (node key₂ value₂ t₃ t₄)
       → treeInvariant (node key₁ value₁ (node key value t₁ t₂) (node key₂ value₂ t₃ t₄))

--
--  stack always contains original top at end (path of the tree)
--
data stackInvariant {n : Level} {A : Set n}  (key : ℕ) : (top orig : bt A) → (stack  : List (bt A)) → Set n where
    s-nil :  {tree0 : bt A} → stackInvariant key tree0 tree0 (tree0 ∷ [])
    s-right :  (tree tree0 tree₁ : bt A) → {key₁ : ℕ } → {v1 : A } → {st : List (bt A)}
        → key₁ < key  →  stackInvariant key (node key₁ v1 tree₁ tree) tree0 st → stackInvariant key tree tree0 (tree ∷ st)
    s-left :  (tree₁ tree0 tree : bt A) → {key₁ : ℕ } → {v1 : A } → {st : List (bt A)}
        → key  < key₁ →  stackInvariant key (node key₁ v1 tree₁ tree) tree0 st → stackInvariant key tree₁ tree0 (tree₁ ∷ st)

data replacedTree  {n : Level} {A : Set n} (key : ℕ) (value : A)  : (before after : bt A ) → Set n where
    r-leaf : replacedTree key value leaf (node key value leaf leaf)
    r-node : {value₁ : A} → {t t₁ : bt A} → replacedTree key value (node key value₁ t t₁) (node key value t t₁)
    r-right : {k : ℕ } {v1 : A} → {t t1 t2 : bt A}
          → k < key →  replacedTree key value t2 t →  replacedTree key value (node k v1 t1 t2) (node k v1 t1 t)
    r-left : {k : ℕ } {v1 : A} → {t t1 t2 : bt A}
          → key < k →  replacedTree key value t1 t →  replacedTree key value (node k v1 t1 t2) (node k v1 t t2)

add< : { i : ℕ } (j : ℕ ) → i < suc i + j
add<  {i} j = begin
        suc i ≤⟨ m≤m+n (suc i) j ⟩
        suc i + j ∎  where open ≤-Reasoning

treeTest1  : bt ℕ
treeTest1  =  node 0 0 leaf (node 3 1 (node 2 5 (node 1 7 leaf leaf ) leaf) (node 5 5 leaf leaf))
treeTest2  : bt ℕ
treeTest2  =  node 3 1 (node 2 5 (node 1 7 leaf leaf ) leaf) (node 5 5 leaf leaf)

treeInvariantTest1  : treeInvariant treeTest1
treeInvariantTest1  = t-right _ _ (m≤m+n _ 2)
    ⟪ add< _ , ⟪ ⟪ add< _ , _ ⟫ , _ ⟫ ⟫
    ⟪ add< _ , ⟪ _ , _ ⟫ ⟫ (t-node _ _ _ (add< 0) (add< 1) ⟪ add< _ , ⟪ _ , _ ⟫ ⟫  _ _ _ (t-left _ _ (add< 0) _ _ (t-single 1 7)) (t-single 5 5) )

stack-top :  {n : Level} {A : Set n} (stack  : List (bt A)) → Maybe (bt A)
stack-top [] = nothing
stack-top (x ∷ s) = just x

stack-last :  {n : Level} {A : Set n} (stack  : List (bt A)) → Maybe (bt A)
stack-last [] = nothing
stack-last (x ∷ []) = just x
stack-last (x ∷ s) = stack-last s

stackInvariantTest1 : stackInvariant 4 treeTest2 treeTest1 ( treeTest2 ∷ treeTest1 ∷ [] )
stackInvariantTest1 = s-right _ _ _ (add< 3) (s-nil  )

si-property0 :  {n : Level} {A : Set n} {key : ℕ} {tree tree0 : bt A} → {stack  : List (bt A)} →  stackInvariant key tree tree0 stack → ¬ ( stack ≡ [] )
si-property0  (s-nil  ) ()
si-property0  (s-right _ _ _ x si) ()
si-property0  (s-left _ _ _ x si) ()

si-property1 :  {n : Level} {A : Set n} {key : ℕ} {tree tree0 tree1 : bt A} → {stack  : List (bt A)} →  stackInvariant key tree tree0 (tree1 ∷ stack)
   → tree1 ≡ tree
si-property1 (s-nil   ) = refl
si-property1 (s-right _ _ _ _  si) = refl
si-property1 (s-left _ _ _ _  si) = refl

si-property2 :  {n : Level} {A : Set n} {key : ℕ} {tree tree0 tree1 : bt A} → (stack  : List (bt A)) →  stackInvariant key tree tree0 (tree1 ∷ stack)
   → ¬ ( just leaf ≡ stack-last stack )
si-property2 (.leaf ∷ []) (s-right _ _ tree₁ x ()) refl
si-property2 (x₁ ∷ x₂ ∷ stack) (s-right _ _ tree₁ x si) eq = si-property2 (x₂ ∷ stack) si eq
si-property2 (.leaf ∷ []) (s-left _ _ tree₁ x ()) refl
si-property2 (x₁ ∷ x₂ ∷ stack) (s-left _ _ tree₁ x si) eq = si-property2 (x₂ ∷ stack) si eq

si-property-last :  {n : Level} {A : Set n}  (key : ℕ) (tree tree0 : bt A) → (stack  : List (bt A)) →  stackInvariant key tree tree0 stack
   → stack-last stack ≡ just tree0
si-property-last key t t0 (t ∷ [])  (s-nil )  = refl
si-property-last key t t0 (.t ∷ x ∷ st) (s-right _ _ _ _ si ) with  si-property1 si
... | refl = si-property-last key x t0 (x ∷ st)   si
si-property-last key t t0 (.t ∷ x ∷ st) (s-left _ _ _ _ si ) with  si-property1  si
... | refl = si-property-last key x t0 (x ∷ st)   si


-- Diffkey : {n : Level} (A : Set n) (tree0 : bt A) → (key : ℕ) →  (tree : bt A) → (stack  : List (bt A)) → (si : stackInvariant key tree tree0 stack) → Set
-- Diffkey A leaf key .leaf .(leaf ∷ []) s-nil = ?
-- Diffkey A (node key₁ value tree0 tree1) key .(node key₁ value tree0 tree1) .(node key₁ value tree0 tree1 ∷ []) s-nil = ?
-- Diffkey A tree0 key leaf .(leaf ∷ _) (s-right .leaf .tree0 tree₁ x si) = ?
-- Diffkey A tree0 key (node key₁ value tree tree₂) .(node key₁ value tree tree₂ ∷ _) (s-right .(node key₁ value tree tree₂) .tree0 tree₁ x si) = ?
-- Diffkey A tree0 key tree .(tree ∷ _) (s-left .tree .tree0 tree₁ x si) = ?

-- si-property-ne :  {n : Level} {A : Set n}  (key : ℕ) (tree tree0 : bt A) → (stack  : List (bt A)) →  stackInvariant key tree tree0 stack
--    → length stack > 1 → ¬ ( node-key tree ≡ just key )
-- si-property-ne = ?

rt-property1 :  {n : Level} {A : Set n} (key : ℕ) (value : A) (tree tree1 : bt A ) → replacedTree key value tree tree1 → ¬ ( tree1 ≡ leaf )
rt-property1 {n} {A} key value .leaf .(node key value leaf leaf) r-leaf ()
rt-property1 {n} {A} key value .(node key _ _ _) .(node key value _ _) r-node ()
rt-property1 {n} {A} key value .(node _ _ _ _) _ (r-right x rt) = λ ()
rt-property1 {n} {A} key value .(node _ _ _ _) _ (r-left x rt) = λ ()

rt-property-leaf : {n : Level} {A : Set n} {key : ℕ} {value : A} {repl : bt A} → replacedTree key value leaf repl → repl ≡ node key value leaf leaf
rt-property-leaf r-leaf = refl

rt-property-¬leaf : {n : Level} {A : Set n} {key : ℕ} {value : A} {tree : bt A} → ¬ replacedTree key value tree leaf
rt-property-¬leaf ()

rt-property-key : {n : Level} {A : Set n} {key key₂ key₃ : ℕ} {value value₂ value₃ : A} {left left₁ right₂ right₃ : bt A}
    →  replacedTree key value (node key₂ value₂ left right₂) (node key₃ value₃ left₁ right₃) → key₂ ≡ key₃
rt-property-key r-node = refl
rt-property-key (r-right x ri) = refl
rt-property-key (r-left x ri) = refl

nat-≤> : { x y : ℕ } → x ≤ y → y < x → ⊥
nat-≤>  (s≤s x<y) (s≤s y<x) = nat-≤> x<y y<x
nat-<> : { x y : ℕ } → x < y → y < x → ⊥
nat-<>  (s≤s x<y) (s≤s y<x) = nat-<> x<y y<x

open _∧_


depth-1< : {i j : ℕ} →   suc i ≤ suc (i Data.Nat.⊔ j )
depth-1< {i} {j} = s≤s (m≤m⊔n _ j)

depth-2< : {i j : ℕ} →   suc i ≤ suc (j Data.Nat.⊔ i )
depth-2< {i} {j} = s≤s (m≤n⊔m j i)

depth-3< : {i : ℕ } → suc i ≤ suc (suc i)
depth-3< {zero} = s≤s ( z≤n )
depth-3< {suc i} = s≤s (depth-3< {i} )


treeLeftDown  : {n : Level} {A : Set n} {k : ℕ} {v1 : A}  → (tree tree₁ : bt A )
      → treeInvariant (node k v1 tree tree₁)
      →      treeInvariant tree
treeLeftDown {n} {A} {_} {v1} leaf leaf (t-single k1 v1) = t-leaf
treeLeftDown {n} {A} {_} {v1} .leaf .(node _ _ _ _) (t-right _ _ x _ _ ti) = t-leaf
treeLeftDown {n} {A} {_} {v1} .(node _ _ _ _) .leaf (t-left _ _ x _ _ ti) = ti
treeLeftDown {n} {A} {_} {v1} .(node _ _ _ _) .(node _ _ _ _) (t-node _ _ _ x x₁ _ _ _ _ ti ti₁) = ti

treeRightDown  : {n : Level} {A : Set n} {k : ℕ} {v1 : A}  → (tree tree₁ : bt A )
      → treeInvariant (node k v1 tree tree₁)
      →      treeInvariant tree₁
treeRightDown {n} {A} {_} {v1} .leaf .leaf (t-single _ .v1) = t-leaf
treeRightDown {n} {A} {_} {v1} .leaf .(node _ _ _ _) (t-right _ _ x _ _ ti) = ti
treeRightDown {n} {A} {_} {v1} .(node _ _ _ _) .leaf (t-left _ _ x _ _ ti) = t-leaf
treeRightDown {n} {A} {_} {v1} .(node _ _ _ _) .(node _ _ _ _) (t-node _ _ _ x x₁ _ _ _ _ ti ti₁) = ti₁

findP : {n m : Level} {A : Set n} {t : Set m} → (key : ℕ) → (tree tree0 : bt A ) → (stack : List (bt A))
           →  treeInvariant tree ∧ stackInvariant key tree tree0 stack
           → (next : (tree1 : bt A) → (stack : List (bt A)) → treeInvariant tree1 ∧ stackInvariant key tree1 tree0 stack → bt-depth tree1 < bt-depth tree   → t )
           → (exit : (tree1 : bt A) → (stack : List (bt A)) → treeInvariant tree1 ∧ stackInvariant key tree1 tree0 stack
                 → (tree1 ≡ leaf ) ∨ ( node-key tree1 ≡ just key )  → t ) → t
findP key leaf tree0 st Pre _ exit = exit leaf st Pre (case1 refl)
findP key (node key₁ v1 tree tree₁) tree0 st Pre next exit with <-cmp key key₁
findP key n tree0 st Pre _ exit | tri≈ ¬a refl ¬c = exit n st Pre (case2 refl)
findP {n} {_} {A} key (node key₁ v1 tree tree₁) tree0 st  Pre next _ | tri< a ¬b ¬c = next tree (tree ∷ st)
       ⟪ treeLeftDown tree tree₁ (proj1 Pre)  , findP1 a st (proj2 Pre) ⟫ depth-1< where
   findP1 : key < key₁ → (st : List (bt A)) →  stackInvariant key (node key₁ v1 tree tree₁) tree0 st → stackInvariant key tree tree0 (tree ∷ st)
   findP1 a (x ∷ st) si = s-left _ _ _ a si
findP key n@(node key₁ v1 tree tree₁) tree0 st Pre next _ | tri> ¬a ¬b c = next tree₁ (tree₁ ∷ st) ⟪ treeRightDown tree tree₁ (proj1 Pre) , s-right _ _ _ c (proj2 Pre) ⟫ depth-2<

replaceTree1 : {n  : Level} {A : Set n} {t t₁ : bt A } → ( k : ℕ ) → (v1 value : A ) →  treeInvariant (node k v1 t t₁) → treeInvariant (node k value t t₁)
replaceTree1 k v1 value (t-single .k .v1) = t-single k value
replaceTree1 k v1 value (t-right _ _ x a b t) = t-right _ _ x a b t
replaceTree1 k v1 value (t-left _ _ x a b t) = t-left _ _ x a b t
replaceTree1 k v1 value (t-node _ _ _ x x₁ a b c d t t₁) = t-node _ _ _ x x₁ a b c d t t₁

open import Relation.Binary.Definitions

lemma3 : {i j : ℕ} → 0 ≡ i → j < i → ⊥
lemma3 refl ()
lemma5 : {i j : ℕ} → i < 1 → j < i → ⊥
lemma5 (s≤s z≤n) ()
¬x<x : {x : ℕ} → ¬ (x < x)
¬x<x (s≤s lt) = ¬x<x lt

child-replaced :  {n : Level} {A : Set n} (key : ℕ)   (tree : bt A) → bt A
child-replaced key leaf = leaf
child-replaced key (node key₁ value left right) with <-cmp key key₁
... | tri< a ¬b ¬c = left
... | tri≈ ¬a b ¬c = node key₁ value left right
... | tri> ¬a ¬b c = right

record replacePR {n : Level} {A : Set n} (key : ℕ) (value : A) (tree repl : bt A ) (stack : List (bt A)) (C : bt A → bt A → List (bt A) → Set n) : Set n where
   field
     tree0 : bt A
     ti : treeInvariant tree0
     si : stackInvariant key tree tree0 stack
     ri : replacedTree key value (child-replaced key tree ) repl
     ci : C tree repl stack     -- data continuation

record replacePR' {n : Level} {A : Set n} (key : ℕ) (value : A) (orig : bt A ) (stack : List (bt A))  : Set n where
   field
     tree repl : bt A
     ti : treeInvariant orig
     si : stackInvariant key tree orig stack
     ri : replacedTree key value (child-replaced key tree) repl
     --   treeInvariant of tree and repl is inferred from ti, si and ri.

replaceNodeP : {n m : Level} {A : Set n} {t : Set m} → (key : ℕ) → (value : A) → (tree : bt A)
    → (tree ≡ leaf ) ∨ ( node-key tree ≡ just key )
    → (treeInvariant tree ) → ((tree1 : bt A) → treeInvariant tree1 →  replacedTree key value (child-replaced key tree) tree1 → t) → t
replaceNodeP k v1 leaf C P next = next (node k v1 leaf leaf) (t-single k v1 ) r-leaf
replaceNodeP k v1 (node .k value t t₁) (case2 refl) P next = next (node k v1 t t₁) (replaceTree1 k value v1 P)
     (subst (λ j → replacedTree k v1 j  (node k v1 t t₁) ) repl00 r-node) where
         repl00 : node k value t t₁ ≡ child-replaced k (node k value t t₁)
         repl00 with <-cmp k k
         ... | tri< a ¬b ¬c = ⊥-elim (¬b refl)
         ... | tri≈ ¬a b ¬c = refl
         ... | tri> ¬a ¬b c = ⊥-elim (¬b refl)

replaceP : {n m : Level} {A : Set n} {t : Set m}
     → (key : ℕ) → (value : A) → {tree : bt A} ( repl : bt A)
     → (stack : List (bt A)) → replacePR key value tree repl stack (λ _ _ _ → Lift n ⊤)
     → (next : ℕ → A → {tree1 : bt A } (repl : bt A) → (stack1 : List (bt A))
         → replacePR key value tree1 repl stack1 (λ _ _ _ → Lift n ⊤) → length stack1 < length stack → t)
     → (exit : (tree1 repl : bt A) → treeInvariant tree1 ∧ replacedTree key value tree1 repl → t) → t
replaceP key value {tree}  repl [] Pre next exit = ⊥-elim ( si-property0 (replacePR.si Pre) refl ) -- can't happen
replaceP key value {tree}  repl (leaf ∷ []) Pre next exit with  si-property-last  _ _ _ _  (replacePR.si Pre)-- tree0 ≡ leaf
... | refl  =  exit (replacePR.tree0 Pre) (node key value leaf leaf) ⟪ replacePR.ti Pre ,  r-leaf ⟫
replaceP key value {tree}  repl (node key₁ value₁ left right ∷ []) Pre next exit with <-cmp key key₁
... | tri< a ¬b ¬c = exit (replacePR.tree0 Pre) (node key₁ value₁ repl right ) ⟪ replacePR.ti Pre , repl01 ⟫ where
    repl01 : replacedTree key value (replacePR.tree0 Pre) (node key₁ value₁ repl right )
    repl01 with si-property1 (replacePR.si Pre) | si-property-last  _ _ _ _  (replacePR.si Pre)
    repl01 | refl | refl = subst (λ k → replacedTree key value  (node key₁ value₁ k right ) (node key₁ value₁ repl right )) repl02 (r-left a repl03) where
        repl03 : replacedTree key value ( child-replaced key (node key₁ value₁ left right)) repl
        repl03 = replacePR.ri Pre
        repl02 : child-replaced key (node key₁ value₁ left right) ≡ left
        repl02 with <-cmp key key₁
        ... | tri< a ¬b ¬c = refl
        ... | tri≈ ¬a b ¬c = ⊥-elim ( ¬a a)
        ... | tri> ¬a ¬b c = ⊥-elim ( ¬a a)
... | tri≈ ¬a b ¬c = exit (replacePR.tree0 Pre) repl ⟪ replacePR.ti Pre , repl01 ⟫ where
    repl01 : replacedTree key value (replacePR.tree0 Pre) repl
    repl01 with si-property1 (replacePR.si Pre) | si-property-last  _ _ _ _  (replacePR.si Pre)
    repl01 | refl | refl = subst (λ k → replacedTree key value k repl) repl02 (replacePR.ri Pre) where
        repl02 : child-replaced key (node key₁ value₁ left right) ≡ node key₁ value₁ left right
        repl02 with <-cmp key key₁
        ... | tri< a ¬b ¬c = ⊥-elim ( ¬b b)
        ... | tri≈ ¬a b ¬c = refl
        ... | tri> ¬a ¬b c = ⊥-elim ( ¬b b)
... | tri> ¬a ¬b c = exit (replacePR.tree0 Pre) (node key₁ value₁ left repl  ) ⟪ replacePR.ti Pre , repl01 ⟫ where
    repl01 : replacedTree key value (replacePR.tree0 Pre) (node key₁ value₁ left repl )
    repl01 with si-property1 (replacePR.si Pre) | si-property-last  _ _ _ _  (replacePR.si Pre)
    repl01 | refl | refl = subst (λ k → replacedTree key value  (node key₁ value₁ left k ) (node key₁ value₁ left repl )) repl02 (r-right c repl03) where
        repl03 : replacedTree key value ( child-replaced key (node key₁ value₁ left right)) repl
        repl03 = replacePR.ri Pre
        repl02 : child-replaced key (node key₁ value₁ left right) ≡ right
        repl02 with <-cmp key key₁
        ... | tri< a ¬b ¬c = ⊥-elim ( ¬c c)
        ... | tri≈ ¬a b ¬c = ⊥-elim ( ¬c c)
        ... | tri> ¬a ¬b c = refl
replaceP {n} {_} {A} key value  {tree}  repl (leaf ∷ st@(tree1 ∷ st1)) Pre next exit = next key value repl st Post ≤-refl where
    Post :  replacePR key value tree1 repl (tree1 ∷ st1) (λ _ _ _ → Lift n ⊤)
    Post with replacePR.si Pre
    ... | s-right  _ _ tree₁ {key₂} {v1} x si = record { tree0 = replacePR.tree0 Pre ; ti = replacePR.ti Pre ; si = repl10 ; ri = repl12 ; ci = lift tt } where
        repl09 : tree1 ≡ node key₂ v1 tree₁ leaf
        repl09 = si-property1 si
        repl10 : stackInvariant key tree1 (replacePR.tree0 Pre) (tree1 ∷ st1)
        repl10 with si-property1 si
        ... | refl = si
        repl07 : child-replaced key (node key₂ v1 tree₁ leaf) ≡ leaf
        repl07 with <-cmp key key₂
        ... |  tri< a ¬b ¬c = ⊥-elim (¬c x)
        ... |  tri≈ ¬a b ¬c = ⊥-elim (¬c x)
        ... |  tri> ¬a ¬b c = refl
        repl12 : replacedTree key value (child-replaced key  tree1  ) repl
        repl12 = subst₂ (λ j k → replacedTree key value j k ) (sym (subst (λ k → child-replaced key k ≡ leaf) (sym repl09) repl07 ) ) (sym (rt-property-leaf (replacePR.ri Pre))) r-leaf
    ... | s-left  _ _ tree₁ {key₂} {v1} x si = record { tree0 = replacePR.tree0 Pre ; ti = replacePR.ti Pre ; si = repl10 ; ri = repl12 ; ci = lift tt } where
        repl09 : tree1 ≡ node key₂ v1 leaf tree₁
        repl09 = si-property1 si
        repl10 : stackInvariant key tree1 (replacePR.tree0 Pre) (tree1 ∷ st1)
        repl10 with si-property1 si
        ... | refl = si
        repl07 : child-replaced key (node key₂ v1 leaf tree₁ ) ≡ leaf
        repl07 with <-cmp key key₂
        ... |  tri< a ¬b ¬c = refl
        ... |  tri≈ ¬a b ¬c = ⊥-elim (¬a x)
        ... |  tri> ¬a ¬b c = ⊥-elim (¬a x)
        repl12 : replacedTree key value (child-replaced key  tree1  ) repl
        repl12 = subst₂ (λ j k → replacedTree key value j k ) (sym (subst (λ k → child-replaced key k ≡ leaf) (sym repl09) repl07) ) (sym (rt-property-leaf (replacePR.ri Pre ))) r-leaf
       -- repl12 = subst₂ (λ j k → replacedTree key value j k ) (sym (subst (λ k → child-replaced key k ≡ leaf) (sym repl09) repl07 ) ) (sym (rt-property-leaf (replacePR.ri Pre))) r-leaf
replaceP {n} {_} {A} key value {tree}  repl (node key₁ value₁ left right ∷ st@(tree1 ∷ st1)) Pre next exit  with <-cmp key key₁
... | tri< a ¬b ¬c = next key value (node key₁ value₁ repl right ) st Post ≤-refl where
    Post : replacePR key value tree1 (node key₁ value₁ repl right ) st (λ _ _ _ → Lift n ⊤)
    Post with replacePR.si Pre
    ... | s-right _ _ tree₁ {key₂} {v1} lt si = record { tree0 = replacePR.tree0 Pre ; ti = replacePR.ti Pre ; si = repl10 ; ri = repl12 ; ci = lift tt } where
        repl09 : tree1 ≡ node key₂ v1 tree₁ (node key₁ value₁ left right)
        repl09 = si-property1 si
        repl10 : stackInvariant key tree1 (replacePR.tree0 Pre) (tree1 ∷ st1)
        repl10 with si-property1 si
        ... | refl = si
        repl03 : child-replaced key (node key₁ value₁ left right) ≡ left
        repl03 with <-cmp key key₁
        ... | tri< a1 ¬b ¬c = refl
        ... | tri≈ ¬a b ¬c = ⊥-elim (¬a a)
        ... | tri> ¬a ¬b c = ⊥-elim (¬a a)
        repl02 : child-replaced key (node key₂ v1 tree₁ (node key₁ value₁ left right) ) ≡ node key₁ value₁ left right
        repl02 with repl09 | <-cmp key key₂
        ... | refl | tri< a ¬b ¬c = ⊥-elim (¬c lt)
        ... | refl | tri≈ ¬a b ¬c = ⊥-elim (¬c lt)
        ... | refl | tri> ¬a ¬b c = refl
        repl04 : node key₁ value₁ (child-replaced key (node key₁ value₁ left right)) right ≡ child-replaced key tree1
        repl04  = begin
            node key₁ value₁ (child-replaced key (node key₁ value₁ left right)) right ≡⟨ cong (λ k → node key₁ value₁ k right) repl03  ⟩
            node key₁ value₁ left right ≡⟨ sym repl02 ⟩
            child-replaced key  (node key₂ v1 tree₁ (node key₁ value₁ left right) ) ≡⟨ cong (λ k → child-replaced key k ) (sym repl09) ⟩
            child-replaced key tree1 ∎  where open ≡-Reasoning
        repl12 : replacedTree key value (child-replaced key  tree1  ) (node key₁ value₁ repl right)
        repl12 = subst (λ k → replacedTree key value k (node key₁ value₁ repl right) ) repl04  (r-left a (replacePR.ri Pre))
    ... | s-left _ _ tree₁ {key₂} {v1} lt si = record { tree0 = replacePR.tree0 Pre ; ti = replacePR.ti Pre ; si = repl10 ; ri = repl12 ; ci = lift tt } where
        repl09 : tree1 ≡ node key₂ v1 (node key₁ value₁ left right) tree₁
        repl09 = si-property1 si
        repl10 : stackInvariant key tree1 (replacePR.tree0 Pre) (tree1 ∷ st1)
        repl10 with si-property1 si
        ... | refl = si
        repl03 : child-replaced key (node key₁ value₁ left right) ≡ left
        repl03 with <-cmp key key₁
        ... | tri< a1 ¬b ¬c = refl
        ... | tri≈ ¬a b ¬c = ⊥-elim (¬a a)
        ... | tri> ¬a ¬b c = ⊥-elim (¬a a)
        repl02 : child-replaced key (node key₂ v1 (node key₁ value₁ left right) tree₁) ≡ node key₁ value₁ left right
        repl02 with repl09 | <-cmp key key₂
        ... | refl | tri< a ¬b ¬c = refl
        ... | refl | tri≈ ¬a b ¬c = ⊥-elim (¬a lt)
        ... | refl | tri> ¬a ¬b c = ⊥-elim (¬a lt)
        repl04 : node key₁ value₁ (child-replaced key (node key₁ value₁ left right)) right ≡ child-replaced key tree1
        repl04  = begin
            node key₁ value₁ (child-replaced key (node key₁ value₁ left right)) right ≡⟨ cong (λ k → node key₁ value₁ k right) repl03  ⟩
            node key₁ value₁ left right ≡⟨ sym repl02 ⟩
            child-replaced key  (node key₂ v1 (node key₁ value₁ left right) tree₁) ≡⟨ cong (λ k → child-replaced key k ) (sym repl09) ⟩
            child-replaced key tree1 ∎  where open ≡-Reasoning
        repl12 : replacedTree key value (child-replaced key  tree1  ) (node key₁ value₁ repl right)
        repl12 = subst (λ k → replacedTree key value k (node key₁ value₁ repl right) ) repl04  (r-left a (replacePR.ri Pre))
... | tri≈ ¬a b ¬c = next key value (node key₁ value  left right ) st Post ≤-refl where
    Post :  replacePR key value tree1 (node key₁ value left right ) (tree1 ∷ st1) (λ _ _ _ → Lift n ⊤)
    Post with replacePR.si Pre
    ... | s-right  _ _ tree₁ {key₂} {v1} x si = record { tree0 = replacePR.tree0 Pre ; ti = replacePR.ti Pre ; si = repl10 ; ri = repl12 b ; ci = lift tt } where
        repl09 : tree1 ≡ node key₂ v1 tree₁ tree -- (node key₁ value₁  left right)
        repl09 = si-property1 si
        repl10 : stackInvariant key tree1 (replacePR.tree0 Pre) (tree1 ∷ st1)
        repl10 with si-property1 si
        ... | refl = si
        repl07 : child-replaced key (node key₂ v1 tree₁ tree) ≡ tree
        repl07 with <-cmp key key₂
        ... |  tri< a ¬b ¬c = ⊥-elim (¬c x)
        ... |  tri≈ ¬a b ¬c = ⊥-elim (¬c x)
        ... |  tri> ¬a ¬b c = refl
        repl12 : (key ≡ key₁) → replacedTree key value (child-replaced key  tree1  ) (node key₁ value left right )
        repl12 refl with repl09
        ... | refl = subst (λ k → replacedTree key value k (node key₁ value left right )) (sym repl07) r-node
    ... | s-left  _ _ tree₁ {key₂} {v1} x si = record { tree0 = replacePR.tree0 Pre ; ti = replacePR.ti Pre ; si = repl10 ; ri = repl12 b ; ci = lift tt } where
        repl09 : tree1 ≡ node key₂ v1 tree tree₁
        repl09 = si-property1 si
        repl10 : stackInvariant key tree1 (replacePR.tree0 Pre) (tree1 ∷ st1)
        repl10 with si-property1 si
        ... | refl = si
        repl07 : child-replaced key (node key₂ v1 tree tree₁ ) ≡ tree
        repl07 with <-cmp key key₂
        ... |  tri< a ¬b ¬c = refl
        ... |  tri≈ ¬a b ¬c = ⊥-elim (¬a x)
        ... |  tri> ¬a ¬b c = ⊥-elim (¬a x)
        repl12 : (key ≡ key₁) → replacedTree key value (child-replaced key  tree1  ) (node key₁ value left right )
        repl12 refl with repl09
        ... | refl = subst (λ k → replacedTree key value k (node key₁ value left right )) (sym repl07) r-node
... | tri> ¬a ¬b c = next key value (node key₁ value₁ left repl ) st Post ≤-refl where
    Post : replacePR key value tree1 (node key₁ value₁ left repl ) st (λ _ _ _ → Lift n ⊤)
    Post with replacePR.si Pre
    ... | s-right _ _ tree₁ {key₂} {v1} lt si = record { tree0 = replacePR.tree0 Pre ; ti = replacePR.ti Pre ; si = repl10 ; ri = repl12 ; ci = lift tt } where
        repl09 : tree1 ≡ node key₂ v1 tree₁ (node key₁ value₁ left right)
        repl09 = si-property1 si
        repl10 : stackInvariant key tree1 (replacePR.tree0 Pre) (tree1 ∷ st1)
        repl10 with si-property1 si
        ... | refl = si
        repl03 : child-replaced key (node key₁ value₁ left right) ≡ right
        repl03 with <-cmp key key₁
        ... | tri< a1 ¬b ¬c = ⊥-elim (¬c c)
        ... | tri≈ ¬a b ¬c = ⊥-elim (¬c c)
        ... | tri> ¬a ¬b c = refl
        repl02 : child-replaced key (node key₂ v1 tree₁ (node key₁ value₁ left right) ) ≡ node key₁ value₁ left right
        repl02 with repl09 | <-cmp key key₂
        ... | refl | tri< a ¬b ¬c = ⊥-elim (¬c lt)
        ... | refl | tri≈ ¬a b ¬c = ⊥-elim (¬c lt)
        ... | refl | tri> ¬a ¬b c = refl
        repl04 : node key₁ value₁ left (child-replaced key (node key₁ value₁ left right)) ≡ child-replaced key tree1
        repl04  = begin
            node key₁ value₁ left (child-replaced key (node key₁ value₁ left right)) ≡⟨ cong (λ k → node key₁ value₁ left k ) repl03 ⟩
            node key₁ value₁ left right ≡⟨ sym repl02 ⟩
            child-replaced key  (node key₂ v1 tree₁ (node key₁ value₁ left right) ) ≡⟨ cong (λ k → child-replaced key k ) (sym repl09) ⟩
            child-replaced key tree1 ∎  where open ≡-Reasoning
        repl12 : replacedTree key value (child-replaced key  tree1  ) (node key₁ value₁ left repl)
        repl12 = subst (λ k → replacedTree key value k (node key₁ value₁ left repl) ) repl04 (r-right c (replacePR.ri Pre))
    ... | s-left _ _ tree₁ {key₂} {v1} lt si = record { tree0 = replacePR.tree0 Pre ; ti = replacePR.ti Pre ; si = repl10 ; ri = repl12 ; ci = lift tt } where
        repl09 : tree1 ≡ node key₂ v1 (node key₁ value₁ left right) tree₁
        repl09 = si-property1 si
        repl10 : stackInvariant key tree1 (replacePR.tree0 Pre) (tree1 ∷ st1)
        repl10 with si-property1 si
        ... | refl = si
        repl03 : child-replaced key (node key₁ value₁ left right) ≡ right
        repl03 with <-cmp key key₁
        ... | tri< a1 ¬b ¬c = ⊥-elim (¬c c)
        ... | tri≈ ¬a b ¬c = ⊥-elim (¬c c)
        ... | tri> ¬a ¬b c = refl
        repl02 : child-replaced key (node key₂ v1 (node key₁ value₁ left right) tree₁) ≡ node key₁ value₁ left right
        repl02 with repl09 | <-cmp key key₂
        ... | refl | tri< a ¬b ¬c = refl
        ... | refl | tri≈ ¬a b ¬c = ⊥-elim (¬a lt)
        ... | refl | tri> ¬a ¬b c = ⊥-elim (¬a lt)
        repl04 : node key₁ value₁ left (child-replaced key (node key₁ value₁ left right)) ≡ child-replaced key tree1
        repl04  = begin
            node key₁ value₁ left (child-replaced key (node key₁ value₁ left right)) ≡⟨ cong (λ k → node key₁ value₁ left k ) repl03 ⟩
            node key₁ value₁ left right ≡⟨ sym repl02 ⟩
            child-replaced key  (node key₂ v1 (node key₁ value₁ left right) tree₁) ≡⟨ cong (λ k → child-replaced key k ) (sym repl09) ⟩
            child-replaced key tree1 ∎  where open ≡-Reasoning
        repl12 : replacedTree key value (child-replaced key  tree1  ) (node key₁ value₁ left repl)
        repl12 = subst (λ k → replacedTree key value k (node key₁ value₁ left repl) ) repl04  (r-right c (replacePR.ri Pre))

TerminatingLoopS : {l m : Level} {t : Set l} (Index : Set m ) → {Invraiant : Index → Set m } → ( reduce : Index → ℕ)
   → (r : Index) → (p : Invraiant r)
   → (loop : (r : Index)  → Invraiant r → (next : (r1 : Index)  → Invraiant r1 → reduce r1 < reduce r  → t ) → t) → t
TerminatingLoopS {_} {_} {t} Index {Invraiant} reduce r p loop with <-cmp 0 (reduce r)
... | tri≈ ¬a b ¬c = loop r p (λ r1 p1 lt → ⊥-elim (lemma3 b lt) )
... | tri< a ¬b ¬c = loop r p (λ r1 p1 lt1 → TerminatingLoop1 (reduce r) r r1 (m≤n⇒m≤1+n lt1) p1 lt1 ) where
    TerminatingLoop1 : (j : ℕ) → (r r1 : Index) → reduce r1 < suc j  → Invraiant r1 →  reduce r1 < reduce r → t
    TerminatingLoop1 zero r r1 n≤j p1 lt = loop r1 p1 (λ r2 p1 lt1 → ⊥-elim (lemma5 n≤j lt1))
    TerminatingLoop1 (suc j) r r1  n≤j p1 lt with <-cmp (reduce r1) (suc j)
    ... | tri< a ¬b ¬c = TerminatingLoop1 j r r1 a p1 lt
    ... | tri≈ ¬a b ¬c = loop r1 p1 (λ r2 p2 lt1 → TerminatingLoop1 j r1 r2 (subst (λ k → reduce r2 < k ) b lt1 ) p2 lt1 )
    ... | tri> ¬a ¬b c =  ⊥-elim ( nat-≤> c n≤j )

open _∧_

ri-tr>  : {n : Level} {A : Set n}  → (tree repl : bt A) → (key key₁ : ℕ) → (value : A)
     → replacedTree key value tree repl → key₁ < key → tr> key₁ tree → tr> key₁ repl
ri-tr> .leaf .(node key value leaf leaf) key key₁ value r-leaf a tgt = ⟪ a , ⟪ tt , tt ⟫ ⟫
ri-tr> .(node key _ _ _) .(node key value _ _) key key₁ value r-node a tgt = ⟪ a , ⟪ proj1 (proj2 tgt) , proj2 (proj2 tgt) ⟫ ⟫
ri-tr> .(node _ _ _ _) .(node _ _ _ _) key key₁ value (r-right x ri) a tgt = ⟪ proj1 tgt , ⟪ proj1 (proj2 tgt) , ri-tr> _ _ _ _ _ ri a (proj2 (proj2 tgt)) ⟫ ⟫
ri-tr> .(node _ _ _ _) .(node _ _ _ _) key key₁ value (r-left x ri) a tgt = ⟪ proj1 tgt , ⟪  ri-tr> _ _ _ _ _ ri a (proj1 (proj2 tgt)) , proj2 (proj2 tgt)  ⟫ ⟫

ri-tr<  : {n : Level} {A : Set n}  → (tree repl : bt A) → (key key₁ : ℕ) → (value : A)
     → replacedTree key value tree repl → key < key₁ → tr< key₁ tree → tr< key₁ repl
ri-tr< .leaf .(node key value leaf leaf) key key₁ value r-leaf a tgt = ⟪ a , ⟪ tt , tt ⟫ ⟫
ri-tr< .(node key _ _ _) .(node key value _ _) key key₁ value r-node a tgt = ⟪ a , ⟪ proj1 (proj2 tgt) , proj2 (proj2 tgt) ⟫ ⟫
ri-tr< .(node _ _ _ _) .(node _ _ _ _) key key₁ value (r-right x ri) a tgt = ⟪ proj1 tgt , ⟪ proj1 (proj2 tgt) , ri-tr< _ _ _ _ _ ri a (proj2 (proj2 tgt)) ⟫ ⟫
ri-tr< .(node _ _ _ _) .(node _ _ _ _) key key₁ value (r-left x ri) a tgt = ⟪ proj1 tgt , ⟪  ri-tr< _ _ _ _ _ ri a (proj1 (proj2 tgt)) , proj2 (proj2 tgt)  ⟫ ⟫

<-tr>  : {n : Level} {A : Set n}  → {tree : bt A} → {key₁ key₂ : ℕ} → tr> key₁ tree → key₂ < key₁  → tr> key₂ tree
<-tr> {n} {A} {leaf} {key₁} {key₂} tr lt = tt
<-tr> {n} {A} {node key value t t₁} {key₁} {key₂} tr lt = ⟪ <-trans lt (proj1 tr) , ⟪ <-tr> (proj1 (proj2 tr)) lt , <-tr> (proj2 (proj2 tr)) lt ⟫ ⟫

>-tr<  : {n : Level} {A : Set n}  → {tree : bt A} → {key₁ key₂ : ℕ} → tr< key₁ tree → key₁ < key₂  → tr< key₂ tree
>-tr<  {n} {A} {leaf} {key₁} {key₂} tr lt = tt
>-tr<  {n} {A} {node key value t t₁} {key₁} {key₂} tr lt = ⟪ <-trans (proj1 tr) lt , ⟪ >-tr< (proj1 (proj2 tr)) lt , >-tr< (proj2 (proj2 tr)) lt ⟫ ⟫

RTtoTI0  : {n : Level} {A : Set n}  → (tree repl : bt A) → (key : ℕ) → (value : A) → treeInvariant tree
     → replacedTree key value tree repl → treeInvariant repl
RTtoTI0 .leaf .(node key value leaf leaf) key value ti r-leaf = t-single key value
RTtoTI0 .(node key _ leaf leaf) .(node key value leaf leaf) key value (t-single .key _) r-node = t-single key value
RTtoTI0 .(node key _ leaf (node _ _ _ _)) .(node key value leaf (node _ _ _ _)) key value (t-right _ _ x a b ti) r-node = t-right _ _ x a b ti
RTtoTI0 .(node key _ (node _ _ _ _) leaf) .(node key value (node _ _ _ _) leaf) key value (t-left _ _ x a b ti) r-node = t-left _ _ x a b ti
RTtoTI0 .(node key _ (node _ _ _ _) (node _ _ _ _)) .(node key value (node _ _ _ _) (node _ _ _ _)) key value (t-node _ _ _ x x₁ a b c d ti ti₁) r-node = t-node _ _ _ x x₁ a b c d ti ti₁
-- r-right case
RTtoTI0 (node _ _ leaf leaf) (node _ _ leaf .(node key value leaf leaf)) key value (t-single _ _) (r-right x r-leaf) = t-right _ _ x _ _ (t-single key value)
RTtoTI0 (node _ _ leaf right@(node _ _ _ _)) (node key₁ value₁ leaf leaf) key value (t-right _ _ x₁ a b ti) (r-right x ri) = t-single key₁ value₁
RTtoTI0 (node key₁ _ leaf right@(node key₂ _ left₁ right₁)) (node key₁ value₁ leaf right₃@(node key₃ _ left₂ right₂)) key value (t-right key₄ key₅ x₁ a b ti) (r-right x ri) =
      t-right _ _ (subst (λ k → key₁ < k ) (rt-property-key ri) x₁) (rr00 ri a ) (rr02 ri b) (RTtoTI0 right right₃ key value ti ri) where
         rr00 : replacedTree key value (node key₂ _ left₁ right₁) (node key₃ _ left₂ right₂) → tr> key₁ left₁ → tr> key₁ left₂
         rr00 r-node tb = tb
         rr00 (r-right x ri) tb = tb
         rr00 (r-left x₂ ri) tb = ri-tr> _ _ _ _ _ ri x tb
         rr02 : replacedTree key value (node key₂ _ left₁ right₁) (node key₃ _ left₂ right₂) → tr> key₁ right₁ → tr> key₁ right₂
         rr02 r-node tb = tb
         rr02 (r-right x₂ ri) tb = ri-tr> _ _ _ _ _ ri x tb
         rr02 (r-left x ri) tb = tb
RTtoTI0 (node key₁ _ (node _ _ _ _) leaf) (node key₁ _ (node key₃ value left right) leaf) key value₁ (t-left _ _ x₁ a b ti) (r-right x ())
RTtoTI0 (node key₁ _ (node key₃ _ _ _) leaf) (node key₁ _ (node key₃ value₃ _ _) (node key value leaf leaf)) key value (t-left _ _ x₁ a b ti) (r-right x r-leaf) =
      t-node _ _ _ x₁ x a b tt tt ti (t-single key value)
RTtoTI0 (node key₁ _ (node _ _ left₀ right₀) (node key₂ _ left₁ right₁)) (node key₁ _ (node _ _ left₂ right₂) (node key₃ _ left₃ right₃)) key value (t-node _ _ _ x₁ x₂ a b c d ti ti₁) (r-right x ri) =
      t-node _ _ _ x₁ (subst (λ k → key₁ < k ) (rt-property-key ri) x₂) a b (rr00 ri c) (rr02 ri d) ti (RTtoTI0 _ _ key value ti₁ ri) where
         rr00 : replacedTree key value (node key₂ _ _ _) (node key₃ _ _ _) → tr> key₁ left₁ → tr> key₁ left₃
         rr00 r-node tb = tb
         rr00 (r-right x₃ ri) tb = tb
         rr00 (r-left x₃ ri) tb = ri-tr> _ _ _ _ _ ri x tb
         rr02 : replacedTree key value (node key₂ _ _ _) (node key₃ _ _ _) → tr> key₁ right₁ → tr> key₁ right₃
         rr02 r-node tb = tb
         rr02 (r-right x₃ ri) tb = ri-tr> _ _ _ _ _ ri x tb
         rr02 (r-left x₃ ri) tb = tb
-- r-left case
RTtoTI0 .(node _ _ leaf leaf) .(node _ _ (node key value leaf leaf) leaf) key value (t-single _ _) (r-left x r-leaf) = t-left _ _ x tt tt (t-single _ _ )
RTtoTI0 .(node _ _ leaf (node _ _ _ _)) (node key₁ value₁ (node key value leaf leaf) (node _ _ _ _)) key value (t-right _ _ x₁ a b ti) (r-left x r-leaf) =
      t-node _ _ _ x x₁ tt tt a b (t-single key value) ti
RTtoTI0 (node key₃ _ (node key₂ _ left₁ right₁) leaf) (node key₃ _ (node key₁ value₁ left₂ right₂) leaf) key value (t-left _ _ x₁ a b ti) (r-left x ri) =
      t-left _ _ (subst (λ k → k < key₃ ) (rt-property-key ri) x₁) (rr00 ri a) (rr02 ri b) (RTtoTI0 _ _ key value ti ri) where -- key₁ < key₃
         rr00 : replacedTree key value (node key₂ _ left₁ right₁) (node key₁ _ left₂ right₂) → tr< key₃ left₁ → tr< key₃ left₂
         rr00 r-node tb = tb
         rr00 (r-right x₂ ri) tb = tb
         rr00 (r-left x₂ ri) tb = ri-tr< _ _ _ _ _ ri x tb
         rr02 : replacedTree key value (node key₂ _ left₁ right₁) (node key₁ _ left₂ right₂) → tr< key₃ right₁ → tr< key₃ right₂
         rr02 r-node tb = tb
         rr02 (r-right x₃ ri) tb = ri-tr< _ _ _ _ _ ri x tb
         rr02 (r-left x₃ ri) tb = tb
RTtoTI0 (node key₁ _ (node key₂ _ left₂ right₂) (node key₃ _ left₃ right₃)) (node key₁ _ (node key₄ _ left₄ right₄) (node key₅ _ left₅ right₅)) key value (t-node _ _ _ x₁ x₂ a b c d ti ti₁) (r-left x ri) =
      t-node _ _ _ (subst (λ k → k < key₁ ) (rt-property-key ri) x₁) x₂  (rr00 ri a) (rr02 ri b) c d (RTtoTI0 _ _ key value ti ri) ti₁ where
         rr00 : replacedTree key value (node key₂ _ left₂ right₂) (node key₄ _ left₄ right₄) → tr< key₁ left₂ → tr< key₁ left₄
         rr00 r-node tb = tb
         rr00 (r-right x₃ ri) tb = tb
         rr00 (r-left x₃ ri) tb = ri-tr< _ _ _ _ _ ri x tb
         rr02 : replacedTree key value (node key₂ _ left₂ right₂) (node key₄ _ left₄ right₄) → tr< key₁ right₂ → tr< key₁ right₄
         rr02 r-node tb = tb
         rr02 (r-right x₃ ri) tb = ri-tr< _ _ _ _ _ ri x tb
         rr02 (r-left x₃ ri) tb = tb

-- RTtoTI1  : {n : Level} {A : Set n}  → (tree repl : bt A) → (key : ℕ) → (value : A) → treeInvariant repl
--      → replacedTree key value tree repl → treeInvariant tree
-- RTtoTI1 .leaf .(node key value leaf leaf) key value ti r-leaf = t-leaf
-- RTtoTI1 (node key value₁ leaf leaf) .(node key value leaf leaf) key value (t-single .key .value) r-node = t-single key value₁
-- RTtoTI1 .(node key _ leaf (node _ _ _ _)) .(node key value leaf (node _ _ _ _)) key value (t-right _ _ x a b ti) r-node = t-right _ _ x a b ti
-- RTtoTI1 .(node key _ (node _ _ _ _) leaf) .(node key value (node _ _ _ _) leaf) key value (t-left _ _ x a b ti) r-node = t-left _ _ x a b ti
-- RTtoTI1 .(node key _ (node _ _ _ _) (node _ _ _ _)) .(node key value (node _ _ _ _) (node _ _ _ _)) key value (t-node _ _ _ x x₁ a b c d ti ti₁) r-node = t-node _ _ _ x x₁ a b c d ti ti₁
-- -- r-right case
-- RTtoTI1 (node key₁ value₁ leaf leaf) (node key₁ _ leaf (node _ _ _ _)) key value (t-right _ _ x₁ a b ti) (r-right x r-leaf) = t-single key₁ value₁
-- RTtoTI1 (node key₁ value₁ leaf (node key₂ value₂ t2 t3)) (node key₁ _ leaf (node key₃ _ _ _)) key value (t-right _ _ x₁ a b ti) (r-right x ri) =
--    t-right _ _ (subst (λ k → key₁ < k ) (sym (rt-property-key ri)) x₁) ? ?  (RTtoTI1 _ _ key value ti ri) -- key₁ < key₂
-- RTtoTI1 (node _ _ (node _ _ _ _) leaf) (node _ _ (node _ _ _ _) (node key value _ _)) key value (t-node _ _ _ x₁ x₂ a b c d ti ti₁) (r-right x r-leaf) =
--     t-left _ _ x₁ ? ? ti
-- RTtoTI1 (node key₄ _ (node key₃ _ _ _) (node key₁ value₁ n n₁)) (node key₄ _ (node key₃ _ _ _) (node key₂ _ _ _)) key value (t-node _ _ _ x₁ x₂ a b c d ti ti₁) (r-right x ri) = t-node _ _ _ x₁ (subst (λ k → key₄ < k ) (sym (rt-property-key ri)) x₂) a b ? ? ti (RTtoTI1 _ _ key value ti₁ ri) -- key₄ < key₁
-- -- r-left case
-- RTtoTI1 (node key₁ value₁ leaf leaf) (node key₁ _ _ leaf) key value (t-left _ _ x₁ a b ti) (r-left x ri) = t-single key₁ value₁
-- RTtoTI1 (node key₁ _ (node key₂ value₁ n n₁) leaf) (node key₁ _ (node key₃ _ _ _) leaf) key value (t-left _ _ x₁ a b ti) (r-left x ri) =
--    t-left _ _ (subst (λ k → k < key₁ ) (sym (rt-property-key ri)) x₁) ? ? (RTtoTI1 _ _ key value ti ri) -- key₂ < key₁
-- RTtoTI1 (node key₁ value₁ leaf _) (node key₁ _ _ _) key value (t-node _ _ _ x₁ x₂ a b c d ti ti₁) (r-left x r-leaf) = t-right _ _ x₂ c d ti₁
-- RTtoTI1 (node key₁ value₁ (node key₂ value₂ n n₁) _) (node key₁ _ _ _) key value (t-node _ _ _ x₁ x₂ a b c d ti ti₁) (r-left x ri) =
--     t-node _ _ _ (subst (λ k → k < key₁ ) (sym (rt-property-key ri)) x₁) x₂ ? ? c d (RTtoTI1 _ _ key value ti ri) ti₁ -- key₂ < key₁

insertTreeP : {n m : Level} {A : Set n} {t : Set m} → (tree : bt A) → (key : ℕ) → (value : A) → treeInvariant tree
     → (exit : (tree repl : bt A) → treeInvariant repl ∧ replacedTree key value tree repl → t ) → t
insertTreeP {n} {m} {A} {t} tree key value P0 exit =
   TerminatingLoopS (bt A ∧ List (bt A) ) {λ p → treeInvariant (proj1 p) ∧ stackInvariant key (proj1 p) tree (proj2 p) } (λ p → bt-depth (proj1 p)) ⟪ tree , tree ∷ [] ⟫  ⟪ P0 , s-nil ⟫
       $ λ p P loop → findP key (proj1 p)  tree (proj2 p) P (λ t s P1 lt → loop ⟪ t ,  s  ⟫ P1 lt )
       $ λ t s P C → replaceNodeP key value t C (proj1 P)
       $ λ t1 P1 R → TerminatingLoopS (List (bt A) ∧ bt A ∧ bt A )
            {λ p → replacePR key value  (proj1 (proj2 p)) (proj2 (proj2 p)) (proj1 p)  (λ _ _ _ → Lift n ⊤ ) }
               (λ p → length (proj1 p)) ⟪ s , ⟪ t , t1 ⟫ ⟫ record { tree0 = tree ; ti = P0 ; si = proj2 P ; ri = R ; ci = lift tt }
       $  λ p P1 loop → replaceP key value  (proj2 (proj2 p)) (proj1 p) P1
            (λ key value {tree1} repl1 stack P2 lt → loop ⟪ stack , ⟪ tree1 , repl1  ⟫ ⟫ P2 lt )
       $ λ tree repl P → exit tree repl ⟪ RTtoTI0 _ _ _ _ (proj1 P) (proj2 P) , proj2 P ⟫

insertTestP1 = insertTreeP leaf 1 1 t-leaf
  $ λ _ x0 P0 → insertTreeP x0 2 1 (proj1 P0)
  $ λ _ x1 P1 → insertTreeP x1 3 2 (proj1 P1)
  $ λ _ x2 P2 → insertTreeP x2 2 2 (proj1 P2) (λ _ x P  → x )

top-value : {n : Level} {A : Set n} → (tree : bt A) →  Maybe A
top-value leaf = nothing
top-value (node key value tree tree₁) = just value

-- is realy inserted?

-- other element is preserved?

-- deletion?


data Color  : Set where
    Red : Color
    Black : Color

RB→bt : {n : Level} (A : Set n) → (bt (Color ∧ A)) → bt A
RB→bt {n} A leaf = leaf
RB→bt {n} A (node key ⟪ C , value ⟫ tr t1) = (node key value (RB→bt A tr) (RB→bt A t1))

color : {n : Level} {A : Set n} → (bt (Color ∧ A)) → Color
color leaf = Black
color (node key ⟪ C , value ⟫ rb rb₁) = C

to-red : {n : Level} {A : Set n} → (tree : bt (Color ∧ A)) → bt (Color ∧ A)
to-red leaf = leaf
to-red (node key ⟪ _ , value ⟫ t t₁) = (node key ⟪ Red , value ⟫ t t₁)

to-black : {n : Level} {A : Set n} → (tree : bt (Color ∧ A)) → bt (Color ∧ A)
to-black leaf = leaf
to-black (node key ⟪ _ , value ⟫ t t₁) = (node key ⟪ Black , value ⟫ t t₁)

black-depth : {n : Level} {A : Set n} → (tree : bt (Color ∧ A) ) → ℕ
black-depth leaf = 0
black-depth (node key ⟪ Red , value ⟫  t t₁) = black-depth t  ⊔ black-depth t₁
black-depth (node key ⟪ Black , value ⟫  t t₁) = suc (black-depth t  ⊔ black-depth t₁ )

zero≢suc : { m : ℕ } → zero ≡ suc m → ⊥
zero≢suc ()
suc≢zero : {m : ℕ } → suc m ≡ zero → ⊥
suc≢zero ()


data RBtreeInvariant {n : Level} {A : Set n} : (tree : bt (Color ∧ A)) → Set n where
    rb-leaf :  RBtreeInvariant leaf
    rb-single : {c : Color} → (key : ℕ) → (value : A) →  RBtreeInvariant (node key ⟪ c , value ⟫ leaf leaf)
    rb-right-red : {key key₁ : ℕ} → {value value₁ : A} → {t t₁ : bt (Color ∧ A)} → key < key₁
       → black-depth t ≡ black-depth t₁
       → RBtreeInvariant (node key₁ ⟪ Black , value₁ ⟫ t t₁)
       → RBtreeInvariant (node key  ⟪ Red ,   value  ⟫ leaf (node key₁ ⟪ Black , value₁ ⟫ t t₁))
    rb-right-black : {key key₁ : ℕ} → {value value₁ : A} → {t t₁ : bt (Color ∧ A)} → key < key₁ → {c : Color}
       → black-depth t ≡ black-depth t₁
       → RBtreeInvariant (node key₁ ⟪ c     , value₁ ⟫ t t₁)
       → RBtreeInvariant (node key  ⟪ Black , value  ⟫ leaf (node key₁ ⟪ c , value₁ ⟫ t t₁))
    rb-left-red : {key key₁ : ℕ} → {value value₁ : A} → {t t₁ : bt (Color ∧ A)} → key₁ < key
       → black-depth t ≡ black-depth t₁
       → RBtreeInvariant (node key₁ ⟪ Black , value₁ ⟫ t t₁)
       → RBtreeInvariant (node key  ⟪ Red ,   value  ⟫ (node key₁ ⟪ Black , value₁ ⟫ t t₁) leaf )
    rb-left-black : {key key₁ : ℕ} → {value value₁ : A} → {t t₁ : bt (Color ∧ A)} → {c : Color} → key₁ < key
       → black-depth t ≡ black-depth t₁
       → RBtreeInvariant (node key₁ ⟪ c     , value₁ ⟫ t t₁)
       → RBtreeInvariant (node key  ⟪ Black , value  ⟫ (node key₁ ⟪ c , value₁ ⟫ t t₁) leaf)
    rb-node-red  : {key key₁ key₂ : ℕ} → {value value₁ value₂ : A} → {t₁ t₂ t₃ t₄ : bt (Color ∧ A)} → key < key₁ → key₁ < key₂
       → black-depth (node key  ⟪ Black  , value  ⟫ t₁ t₂) ≡ black-depth (node key₂ ⟪ Black , value₂ ⟫ t₃ t₄)
       → RBtreeInvariant (node key ⟪ Black , value ⟫ t₁ t₂)
       → RBtreeInvariant (node key₂ ⟪ Black , value₂ ⟫ t₃ t₄)
       → RBtreeInvariant (node key₁ ⟪ Red , value₁ ⟫ (node key ⟪ Black , value ⟫ t₁ t₂) (node key₂ ⟪ Black , value₂ ⟫ t₃ t₄))
    rb-node-black : {key key₁ key₂ : ℕ} → {value value₁ value₂ : A} → {t₁ t₂ t₃ t₄ : bt (Color ∧ A)} → key < key₁ → key₁ < key₂
       → {c c₁ : Color}
       → black-depth (node key  ⟪ c  , value  ⟫ t₁ t₂) ≡ black-depth (node key₂ ⟪ c₁ , value₂ ⟫ t₃ t₄)
       → RBtreeInvariant (node key  ⟪ c  , value  ⟫ t₁ t₂)
       → RBtreeInvariant (node key₂ ⟪ c₁ , value₂ ⟫ t₃ t₄)
       → RBtreeInvariant (node key₁ ⟪ Black , value₁ ⟫ (node key ⟪ c , value ⟫ t₁ t₂) (node key₂ ⟪ c₁ , value₂ ⟫ t₃ t₄))

RightDown : {n : Level} {A : Set n} → bt (Color ∧ A) → bt (Color ∧ A)
RightDown leaf = leaf
RightDown (node key ⟪ c , value ⟫ t1 t2) = t2
LeftDown : {n : Level} {A :  Set n} → bt (Color ∧ A) → bt (Color ∧ A)
LeftDown leaf = leaf
LeftDown (node key ⟪ c , value ⟫ t1 t2 ) = t1

RBtreeLeftDown : {n : Level} {A : Set n} {key : ℕ} {value : A} {c : Color}
 →  (tleft tright : bt (Color ∧ A))
 → RBtreeInvariant (node key ⟪ c , value ⟫ tleft tright)
 → RBtreeInvariant tleft
RBtreeLeftDown leaf leaf (rb-single k1 v) = rb-leaf
RBtreeLeftDown leaf (node key ⟪ Black , value ⟫ t1 t2 ) (rb-right-red x bde rbti) = rb-leaf
RBtreeLeftDown leaf (node key ⟪ Black , value ⟫ t1 t2 ) (rb-right-black x bde rbti) = rb-leaf
RBtreeLeftDown leaf (node key ⟪ Red , value ⟫ t1 t2 ) (rb-right-black x bde rbti)= rb-leaf
RBtreeLeftDown (node key ⟪ Black , value ⟫ t t₁) leaf (rb-left-black x bde ti) = ti
RBtreeLeftDown (node key ⟪ Black , value ⟫ t t₁) leaf (rb-left-red x bde ti)= ti
RBtreeLeftDown (node key ⟪ Red , value ⟫ t t₁) leaf (rb-left-black x bde ti) = ti
RBtreeLeftDown (node key ⟪ Black , value ⟫ t t₁) (node key₁ ⟪ Black , value1 ⟫ t1 t2) (rb-node-black x x1 bde1 til tir) = til
RBtreeLeftDown (node key ⟪ Black , value ⟫ t t₁) (node key₁ ⟪ Black , value1 ⟫ t1 t2) (rb-node-red x x1 bde1 til tir) = til
RBtreeLeftDown (node key ⟪ Red , value ⟫ t t₁) (node key₁ ⟪ Black , value1 ⟫ t1 t2) (rb-node-black x x1 bde1 til tir) = til
RBtreeLeftDown (node key ⟪ Black , value ⟫ t t₁) (node key₁ ⟪ Red , value1 ⟫ t1 t2) (rb-node-black x x1 bde1 til tir) = til
RBtreeLeftDown (node key ⟪ Red , value ⟫ t t₁) (node key₁ ⟪ Red , value1 ⟫ t1 t2) (rb-node-black x x1 bde1 til tir) = til

RBtreeRightDown : {n : Level} {A : Set n} { key : ℕ} {value : A} {c : Color}
 → (tleft tright : bt (Color ∧ A))
 → RBtreeInvariant (node key ⟪ c , value ⟫ tleft tright)
 → RBtreeInvariant tright
RBtreeRightDown leaf leaf (rb-single k1 v1 ) = rb-leaf
RBtreeRightDown leaf (node key ⟪ Black , value ⟫ t1 t2 ) (rb-right-red x bde rbti) = rbti
RBtreeRightDown leaf (node key ⟪ Black , value ⟫ t1 t2 ) (rb-right-black x bde rbti) = rbti
RBtreeRightDown leaf (node key ⟪ Red , value ⟫ t1 t2 ) (rb-right-black x bde rbti)= rbti
RBtreeRightDown (node key ⟪ Black , value ⟫ t t₁) leaf (rb-left-black x bde ti) = rb-leaf
RBtreeRightDown (node key ⟪ Black , value ⟫ t t₁) leaf (rb-left-red x bde ti) = rb-leaf
RBtreeRightDown (node key ⟪ Red , value ⟫ t t₁) leaf (rb-left-black x bde ti) = rb-leaf
RBtreeRightDown (node key ⟪ Black , value ⟫ t t₁) (node key₁ ⟪ Black , value1 ⟫ t1 t2) (rb-node-black x x1 bde1 til tir) = tir
RBtreeRightDown (node key ⟪ Black , value ⟫ t t₁) (node key₁ ⟪ Black , value1 ⟫ t1 t2) (rb-node-red x x1 bde1 til tir) = tir
RBtreeRightDown (node key ⟪ Red , value ⟫ t t₁) (node key₁ ⟪ Black , value1 ⟫ t1 t2) (rb-node-black x x1 bde1 til tir) = tir
RBtreeRightDown (node key ⟪ Black , value ⟫ t t₁) (node key₁ ⟪ Red , value1 ⟫ t1 t2) (rb-node-black x x1 bde1 til tir) = tir
RBtreeRightDown (node key ⟪ Red , value ⟫ t t₁) (node key₁ ⟪ Red , value1 ⟫ t1 t2) (rb-node-black x x1 bde1 til tir) = tir

--
--  findRBT exit with replaced node
--     case-eq        node value is replaced,  just do replacedTree and rebuild rb-invariant
--     case-leaf      insert new single node
--        case1       if parent node is black, just do replacedTree and rebuild rb-invariant
--        case2       if parent node is red,   increase blackdepth, do rotatation
--

findRBT : {n m : Level} {A : Set n} {t : Set m} → (key : ℕ) → (tree tree0 : bt (Color ∧ A) )
           → (stack : List (bt (Color ∧ A)))
           → RBtreeInvariant tree ∧  stackInvariant key tree tree0 stack
           → (next : (tree1 : bt (Color ∧ A) ) → (stack : List (bt (Color ∧ A)))
                   → RBtreeInvariant tree1 ∧ stackInvariant key tree1 tree0 stack
                   → bt-depth tree1 < bt-depth tree → t )
           → (exit : (tree1 : bt (Color ∧ A)) → (stack : List (bt (Color ∧ A)))
                 → RBtreeInvariant tree1 ∧ stackInvariant key tree1 tree0 stack
                 → (tree1 ≡ leaf ) ∨ ( node-key tree1 ≡ just key )  → t ) → t
findRBT key leaf tree0 stack rb0 next exit = exit leaf stack rb0 (case1 refl)
findRBT key (node key₁ value left right) tree0 stack rb0 next exit with <-cmp key key₁
findRBT key (node key₁ value left right) tree0 stack  rb0 next exit | tri< a ¬b ¬c
 = next left (left ∷ stack) ⟪ RBtreeLeftDown left right (_∧_.proj1 rb0) , s-left _ _ _ a (_∧_.proj2 rb0) ⟫  depth-1<
findRBT key n tree0 stack  rb0 _ exit | tri≈ ¬a refl ¬c = exit n stack rb0 (case2 refl)
findRBT key (node key₁ value left right) tree0 stack  rb0 next exit | tri> ¬a ¬b c
 = next right (right ∷ stack) ⟪ RBtreeRightDown left right (_∧_.proj1 rb0), s-right _ _ _ c (_∧_.proj2 rb0) ⟫ depth-2<



findTest : {n m : Level} {A : Set n } {t : Set m }
 → (key : ℕ)
 → (tree0 : bt (Color ∧ A))
 → RBtreeInvariant tree0
 → (exit : (tree1 : bt (Color ∧ A))
   → (stack : List (bt (Color ∧ A)))
   → RBtreeInvariant tree1 ∧ stackInvariant key tree1 tree0 stack
   → (tree1 ≡ leaf ) ∨ ( node-key tree1 ≡ just key )  → t ) → t
findTest {n} {m} {A} {t} k tr0 rb0 exit = TerminatingLoopS (bt (Color ∧ A) ∧ List (bt (Color ∧ A)))
 {λ p → RBtreeInvariant (proj1 p) ∧ stackInvariant k (proj1 p) tr0 (proj2 p) } (λ p → bt-depth (proj1 p)) ⟪ tr0 , tr0 ∷ [] ⟫ ⟪ rb0 , s-nil ⟫
       $ λ p RBP loop → findRBT k (proj1 p) tr0 (proj2 p) RBP  (λ t1 s1 P2 lt1 → loop ⟪ t1 ,  s1  ⟫ P2 lt1 )
       $ λ tr1 st P2 O → exit tr1 st P2 O


testRBTree0 :  bt (Color ∧ ℕ)
testRBTree0 = node 8 ⟪ Black , 800 ⟫ (node 5 ⟪ Red , 500 ⟫ (node 2 ⟪ Black , 200 ⟫ leaf leaf) (node 6 ⟪ Black , 600 ⟫ leaf leaf)) (node 10 ⟪ Red , 1000 ⟫ (leaf) (node 15 ⟪ Black , 1500 ⟫ (node 14 ⟪ Red , 1400 ⟫ leaf leaf) leaf))

record result {n : Level} {A : Set n} {key : ℕ} {tree0 : bt (Color ∧ A)} : Set n where
   field
     tree : bt (Color ∧ A)
     stack : List (bt (Color ∧ A))
     ti : RBtreeInvariant tree
     si : stackInvariant key tree tree0 stack

testRBI0 : RBtreeInvariant testRBTree0
testRBI0 = rb-node-black (add< 2) (add< 1) refl (rb-node-red (add< 2) (add< 0) refl (rb-single 2 200) (rb-single 6 600)) (rb-right-red (add< 4) refl (rb-left-black (add< 0) refl (rb-single 14 1400) ))

findRBTreeTest : result
findRBTreeTest = findTest 14 testRBTree0 testRBI0
       $ λ tr s P O → (record {tree = tr ; stack = s ; ti = (proj1 P) ; si = (proj2 P)})

-- create replaceRBTree with rotate

data replacedRBTree  {n : Level} {A : Set n} (key : ℕ) (value : A)  : (before after : bt (Color ∧ A) ) → Set n where
    -- no rotation case
    rbr-leaf : replacedRBTree key value leaf (node key ⟪ Red , value ⟫ leaf leaf)
    rbr-node : {value₁ : A} → {ca : Color } → {t t₁ : bt (Color ∧ A)} → replacedRBTree key value (node key ⟪ ca , value₁ ⟫ t t₁) (node key ⟪ ca , value ⟫ t t₁)
    rbr-right : {k : ℕ } {v1 : A} → {ca : Color} → {t t1 t2 : bt (Color ∧ A)}
          → k < key →  replacedRBTree key value t2 t →  replacedRBTree key value (node k ⟪ ca , v1 ⟫ t1 t2) (node k ⟪ ca , v1 ⟫ t1 t)
    rbr-left  : {k : ℕ } {v1 : A} → {ca : Color} → {t t1 t2 : bt (Color ∧ A)}
          → key < k →  replacedRBTree key value t1 t →  replacedRBTree key value (node k ⟪ ca , v1 ⟫ t1 t2) (node k ⟪ ca , v1 ⟫ t t2) -- k < key → key < k
    -- case1 parent is black
    rbr-black-right : {t t₁ t₂ : bt (Color ∧ A)} {value₁ : A} {key₁ : ℕ}
         → color t₂ ≡ Red → key₁ < key  → replacedRBTree key value t₁ t₂
         → replacedRBTree key value (node key₁ ⟪ Black , value₁ ⟫ t t₁) (node key₁ ⟪ Black , value₁ ⟫ t t₂)
    rbr-black-left : {t t₁ t₂ : bt (Color ∧ A)} {value₁ : A} {key₁ : ℕ}
         → color t₂ ≡ Red  → key < key₁ → replacedRBTree key value t₁ t₂
         → replacedRBTree key value (node key₁ ⟪ Black , value₁ ⟫ t₁ t) (node key₁ ⟪ Black , value₁ ⟫ t₂ t)

    -- case2 both parent and uncle are red (should we check uncle color?), flip color and up
    rbr-flip-ll : {t t₁ t₂ uncle : bt (Color ∧ A)} {kg kp : ℕ} {vg vp : A}
         → color t₂ ≡ Red → key < kp  → replacedRBTree key value t₁ t₂
         → replacedRBTree key value (node kg ⟪ Black , vg ⟫ (node kp ⟪ Red   , vp ⟫ t₁ t)           uncle)
                                    (node kg ⟪ Red ,   vg ⟫ (node kp ⟪ Black , vp ⟫ t₂ t) (to-black uncle))
    rbr-flip-lr : {t t₁ t₂ uncle : bt (Color ∧ A)} {kg kp : ℕ} {vg vp : A}
         → color t₂ ≡ Red →  kp < key → key < kg   → replacedRBTree key value t₁ t₂
         → replacedRBTree key value (node kg ⟪ Black , vg ⟫ (node kp ⟪ Red   , vp ⟫ t t₁)           uncle)
                                    (node kg ⟪ Red ,   vg ⟫ (node kp ⟪ Black , vp ⟫ t t₂) (to-black uncle))
    rbr-flip-rl : {t t₁ t₂ uncle : bt (Color ∧ A)} {kg kp : ℕ} {vg vp : A}
         → color t₂ ≡ Red → kg < key → key < kp  → replacedRBTree key value t₁ t₂
         → replacedRBTree key value (node kg ⟪ Black , vg ⟫ uncle            (node kp ⟪ Red   , vp ⟫ t₁ t))
                                    (node kg ⟪ Red ,   vg ⟫ (to-black uncle) (node kp ⟪ Black , vp ⟫ t₂ t))
    rbr-flip-rr : {t t₁ t₂ uncle : bt (Color ∧ A)} {kg kp : ℕ} {vg vp : A}
         → color t₂ ≡ Red → kp < key   → replacedRBTree key value t₁ t₂
         → replacedRBTree key value (node kg ⟪ Black , vg ⟫ uncle            (node kp ⟪ Red   , vp ⟫ t t₁))
                                    (node kg ⟪ Red ,   vg ⟫ (to-black uncle) (node kp ⟪ Black , vp ⟫ t t₂))

    -- case6 the node is outer, rotate grand
    rbr-rotate-ll : {t t₁ t₂ uncle : bt (Color ∧ A)} {kg kp : ℕ} {vg vp : A}
         → color t₂ ≡ Red → key < kp  → replacedRBTree key value t₁ t₂
         → replacedRBTree key value (node kg ⟪ Black , vg ⟫ (node kp ⟪ Red , vp ⟫ t₁ t)    uncle)
                                    (node kp ⟪ Black , vp ⟫ t₂                             (node kg ⟪ Red , vg ⟫ t uncle))
    rbr-rotate-rr : {t t₁ t₂ uncle : bt (Color ∧ A)} {kg kp : ℕ} {vg vp : A}
         → color t₂ ≡ Red → kp < key → replacedRBTree key value t₁ t₂
         → replacedRBTree key value (node kg ⟪ Black , vg ⟫ uncle                          (node kp ⟪ Red   , vp ⟫ t t₁))
                                    (node kp ⟪ Black , vp ⟫ (node kg ⟪ Red , vg ⟫ uncle t) t₂ )
    -- case56 the node is inner, make it outer and rotate grand
    rbr-rotate-lr : {t t₁ uncle : bt (Color ∧ A)} (t₂ t₃ : bt (Color ∧ A)) (kg kp kn : ℕ) {vg vp vn : A}
         → kp < kn → kn < kg
         → replacedRBTree key value t₁ (node kn ⟪ Red , vn ⟫ t₂ t₃)
         → replacedRBTree key value (node kg ⟪ Black , vg ⟫ (node kp ⟪ Red , vp ⟫ t t₁)     uncle)
                                    (node kn ⟪ Black , vn ⟫ (node kp ⟪ Red , vp ⟫ t t₂)     (node kg ⟪ Red , vg ⟫ t₃ uncle))
    rbr-rotate-rl : {t t₁ uncle : bt (Color ∧ A)} (t₂ t₃ : bt (Color ∧ A)) (kg kp kn : ℕ) {vg vp vn : A}
         → kg < kn → kn < kp
         → replacedRBTree key value t₁ (node kn ⟪ Red , vn ⟫ t₂ t₃)
         → replacedRBTree key value (node kg ⟪ Black , vg ⟫ uncle                           (node kp ⟪ Red , vp ⟫ t₁ t))
                                    (node kn ⟪ Black , vn ⟫ (node kg ⟪ Red , vg ⟫ uncle t₂) (node kp ⟪ Red , vp ⟫ t₃ t))


--
-- Parent Grand Relation
--   should we require stack-invariant?
--

data ParentGrand {n : Level} {A : Set n} (self : bt A) : (parent uncle grand : bt A) → Set n where
    s2-s1p2 : {kp kg : ℕ} {vp vg : A} → {n1 n2 : bt A} {parent grand : bt A }
        → parent ≡ node kp vp self n1 → grand ≡ node kg vg parent n2 → ParentGrand self parent n2 grand
    s2-1sp2 : {kp kg : ℕ} {vp vg : A} → {n1 n2 : bt A} {parent grand : bt A }
        → parent ≡ node kp vp n1 self → grand ≡ node kg vg parent n2 → ParentGrand self parent n2 grand
    s2-s12p : {kp kg : ℕ} {vp vg : A} → {n1 n2 : bt A} {parent grand : bt A }
        → parent ≡ node kp vp self n1 → grand ≡ node kg vg n2 parent → ParentGrand self parent n2 grand
    s2-1s2p : {kp kg : ℕ} {vp vg : A} → {n1 n2 : bt A} {parent grand : bt A }
        → parent ≡ node kp vp n1 self → grand ≡ node kg vg n2 parent → ParentGrand self parent n2 grand

record PG {n : Level } (A : Set n) (self : bt A) (stack : List (bt A)) : Set n where
    field
       parent grand uncle : bt A
       pg : ParentGrand self parent uncle grand
       rest : List (bt A)
       stack=gp : stack ≡ ( self ∷ parent ∷ grand ∷ rest )

--
-- RBI : Invariant on InsertCase2
--     color repl ≡ Red ∧ black-depth repl ≡ suc (black-depth tree)
--

data RBI-state  {n : Level} {A : Set n} (key : ℕ) : (tree repl : bt (Color ∧ A) ) → Set n where
   rebuild : {tree repl : bt (Color ∧ A) } → black-depth repl ≡ black-depth (child-replaced key tree)
       → RBI-state key tree repl   -- one stage up
   rotate  : {tree repl : bt (Color ∧ A) } → color repl ≡ Red → black-depth repl ≡ black-depth (child-replaced key tree)
       → RBI-state key tree repl   -- two stages up

record RBI {n : Level} {A : Set n} (key : ℕ) (value : A) (orig repl : bt (Color ∧ A) ) (stack : List (bt (Color ∧ A)))  : Set n where
   field
       tree : bt (Color ∧ A)
       origti : treeInvariant orig
       origrb : RBtreeInvariant orig
       treerb : RBtreeInvariant tree     -- tree node te be replaced
       replrb : RBtreeInvariant repl
       si : stackInvariant key tree orig stack
       rotated : replacedRBTree key value tree repl
       state : RBI-state key tree repl

tr>-to-black : {n : Level} {A : Set n} {key : ℕ} {tree : bt (Color ∧ A)} → tr> key tree → tr> key (to-black tree)
tr>-to-black {n} {A} {key} {leaf} tr = tt
tr>-to-black {n} {A} {key} {node key₁ value tree tree₁} tr = tr

tr<-to-black : {n : Level} {A : Set n} {key : ℕ} {tree : bt (Color ∧ A)} → tr< key tree → tr< key (to-black tree)
tr<-to-black {n} {A} {key} {leaf} tr = tt
tr<-to-black {n} {A} {key} {node key₁ value tree tree₁} tr = tr

RB-repl→ti>  : {n : Level} {A : Set n}  → (tree repl : bt (Color ∧ A)) → (key key₁ : ℕ) → (value : A)
     → replacedRBTree key value tree repl → key₁ < key → tr> key₁ tree → tr> key₁ repl
RB-repl→ti> .leaf .(node key ⟪ Red , value ⟫ leaf leaf) key key₁ value rbr-leaf lt tr = ⟪ lt , ⟪ tt , tt ⟫ ⟫
RB-repl→ti> .(node key ⟪ _ , _ ⟫ _ _) .(node key ⟪ _ , value ⟫ _ _) key key₁ value rbr-node lt tr = tr
RB-repl→ti> .(node _ ⟪ _ , _ ⟫ _ _) .(node _ ⟪ _ , _ ⟫ _ _) key key₁ value (rbr-right x rbt) lt tr
   = ⟪ proj1 tr , ⟪ proj1 (proj2 tr) , RB-repl→ti> _ _ _ _ _ rbt lt (proj2 (proj2 tr)) ⟫ ⟫
RB-repl→ti> .(node _ ⟪ _ , _ ⟫ _ _) .(node _ ⟪ _ , _ ⟫ _ _) key key₁ value (rbr-left x rbt) lt tr
   = ⟪ proj1 tr , ⟪ RB-repl→ti> _ _ _ _ _ rbt lt (proj1 (proj2 tr)) , proj2 (proj2 tr) ⟫ ⟫
RB-repl→ti> .(node _ ⟪ Black , _ ⟫ _ _) .(node _ ⟪ Black , _ ⟫ _ _) key key₁ value (rbr-black-right x _ rbt) lt tr
   = ⟪ proj1 tr , ⟪ proj1 (proj2 tr) , RB-repl→ti> _ _ _ _ _ rbt lt (proj2 (proj2 tr)) ⟫ ⟫
RB-repl→ti> .(node _ ⟪ Black , _ ⟫ _ _) .(node _ ⟪ Black , _ ⟫ _ _) key key₁ value (rbr-black-left x _ rbt) lt tr
   = ⟪ proj1 tr , ⟪ RB-repl→ti> _ _ _ _ _ rbt lt (proj1 (proj2 tr)) , proj2 (proj2 tr) ⟫ ⟫
RB-repl→ti> .(node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ _ _) _) .(node _ ⟪ Red , _ ⟫ (node _ ⟪ Black , _ ⟫ _ _) (to-black _)) key key₁ value (rbr-flip-ll x _ rbt) lt tr
   = ⟪ proj1 tr , ⟪ ⟪ proj1 (proj1 (proj2 tr))  , ⟪ RB-repl→ti> _ _ _ _ _ rbt lt (proj1 (proj2 (proj1 (proj2 tr))))
       , proj2 (proj2 (proj1 (proj2 tr))) ⟫ ⟫  , tr>-to-black (proj2 (proj2 tr)) ⟫ ⟫
RB-repl→ti> .(node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ _ _) _) .(node _ ⟪ Red , _ ⟫ (node _ ⟪ Black , _ ⟫ _ _) (to-black _)) key key₁ value
   (rbr-flip-lr x _ _ rbt) lt ⟪ tr3 , ⟪ ⟪ tr4 , ⟪ tr6 , tr7 ⟫ ⟫ , tr5 ⟫ ⟫ = ⟪ tr3 , ⟪ ⟪ tr4 , ⟪ tr6 ,  RB-repl→ti> _ _ _ _ _ rbt lt tr7 ⟫ ⟫  , tr>-to-black tr5 ⟫ ⟫
RB-repl→ti> .(node _ ⟪ Black , _ ⟫ _ (node _ ⟪ Red , _ ⟫ _ _)) .(node _ ⟪ Red , _ ⟫ (to-black _) (node _ ⟪ Black , _ ⟫ _ _)) key key₁ value
   (rbr-flip-rl x _ _ rbt) lt ⟪ tr3 , ⟪ tr5 , ⟪ tr4 , ⟪ tr6 , tr7 ⟫ ⟫  ⟫ ⟫ = ⟪ tr3 , ⟪ tr>-to-black tr5 , ⟪ tr4 , ⟪  RB-repl→ti> _ _ _ _ _ rbt lt tr6 , tr7 ⟫ ⟫   ⟫ ⟫
RB-repl→ti> .(node _ ⟪ Black , _ ⟫ _ (node _ ⟪ Red , _ ⟫ _ _)) .(node _ ⟪ Red , _ ⟫ (to-black _) (node _ ⟪ Black , _ ⟫ _ _)) key key₁ value
   (rbr-flip-rr x _ rbt) lt ⟪ tr3 , ⟪ tr5 , ⟪ tr4 , ⟪ tr6 , tr7 ⟫ ⟫ ⟫ ⟫ = ⟪ tr3 , ⟪ tr>-to-black tr5 , ⟪ tr4 , ⟪ tr6 ,  RB-repl→ti> _ _ _ _ _ rbt lt tr7 ⟫ ⟫   ⟫ ⟫
RB-repl→ti> .(node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ _ _) _) .(node _ ⟪ Black , _ ⟫ _ (node _ ⟪ Red , _ ⟫ _ _)) key key₁ value
   (rbr-rotate-ll x lt2 rbt) lt ⟪ tr3 , ⟪ ⟪ tr4 , ⟪ tr6 , tr7 ⟫ ⟫ , tr5  ⟫ ⟫  = ⟪ tr4 , ⟪  RB-repl→ti> _ _ _ _ _ rbt lt tr6 , ⟪ tr3 , ⟪ tr7 , tr5 ⟫ ⟫ ⟫ ⟫
RB-repl→ti> .(node _ ⟪ Black , _ ⟫ _ (node _ ⟪ Red , _ ⟫ _ _)) .(node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ _ _) _) key key₁ value
   (rbr-rotate-rr x lt2 rbt) lt ⟪ tr3 , ⟪ tr5 , ⟪ tr4 , ⟪ tr6 , tr7 ⟫ ⟫  ⟫ ⟫  = ⟪ tr4 , ⟪ ⟪ tr3 , ⟪ tr5 , tr6 ⟫ ⟫ , RB-repl→ti> _ _ _ _ _ rbt lt tr7 ⟫ ⟫
RB-repl→ti> (node kg ⟪ Black , _ ⟫ (node kp ⟪ Red , _ ⟫ _ _) _) (node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ _ _) (node _ ⟪ Red , _ ⟫ _ _)) key key₁ value
   (rbr-rotate-lr left right _ _ kn _ _ rbt) lt ⟪ tr3 , ⟪ ⟪ tr4 , ⟪ tr6 , tr7 ⟫ ⟫ , tr5  ⟫ ⟫  = ⟪ rr00 , ⟪ ⟪ tr4 , ⟪ tr6 , proj1 (proj2 rr01) ⟫ ⟫ , ⟪ tr3 , ⟪ proj2 (proj2 rr01) , tr5 ⟫ ⟫ ⟫ ⟫ where
       rr01 : (key₁ < kn) ∧ tr> key₁ left  ∧ tr> key₁ right
       rr01 = RB-repl→ti> _ _ _ _ _ rbt lt tr7 
       rr00 : key₁ < kn
       rr00 = proj1 rr01
RB-repl→ti> .(node _ ⟪ Black , _ ⟫ _ (node _ ⟪ Red , _ ⟫ _ _)) .(node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ _ _) (node _ ⟪ Red , _ ⟫ _ _)) key key₁ value
   (rbr-rotate-rl left right kg kp kn _ _ rbt) lt ⟪ tr3 , ⟪ tr5 , ⟪ tr4 , ⟪ tr6 , tr7 ⟫ ⟫  ⟫ ⟫  = ⟪ rr00 , ⟪  ⟪ tr3 , ⟪ tr5 , proj1 (proj2 rr01) ⟫ ⟫ , ⟪ tr4 , ⟪ proj2 (proj2 rr01) , tr7 ⟫ ⟫ ⟫ ⟫ where
       rr01 : (key₁ < kn) ∧ tr> key₁ left  ∧ tr> key₁ right
       rr01 = RB-repl→ti> _ _ _ _ _ rbt lt tr6
       rr00 : key₁ < kn
       rr00 = proj1 rr01

RB-repl→ti<  : {n : Level} {A : Set n}  → (tree repl : bt (Color ∧ A)) → (key key₁ : ℕ) → (value : A)
     → replacedRBTree key value tree repl → key < key₁ → tr< key₁ tree → tr< key₁ repl
RB-repl→ti< .leaf .(node key ⟪ Red , value ⟫ leaf leaf) key key₁ value rbr-leaf lt tr = ⟪ lt , ⟪ tt , tt ⟫ ⟫
RB-repl→ti< .(node key ⟪ _ , _ ⟫ _ _) .(node key ⟪ _ , value ⟫ _ _) key key₁ value rbr-node lt tr = tr
RB-repl→ti< .(node _ ⟪ _ , _ ⟫ _ _) .(node _ ⟪ _ , _ ⟫ _ _) key key₁ value (rbr-right x rbt) lt tr
   = ⟪ proj1 tr , ⟪ proj1 (proj2 tr) , RB-repl→ti< _ _ _ _ _ rbt lt (proj2 (proj2 tr)) ⟫ ⟫
RB-repl→ti< .(node _ ⟪ _ , _ ⟫ _ _) .(node _ ⟪ _ , _ ⟫ _ _) key key₁ value (rbr-left x rbt) lt tr
   = ⟪ proj1 tr , ⟪ RB-repl→ti< _ _ _ _ _ rbt lt (proj1 (proj2 tr)) , proj2 (proj2 tr) ⟫ ⟫
RB-repl→ti< .(node _ ⟪ Black , _ ⟫ _ _) .(node _ ⟪ Black , _ ⟫ _ _) key key₁ value (rbr-black-right x _ rbt) lt tr
   = ⟪ proj1 tr , ⟪ proj1 (proj2 tr) , RB-repl→ti< _ _ _ _ _ rbt lt (proj2 (proj2 tr)) ⟫ ⟫
RB-repl→ti< .(node _ ⟪ Black , _ ⟫ _ _) .(node _ ⟪ Black , _ ⟫ _ _) key key₁ value (rbr-black-left x _ rbt) lt tr
   = ⟪ proj1 tr , ⟪ RB-repl→ti< _ _ _ _ _ rbt lt (proj1 (proj2 tr)) , proj2 (proj2 tr) ⟫ ⟫
RB-repl→ti< .(node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ _ _) _) .(node _ ⟪ Red , _ ⟫ (node _ ⟪ Black , _ ⟫ _ _) (to-black _)) key key₁ value (rbr-flip-ll x _ rbt) lt tr
   = ⟪ proj1 tr , ⟪ ⟪ proj1 (proj1 (proj2 tr))  , ⟪ RB-repl→ti< _ _ _ _ _ rbt lt (proj1 (proj2 (proj1 (proj2 tr))))
       , proj2 (proj2 (proj1 (proj2 tr))) ⟫ ⟫  , tr<-to-black (proj2 (proj2 tr)) ⟫ ⟫
RB-repl→ti< .(node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ _ _) _) .(node _ ⟪ Red , _ ⟫ (node _ ⟪ Black , _ ⟫ _ _) (to-black _)) key key₁ value
   (rbr-flip-lr x _ _ rbt) lt ⟪ tr3 , ⟪ ⟪ tr4 , ⟪ tr6 , tr7 ⟫ ⟫ , tr5 ⟫ ⟫ = ⟪ tr3 , ⟪ ⟪ tr4 , ⟪ tr6 ,  RB-repl→ti< _ _ _ _ _ rbt lt tr7 ⟫ ⟫  , tr<-to-black tr5 ⟫ ⟫
RB-repl→ti< .(node _ ⟪ Black , _ ⟫ _ (node _ ⟪ Red , _ ⟫ _ _)) .(node _ ⟪ Red , _ ⟫ (to-black _) (node _ ⟪ Black , _ ⟫ _ _)) key key₁ value
   (rbr-flip-rl x _ _ rbt) lt ⟪ tr3 , ⟪ tr5 , ⟪ tr4 , ⟪ tr6 , tr7 ⟫ ⟫  ⟫ ⟫ = ⟪ tr3 , ⟪ tr<-to-black tr5 , ⟪ tr4 , ⟪  RB-repl→ti< _ _ _ _ _ rbt lt tr6 , tr7 ⟫ ⟫   ⟫ ⟫
RB-repl→ti< .(node _ ⟪ Black , _ ⟫ _ (node _ ⟪ Red , _ ⟫ _ _)) .(node _ ⟪ Red , _ ⟫ (to-black _) (node _ ⟪ Black , _ ⟫ _ _)) key key₁ value
   (rbr-flip-rr x _ rbt) lt ⟪ tr3 , ⟪ tr5 , ⟪ tr4 , ⟪ tr6 , tr7 ⟫ ⟫ ⟫ ⟫ = ⟪ tr3 , ⟪ tr<-to-black tr5 , ⟪ tr4 , ⟪ tr6 ,  RB-repl→ti< _ _ _ _ _ rbt lt tr7 ⟫ ⟫   ⟫ ⟫
RB-repl→ti< .(node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ _ _) _) .(node _ ⟪ Black , _ ⟫ _ (node _ ⟪ Red , _ ⟫ _ _)) key key₁ value
   (rbr-rotate-ll x lt2 rbt) lt ⟪ tr3 , ⟪ ⟪ tr4 , ⟪ tr6 , tr7 ⟫ ⟫ , tr5  ⟫ ⟫  = ⟪ tr4 , ⟪  RB-repl→ti< _ _ _ _ _ rbt lt tr6 , ⟪ tr3 , ⟪ tr7 , tr5 ⟫ ⟫ ⟫ ⟫
RB-repl→ti< .(node _ ⟪ Black , _ ⟫ _ (node _ ⟪ Red , _ ⟫ _ _)) .(node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ _ _) _) key key₁ value
   (rbr-rotate-rr x lt2 rbt) lt ⟪ tr3 , ⟪ tr5 , ⟪ tr4 , ⟪ tr6 , tr7 ⟫ ⟫  ⟫ ⟫  = ⟪ tr4 , ⟪ ⟪ tr3 , ⟪ tr5 , tr6 ⟫ ⟫ , RB-repl→ti< _ _ _ _ _ rbt lt tr7 ⟫ ⟫
RB-repl→ti< (node kg ⟪ Black , _ ⟫ (node kp ⟪ Red , _ ⟫ _ _) _) (node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ _ _) (node _ ⟪ Red , _ ⟫ _ _)) key key₁ value
   (rbr-rotate-lr left right _ _ kn _ _ rbt) lt ⟪ tr3 , ⟪ ⟪ tr4 , ⟪ tr6 , tr7 ⟫ ⟫ , tr5  ⟫ ⟫  = ⟪ rr00 , ⟪ ⟪ tr4 , ⟪ tr6 , proj1 (proj2 rr01) ⟫ ⟫ , ⟪ tr3 , ⟪ proj2 (proj2 rr01) , tr5 ⟫ ⟫ ⟫ ⟫ where
       rr01 : (kn < key₁ ) ∧ tr< key₁ left  ∧ tr< key₁ right
       rr01 = RB-repl→ti< _ _ _ _ _ rbt lt tr7 
       rr00 : kn < key₁ 
       rr00 = proj1 rr01
RB-repl→ti< .(node _ ⟪ Black , _ ⟫ _ (node _ ⟪ Red , _ ⟫ _ _)) .(node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ _ _) (node _ ⟪ Red , _ ⟫ _ _)) key key₁ value
   (rbr-rotate-rl left right kg kp kn _ _ rbt) lt ⟪ tr3 , ⟪ tr5 , ⟪ tr4 , ⟪ tr6 , tr7 ⟫ ⟫  ⟫ ⟫  = ⟪ rr00 , ⟪  ⟪ tr3 , ⟪ tr5 , proj1 (proj2 rr01) ⟫ ⟫ , ⟪ tr4 , ⟪ proj2 (proj2 rr01) , tr7 ⟫ ⟫ ⟫ ⟫ where
       rr01 : (kn < key₁ ) ∧ tr< key₁ left  ∧ tr< key₁ right
       rr01 = RB-repl→ti< _ _ _ _ _ rbt lt tr6
       rr00 : kn < key₁ 
       rr00 = proj1 rr01

RB-repl→ti : {n : Level} {A : Set n} → (tree repl : bt (Color ∧ A) ) → (key : ℕ ) → (value : A) → treeInvariant tree 
       → replacedRBTree key value tree repl → treeInvariant repl
RB-repl→ti .leaf .(node key ⟪ Red , value ⟫ leaf leaf) key value ti rbr-leaf = t-single key ⟪ Red , value ⟫
RB-repl→ti .(node key ⟪ _ , _ ⟫ leaf leaf) .(node key ⟪ _ , value ⟫ leaf leaf) key value (t-single .key .(⟪ _ , _ ⟫)) rbr-node = t-single key ⟪ _ , value ⟫
RB-repl→ti .(node key ⟪ _ , _ ⟫ leaf (node key₁ _ _ _)) .(node key ⟪ _ , value ⟫ leaf (node key₁ _ _ _)) key value 
   (t-right .key key₁ x x₁ x₂ ti) rbr-node = t-right key key₁ x x₁ x₂ ti
RB-repl→ti .(node key ⟪ _ , _ ⟫ (node key₁ _ _ _) leaf) .(node key ⟪ _ , value ⟫ (node key₁ _ _ _) leaf) key value 
   (t-left key₁ .key x x₁ x₂ ti) rbr-node = t-left key₁ key x x₁ x₂ ti
RB-repl→ti .(node key ⟪ _ , _ ⟫ (node key₁ _ _ _) (node key₂ _ _ _)) .(node key ⟪ _ , value ⟫ (node key₁ _ _ _) (node key₂ _ _ _)) key value 
   (t-node key₁ .key key₂ x x₁ x₂ x₃ x₄ x₅ ti ti₁) rbr-node = t-node key₁ key key₂ x x₁ x₂ x₃ x₄ x₅ ti ti₁
RB-repl→ti (node key₁ ⟪ ca , v1 ⟫ leaf leaf) (node key₁ ⟪ ca , v1 ⟫ leaf tree@(node key₂ value₁ t t₁)) key value 
   (t-single key₁ ⟪ ca , v1 ⟫) (rbr-right x trb) = t-right _ _  (proj1 rr00) (proj1 (proj2 rr00)) (proj2 (proj2 rr00)) (RB-repl→ti _ _ _ _ t-leaf trb) where
        rr00 : (key₁ < key₂ ) ∧ tr> key₁ t ∧ tr> key₁ t₁
        rr00 = RB-repl→ti> _ _ _ _ _ trb x tt
RB-repl→ti (node _ ⟪ _ , _ ⟫ leaf (node key₁ _ _ _)) (node key₂ ⟪ ca , v1 ⟫ leaf (node key₃ value₁ t t₁)) key value 
   (t-right _ key₁ x₁ x₂ x₃ ti) (rbr-right x trb) = t-right _ _ (proj1 rr00) (proj1 (proj2 rr00)) (proj2 (proj2 rr00)) (RB-repl→ti _ _ _ _ ti trb) where
        rr00 : (key₂ < key₃) ∧ tr> key₂ t ∧ tr> key₂ t₁ 
        rr00 = RB-repl→ti> _ _ _ _ _ trb x ⟪ x₁ , ⟪ x₂ , x₃ ⟫ ⟫
RB-repl→ti .(node key₂ ⟪ ca , v1 ⟫ (node key₁ value₁ t t₁) leaf) (node key₂ ⟪ ca , v1 ⟫ (node key₁ value₁ t t₁) (node key₃ value₂ t₂ t₃)) key value 
   (t-left key₁ _ x₁ x₂ x₃ ti) (rbr-right x trb) = t-node _ _ _ x₁ (proj1 rr00) x₂ x₃ (proj1 (proj2 rr00)) (proj2 (proj2 rr00)) ti (RB-repl→ti _ _ _ _ t-leaf trb) where
        rr00 : (key₂ < key₃) ∧ tr> key₂ t₂ ∧ tr> key₂ t₃
        rr00 = RB-repl→ti> _ _ _ _ _ trb x tt
RB-repl→ti .(node key₃ ⟪ ca , v1 ⟫ (node key₁ v2 t₁ t₂) (node key₂ _ _ _)) (node key₃ ⟪ ca , v1 ⟫ (node key₁ v2 t₁ t₂) (node key₄ value₁ t₃ t₄)) key value 
   (t-node key₁ _ key₂ x₁ x₂ x₃ x₄ x₅ x₆ ti ti₁) (rbr-right x trb) = t-node _ _ _ x₁ 
     (proj1 rr00) x₃ x₄ (proj1 (proj2 rr00)) (proj2 (proj2 rr00)) ti (RB-repl→ti _ _ _ _ ti₁ trb) where
        rr00 : (key₃ < key₄) ∧ tr> key₃ t₃ ∧ tr> key₃ t₄
        rr00 = RB-repl→ti> _ _ _ _ _ trb x ⟪ x₂ , ⟪ x₅ , x₆ ⟫ ⟫
RB-repl→ti .(node key₁ ⟪ _ , _ ⟫ leaf leaf) (node key₁ ⟪ _ , _ ⟫ (node key₂ value₁ left left₁) leaf) key value 
   (t-single _ .(⟪ _ , _ ⟫)) (rbr-left x trb) = t-left _ _ (proj1 rr00) (proj1 (proj2 rr00)) (proj2 (proj2 rr00)) (RB-repl→ti _ _ _ _ t-leaf trb) where
        rr00 : (key₂ < key₁) ∧ tr< key₁ left ∧ tr< key₁ left₁
        rr00 = RB-repl→ti< _ _ _ _ _ trb x tt
RB-repl→ti .(node key₂ ⟪ _ , _ ⟫ leaf (node key₁ _ t₁ t₂)) (node key₂ ⟪ _ , _ ⟫ (node key₃ value₁ t t₃) (node key₁ _ t₁ t₂)) key value 
   (t-right _ key₁ x₁ x₂ x₃ ti) (rbr-left x trb) = t-node _ _ _ (proj1 rr00) x₁  (proj1 (proj2 rr00))(proj2 (proj2 rr00)) x₂ x₃ rr01 ti where
        rr00 : (key₃ < key₂) ∧ tr< key₂ t ∧ tr< key₂ t₃
        rr00 = RB-repl→ti< _ _ _ _ _ trb x tt
        rr01 : treeInvariant (node key₃ value₁ t t₃)
        rr01 = RB-repl→ti _ _ _ _ t-leaf trb
RB-repl→ti .(node _ ⟪ _ , _ ⟫ (node key₁ _ _ _) leaf) (node key₃ ⟪ _ , _ ⟫ (node key₂ value₁ t t₁) leaf) key value 
    (t-left key₁ _ x₁ x₂ x₃ ti) (rbr-left x trb) = t-left key₂ _ (proj1 rr00) (proj1 (proj2 rr00)) (proj2 (proj2 rr00)) (RB-repl→ti _ _ _ _ ti trb) where
        rr00 : (key₂ < key₃) ∧ tr< key₃ t ∧ tr< key₃ t₁
        rr00 = RB-repl→ti< _ _ _ _ _ trb x ⟪ x₁ , ⟪ x₂ , x₃ ⟫ ⟫
RB-repl→ti .(node key₃ ⟪ _ , _ ⟫ (node key₁ _ _ _) (node key₂ _ t₁ t₂)) (node key₃ ⟪ _ , _ ⟫ (node key₄ value₁ t t₃) (node key₂ _ t₁ t₂)) key value 
    (t-node key₁ _ key₂ x₁ x₂ x₃ x₄ x₅ x₆ ti ti₁) (rbr-left x trb) = t-node _ _ _ (proj1 rr00) x₂ (proj1 (proj2 rr00))  (proj2 (proj2 rr00))  x₅ x₆ (RB-repl→ti _ _ _ _ ti trb) ti₁ where
        rr00 : (key₄ < key₃) ∧ tr< key₃ t ∧ tr< key₃ t₃
        rr00 = RB-repl→ti< _ _ _ _ _ trb x ⟪ x₁ , ⟪ x₃ , x₄ ⟫ ⟫
RB-repl→ti .(node x₁ ⟪ Black , c ⟫ leaf leaf) (node x₁ ⟪ Black , c ⟫ leaf (node key₁ value₁ t t₁)) key value 
    (t-single x₂ .(⟪ Black , c ⟫)) (rbr-black-right x x₄ trb) = t-right _ _ (proj1 rr00) (proj1 (proj2 rr00)) (proj2 (proj2 rr00)) (RB-repl→ti _ _ _ _ t-leaf trb) where
        rr00 : (x₁ < key₁) ∧ tr> x₁ t ∧ tr> x₁ t₁    
        rr00 = RB-repl→ti> _ _ _ _ _ trb x₄ tt
RB-repl→ti .(node key₂ ⟪ Black , _ ⟫ leaf (node key₁ _ _ _)) (node key₂ ⟪ Black , _ ⟫ leaf (node key₃ value₁ t₂ t₃)) key value 
    (t-right _ key₁ x₁ x₂ x₃ ti) (rbr-black-right  x x₄ trb) = t-right _ _ (proj1 rr00) (proj1 (proj2 rr00)) (proj2 (proj2 rr00)) (RB-repl→ti _ _ _ _ ti trb) where
        rr00 : (key₂ < key₃) ∧ tr> key₂ t₂ ∧ tr> key₂ t₃
        rr00 = RB-repl→ti> _ _ _ _ _ trb x₄ ⟪ x₁ , ⟪ x₂ , x₃ ⟫ ⟫
RB-repl→ti .(node key₂ ⟪ Black , _ ⟫ (node key₁ _ _ _) leaf) (node key₂ ⟪ Black , _ ⟫ (node key₁ _ _ _) (node key₃ value₁ t₂ t₃)) key value (t-left key₁ _ x₁ x₂ x₃ ti) (rbr-black-right x x₄ trb) = t-node _ _ _ x₁ (proj1 rr00) x₂ x₃ (proj1 (proj2 rr00)) (proj2 (proj2 rr00)) ti (RB-repl→ti _ _ _ _ t-leaf trb) where
        rr00 : (key₂ < key₃) ∧ tr> key₂ t₂ ∧ tr> key₂ t₃
        rr00 = RB-repl→ti> _ _ _ _ _ trb x₄ tt
RB-repl→ti .(node key₃ ⟪ Black , _ ⟫ (node key₁ _ _ _) (node key₂ _ _ _)) (node key₃ ⟪ Black , _ ⟫ (node key₁ _ _ _) (node key₄ value₁ t₂ t₃)) key value 
      (t-node key₁ _ key₂ x₁ x₂ x₃ x₄ x₅ x₆ ti ti₁) (rbr-black-right x x₇ trb) = t-node _ _ _ x₁ (proj1 rr00) x₃ x₄ (proj1 (proj2 rr00)) (proj2 (proj2 rr00)) ti (RB-repl→ti _ _ _ _ ti₁ trb) where
        rr00 : (key₃ < key₄) ∧ tr> key₃ t₂ ∧ tr> key₃ t₃
        rr00 = RB-repl→ti> _ _ _ _ _ trb x₇ ⟪ x₂ , ⟪ x₅ , x₆ ⟫ ⟫
RB-repl→ti .(node key₂ ⟪ Black , _ ⟫ leaf leaf) (node key₂ ⟪ Black , _ ⟫ (node key₁ value₁ t t₁) .leaf) key value 
       (t-single .key₂ .(⟪ Black , _ ⟫)) (rbr-black-left x x₇ trb) = t-left _ _ (proj1 rr00) (proj1 (proj2 rr00)) (proj2 (proj2 rr00)) (RB-repl→ti _ _ _ _ t-leaf trb) where
        rr00 : (key₁ < key₂) ∧ tr< key₂ t ∧ tr< key₂ t₁
        rr00 = RB-repl→ti< _ _ _ _ _ trb x₇ tt
RB-repl→ti .(node key₂ ⟪ Black , _ ⟫ leaf (node key₁ _ _ _)) (node key₂ ⟪ Black , _ ⟫ (node key₃ value₁ t t₁) .(node key₁ _ _ _)) key value 
       (t-right .key₂ key₁ x₁ x₂ x₃ ti) (rbr-black-left x x₇ trb) = t-node _ _ _ (proj1 rr00) x₁ (proj1 (proj2 rr00)) (proj2 (proj2 rr00))  x₂ x₃ (RB-repl→ti _ _ _ _ t-leaf trb) ti where
        rr00 : (key₃ < key₂) ∧ tr< key₂ t ∧ tr< key₂ t₁
        rr00 = RB-repl→ti< _ _ _ _ _ trb x₇ tt
RB-repl→ti .(node key₂ ⟪ Black , _ ⟫ (node key₁ _ _ _) leaf) (node key₂ ⟪ Black , _ ⟫ (node key₃ value₁ t t₁) .leaf) key value 
       (t-left key₁ .key₂ x₁ x₂ x₃ ti) (rbr-black-left x x₇ trb) = t-left _ _ (proj1 rr00) (proj1 (proj2 rr00)) (proj2 (proj2 rr00)) (RB-repl→ti _ _ _ _ ti trb) where
        rr00 : (key₃ < key₂) ∧ tr< key₂ t ∧ tr< key₂ t₁
        rr00 = RB-repl→ti< _ _ _ _ _ trb x₇ ⟪ x₁ , ⟪ x₂ , x₃ ⟫ ⟫
RB-repl→ti .(node key₂ ⟪ Black , _ ⟫ (node key₁ _ _ _) (node key₃ _ _ _)) (node key₂ ⟪ Black , _ ⟫ (node key₄ value₁ t t₁) .(node key₃ _ _ _)) key value 
     (t-node key₁ .key₂ key₃ x₁ x₂ x₃ x₄ x₅ x₆ ti ti₁) (rbr-black-left x x₇ trb) = t-node _ _ _ (proj1 rr00) x₂ (proj1 (proj2 rr00)) (proj2 (proj2 rr00)) x₅ x₆ (RB-repl→ti _ _ _ _ ti trb) ti₁ where
        rr00 : (key₄ < key₂) ∧ tr< key₂ t ∧ tr< key₂ t₁
        rr00 = RB-repl→ti< _ _ _ _ _ trb x₇ ⟪ x₁ , ⟪ x₃ , x₄ ⟫ ⟫
RB-repl→ti .(node key₂ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ _ t₁) leaf) (node key₂ ⟪ Red , value₁ ⟫ (node key₁ ⟪ Black , value₂ ⟫ t t₁) .(to-black leaf)) key value 
      (t-left _ .key₂ x₁ x₂ x₃ ti) (rbr-flip-ll x lt trb) = t-left _ _ x₁ rr00 x₃ (RTtoTI0 _ _ _ _ rr02 r-node ) where
        rr00 : tr< key₂ t 
        rr00 = RB-repl→ti< _ _ _ _ _ trb (<-trans lt x₁) x₂
        rr02 : treeInvariant (node key₁ ⟪ Red , value₂  ⟫ t t₁)
        rr02 = RB-repl→ti _ _ _ _ ti (rbr-left lt trb)
RB-repl→ti (node key₂ ⟪ Black , _ ⟫ (node key₁ ⟪ Red , _ ⟫ t₀ t₁) (node key₃ ⟪ c1 , v1 ⟫  left right)) (node key₂ ⟪ Red , value₁ ⟫ (node _ ⟪ Black , value₂ ⟫ t t₁) (node key₃ ⟪ Black , v1 ⟫  left  right)) key value 
       (t-node _ .key₂ key₃ x₁ x₂ x₃ x₄ x₅ x₆ ti ti₁) (rbr-flip-ll x lt trb) = t-node _ _ _ x₁ x₂ rr00 x₄ x₅ x₆ (RTtoTI0 _ _ _ _ rr02 r-node ) (RTtoTI0 _ _ _ _ ti₁ r-node ) where
        rr00 : tr< key₂ t
        rr00 = RB-repl→ti< _ _ _ _ _ trb (<-trans lt x₁)  x₃
        rr02 : treeInvariant (node key₁ ⟪ Red , value₂ ⟫ t t₁)
        rr02  = RB-repl→ti _ _ _ _ ti (rbr-left lt trb)
RB-repl→ti (node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ left right) leaf) (node key₂ ⟪ Red , v1 ⟫ (node key₃ ⟪ Black , v2 ⟫ left right₁) leaf) key value 
      (t-left _ _ x₁ x₂ x₃ ti) (rbr-flip-lr x lt lt2 trb) = t-left _ _ x₁ x₂ rr00 (RTtoTI0 _ _ _ _ rr02 r-node ) where
        rr00 : tr< key₂ right₁
        rr00 = RB-repl→ti< _ _ _ _ _ trb lt2 x₃
        rr02 : treeInvariant (node key₃ ⟪ Red , v2 ⟫ left right₁ )
        rr02 = RB-repl→ti _ _ _ _ ti (rbr-right lt trb)
RB-repl→ti (node key₁ ⟪ Black , v1 ⟫ (node key₂ ⟪ Red , v2 ⟫ t t₁) (node key₃ ⟪ c3 , v3 ⟫ t₂ t₃)) (node key₁ ⟪ Red , _ ⟫ (node _ ⟪ Black , _ ⟫ t t₄) .(to-black (node key₃ ⟪ c3 , _ ⟫ _ _))) key value 
      (t-node _ _ key₃ x₁ x₂ x₃ x₄ x₅ x₆ ti ti₁) (rbr-flip-lr x lt lt2 trb) = t-node _ _ _ x₁ x₂ x₃ rr00 x₅ x₆ (RTtoTI0 _ _ _ _ rr02 r-node ) (RTtoTI0 _ _ _ _ ti₁ r-node ) where
        rr00 : tr< key₁ t₄
        rr00 = RB-repl→ti< _ _ _ _ _ trb lt2 x₄
        rr02 : treeInvariant (node key₂ ⟪ Red , v2 ⟫ t t₄)
        rr02 = RB-repl→ti _ _ _ _ ti (rbr-right lt trb)
RB-repl→ti (node _ ⟪ Black , _ ⟫ leaf (node _ ⟪ Red , _ ⟫ t t₁)) (node key₁ ⟪ Red , v1 ⟫ .(to-black leaf) (node key₂ ⟪ Black , v2 ⟫ t₂ t₁)) key value 
      (t-right _ _ x₁ x₂ x₃ ti) (rbr-flip-rl x lt lt2 trb) = t-right _ _ x₁ rr00 x₃ (RTtoTI0 _ _ _ _ rr02 r-node ) where
        rr00 : tr> key₁ t₂
        rr00 = RB-repl→ti> _ _ _ _ _ trb lt x₂
        rr02 : treeInvariant (node key₂ ⟪ Red , v2 ⟫ t₂ t₁)
        rr02 = RB-repl→ti _ _ _ _ ti (rbr-left lt2 trb)
RB-repl→ti (node _ ⟪ Black , v1 ⟫ (node key₂ ⟪ c2 , v2 ⟫ t t₁) (node _ ⟪ Red , v3 ⟫ t₂ t₃)) (node key₁ ⟪ Red , _ ⟫ .(to-black (node key₂ ⟪ c2 , _ ⟫  _ _)) (node key₃ ⟪ Black , _ ⟫ t₄ t₃)) key value 
      (t-node key₂ _ _ x₁ x₂ x₃ x₄ x₅ x₆ ti ti₁) (rbr-flip-rl x lt lt2 trb) = t-node key₂ _ _ x₁ x₂ x₃ x₄ rr00 x₆ (RTtoTI0 _ _ _ _ ti r-node ) (RTtoTI0 _ _ _ _ rr02 r-node ) where
        rr00 : tr> key₁ t₄
        rr00 = RB-repl→ti> _ _ _ _ _ trb lt x₅
        rr02 : treeInvariant (node key₃ ⟪ Red , v3 ⟫ t₄ t₃)
        rr02 = RB-repl→ti _ _ _ _ ti₁ (rbr-left lt2 trb)
RB-repl→ti (node key₁ ⟪ Black , v1 ⟫ leaf (node key₂ ⟪ Red , v2 ⟫ t t₁)) (node _ ⟪ Red , _ ⟫ .(to-black leaf) (node _ ⟪ Black , v2 ⟫ t t₂)) key value 
    (t-right _ _ x₁ x₂ x₃ ti) (rbr-flip-rr x lt trb) = t-right _ _ x₁ x₂ rr00 (RTtoTI0 _ _ _ _ rr02 r-node ) where
        rr00 : tr> key₁ t₂
        rr00 = RB-repl→ti> _ _ _ _ _ trb (<-trans x₁ lt )  x₃
        rr02 : treeInvariant (node key₂ ⟪ Red , v2 ⟫ t t₂)
        rr02 = RB-repl→ti _ _ _ _ ti (rbr-right lt trb)
RB-repl→ti (node key₁ ⟪ Black , v1 ⟫ (node key₂ ⟪ c2 , v2 ⟫ t t₁) (node key₃ ⟪ Red , c3 ⟫ t₂ t₃)) (node _ ⟪ Red , _ ⟫ .(to-black (node key₂ ⟪ c2 , _ ⟫ _ _)) (node _ ⟪ Black , c3 ⟫ t₂ t₄)) key value 
    (t-node key₂ _ _ x₁ x₂ x₃ x₄ x₅ x₆ ti ti₁) (rbr-flip-rr x lt trb) = t-node key₂ _ _ x₁ x₂ x₃ x₄ x₅ rr00 (RTtoTI0 _ _ _ _ ti r-node ) (RTtoTI0 _ _ _ _ rr02 r-node ) where
        rr00 : tr> key₁ t₄
        rr00 = RB-repl→ti> _ _ _ _ _ trb (<-trans x₂ lt) x₆
        rr02 : treeInvariant (node key₃ ⟪ Red , c3 ⟫ t₂ t₄)
        rr02 = RB-repl→ti _ _ _ _ ti₁ (rbr-right lt trb)
RB-repl→ti {_} {A} (node k1 ⟪ Black , c1 ⟫ (node k2 ⟪ Red , c2 ⟫ .leaf .leaf) leaf) (node _ ⟪ Black , _ ⟫ (node key₁ value₁ t₂ t₃) (node _ ⟪ Red , _ ⟫ .leaf leaf)) key value (t-left _ _ x₁ x₂ x₃ 
    (t-single .k2 .(⟪ Red , c2 ⟫))) (rbr-rotate-ll x lt trb) = t-node _ _ _ (proj1 rr10) x₁ (proj1 (proj2 rr10)) (proj2 (proj2 rr10)) tt tt (RB-repl→ti _ _ _ _ t-leaf trb) (t-single _ _ ) where
        rr10 : (key₁ < k2 ) ∧ tr< k2 t₂ ∧ tr< k2 t₃
        rr10 = RB-repl→ti< _ _ _ _ _ trb lt tt 
RB-repl→ti {_} {A} (node k1 ⟪ Black , c1 ⟫ (node k2 ⟪ Red , c2 ⟫ .leaf .(node key₂ _ _ _)) leaf) (node _ ⟪ Black , _ ⟫ (node key₁ value₁ t₂ t₃) (node _ ⟪ Red , _ ⟫ (node key₂ value₂ t₁ t₄) leaf)) key value 
    (t-left _ _ x₁ x₂ x₃ (t-right .k2 key₂ x₄ x₅ x₆ ti)) (rbr-rotate-ll x lt trb) = t-node _ _ _ (proj1 rr10) x₁ (proj1 (proj2 rr10)) (proj2 (proj2 rr10)) ⟪ x₄ , ⟪ x₅ , x₆ ⟫ ⟫  tt rr05 rr04 where
        rr10 : (key₁ < k2 ) ∧ tr< k2 t₂ ∧ tr< k2 t₃
        rr10 = RB-repl→ti< _ _ _ _ _ trb lt tt
        rr04 : treeInvariant (node k1 ⟪ Red , c1 ⟫ (node key₂ value₂ t₁ t₄) leaf)
        rr04 = RTtoTI0 _ _ _ _ (t-left key₂ _ {_} {⟪ Red , c1 ⟫} {t₁} {t₄} (proj1 x₃) (proj1 (proj2 x₃)) (proj2 (proj2 x₃)) ti) r-node
        rr05 : treeInvariant (node key₁ value₁ t₂ t₃)
        rr05 = RB-repl→ti _ _ _ _ t-leaf trb
RB-repl→ti {_} {A} (node k1 ⟪ Black , c1 ⟫ (node k2 ⟪ Red , c2 ⟫ (node key₂ value₂ t₁ t₄) .leaf) leaf) (node _ ⟪ Black , _ ⟫ (node key₁ value₁ t₂ t₃) (node _ ⟪ Red , _ ⟫ .leaf leaf)) key value 
   (t-left _ _ x₁ x₂ x₃ (t-left key₂ .k2 x₄ x₅ x₆ ti)) (rbr-rotate-ll x lt trb) = t-node _ _ _ (proj1 rr10) x₁ (proj1 (proj2 rr10)) (proj2 (proj2 rr10)) tt tt (RB-repl→ti _ _ _ _ ti trb) (t-single _ _) where
        rr10 : (key₁ < k2 ) ∧ tr< k2 t₂ ∧ tr< k2 t₃
        rr10 = RB-repl→ti< _ _ _ _ _ trb lt ⟪ x₄ , ⟪ x₅ , x₆ ⟫ ⟫
RB-repl→ti {_} {A} (node k1 ⟪ Black , c1 ⟫ (node k2 ⟪ Red , c2 ⟫ (node key₂ value₃ left right) (node key₃ value₂ t₄ t₅)) leaf) (node _ ⟪ Black , _ ⟫ (node key₁ value₁ t₂ t₃) (node _ ⟪ Red , _ ⟫ .(node key₃ _ _ _) leaf)) key value 
     (t-left _ _ x₁ x₂ x₃ (t-node key₂ .k2 key₃ x₄ x₅ x₆ x₇ x₈ x₉ ti ti₁)) (rbr-rotate-ll x lt trb) = t-node _ _ _ (proj1 rr10) x₁ (proj1 (proj2 rr10))  (proj2 (proj2 rr10))  ⟪ x₅ , ⟪ x₈ ,  x₉ ⟫ ⟫ tt rr05 rr04 where
        rr06 : key < k2
        rr06 = lt
        rr10 : (key₁ < k2) ∧ tr< k2 t₂ ∧ tr< k2 t₃
        rr10 = RB-repl→ti< _ _ _ _ _ trb rr06 ⟪ x₄ , ⟪ x₆ , x₇ ⟫ ⟫
        rr04 : treeInvariant (node k1 ⟪ Red , c1 ⟫ (node key₃ value₂ t₄ t₅) leaf)
        rr04 = RTtoTI0 _ _ _ _ (t-left _ _ (proj1 x₃) (proj1 (proj2 x₃)) (proj2 (proj2 x₃)) ti₁ ) (r-left (proj1 x₃) r-node) 
        rr05 : treeInvariant (node key₁ value₁ t₂ t₃)
        rr05 = RB-repl→ti _ _ _ _ ti trb
RB-repl→ti (node key₁ ⟪ Black , c1 ⟫ (node key₂ ⟪ Red , c2 ⟫ .leaf .leaf) (node key₃ v3 t₂ t₃)) (node _ ⟪ Black , _ ⟫ (node key₄ value₁ t₄ t₅) (node _ ⟪ Red , _ ⟫ .leaf (node key₃ _ _ _))) key value 
   (t-node _ _ key₃ x₁ x₂ x₃ x₄ x₅ x₆ (t-single .key₂ .(⟪ Red , c2 ⟫)) ti₁) (rbr-rotate-ll x lt trb) = t-node _ _ _ (proj1 rr00) x₁ (proj1 (proj2 rr00))  (proj2 (proj2 rr00))  tt ⟪ <-trans x₁ x₂ , ⟪ <-tr> x₅ x₁ , <-tr> x₆ x₁  ⟫ ⟫  rr02 rr03 where
       rr00 : (key₄ < key₂) ∧ tr< key₂ t₄ ∧ tr< key₂ t₅
       rr00 = RB-repl→ti< _ _ _ _ _ trb lt tt
       rr02 : treeInvariant (node key₄ value₁ t₄ t₅) 
       rr02 = RB-repl→ti _ _ _ _ t-leaf trb
       rr03 : treeInvariant (node key₁ ⟪ Red , c1 ⟫ leaf (node key₃ v3 t₂ t₃))
       rr03 = RTtoTI0 _ _ _ _ (t-right _ _ {v3} {_} x₂ x₅ x₆ ti₁) r-node
RB-repl→ti (node key₁ ⟪ Black , c1 ⟫ (node key₂ ⟪ Red , c2 ⟫ leaf (node key₅ _ _ _)) (node key₃ v3 t₂ t₃)) (node _ ⟪ Black , _ ⟫ (node key₄ value₁ t₄ t₅) (node _ ⟪ Red , _ ⟫ (node key₅ value₂ t₁ t₆) (node key₃ _ _ _))) key value 
    (t-node _ _ key₃ x₁ x₂ x₃ x₄ x₅ x₆ (t-right .key₂ key₅ x₇ x₈ x₉ ti) ti₁) (rbr-rotate-ll x lt trb) = t-node _ _ _ (proj1 rr00) x₁ (proj1 (proj2 rr00)) (proj2 (proj2 rr00)) ⟪ x₇ , ⟪ x₈ , x₉ ⟫ ⟫  ⟪ <-trans x₁ x₂  , ⟪ <-tr> x₅ x₁ , <-tr> x₆ x₁ ⟫ ⟫ rr02 rr03 where
       rr00 : (key₄ < key₂) ∧ tr< key₂ t₄ ∧ tr< key₂ t₅
       rr00 = RB-repl→ti< _ _ _ _ _ trb lt tt
       rr02 : treeInvariant (node key₄ value₁ t₄ t₅)
       rr02 = RB-repl→ti _ _ _ _ t-leaf trb
       rr03 : treeInvariant (node key₁ ⟪ Red , c1 ⟫ (node key₅ value₂ t₁ t₆) (node key₃ v3 t₂ t₃))
       rr03 = RTtoTI0 _ _ _ _ (t-node _ _ _ {_} {v3} {_} {_} {_} {_} {_} (proj1 x₄) x₂ (proj1 (proj2 x₄)) (proj2 (proj2 x₄)) x₅ x₆ ti ti₁ ) r-node
RB-repl→ti (node key₁ ⟪ Black , c1 ⟫ (node key₂ ⟪ Red , c2 ⟫ .(node key₅ _ _ _) .leaf) (node key₃ v3 t₂ t₃)) (node _ ⟪ Black , _ ⟫ (node key₄ value₁ t₄ t₅) (node _ ⟪ Red , _ ⟫ .leaf (node key₃ _ _ _))) key value (t-node _ _ key₃ x₁ x₂ x₃ x₄ x₅ x₆ 
    (t-left key₅ .key₂ x₇ x₈ x₉ ti) ti₁) (rbr-rotate-ll x lt trb) = t-node _ _ _ (proj1 rr00) x₁ (proj1 (proj2 rr00)) (proj2 (proj2 rr00))  tt ⟪ <-trans x₁ x₂  , ⟪ <-tr> x₅ x₁  , <-tr> x₆ x₁ ⟫ ⟫  rr02 rr04 where
        rr00 : (key₄ < key₂) ∧ tr< key₂ t₄ ∧ tr< key₂ t₅
        rr00 = RB-repl→ti< _ _ _ _ _ trb lt ⟪ x₇ , ⟪ x₈ , x₉ ⟫ ⟫
        rr02 : treeInvariant (node key₄ value₁ t₄ t₅)
        rr02 = RB-repl→ti _ _ _ _ ti trb
        rr03 : treeInvariant (node key₁ ⟪ Red , c1 ⟫ (node key₅ _ _ _) (node key₃ v3 t₂ t₃))
        rr03 = RTtoTI0 _ _ _ _ (t-node _ _ _ {_} {v3} {_} {_} {_} {_} {_} (proj1 x₃) x₂ (proj1 (proj2 x₃)) (proj2 (proj2 x₃)) x₅ x₆ ti ti₁) r-node
        rr04 :  treeInvariant (node key₁ ⟪ Red , c1 ⟫ leaf (node key₃ v3 t₂ t₃))
        rr04 = RTtoTI0 _ _ _ _ (t-right _ _ {v3} {_} x₂ x₅ x₆ ti₁) r-node
RB-repl→ti {_} {A} (node key₁ ⟪ Black , c1 ⟫ (node key₂ ⟪ Red , c2 ⟫ .(node key₅ _ _ _) (node key₆ value₆ t₆ t₇)) (node key₃ v3 t₂ t₃)) (node _ ⟪ Black , _ ⟫ (node key₄ value₁ t₄ t₅) (node _ ⟪ Red , _ ⟫ .(node key₆ _ _ _) (node key₃ _ _ _))) key value 
  (t-node _ _ key₃ x₁ x₂ x₃ x₄ x₅ x₆ (t-node key₅ .key₂ key₆ x₇ x₈ x₉ x₁₀ x₁₁ x₁₂ ti ti₂) ti₁) (rbr-rotate-ll x lt trb) = t-node _ _ _ (proj1 rr00) x₁ (proj1 (proj2 rr00)) (proj2 (proj2 rr00)) ⟪ x₈ , ⟪ x₁₁ , x₁₂ ⟫ ⟫  ⟪ <-trans x₁ x₂ , ⟪ rr05 , <-tr> x₆ x₁ ⟫ ⟫ rr02 rr03 where
        rr00 : (key₄ < key₂) ∧ tr< key₂ t₄ ∧ tr< key₂ t₅
        rr00 = RB-repl→ti< _ _ _ _ _ trb lt ⟪ x₇ , ⟪ x₉ , x₁₀ ⟫ ⟫
        rr02 : treeInvariant (node key₄ value₁ t₄ t₅)
        rr02 = RB-repl→ti _ _ _ _ ti trb
        rr03 : treeInvariant (node key₁ ⟪ Red , c1 ⟫ (node key₆ value₆ t₆ t₇) (node key₃ v3 t₂ t₃))
        rr03 = RTtoTI0 _ _ _ _(t-node _ _ _ {_} {value₁} {_} {_} {_} {_} {_} (proj1 x₄) x₂ (proj1 (proj2 x₄)) (proj2 (proj2 x₄)) x₅ x₆ ti₂ ti₁) r-node
        rr05 : tr> key₂ t₂
        rr05 = <-tr> x₅ x₁
RB-repl→ti (node key₁ ⟪ Black , v1 ⟫ leaf (node key₂ ⟪ Red , v2 ⟫ leaf leaf)) (node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ _ _) (node key₃ value₁ t₃ t₄)) key value 
    (t-right .key₁ .key₂ x₁ x₂ x₃ (t-single .key₂ .(⟪ Red , _ ⟫))) (rbr-rotate-rr x lt trb) 
      = t-node _ _ _ x₁ (proj1 rr00) tt tt (proj1 (proj2 rr00)) (proj2 (proj2 rr00)) (t-single _ _) (RB-repl→ti _ _ _ _ t-leaf trb) where
        rr00 : (key₂ < key₃) ∧ tr> key₂ t₃ ∧ tr> key₂ t₄
        rr00 = RB-repl→ti> _ _ _ _ _ trb lt tt
RB-repl→ti (node key₁ ⟪ Black , v1 ⟫ leaf (node key₂ ⟪ Red , v2 ⟫ leaf (node key₃ value₃ t t₁))) (node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ _ _) (node key₄ value₁ t₃ t₄)) key value 
   (t-right .key₁ .key₂ x₁ x₂ x₃ (t-right .key₂ key₃ x₄ x₅ x₆ ti)) (rbr-rotate-rr x lt trb) 
      = t-node _ _ _ x₁ (proj1 rr00) tt tt (proj1 (proj2 rr00)) (proj2 (proj2 rr00)) (t-single _ _ ) (RB-repl→ti _ _ _ _ ti trb) where
        rr00 : (key₂ < key₄) ∧ tr> key₂ t₃ ∧ tr> key₂ t₄
        rr00 = RB-repl→ti> _ _ _ _ _ trb lt ⟪ x₄ , ⟪ x₅ , x₆ ⟫ ⟫ 
RB-repl→ti (node key₁ ⟪ Black , v1 ⟫ leaf (node key₂ ⟪ Red , v2 ⟫ (node key₃ _ _ _) leaf)) (node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ _ _) (node key₄ value₁ t₃ t₄)) key value 
    (t-right .key₁ .key₂ x₁ x₂ x₃ (t-left key₃ .key₂ x₄ x₅ x₆ ti)) (rbr-rotate-rr x lt trb) 
       = t-node _ _ _ x₁ (proj1 rr00) tt ⟪ x₄ , ⟪ x₅ , x₆ ⟫ ⟫ (proj1 (proj2 rr00)) (proj2 (proj2 rr00)) (t-right _ _ (proj1 x₂) (proj1 (proj2 x₂)) (proj2 (proj2 x₂)) ti)  (RB-repl→ti _ _ _ _ t-leaf trb) where
        rr00 : (key₂ < key₄) ∧ tr> key₂ t₃ ∧ tr> key₂ t₄
        rr00 = RB-repl→ti> _ _ _ _ _ trb lt tt
RB-repl→ti (node key₁ ⟪ Black , v1 ⟫ leaf (node key₂ ⟪ Red , v2 ⟫ (node key₃ _ _ _) (node key₄ _ _ _))) (node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ _ _) (node key₅ value₁ t₃ t₄)) key value 
    (t-right .key₁ .key₂ x₁ x₂ x₃ (t-node key₃ .key₂ key₄ x₄ x₅ x₆ x₇ x₈ x₉ ti ti₁)) (rbr-rotate-rr x lt trb) = t-node _ _ _ x₁ (proj1 rr00) tt ⟪ x₄ , ⟪ x₆ , x₇ ⟫ ⟫ (proj1 (proj2 rr00)) (proj2 (proj2 rr00)) (t-right _ _ (proj1 x₂) (proj1 (proj2 x₂)) (proj2 (proj2 x₂)) ti) (RB-repl→ti _ _ _ _ ti₁ trb) where
        rr00 : (key₂ < key₅) ∧ tr> key₂ t₃ ∧ tr> key₂ t₄
        rr00 = RB-repl→ti> _ _ _ _ _ trb lt ⟪ x₅ , ⟪ x₈ , x₉ ⟫ ⟫
RB-repl→ti (node key₁ ⟪ Black , v1 ⟫ .(node key₃ _ _ _) (node key₂ ⟪ Red , v2 ⟫ .leaf .leaf)) (node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ _ _) (node key₄ value₁ t₃ t₄)) key value 
   (t-node key₃ .key₁ .key₂ x₁ x₂ x₃ x₄ x₅ x₆ ti (t-single .key₂ .(⟪ Red , v2 ⟫))) (rbr-rotate-rr x lt trb) 
     = t-node _ _ _ x₂ (proj1 rr00) ⟪ <-trans x₁ x₂ , ⟪ >-tr< x₃ x₂ , >-tr< x₄ x₂ ⟫ ⟫  tt (proj1 (proj2 rr00)) (proj2 (proj2 rr00)) (t-left _ _ x₁ x₃ x₄ ti) (RB-repl→ti _ _ _ _ t-leaf trb) where
        rr00 : (key₂ < key₄) ∧ tr> key₂ t₃ ∧ tr> key₂ t₄
        rr00 = RB-repl→ti> _ _ _ _ _ trb lt tt
RB-repl→ti (node key₁ ⟪ Black , v1 ⟫ (node key₃ v3 t t₁) (node key₂ ⟪ Red , v2 ⟫ leaf (node key₄ _ _ _))) (node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ _ _) (node key₅ value₁ t₃ t₄)) key value 
   (t-node key₃ .key₁ .key₂ x₁ x₂ x₃ x₄ x₅ x₆ ti (t-right .key₂ key₄ x₇ x₈ x₉ ti₁)) (rbr-rotate-rr x lt trb) 
      = t-node _ _ _ x₂ (proj1 rr00) ⟪ <-trans x₁ x₂ , ⟪ >-tr< x₃ x₂ , >-tr< x₄ x₂ ⟫ ⟫ tt (proj1 (proj2 rr00)) (proj2 (proj2 rr00)) (t-left _ _ x₁ x₃ x₄ ti) (RB-repl→ti _ _ _ _ ti₁ trb) where
        rr00 : (key₂ < key₅) ∧ tr> key₂ t₃ ∧ tr> key₂ t₄
        rr00 = RB-repl→ti> _ _ _ _ _ trb lt ⟪ x₇ , ⟪ x₈ , x₉ ⟫ ⟫
RB-repl→ti (node key₁ ⟪ Black , v1 ⟫ (node key₃ _ _ _) (node key₂ ⟪ Red , v2 ⟫ (node key₄ _ _ _) leaf)) (node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ _ _) (node key₅ value₁ t₃ t₄)) key value 
   (t-node key₃ key₁ key₂ x₁ x₂ x₃ x₄ x₅ x₆ ti (t-left key₄ key₂ x₇ x₈ x₉ ti₁)) (rbr-rotate-rr x lt trb) 
      = t-node _ _ _ x₂ (proj1 rr00) ⟪ <-trans x₁ x₂ , ⟪ >-tr< x₃ x₂  , >-tr< x₄ x₂ ⟫ ⟫ ⟪ x₇ , ⟪ x₈ , x₉ ⟫ ⟫ (proj1 (proj2 rr00)) (proj2 (proj2 rr00)) (t-node _ _ _  x₁ (proj1 x₅) x₃ x₄ (proj1 (proj2 x₅)) (proj2 (proj2 x₅)) ti ti₁) (RB-repl→ti _ _ _ _ t-leaf trb) where
        rr00 : (key₂ < key₅) ∧ tr> key₂ t₃ ∧ tr> key₂ t₄
        rr00 = RB-repl→ti> _ _ _ _ _ trb lt tt
RB-repl→ti (node key₁ ⟪ Black , v1 ⟫ (node key₃ _ _ _) (node key₂ ⟪ Red , v2 ⟫ (node key₄ _ left right) (node key₅ _ _ _))) (node _ ⟪ Black , _ ⟫ (node _ ⟪ Red , _ ⟫ _ _) (node key₆ value₁ t₃ t₄)) key value 
   (t-node key₃ key₁ key₂ x₁ x₂ x₃ x₄ x₅ x₆ ti (t-node key₄ key₂ key₅ x₇ x₈ x₉ x₁₀ x₁₁ x₁₂ ti₁ ti₂)) (rbr-rotate-rr x lt trb) 
     = t-node _ _ _ x₂ (proj1 rr00) ⟪ <-trans x₁ x₂ , ⟪ >-tr< x₃ x₂ , >-tr< x₄ x₂ ⟫ ⟫  ⟪ x₇ , ⟪ x₉ , x₁₀ ⟫ ⟫  (proj1 (proj2 rr00)) (proj2 (proj2 rr00)) (RTtoTI0 _ _ _ _ (t-node _ _ _ {_} {value₁} x₁ (proj1 x₅) x₃ x₄  (proj1 (proj2 x₅)) (proj2 (proj2 x₅)) ti ti₁ ) r-node )
     (RB-repl→ti _ _ _ _ ti₂ trb) where
        rr00 : (key₂ < key₆) ∧ tr> key₂ t₃ ∧ tr> key₂ t₄
        rr00 = RB-repl→ti> _ _ _ _ _ trb lt ⟪ x₈ , ⟪ x₁₁ , x₁₂ ⟫ ⟫
RB-repl→ti (node kg ⟪ Black , v1 ⟫ (node kp ⟪ Red , v2 ⟫ leaf leaf) .leaf) (node kn ⟪ Black , _ ⟫ (node kp ⟪ Red , _ ⟫ _ leaf) (node kg ⟪ Red , _ ⟫ leaf _)) key value (t-left .kp .kg x x₁ x₂ ti) (rbr-rotate-lr .leaf .leaf kg kp kn lt1 lt2 trb) = t-node _ _ _ lt1 lt2 tt tt tt tt (t-single _ _) (t-single _ _) 
RB-repl→ti (node kg ⟪ Black , v1 ⟫ (node kp ⟪ Red , v2 ⟫ (node key₁ value₁ t t₁) leaf) .leaf) (node kn ⟪ Black , _ ⟫ (node kp ⟪ Red , _ ⟫ _ t₃) (node kg ⟪ Red , _ ⟫ t₄ _)) key value (t-left .kp .kg x x₁ x₂ ti) (rbr-rotate-lr t₃ t₄ kg kp kn lt1 lt2 trb) = ?
RB-repl→ti (node kg ⟪ Black , v1 ⟫ (node kp ⟪ Red , v2 ⟫ t (node key₁ value₁ t₁ t₂)) .leaf) (node kn ⟪ Black , _ ⟫ (node kp ⟪ Red , _ ⟫ _ t₃) (node kg ⟪ Red , _ ⟫ t₄ _)) key value (t-left .kp .kg x x₁ x₂ ti) (rbr-rotate-lr t₃ t₄ kg kp kn lt1 lt2 trb) = ?
RB-repl→ti (node kg ⟪ Black , v1 ⟫ (node kp ⟪ Red , v2 ⟫ t leaf) .(node key₂ _ _ _)) (node kn ⟪ Black , _ ⟫ (node kp ⟪ Red , _ ⟫ _ t₃) (node kg ⟪ Red , _ ⟫ t₄ _)) key value (t-node .kp .kg key₂ x x₁ x₂ x₃ x₄ x₅ ti ti₁) (rbr-rotate-lr t₃ t₄ kg kp kn lt1 lt2 trb) = ?
RB-repl→ti (node kg ⟪ Black , v1 ⟫ (node kp ⟪ Red , v2 ⟫ t (node key₁ value₁ t₁ t₂)) .(node key₂ _ _ _)) (node kn ⟪ Black , _ ⟫ (node kp ⟪ Red , _ ⟫ _ t₃) (node kg ⟪ Red , _ ⟫ t₄ _)) key value (t-node .kp .kg key₂ x x₁ x₂ x₃ x₄ x₅ ti ti₁) (rbr-rotate-lr t₃ t₄ kg kp kn lt1 lt2 trb) = ?
RB-repl→ti .(node kg ⟪ Black , _ ⟫ _ (node kp ⟪ Red , _ ⟫ _ _)) .(node kn ⟪ Black , _ ⟫ (node kg ⟪ Red , _ ⟫ _ t₂) (node kp ⟪ Red , _ ⟫ leaf _)) key value ti (rbr-rotate-rl t₂ leaf kg kp kn lt1 lt2 trb) = ?
RB-repl→ti .(node kg ⟪ Black , _ ⟫ _ (node kp ⟪ Red , _ ⟫ _ _)) .(node kn ⟪ Black , _ ⟫ (node kg ⟪ Red , _ ⟫ _ t₂) (node kp ⟪ Red , _ ⟫ (node key₁ value₁ t₃ t₄) _)) key value ti (rbr-rotate-rl t₂ (node key₁ value₁ t₃ t₄) kg kp kn lt1 lt2 trb) = ?

--
-- if we consider tree invariant, this may be much simpler and faster
--
stackToPG : {n : Level} {A : Set n} → {key : ℕ } → (tree orig : bt A )
           →  (stack : List (bt A)) → stackInvariant key tree orig stack
           → ( stack ≡ orig ∷ [] ) ∨ ( stack ≡ tree ∷ orig ∷ [] ) ∨ PG A tree stack
stackToPG {n} {A} {key} tree .tree .(tree ∷ []) s-nil = case1 refl
stackToPG {n} {A} {key} tree .(node _ _ _ tree) .(tree ∷ node _ _ _ tree ∷ []) (s-right _ _ _ x s-nil) = case2 (case1 refl)
stackToPG {n} {A} {key} tree .(node k2 v2 t5 (node k1 v1 t2 tree)) (tree ∷ node _ _ _ tree ∷ .(node k2 v2 t5 (node k1 v1 t2 tree) ∷ [])) (s-right tree (node k2 v2 t5 (node k1 v1 t2 tree)) t2 {k1} {v1} x (s-right (node k1 v1 t2 tree) (node k2 v2 t5 (node k1 v1 t2 tree)) t5 {k2} {v2} x₁ s-nil)) = case2 (case2
    record {  parent = node k1 v1 t2 tree ;  grand = _ ; pg = s2-1s2p  refl refl  ; rest = _ ; stack=gp = refl } )
stackToPG {n} {A} {key} tree orig (tree ∷ node _ _ _ tree ∷ .(node k2 v2 t5 (node k1 v1 t2 tree) ∷ _)) (s-right tree orig t2 {k1} {v1} x (s-right (node k1 v1 t2 tree) orig t5 {k2} {v2} x₁ (s-right _ _ _ x₂ si))) = case2 (case2
    record {  parent = node k1 v1 t2 tree ;  grand = _ ; pg = s2-1s2p  refl refl  ; rest = _ ; stack=gp = refl } )
stackToPG {n} {A} {key} tree orig (tree ∷ node _ _ _ tree ∷ .(node k2 v2 t5 (node k1 v1 t2 tree) ∷ _)) (s-right tree orig t2 {k1} {v1} x (s-right (node k1 v1 t2 tree) orig t5 {k2} {v2} x₁ (s-left _ _ _ x₂ si))) = case2 (case2
    record {  parent = node k1 v1 t2 tree ;  grand = _ ; pg = s2-1s2p  refl refl  ; rest = _ ; stack=gp = refl } )
stackToPG {n} {A} {key} tree .(node k2 v2 (node k1 v1 t1 tree) t2) .(tree ∷ node k1 v1 t1 tree ∷ node k2 v2 (node k1 v1 t1 tree) t2 ∷ []) (s-right _ _ t1 {k1} {v1} x (s-left _ _ t2 {k2} {v2} x₁ s-nil)) = case2 (case2
    record {  parent = node k1 v1 t1 tree ;  grand = _ ; pg = s2-1sp2 refl refl ; rest = _ ; stack=gp = refl } )
stackToPG {n} {A} {key} tree orig .(tree ∷ node k1 v1 t1 tree ∷ node k2 v2 (node k1 v1 t1 tree) t2 ∷ _) (s-right _ _ t1 {k1} {v1} x (s-left _ _ t2 {k2} {v2} x₁ (s-right _ _ _ x₂ si))) = case2 (case2
    record {  parent = node k1 v1 t1 tree ;  grand = _ ; pg = s2-1sp2 refl refl ; rest = _ ; stack=gp = refl } )
stackToPG {n} {A} {key} tree orig .(tree ∷ node k1 v1 t1 tree ∷ node k2 v2 (node k1 v1 t1 tree) t2 ∷ _) (s-right _ _ t1 {k1} {v1} x (s-left _ _ t2 {k2} {v2} x₁ (s-left _ _ _ x₂ si))) = case2 (case2
    record {  parent = node k1 v1 t1 tree ;  grand = _ ; pg = s2-1sp2 refl refl ; rest = _ ; stack=gp = refl } )
stackToPG {n} {A} {key} tree .(node _ _ tree _) .(tree ∷ node _ _ tree _ ∷ []) (s-left _ _ t1 {k1} {v1} x s-nil) = case2 (case1 refl)
stackToPG {n} {A} {key} tree .(node _ _ _ (node k1 v1 tree t1)) .(tree ∷ node k1 v1 tree t1 ∷ node _ _ _ (node k1 v1 tree t1) ∷ []) (s-left _ _ t1 {k1} {v1} x (s-right _ _ _ x₁ s-nil)) = case2 (case2
    record {  parent = node k1 v1 tree t1 ;  grand = _ ; pg =  s2-s12p refl refl ; rest = _ ; stack=gp = refl } )
stackToPG {n} {A} {key} tree orig .(tree ∷ node k1 v1 tree t1 ∷ node _ _ _ (node k1 v1 tree t1) ∷ _) (s-left _ _ t1 {k1} {v1} x (s-right _ _ _ x₁ (s-right _ _ _ x₂ si))) = case2 (case2
    record {  parent = node k1 v1 tree t1 ;  grand = _ ; pg =  s2-s12p refl refl ; rest = _ ; stack=gp = refl } )
stackToPG {n} {A} {key} tree orig .(tree ∷ node k1 v1 tree t1 ∷ node _ _ _ (node k1 v1 tree t1) ∷ _) (s-left _ _ t1 {k1} {v1} x (s-right _ _ _ x₁ (s-left _ _ _ x₂ si))) = case2 (case2
    record {  parent = node k1 v1 tree t1 ;  grand = _ ; pg =  s2-s12p refl refl ; rest = _ ; stack=gp = refl } )
stackToPG {n} {A} {key} tree .(node _ _ (node k1 v1 tree t1) _) .(tree ∷ node k1 v1 tree t1 ∷ node _ _ (node k1 v1 tree t1) _ ∷ []) (s-left _ _ t1 {k1} {v1} x (s-left _ _ _ x₁ s-nil)) = case2 (case2
    record {  parent = node k1 v1 tree t1 ;  grand = _ ; pg =  s2-s1p2 refl refl ; rest = _ ; stack=gp = refl } )
stackToPG {n} {A} {key} tree orig .(tree ∷ node k1 v1 tree t1 ∷ node _ _ (node k1 v1 tree t1) _ ∷ _) (s-left _ _ t1 {k1} {v1} x (s-left _ _ _ x₁ (s-right _ _ _ x₂ si))) = case2 (case2
    record {  parent = node k1 v1 tree t1 ;  grand = _ ; pg =  s2-s1p2 refl refl ; rest = _ ; stack=gp = refl } )
stackToPG {n} {A} {key} tree orig .(tree ∷ node k1 v1 tree t1 ∷ node _ _ (node k1 v1 tree t1) _ ∷ _) (s-left _ _ t1 {k1} {v1} x (s-left _ _ _ x₁ (s-left _ _ _ x₂ si))) = case2 (case2
    record {  parent = node k1 v1 tree t1 ;  grand = _ ; pg =  s2-s1p2 refl refl ; rest = _ ; stack=gp = refl } )

stackCase1 : {n : Level} {A : Set n} → {key : ℕ } → {tree orig : bt A }
           →  {stack : List (bt A)} → stackInvariant key tree orig stack
           →  stack ≡ orig ∷ [] → tree ≡ orig
stackCase1 s-nil refl = refl

pg-prop-1 : {n : Level} (A : Set n) → (tree orig : bt A )
           →  (stack : List (bt A)) → (pg : PG A tree stack)
           → (¬  PG.grand pg ≡ leaf ) ∧  (¬  PG.parent pg ≡ leaf)
pg-prop-1 {_} A tree orig stack pg with PG.pg pg
... | s2-s1p2 refl refl = ⟪ (λ () ) , ( λ () ) ⟫
... | s2-1sp2 refl refl = ⟪ (λ () ) , ( λ () ) ⟫
... | s2-s12p refl refl = ⟪ (λ () ) , ( λ () ) ⟫
... | s2-1s2p refl refl = ⟪ (λ () ) , ( λ () ) ⟫

-- PGtoRBinvariant : {n : Level} {A : Set n} → {key d0 ds dp dg : ℕ } → (tree orig : bt (Color ∧ A) )
--            →  RBtreeInvariant orig
--            →  (stack : List (bt (Color ∧ A)))  → (pg : PG (Color ∧ A) tree stack )
--            →  RBtreeInvariant tree ∧  RBtreeInvariant (PG.parent pg) ∧  RBtreeInvariant (PG.grand pg)
-- PGtoRBinvariant = {!!}

RBI-child-replaced : {n : Level} {A : Set n} (tr : bt (Color ∧ A)) (key : ℕ) →  RBtreeInvariant tr → RBtreeInvariant (child-replaced key tr)
RBI-child-replaced {n} {A} leaf key rbi = rbi
RBI-child-replaced {n} {A} (node key₁ value tr tr₁) key rbi with <-cmp key key₁
... | tri< a ¬b ¬c = RBtreeLeftDown _ _ rbi
... | tri≈ ¬a b ¬c = rbi
... | tri> ¬a ¬b c = RBtreeRightDown _ _ rbi

-- this is too complacted to extend all arguments at once
--
-- RBTtoRBI  : {n : Level} {A : Set n}  → (tree repl : bt (Color ∧ A)) → (key : ℕ) → (value : A) → RBtreeInvariant tree
--      → replacedRBTree key value tree repl → RBtreeInvariant repl
-- RBTtoRBI {_} {A} tree repl key value rbi rlt = ?
--
-- create RBT invariant after findRBT, continue to replaceRBT
--
replaceRBTNode : {n m : Level} {A : Set n } {t : Set m }
 → (key : ℕ) (value : A)
 → (tree0 : bt (Color ∧ A))
 → RBtreeInvariant tree0
 → (tree1 : bt (Color ∧ A))
 → (stack : List (bt (Color ∧ A)))
 → RBtreeInvariant tree1 ∧ stackInvariant key tree1 tree0 stack
 → (exit : (r : RBI key value tree0 tree1 stack ) → (tree1 ≡ leaf ) ∨ ( node-key tree1 ≡ just key )) → t
replaceRBTNode = ?

--
-- RBT is blanced with the stack, simply rebuild tree without rototation
--
rebuildRBT : {n m : Level} {A : Set n} {t : Set m}
     → (key : ℕ) → (value : A)
     → (orig repl : bt (Color ∧ A))
     → (stack : List (bt (Color ∧ A)))
     → (r : RBI key value orig repl stack )
     → black-depth repl  ≡ black-depth (child-replaced key (RBI.tree r))
     → (next : (repl1 : (bt (Color ∧ A))) →  (stack1 : List (bt (Color ∧ A)))
        → (r : RBI key value orig repl1 stack1 )
        → length stack1 < length stack  → t )
     → (exit : (repl : bt (Color ∧ A) ) → (stack1 : List (bt (Color ∧ A)))
        →  stack1 ≡ (orig ∷ [])
        →  RBI key value orig repl stack1
        → t ) → t
rebuildRBT = ?

insertCase5 : {n m : Level} {A : Set n} {t : Set m}
     → (key : ℕ) → (value : A)
     → (orig tree : bt (Color ∧ A))
     → (stack : List (bt (Color ∧ A)))
     → (r : RBI key value orig tree stack )
     → (pg : PG (Color ∧ A) tree stack)
     → color (PG.uncle pg) ≡ Black → color (PG.parent pg) ≡ Red
     → (next : (tree1 : (bt (Color ∧ A))) →  (stack1 : List (bt (Color ∧ A)))
        → (r : RBI key value orig tree1 stack1 )
        → length stack1 < length stack  → t ) → t
insertCase5 {n} {m} {A} {t} key value orig tree stack r pg cu=b cp=r next = insertCase51 tree (PG.grand pg) refl refl where
    -- check inner repl case
    --     node-key parent < node-key repl < node-key grand  → rotateLeft  parent    then insertCase6
    --     node-key grand  < node-key repl < node-key parent → rotateRight parent    then insertCase6
    --     else insertCase6
    insertCase51 : (tree1 grand : bt (Color ∧ A)) → tree1 ≡ tree → grand ≡ PG.grand pg → t
    insertCase51 leaf grand teq geq = next ? ? ? ?
    insertCase51 (node kr vr rleft rright) leaf teq geq = ?    -- can't happen
    insertCase51 (node kr vr rleft rright) (node kg vg grand grand₁) teq geq with <-cmp kr kg
    ... | tri< a ¬b ¬c = insertCase511 (PG.parent pg) refl where
          insertCase511 : (parent : bt (Color ∧ A)) → parent ≡ PG.parent pg → t
          insertCase511 leaf peq = ⊥-elim (proj2 (pg-prop-1 _ tree orig stack pg) (sym peq) )
          insertCase511 (node key₂ ⟪ co , value ⟫ n1 n2) peq with <-cmp key key₂
          ... | tri< a ¬b ¬c = next ? ? ? ?
          ... | tri≈ ¬a b ¬c = ? -- can't happen
          ... | tri> ¬a ¬b c = next ? ? ? ? --- rotareRight → insertCase6 key value orig ? stack ? pg next exit
    ... | tri≈ ¬a b ¬c = ? -- can't happen
    ... | tri> ¬a ¬b c = ? where
          insertCase511 : (parent : bt (Color ∧ A)) → parent ≡ PG.parent pg → t
          insertCase511 leaf peq = ⊥-elim (proj2 (pg-prop-1 _ tree orig stack pg) (sym peq) )
          insertCase511 (node key₂ ⟪ co , value ⟫ n1 n2) peq with <-cmp key key₂
          ... | tri< a ¬b ¬c = next ? ? ? ? --- rotareLeft → insertCase6 key value orig ? stack ? pg next exit
          ... | tri≈ ¬a b ¬c = ? -- can't happen
          ... | tri> ¬a ¬b c = next ? ? ? ?

--
-- replaced node increase blackdepth, so we need tree rotate
--
-- case2 tree is Red
--
--   go upward until
--
--   if root
--       insert top
--   if unkle is leaf or Black
--       go insertCase5/6
--
--   make color tree ≡ Black , color unkle ≡ Black, color grand ≡ Red
--   loop with grand as repl
--
-- case5/case6 rotation
--
--   rotate and rebuild replaceTree and rb-invariant


replaceRBP : {n m : Level} {A : Set n} {t : Set m}
     → (key : ℕ) → (value : A)
     → (orig repl : bt (Color ∧ A))
     → (stack : List (bt (Color ∧ A)))
     → (r : RBI key value orig repl stack )
     → (next : (repl1 : (bt (Color ∧ A))) →  (stack1 : List (bt (Color ∧ A)))
        → (r : RBI key value orig repl1 stack1 )
        → length stack1 < length stack  → t )
     → (exit : (repl : bt (Color ∧ A) ) → (stack1 : List (bt (Color ∧ A)))
        →  stack1 ≡ (orig ∷ [])
        →  RBI key value orig repl stack1
        → t ) → t
replaceRBP {n} {m} {A} {t} key value orig repl stack r next exit with RBI.state r
... | rebuild bdepth-eq = rebuildRBT key value orig repl stack r bdepth-eq next exit
... | rotate repl-red pbdeth< with stackToPG (RBI.tree r) orig stack (RBI.si r)
... | case1 eq  = exit repl stack eq r     -- no stack, replace top node
... | case2 (case1 eq) = insertCase12 orig refl (RBI.si r)  where
    --
    -- we have no grand parent
    -- eq : stack₁ ≡ RBI.tree r ∷ orig ∷ []
    -- change parent color ≡ Black and exit
    --
    -- one level stack, orig is parent of repl
    rb01 : stackInvariant key (RBI.tree r) orig stack
    rb01 = RBI.si r
    insertCase12 :  (tr0 : bt (Color ∧ A)) → tr0 ≡ orig
       → stackInvariant key (RBI.tree r) orig stack
       → t
    insertCase12 leaf eq1 si = ⊥-elim (rb04 eq eq1 si) where -- can't happen
       rb04 : {stack : List ( bt ( Color ∧ A))} → stack ≡ RBI.tree r ∷ orig ∷ [] → leaf ≡ orig → stackInvariant key (RBI.tree r) orig stack →   ⊥
       rb04  refl refl (s-right tree leaf tree₁ x si) = si-property2 _ (s-right tree leaf tree₁ x si) refl
       rb04  refl refl (s-left tree₁ leaf tree x si) = si-property2 _  (s-left tree₁ leaf tree x si) refl
    insertCase12  tr0@(node key₁ value₁ left right) refl si with <-cmp key key₁
    ... | tri< a ¬b ¬c = {!!} where
       rb04 : stackInvariant key (RBI.tree r) orig stack → stack ≡ RBI.tree r ∷ orig ∷ [] → tr0 ≡ orig → left ≡ RBI.tree r
       rb04 (s-left tree₁ .(node key₁ value₁ left right) tree {key₂} x s-nil) refl refl = refl
       rb04 (s-right tree .(node key₁ _ tree₁ tree) tree₁ x s-nil) refl refl with si-property1 si
       ... | refl = ⊥-elim ( nat-<> x a  )
    ... | tri≈ ¬a b ¬c = {!!} -- can't happen
    ... | tri> ¬a ¬b c = insertCase13 value₁ refl pbdeth< where
       rb04 : stackInvariant key (RBI.tree r) orig stack → stack ≡ RBI.tree r ∷ orig ∷ [] → tr0 ≡ orig → right ≡ RBI.tree r
       rb04 (s-right tree .(node key₁ _ tree₁ tree) tree₁ x s-nil) refl refl = refl
       rb04 (s-left tree₁ .(node key₁ value₁ left right) tree {key₂} x si) refl refl with si-property1 si
       ... | refl = ⊥-elim ( nat-<> x c  )
       --
       --  RBI key value (node key₁ ⟪ Black , value₄ ⟫ left right) repl stack
       --
       insertCase13 : (v : Color ∧ A ) → v ≡ value₁ → black-depth repl ≡ black-depth (child-replaced key (RBI.tree r)) → t
       insertCase13 ⟪ cl , value₄ ⟫ refl beq with <-cmp key key₁ | child-replaced key (node key₁ ⟪ cl , value₄ ⟫ left right) in creq
       ... | tri< a ¬b ¬c | cr = ⊥-elim (¬c c)
       ... | tri≈ ¬a b ¬c | cr = ⊥-elim (¬c c)
       ... | tri> ¬a ¬b c | cr = exit (node key₁ ⟪ Black , value₄ ⟫ left repl) (orig ∷ [])  refl record {
         tree = orig
         ; origti = RBI.origti r
         ; origrb = RBI.origrb r
         ; treerb = RBI.origrb r
         ; replrb = ?
         ; si = s-nil
         ; rotated = ?
         ; state = rebuild ?
         } where
           rb09 : {n : Level} {A : Set n} →  {key key1 key2 : ℕ}  {value value1  : A} {t1 t2  : bt (Color ∧ A)}
            → RBtreeInvariant (node key ⟪ Red , value ⟫ leaf (node key1 ⟪ Black , value1 ⟫ t1 t2))
            → key < key1
           rb09 (rb-right-red x x0 x2) = x
           -- rb05 should more general
           tkey : {n : Level} {A : Set n } → (rbt : bt (Color ∧ A)) → ℕ
           tkey (node key value t t2) = key
           tkey leaf = {!!} -- key is none
... | case2 (case2 pg) with PG.uncle pg in uneq
... | leaf = ? -- insertCase5
... | node key₁ ⟪ Black , value₁ ⟫ t₁ t₂ = ? -- insertCase5
... | node key₁ ⟪ Red , value₁ ⟫ t₁ t₂ with PG.pg pg
... | s2-s1p2 {kp} {kg} {vp} {vg} {n1} {n2} x x₁ = next (to-red (node kg vg (to-black (node kp vp repl n1)) (to-black (PG.uncle pg)))) (PG.rest pg)
    record {
         tree = PG.grand pg
         ; origti = RBI.origti r
         ; origrb = RBI.origrb r
         ; treerb = ?
         ; replrb = ?
         ; si = ?
         ; rotated = ?
         ; state = rotate refl ?
     }  ?
... | s2-1sp2 {kp} {kg} {vp} {vg} {n1} {n2} x x₁ = ?
... | s2-s12p {kp} {kg} {vp} {vg} {n1} {n2} x x₁ = ?
... | s2-1s2p {kp} {kg} {vp} {vg} {n1} {n2} x x₁ = ?