package jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.impl;

import java.nio.ByteBuffer;
import java.util.Iterator;
import fj.P2;
import fj.data.List;
import fj.data.TreeMap;
import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.core.Node;
import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.trasnformer.EditableChildren;
import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.trasnformer.EditableNode;
import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util.DefaultEither;
import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util.Either;
import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util.Error;
import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util.IterableWrapper;

public class DefaultChildren implements EditableChildren<DefaultNode>
{
	private final List<DefaultNode> children;
	private final TreeMap<String,ByteBuffer> attrs;
	
	public DefaultChildren(List<DefaultNode> _children,TreeMap<String,ByteBuffer> _attrs)
	{
		children = _children;
		attrs = _attrs;
	}
	
	public Either<Error,DefaultNode> replaceNode(DefaultNode _target,int _pos)
	{
		if(check(_pos)){
			return DefaultEither.newA(OUT_OF_RANGE);
		}
		
		P2<List<DefaultNode>,List<DefaultNode>> split = children.splitAt(_pos);
		List<DefaultNode> head = split._1();
		List<DefaultNode> tail = split._2().tail().cons(_target);
		List<DefaultNode> newList = head.append(tail);
		
		DefaultNode newNode = new DefaultNode(newList,attrs);
		return DefaultEither.newB(newNode);
	}
	
	@Override
	public int size()
	{
		return children.length();
	}
	
	@Override
	public Either<Error,DefaultNode> addNewChildAt(int _pos)
	{
		if(!check(_pos)){
			return DefaultEither.newA(OUT_OF_RANGE);
		}
		
		P2<List<DefaultNode>,List<DefaultNode>> split = children.splitAt(_pos);
		List<DefaultNode> newChildren = split._1().snoc(new DefaultNode()).append(split._2());
		DefaultNode newNode = new DefaultNode(newChildren,attrs);
		
		return DefaultEither.newB(newNode);
	}
	
	@Override
	public Either<Error,DefaultNode> deleteChildAt(int _pos)
	{
		if(!check(_pos)){
			return DefaultEither.newA(OUT_OF_RANGE);
		}
		
		P2<List<DefaultNode>,List<DefaultNode>> split = children.splitAt(_pos);
		List<DefaultNode> newChildren = split._1().init().append(split._2());
		
		DefaultNode newNode = new DefaultNode(newChildren,attrs);
		
		return DefaultEither.newB(newNode);
	}
	
	public boolean check(int _pos)
	{
		if(children.length() < _pos){
			return false;
		}
		
		return true;
	}

	@Override
	public Iterator<Node> iterator()
	{
		return (new IterableWrapper<Node>(children)).iterator();
	}
}