#!/usr/bin/env python3.0


import sys
import re
import getopt

reserved_words = [ "if", "for", "switch", "return", "while", "else", ]

PATTERN =  "([a-zA-Z_][\w\s]*\**)\s([a-zA-Z_]\w*)\s*\(([^{/;]*)\)\s*\{"
# TODO: 関数パラメータ内にコメントがあると正しく動かない!
# TODO: int * const * とか大丈夫?
PROG = re.compile(PATTERN, re.S)

omit_static=False
add_extern=""

def truncate_comments(data):
	pass

def check_reserved_word(decl):
	""" return true if decl's type and name is not reserved word. """

	if decl["name"] in reserved_words or decl["type"] in reserved_words:
		return False
	return True

def read_decls(file):
	declarators = []

	# open the file and read all lines into a string.
	try:
		fo = open(file, 'r')
		lines = fo.readlines()
		data = "".join(lines)
		truncate_comments(data)
	except IOError:
		print("cannot read file %s" % file)
		return None

	# find all matched strings.
	# moiter is iterator of MatchObject.
	moiter = PROG.finditer(data)
	for mo in moiter:
		tmp = { "type": mo.group(1),
				"name": mo.group(2),
				"parms": mo.group(3),
				"offset": mo.start() }
		if check_reserved_word(tmp):
			declarators.append(tmp)

	return declarators

def debug_print(decl):
	for (key,value) in list(decl.items()):
		if isinstance(value, str):
			decl[key] = value.replace("\n"," ").replace("\t"," ")

	print("Type:\t{0:s}".format(decl["type"]))
	print("Name:\t{0:s}".format(decl["name"]))
	print("Params:\t{0:s}".format(decl["parms"]))
	print("offset:\t{0:d}".format(decl["offset"]))
	print("")

def format_print(decl, file):
	for (key,value) in list(decl.items()):
		if isinstance(value, str):
			decl[key] = value.replace("\n"," ").replace("\t"," ")

	print("/* defined in file {0:s} at offset {1:d} */".format(file,decl["offset"]))
	print("{3:s}{0:s} {1:s} ({2:s});".format(decl["type"],decl["name"],decl["parms"], add_extern))
	print("")

def getoptions():
	global omit_static, add_extern

	try:
		opts, args = getopt.getopt(sys.argv[1:], 'se', [ 'omit-static', 'add-extern' ])
	except getopt.GetoptError as err:
		print(err)
		usage()
		sys.exit(2)

	for opt,a in opts:
		if opt in ("-s", "--omit-static"):
			omit_static=True
		elif opt in ("-e", "--add-extern"):
			add_extern="extern "
		else:
			print("unhandled option {0}".format(opt))
			usage()
	
	return args

def usage():
	print( """\
Usage: {0:s} OPION... [FILE]...
OPTIONS:
	-s, --omit-static	omit static functions
	-e, --add-extern	add extern to all function declarations
	""".format(sys.argv[0]))

def main():

	# option handling.
	args = getoptions()

	for file in args:
		# read function declaration from each file.
		decls = read_decls(file)
		if decls==None or len(decls)==0:
			# no function found.
			print("{0} have no function definition!".format(file))
			continue

		for decl in decls:
			if omit_static and 0 <= decl["type"].find("static"):
				# static function is ignored.
				continue
			#debug_print(decl)
			format_print(decl, file)

main()