#!/usr/bin/env python3
# -*- coding: utf-8 -*-
#
#  SSnR.py
#
#  Copyright 2017 Rémi BERTHO <remi.bertho@dalan.fr>
#
#  This program is free software; you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation; either version 3 of the License, or
#  (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
#  You should have received a copy of the GNU General Public License
#  along with this program; if not, write to the Free Software
#  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
#  MA 02110-1301, USA.
#
#

import sys
import os.path
from os import walk
import argparse
import regex

def main():
	"""
	Main function
	"""
	parser = argparse.ArgumentParser(description='Search and replace tool', prog='SSnR')
	parser.add_argument('-e', '--regex', help='Regex', required=True)
	parser.add_argument('-s', '--string', help='String', required=False)
	parser.add_argument('-i', '--input', help='Input file', required=False, nargs='+')
	parser.add_argument('-p', '--regex_input', help='Regex input file', required=False)
	parser.add_argument('-l', '--regex_output', help='Regex output file', required=False)
	parser.add_argument('-o', '--output', help='Output file', required=False)
	parser.add_argument('-r', '--replace', help='Replace', required=False)
	parser.add_argument('-m', '--print_nb_match', help='Print the number of match in replace',
	                    required=False, action='store_true')
	parser.add_argument('-c', '--ignore_case', help='Ignore the case',
	                    required=False, action='store_true')
	parser.add_argument('-u', '--recursive', help='Use the regex input recrusivly in the folders',
	                    required=False, action='store_true')

	args = vars(parser.parse_args())

	# Compile regex
	try:
		ex = compile_regex(args["regex"], args["ignore_case"])
	except SyntaxError as exception:
		print("Error when compiling regex: " + str(exception))
		return -1
	except regex.error as exception:
		print("Error when compiling regex: " + exception.msg)
		return -1

	# Get input
	filenames = []
	if args["regex_input"] is not None:
		try:
			input_ex = compile_regex(args["regex_input"], False)
		except SyntaxError as exception:
			print("Error when compiling input regex: " + str(exception))
			return -1
		except regex.error as exception:
			print("Error when compiling input regex: " + exception.msg)
			return -1
		for (dirpath, dirnames, dir_filenames) in walk("."):
			for filename in dir_filenames:
				if input_ex.fullmatch(filename):
					filenames.append(os.path.join(dirpath, filename))
					is_file = True
			if not args["recursive"]:
				break
		if not filenames:
			print("Error: no input file")
			return -1
	elif args["input"] is not None:
		for input_file in args["input"]:
			if os.path.isfile(input_file):
				is_file = True
				filenames.append(input_file)
			else:
				print("Error: file not found: " + str(args["input"]))
		if not filenames:
			print("Error: no input file")
			return -1
	elif args["string"] is not None:
		string = args["string"]
		is_file = False
	else:
		string = sys.stdin.read()
		is_file = False

	# Get output
	output_files = []
	if args["regex_output"] is not None:
		if input_ex is None:
			print("Error: You need a regex input file to use a regex output file")
			return -1
		for input_filename in filenames:
			try:
				output_file = open((input_ex.subn(args["regex_output"], input_filename))[0], "w",
				                   encoding="utf8")
				output_files.append(output_file)
			except OSError as exception:
				print("Error: file not found: " + str(exception))
				return -1
		use_output_file = True
	elif args["output"] is not None:
		try:
			output_file = open(args["output"], "w", encoding="utf8")
			output_files.append(output_file)
		except OSError as exception:
			print("Error: file not found: " + str(exception))
			return -1
		use_output_file = True
	else:
		use_output_file = False

	# Search or replace
	file_index = 0
	if is_file:
		for filename in filenames:
			try:
				with open(filename, "r", encoding="utf8") as file:
					string = file.read()
			except OSError as exception:
				print("Error: file \"" + filename + "\" not found: " + str(exception))
				continue
			except UnicodeDecodeError as exception:
				print("Error: the file \"" + filename + "\" is not UTF-8 encoded: " + str(exception))
				continue

			if args["replace"] is not None:
				replace_string, nb_replace = replace(ex, string, args["replace"])
				if use_output_file:
					output_files[file_index].write(replace_string)
					print("File: " + filename)
					print(" - Number of replace: " + str(nb_replace))
					if len(output_files) > 1:
						file_index += 1
				else:
					print(replace_string)
					if args["print_nb_match"]:
						print("File: " + filename)
						print(" - Number of replace: " + str(nb_replace))
			else:
				nb_match, str_found = search(ex, string, is_file)
				if nb_match > 0:
					print("File: " + filename)
					print(" - Number of match: " + str(nb_match))
					print(str_found)
	else:
		if args["replace"] is not None:
			replace_string, nb_replace = replace(ex, string, args["replace"])
			if use_output_file:
				print("Number of replace: " + str(nb_replace))
				output_files[0].write(replace_string)
			else:
				print(replace_string)
				if args["print_nb_match"]:
					print("Number of replace: " + str(nb_replace))
		else:
			nb_match, str_found = search(ex, string, is_file)
			print("Number of match: " + str(nb_match))
			print(str_found)
	return 0

def compile_regex(ex, ignore_case):
	"""
	Compile regex
		:param ex: Regular expression
	"""
	if ignore_case:
		regex_compile = regex.compile(ex, regex.MULTILINE | regex.IGNORECASE)
	else:
		regex_compile = regex.compile(ex, regex.MULTILINE)

	if regex_compile is None:
		raise SyntaxError('Error in the regex')
	else:
		return regex_compile

def search(ex, string, is_file):
	"""
	Search in a string
		:param ex: Regular expression
		:param string: A string
	"""
	if is_file:
		new_lines = get_line_pos(string)

	ite = ex.finditer(string)
	nb_match = 0
	str_found = ""
	for match in ite:
		nb_match += 1
		if is_file:
			num_line, begin_pos, end_pos = find_line(match.start(0), match.end(0), new_lines)
			str_found += " - Found \"%s\" at line %d [%d:%d]\n" % (match.group(0), num_line, begin_pos, end_pos)
		else:
			str_found += " - Found \"%s\" at [%d:%d]\n" % (match.group(0), match.start(0), match.end(0))
	return nb_match, str_found


def replace(ex, string, replace_string):
	"""
	Replace in a string
		:param ex: Regular expression
		:param string: A string
		:param print_nb: Print the number of match
	"""
	res = ex.subn(replace_string, string)
	return res[0], res[1]

def get_line_pos(string):
	"""
	Get new lines postion in a string
		:param string: a string
	"""
	ex =	regex.compile("^", regex.MULTILINE)
	ite = ex.finditer(string)
	new_lines = []
	for match in ite:
		new_lines.append(match.start(0))
	return new_lines

def find_line(begin_pos, end_pos, new_lines):
	"""
	Find the line number and the position in the line
		:param pos: the position to find the line
		:param new_lines: then new lines
	"""
	num_line = 0
	old_pos_line = 0
	for pos_line in new_lines:
		if pos_line > begin_pos:
			return num_line, begin_pos - old_pos_line + 1, end_pos - old_pos_line
		num_line += 1
		old_pos_line = pos_line
	return num_line, begin_pos - old_pos_line + 1, end_pos - old_pos_line


if __name__ == '__main__':
	sys.exit(main())