#!/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 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)
	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')

	args = vars(parser.parse_args())

	# Get input
	if args["input"] is not None:
		try:
			with open(args["input"], "r") as file:
				string = file.read()
		except OSError as exception:
			print("Error: file not found: " + str(exception))
			return -1
		is_file = True
	elif args["string"] is not None:
		string = args["string"]
		is_file = False
	else:
		print("Error: You need an input string or file")
		return -1

	# Get output
	if args["output"] is not None:
		try:
			output_file = open(args["output"], "w")
		except OSError as exception:
			print("Error: file not found: " + str(exception))
			return -1
		use_output_file = True
	else:
		use_output_file = False

	# Compile regex
	try:
		ex = compile_regex(args["regex"])
	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

	# Search or replace
	if args["replace"] is not None:
		replace_string = replace(ex, string, args["replace"], args["print_nb_match"])
		if use_output_file:
			output_file.write(replace_string)
		else:
			print(replace_string)
	else:
		search(ex, string, is_file)
	return 0

def compile_regex(ex):
	"""
	Compile regex
		:param ex: Regular expression
	"""
	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
	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)
			print(" - Found \"" + match.group(0) + "\" at line " + str(num_line) + " [" + str(begin_pos) +
			      ":" + str(end_pos) + "]")
		else:
			print(" - Found \"" + match.group(0) + "\" at [" + str(match.start(0) + 1) +
			      ":" + str(match.end(0)) + "]")
	print("Number of match: " + str(nb_match))


def replace(ex, string, replace_string, print_nb):
	"""
	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)
	if print_nb:
		print("Number of match: " + str(res[1]))
	return res[0]

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


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