# Copyright (C) 2010 David Barnett <davidbarnett2@gmail.com>
# Copyright (C) 2010, 2011  Roman Zimbelmann <romanz@lavabit.com>
# This software is distributed under the terms of the GNU GPL version 3.

"""
A library to help to convert ANSI codes to curses instructions.
"""

from ranger.gui import color
import re

ansi_re = re.compile('(\x1b' + r'\[\d*(?:;\d+)*?[a-zA-Z])')
reset = '\x1b[0m'

def split_ansi_from_text(ansi_text):
	return ansi_re.split(ansi_text)

def text_with_fg_bg_attr(ansi_text):
	for chunk in split_ansi_from_text(ansi_text):
		if chunk and chunk[0] == '\x1b':
			if chunk[-1] != 'm':
				continue
			match = re.match(r'^.\[(.*).$', chunk)
			attr_args = match.group(1)
			fg, bg, attr = -1, -1, 0

			# Convert arguments to attributes/colors
			for arg in attr_args.split(';'):
				try:
					n = int(arg)
				except:
					if arg == '':
						n = 0
					else:
						continue
				if n == 0:
					fg, bg, attr = -1, -1, 0
				elif n == 1:
					attr |= color.bold
				elif n == 4:
					attr |= color.underline
				elif n == 5:
					attr |= color.blink
				elif n == 7:
					attr |= color.reverse
				elif n == 8:
					attr |= color.invisible
				elif n >= 30 and n <= 37:
					fg = n - 30
				elif n == 39:
					fg = -1
				elif n >= 40 and n <= 47:
					bg = n - 40
				elif n == 49:
					bg = -1
			yield (fg, bg, attr)
		else:
			yield chunk

def char_len(ansi_text):
	"""
	Count the number of visible characters.

	>>> char_len("\x1b[0;30;40mX\x1b[0m")
	1
	>>> char_len("\x1b[0;30;40mXY\x1b[0m")
	2
	>>> char_len("\x1b[0;30;40mX\x1b[0mY")
	2
	>>> char_len("hello")
	5
	>>> char_len("")
	0
	"""
	return len(ansi_re.sub('', ansi_text))

def char_slice(ansi_text, start, length):
	"""
	Slices a string with respect to ansi code sequences

	Acts as if the ansi codes aren't there, slices the text from the
	given start point to the given length and adds the codes back in.

	>>> test_string = "abcde\x1b[30mfoo\x1b[31mbar\x1b[0mnormal"
	>>> split_ansi_from_text(test_string)
	['abcde', '\\x1b[30m', 'foo', '\\x1b[31m', 'bar', '\\x1b[0m', 'normal']
	>>> char_slice(test_string, 1, 3)
	'bcd'
	>>> char_slice(test_string, 5, 6)
	'\\x1b[30mfoo\\x1b[31mbar'
	>>> char_slice(test_string, 0, 8)
	'abcde\\x1b[30mfoo'
	>>> char_slice(test_string, 4, 4)
	'e\\x1b[30mfoo'
	>>> char_slice(test_string, 11, 100)
	'\\x1b[0mnormal'
	>>> char_slice(test_string, 9, 100)
	'\\x1b[31mar\\x1b[0mnormal'
	>>> char_slice(test_string, 9, 4)
	'\\x1b[31mar\\x1b[0mno'
	"""
	chunks = []
	last_color = ""
	pos = old_pos = 0
	for i, chunk in enumerate(split_ansi_from_text(ansi_text)):
		if i % 2 == 1:
			last_color = chunk
			continue

		old_pos = pos
		pos += len(chunk)
		if pos <= start:
			pass # seek
		elif old_pos < start and pos >= start:
			chunks.append(last_color)
			chunks.append(chunk[start-old_pos:start-old_pos+length])
		elif pos > length + start:
			chunks.append(last_color)
			chunks.append(chunk[:start-old_pos+length])
		else:
			chunks.append(last_color)
			chunks.append(chunk)
		if pos - start >= length:
			break
	return ''.join(chunks)

if __name__ == '__main__':
	import doctest
	doctest.testmod()