# Copyright (c) 2018 Daniel Knüttel                                    #
#                                                                      #
# This file is part of mathbot.                                        #
#                                                                      #
# mathbot 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.                                  #
#                                                                      #
# mathbot 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 mathbot.  If not, see <http://www.gnu.org/licenses/>.     #
#                                                                      #

from telegram.ext import RegexHandler
from .rendering import get_png
from .static import static_content

import logging

logger = logging.getLogger(__name__)

def handle_exception_in_get_png(bot, update, exception, text):
	update.message.reply_text("**Error** while processing '__{}__'.\n\nException was: **{}**.".format(text, exception), parse_mode = "Markdown")

def render_math(bot, update):
	text = update.message.text[len("/rmath"):]
	tex = text

	try:
		png = get_png(tex)
	except Exception as e:
		handle_exception_in_get_png(bot, update, e, tex)
		return
	
	update.message.reply_photo(png, caption = "{}".format(text))

def render_math_caption(bot, update):
	text = update.message.text[len("/rcmath"):]

	if( not ("<" in text and ">" in text)):
		update.message.reply_text("**Error**: missing caption seperators: < and >", parse_mode = "Markdown")
		return

	caption = text[text.index("<") + 1:text.index(">")]
	text = text[text.index(">") + 1:]

	tex = text

	try:
		png = get_png(tex)
	except Exception as e:
		handle_exception_in_get_png(bot, update, e, tex)
		return
	
	update.message.reply_photo(png, caption = "{}\n\nLaTeX: {}".format(caption, text))

def substitute_render_math(bot, update):
	text = update.message.text[len("/rsmath"):]
	tex = text.replace("/", "\\")

	try:
		png = get_png(tex)
	except Exception as e:
		handle_exception_in_get_png(bot, update, e, tex)
		return
	
	update.message.reply_photo(png, caption = "{}".format(tex))

def substitute_render_math_caption(bot, update):
	text = update.message.text[len("/rscmath"):]

	if( not ("<" in text and ">" in text)):
		update.message.reply_text("**Error**: missing caption seperators: < and >", parse_mode = "Markdown")
		return

	caption = text[text.index("<") + 1:text.index(">")]
	text = text[text.index(">") + 1:]

	tex = text.replace("/", "\\")

	try:
		png = get_png(tex)
	except Exception as e:
		handle_exception_in_get_png(bot, update, e, tex)
		return
	
	update.message.reply_photo(png, caption = "{}\n\nLaTeX: {}".format(caption, tex))


def help(bot, update):
	update.message.reply_text(static_content.help_text, parse_mode = "Markdown")