# -*- coding: utf-8 -*-
#
# Copyright (c) 2016 by Simmo Saan <simmo.saan@gmail.com>
#
# 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, see <http://www.gnu.org/licenses/>.
#

#
# History:
#
# 2016-06-30, Simmo Saan <simmo.saan@gmail.com>
#   version 0.8: support vulgar fractions and \sqrt
# 2016-06-18, Simmo Saan <simmo.saan@gmail.com>
#   version 0.7: support super-, subscripts and \frac
# 2016-06-17, Simmo Saan <simmo.saan@gmail.com>
#   version 0.6: add subcommands for manual reload/redownload
# 2016-06-15, Simmo Saan <simmo.saan@gmail.com>
#   version 0.5: remove lxml dependency
# 2016-06-15, Simmo Saan <simmo.saan@gmail.com>
#   version 0.4: more options for replacement location fine tuning
# 2016-06-14, Simmo Saan <simmo.saan@gmail.com>
#   version 0.3: options for disabling/enabling replacements by location
# 2016-06-14, Simmo Saan <simmo.saan@gmail.com>
#   version 0.2: automatically load XML from W3 website if not available
# 2016-06-13, Simmo Saan <simmo.saan@gmail.com>
#   version 0.1: initial script
#

"""
Replace LaTeX with unicode representations
"""

from __future__ import print_function

SCRIPT_NAME = "latex_unicode"
SCRIPT_AUTHOR = "Simmo Saan <simmo.saan@gmail.com>"
SCRIPT_VERSION = "0.8"
SCRIPT_LICENSE = "GPL3"
SCRIPT_DESC = "Replace LaTeX with unicode representations"

SCRIPT_REPO = "https://github.com/sim642/latex_unicode"

SCRIPT_COMMAND = SCRIPT_NAME

IMPORT_OK = True

try:
	import weechat
except ImportError:
	print("This script must be run under WeeChat.")
	print("Get WeeChat now at: http://www.weechat.org/")
	IMPORT_OK = False

import os
import xml.etree.ElementTree as ET
import re

SETTINGS = {
	"input": (
		"on",
		"replace LaTeX in input display: off, on",
		True),
	"send": (
		"on",
		"replace LaTeX in input sending: off, on",
		True),
	"buffer": (
		"on",
		"replace LaTeX in buffer: off, on",
		True)
}

SETTINGS_PREFIX = "plugins.var.python.{}.".format(SCRIPT_NAME)

hooks = []

xml_path = None
replacements = []
scripts = {
	u"0": (u"⁰", u"₀"),
	u"1": (u"¹", u"₁"),
	u"2": (u"²", u"₂"),
	u"3": (u"³", u"₃"),
	u"4": (u"⁴", u"₄"),
	u"5": (u"⁵", u"₅"),
	u"6": (u"⁶", u"₆"),
	u"7": (u"⁷", u"₇"),
	u"8": (u"⁸", u"₈"),
	u"9": (u"⁹", u"₉"),

	u"A": (u"ᴬ", None),
	u"B": (u"ᴮ", None),
	u"D": (u"ᴰ", None),
	u"E": (u"ᴱ", None),
	u"G": (u"ᴳ", None),
	u"H": (u"ᴴ", None),
	u"I": (u"ᴵ", None),
	u"J": (u"ᴶ", None),
	u"K": (u"ᴷ", None),
	u"L": (u"ᴸ", None),
	u"M": (u"ᴹ", None),
	u"N": (u"ᴺ", None),
	u"O": (u"ᴼ", None),
	u"P": (u"ᴾ", None),
	u"R": (u"ᴿ", None),
	u"T": (u"ᵀ", None),
	u"U": (u"ᵁ", None),
	u"V": (u"ⱽ", None),
	u"W": (u"ᵂ", None),

	u"a": (u"ᵃ", u"ₐ"),
	u"b": (u"ᵇ", None),
	u"c": (u"ᶜ", None),
	u"d": (u"ᵈ", None),
	u"e": (u"ᵉ", u"ₑ"),
	u"f": (u"ᶠ", None),
	u"g": (u"ᵍ", None),
	u"h": (u"ʰ", u"ₕ"),
	u"i": (u"ⁱ", u"ᵢ"),
	u"j": (u"ʲ", u"ⱼ"),
	u"k": (u"ᵏ", u"ₖ"),
	u"l": (u"ˡ", u"ₗ"),
	u"m": (u"ᵐ", u"ₘ"),
	u"n": (u"ⁿ", u"ₙ"),
	u"o": (u"ᵒ", u"ₒ"),
	u"p": (u"ᵖ", u"ₚ"),
	u"r": (u"ʳ", u"ᵣ"),
	u"s": (u"ˢ", u"ₛ"),
	u"t": (u"ᵗ", u"ₜ"),
	u"u": (u"ᵘ", u"ᵤ"),
	u"v": (u"ᵛ", u"ᵥ"),
	u"w": (u"ʷ", None),
	u"x": (u"ˣ", u"ₓ"),
	u"y": (u"ʸ", None),
	u"z": (u"ᶻ", None),

	u"+": (u"⁺", u"₊"),
	u"-": (u"⁻", u"₋"),
	u"=": (u"⁼", u"₌"),
	u"(": (u"⁽", u"₍"),
	u")": (u"⁾", u"₎"),

	u"β": (u"ᵝ", u"ᵦ"),
	u"γ": (u"ᵞ", u"ᵧ"),
	u"δ": (u"ᵟ", None),
	u"θ": (u"ᶿ", None),
	u"ι": (u"ᶥ", None),
	u"ρ": (None, u"ᵨ"),
	u"φ": (u"ᵠ", u"ᵩ"),
	u"χ": (u"ᵡ", u"ᵪ"),
}
# https://en.wikipedia.org/wiki/Number_Forms
vulgar_fractions = {
	(u"1", u"4"): u"¼",
	(u"1", u"2"): u"½",
	(u"3", u"4"): u"¾",
	(u"1", u"4"): u"¼",
	(u"1", u"7"): u"⅐",
	(u"1", u"9"): u"⅑",
	(u"1", u"10"): u"⅒",
	(u"1", u"3"): u"⅓",
	(u"2", u"3"): u"⅔",
	(u"1", u"5"): u"⅕",
	(u"2", u"5"): u"⅖",
	(u"3", u"5"): u"⅗",
	(u"4", u"5"): u"⅘",
	(u"1", u"6"): u"⅙",
	(u"5", u"6"): u"⅚",
	(u"1", u"8"): u"⅛",
	(u"3", u"8"): u"⅜",
	(u"5", u"8"): u"⅝",
	(u"7", u"8"): u"⅞",
	(u"0", u"3"): u"↉",
}

def log(string):
	"""Log script's message to core buffer."""

	weechat.prnt("", "{}: {}".format(SCRIPT_NAME, string))

def error(string):
	"""Log script's error to core buffer."""

	weechat.prnt("", "{}{}: {}".format(weechat.prefix("error"), SCRIPT_NAME, string))

def setup():
	"""Load replacements from available resource."""

	global xml_path
	xml_path = weechat.string_eval_path_home("%h/latex_unicode.xml", "", "", "")

	if os.path.isfile(xml_path):
		setup_from_file()
	else:
		setup_from_url()

def setup_from_url():
	"""Download replacements and store them in weechat home directory."""

	log("downloading XML...")
	weechat.hook_process_hashtable("url:https://www.w3.org/Math/characters/unicode.xml",
		{
			"file_out": xml_path
		},
		30000, "download_cb", "")

def download_cb(data, command, return_code, out, err):
	"""Load downloaded replacements."""

	log("downloaded XML")
	setup_from_file()
	return weechat.WEECHAT_RC_OK

def setup_from_file():
	"""Load replacements from file in weechat home directory."""

	log("loading XML...")
	global replacements

	root = ET.parse(xml_path)
	for character in root.findall("character"):
		dec = character.get("dec")
		if "-" not in dec: # is not a range of characters
			char = unichr(int(dec))
			
			ams = character.find("AMS")
			if ams is not None:
				replacements.append((ams.text, char))

			latex = character.find("latex")
			if latex is not None:
				latex = latex.text.strip()
				if latex[0] == "\\": # only add \commands
					replacements.append((latex, char))

	replacements = sorted(replacements, key=lambda replacement: len(replacement[0]), reverse=True) # sort by tex string length descendingly

	log("loaded XML")
	hook_modifiers()

def hook_modifiers():
	"""Update modifier hooks to match settings."""

	# remove existing modifier hooks
	global hooks
	for hook in hooks:
		weechat.unhook(hook)
	hooks = []

	# add hooks according to settings

	input_option = weechat.config_get_plugin("input")
	if weechat.config_string_to_boolean(input_option):
		hooks.append(weechat.hook_modifier("input_text_display", "modifier_cb", ""))

	send_option = weechat.config_get_plugin("send")
	if weechat.config_string_to_boolean(send_option):
		hooks.append(weechat.hook_modifier("input_text_for_buffer", "modifier_cb", ""))

	buffer_option = weechat.config_get_plugin("buffer")
	if weechat.config_string_to_boolean(buffer_option):
		hooks.append(weechat.hook_modifier("weechat_print", "modifier_cb", ""))

def replace_xml_replacements(string):
	"""Apply XML replacements to message."""

	for tex, char in replacements:
		string = string.replace(tex, char)
	return string

def latex_ungroup(string):
	"""Remove grouping curly braces if present."""

	grouped = string.startswith("{") and string.endswith("}")
	if grouped:
		string = string[1:-1]
	return string

def replace_script(string, script):
	"""Regex substitution function for scripts."""

	grouped = string.startswith("{") and string.endswith("}")
	if grouped:
		string = string[1:-1]

	if script == 1 and not grouped and string.isalpha(): # if ungrouped letter subscript
		return None

	chars = list(string)
	all = True
	for i in xrange(len(chars)):
		if chars[i] in scripts and scripts[chars[i]][script] is not None:
			chars[i] = scripts[chars[i]][script]
		else:
			all = False
			break

	if all:
		return "".join(chars)
	else:
		return None

def replace_scripts(string):
	"""Apply super- and subscript replacements to message."""

	def replace(match, script):
		replaced = replace_script(match.group(1), script)
		return replaced if replaced is not None else match.group(0)

	string = re.sub(r"\^({[^}]+}|[^{}])", lambda match: replace(match, 0), string, flags=re.UNICODE)
	string = re.sub(r"_({[^}]+}|[^{}])", lambda match: replace(match, 1), string, flags=re.UNICODE)

	def replace_frac(match):
		vulgar_pair = (latex_ungroup(match.group(1)), latex_ungroup(match.group(2)))
		if vulgar_pair in vulgar_fractions:
			return vulgar_fractions[vulgar_pair]

		replaced1 = replace_script(match.group(1), 0)
		replaced2 = replace_script(match.group(2), 1)
		if replaced1 is not None and replaced2 is not None:
			return replaced1 + u"⁄" + replaced2
		else:
			return match.group(0)

	string = re.sub(r"\\frac({[^}]+}|[^{}])({[^}]+}|[^{}])", replace_frac, string, flags=re.UNICODE)

	def replace_sqrt(match):
		under = match.group(2)
		if under is not None:
			under = re.sub(r"(.)", u"\\1\u0305", latex_ungroup(under), flags=re.UNICODE)
		else:
			under = ""

		if match.group(1) is None:
			return u"√" + under

		replaced = replace_script(match.group(1), 0)
		if replaced is not None:
			return replaced + u"√" + under
		else:
			return match.group(0)

	string = re.sub(r"\\sqrt(?:\[([^\]]+)\])?({[^}]+}|[^{}])?", replace_sqrt, string, flags=re.UNICODE)

	return string

def latex_unicode_replace(string):
	"""Apply all latex_unicode replacements."""

	string = string.decode("utf-8")
	string = replace_xml_replacements(string)
	string = replace_scripts(string)
	return string.encode("utf-8")

def modifier_cb(data, modifier, modifier_data, string):
	"""Handle modifier hooks."""

	return latex_unicode_replace(string)

def command_cb(data, buffer, args):
	"""Handle command hook."""

	args = args.split()

	if len(args) >= 1:
		if args[0] == "reload":
			setup_from_file()
			return weechat.WEECHAT_RC_OK
		elif args[0] == "redownload":
			setup_from_url()
			return weechat.WEECHAT_RC_OK

	error("invalid arguments")
	return weechat.WEECHAT_RC_ERROR

def config_cb(data, option, value):
	"""Handle config hooks (option changes)."""

	option = option[len(SETTINGS_PREFIX):]

	if SETTINGS[option][2]: # if option requires modifier hooks update
		hook_modifiers()

	return weechat.WEECHAT_RC_OK

if __name__ == "__main__" and IMPORT_OK:
	if weechat.register(SCRIPT_NAME, SCRIPT_AUTHOR, SCRIPT_VERSION, SCRIPT_LICENSE, SCRIPT_DESC, "", ""):
		weechat.hook_command(SCRIPT_COMMAND, SCRIPT_DESC,
"""reload
 || redownload""",
"""    reload: reload replacements from XML file
redownload: redownload replacements XML file and load it""",
"""reload
 || redownload""",
		"command_cb", "")

		for option, value in SETTINGS.items():
			if not weechat.config_is_set_plugin(option):
				weechat.config_set_plugin(option, value[0])

			weechat.config_set_desc_plugin(option, "%s (default: \"%s\")" % (value[1], value[0]))

		weechat.hook_config(SETTINGS_PREFIX + "*", "config_cb", "")

		setup()