# SPDX-FileCopyrightText: 2016-2019 Simmo Saan <simmo.saan@gmail.com>
#
# SPDX-License-Identifier: GPL-3.0-or-later
#
# 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:
#
# 2025-04-19, Sébastien Helleu <flashcode@flashtux.org>:
#   version 1.2.1: replace tabs by spaces, add SPDX copyright and license tags,
#                  remove coding charset
# 2021-05-02, Sébastien Helleu <flashcode@flashtux.org>:
#   version 1.2: add compatibility with WeeChat >= 3.2 (XDG directories)
# 2019-06-27, Simmo Saan <simmo.saan@gmail.com>
#   version 1.1: fix completion newlines
# 2018-06-19, Simmo Saan <simmo.saan@gmail.com>
#   version 1.0: add Python 2/3 compatibility
# 2016-11-01, Simmo Saan <simmo.saan@gmail.com>
#   version 0.9: remove ungrouped script replacement
# 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 = "1.2.1"
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
import sys

PY2 = sys.version_info < (3,)
if PY2:
    chr = unichr
    range = xrange

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
    options = {
        "directory": "cache",
    }
    xml_path = weechat.string_eval_path_home("%h/latex_unicode.xml", {}, {}, options)

    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 = chr(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]

    chars = list(string)
    all = True
    for i in range(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."""

    if PY2:
        string = string.decode("utf-8")

    string = replace_xml_replacements(string)
    string = replace_scripts(string)

    if PY2:
        string = string.encode("utf-8")

    return string

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""".replace("\n", ""),
        "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()