"""
TeX extension for qrm
---
Copyright (C) 2021-2023 classabbyamp, 0x5c

SPDX-License-Identifier: LiLiQ-Rplus-1.1
"""


import aiohttp
from io import BytesIO
from urllib.parse import urljoin

import discord
import discord.ext.commands as commands

import common as cmn
import data.options as opt


class TexCog(commands.Cog):
    def __init__(self, bot: commands.Bot):
        self.bot = bot
        self.session = aiohttp.ClientSession(connector=bot.qrm.connector)
        with open(cmn.paths.resources / "template.1.tex") as latex_template:
            self.template = latex_template.read()

    @commands.command(name="tex", aliases=["latex"], category=cmn.Cats.UTILS)
    async def tex(self, ctx: commands.Context, *, expr: str):
        """Renders a LaTeX expression.

        In paragraph mode by default. To render math, add `$` around math expressions.
        """
        payload = {
            "format": "png",
            "code": self.template.replace("#CONTENT#", expr),
            "quality": 50
        }

        with ctx.typing():
            # ask rTeX to render our expression
            async with self.session.post(urljoin(opt.rtex_instance, "api/v2"), json=payload) as r:
                if r.status != 200:
                    raise cmn.BotHTTPError(r)

                render_result = await r.json()
                if render_result["status"] != "success":
                    embed = cmn.embed_factory(ctx)
                    embed.title = "LaTeX Rendering Failed!"
                    embed.description = ("Here are some common reasons:\n"
                                         "• Did you forget to use math mode? Surround math expressions with `$`,"
                                         " like `$x^3$`.\n"
                                         "• Are you using a command from a package? It might not be available.\n"
                                         "• Are you including the document headers? We already did that for you.")
                    embed.colour = cmn.colours.bad
                    await ctx.send(embed=embed)
                    return

            # if rendering went well, download the file given in the response
            async with self.session.get(urljoin(opt.rtex_instance, "api/v2/" + render_result["filename"])) as r:
                png_buffer = BytesIO(await r.read())

            embed = cmn.embed_factory(ctx)
            embed.title = "LaTeX Expression"
            embed.description = "Rendered by [rTeX](https://rtex.probablyaweb.site/)."
            embed.set_image(url="attachment://tex.png")
            await ctx.send(file=discord.File(png_buffer, "tex.png"), embed=embed)


def setup(bot: commands.Bot):
    bot.add_cog(TexCog(bot))