import re

import discord
from discord.ext import commands


class Authorization(commands.Cog):
    kruh_pattern = r"kruh-[0-9]{2}"
    ukco_pattern = r"[0-9]{8}"
    help_message = \
"""Usage: `!grant_role kruh-## UKCO`
- Replace `##` with your study group number
- Replace `UKCO` with your UKCO (8-digit personal number)."""

    def __init__(self, bot: commands.Bot):
        super().__init__()
        self.bot = bot
        self.logger = bot.logger
        self.guild = bot.get_guild(bot.config["guild_ID"])
        self.kruh_roles = bot.config["kruhove_role"]

    @commands.slash_command()
    async def grant_role(self, ctx: discord.ApplicationContext, kruh: str, ukco: str):
        kruh = kruh.lower()

        if not re.fullmatch(self.kruh_pattern, kruh):
            await self.error(ctx, "Invalid Kruh format")
            await self.help(ctx)
            return

        if not re.fullmatch(self.ukco_pattern, ukco):
            await self.error(ctx, 'Invalid UKCO format')
            await self.help(ctx)
            return

        if not kruh in self.kruh_roles:
            await self.error(ctx, "Unrecognized Kruh")
            return

        kruh_role_id = self.kruh_roles[kruh]

        guild: discord.Guild = self.guild
        kruh_role = guild.get_role(kruh_role_id)
        if kruh_role is None:
            self.log(f"Role with id [{kruh_role_id}] not found!")
            await self.error(ctx, "Error while assigning role")
            return

        await ctx.author.add_roles(kruh_role)

        self.log(f'Granted role [{kruh_role.name}] to [{ctx.author.mention}] in [{guild.name}] corresponding to the study group [{kruh}].')
        await ctx.respond(f"{ctx.author.mention} has been granted the [{kruh_role.name}] role on the [{guild.name}] server.")

    async def error(self, ctx: discord.ApplicationContext, message: str):
        await ctx.respond(f'**Error:** {message}')

    async def help(self, ctx: discord.ApplicationContext):
        await ctx.respond(self.help_message)

    async def log(self, message: str):
        self.logger.info(message)


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