import logging
import asyncio
from typing import Dict

import discord
from discord.ext import commands

from .common import Cog

log = logging.getLogger(__name__)
UserID = int

async def shell(command: str):
    process = await asyncio.create_subprocess_shell(
        command,
        stderr=asyncio.subprocess.PIPE,
        stdout=asyncio.subprocess.PIPE,
    )

    out, err = map(lambda s: s.decode('utf-8'), await process.communicate())
    return f'{out}{err}'.strip()


async def distance(s, len_s, t, len_t):
    cost = 0

    if not len_s:
        return len_t

    if not len_t:
        return len_s

    if s[len_s - 1] == t[len_t - 1]:
        cost = 0
    else:
        cost = 1

    l = [
        (await distance(s, len_s - 1, t, len_t)) + 1,
        (await distance(s, len_s, t, len_t - 1)) + 1,
        (await distance(s, len_s - 1, t, len_t - 1)) + cost
    ]

    return min(l)


class Rsudo(Cog):
    def __init__(self, bot):
        super().__init__(bot)

    async def lookupuser(self, uname: str) -> Dict[UserID, float]:
        lu = len(uname)

        cchan = self.bot.get_channel(
            self.bot.config.command_channel
        )

        if not cchan:
            return None

        members = cchan.guild.members
        scores = {}
        for member in members:
            if member.bot: continue

            lmn = len(member.name)
            d = await distance(member.name, lmn, uname, lu)
            scores[member.id] = d

            if uname in member.name or uname in member.nick:
                scores[member.id] = -1

        users = sorted(scores.keys(), key=lambda k: scores[k])
        if not users:
            return None

        return users[0]

    async def create_request(self, message):
        command_channel = self.bot.get_channel(
            self.bot.config.command_channel
        )

        if command_channel is None:
            log.warning('command channel not found')
            return

        # parse it, follows format command,uid,username
        sp = message.split(',')
        username = sp[-1]
        uid = sp[-2]

        command = ','.join(sp[:-2])

        log.info(f'[rsudo] {uid!r} {command!r}')

        embed = discord.Embed(
            title=f'RSudo request from UID {uid} UNAME {username!r}',
            description=f'```sh\n{command}```',
            color=discord.Color.purple(),
        )
        msg = await command_channel.send(embed=embed)

        await msg.add_reaction('\N{WHITE HEAVY CHECK MARK}')
        await msg.add_reaction('\N{CROSS MARK}')

        emoji = {
            '\N{WHITE HEAVY CHECK MARK}': True,
            '\N{CROSS MARK}': False,
        }

        def check(_reaction, _user):
            if _user is None:
                return False

            if _reaction.message.id != msg.id:
                return

            if _reaction.emoji not in emoji.keys():
                return False

            return discord.utils.get(_user.roles, id=self.bot.config.admin_role) is not None

        reaction, admin = await self.bot.wait_for('reaction_add', check=check)
        try:
            await msg.clear_reactions()
        except:
            log.error('can not remove reactions')

        should_execute = emoji.get(reaction.emoji)

        user = None
        # todo: get user ID from ldap to send results later

        if should_execute:
            log.info(f'executing command for {uid}, accepted by {admin} {admin.id}')

            async with command_channel.typing():
                embed.colour = discord.Color.green()
                embed.add_field(name='status', value=f'Accepted by {admin} {admin.id}')

                await msg.edit(embed=embed)

                # todo: does this not execute in the wrong directory?
                out = await shell(command)

            # output may be very long
            paginator = commands.Paginator(prefix='```sh\n', suffix='```')
            for line in out.split('\n'):
                paginator.add_line(line.strip())

            for page in paginator.pages:
                await command_channel.send(page)

            try:
                await user.send(f'Your request for the command {command} was accepted:')

                for page in paginator.pages:
                    await user.send(page)
            except discord.HTTPException:
                await command_channel.send(f'Failed to send results to {user}.')
        else:
            log.info(f'not executing command for {uid}, denied by {admin} {admin.id}')

            embed.colour = discord.Color.red()
            embed.add_field(name='status', value=f'Denied by {admin} {admin.id}')

            await msg.edit(embed=embed)

            try:
                await user.send(f'Your request for the command {command} was denied.')
            except discord.HTTPException:
                await command_channel.send(f'Failed to send denial message to {user}.')

    @commands.command()
    async def lookup(self, ctx, uname: str):
        u = await self.lookupuser(uname)
        if not u:
            return await ctx.send('none found')

        u = self.bot.get_user(u)
        await ctx.send(repr(u))

def setup(bot):
    bot.add_cog(Rsudo(bot))