import asyncio
import contextlib
import logging
from datetime import datetime, timedelta, timezone
from typing import Optional, Union

import discord
from redbot.core import commands, i18n, checks, modlog
from redbot.core.commands import UserInputOptional
from redbot.core.utils import AsyncIter
from redbot.core.utils.chat_formatting import pagify, humanize_number, bold, humanize_list
from redbot.core.utils.mod import is_allowed_by_hierarchy, get_audit_reason
from .abc import MixinMeta
from .converters import RawUserIds

log = logging.getLogger("red.mod")
_ = i18n.Translator("Mod", __file__)


class KickBanMixin(MixinMeta):
    """
    Kick and ban commands and tasks go here.
    """

    @staticmethod
    async def get_invite_for_reinvite(ctx: commands.Context, max_age: int = 86400):
        """Handles the reinvite logic for getting an invite
        to send the newly unbanned user
        :returns: :class:`Invite`"""
        guild = ctx.guild
        my_perms: discord.Permissions = guild.me.guild_permissions
        if my_perms.manage_guild or my_perms.administrator:
            if "VANITY_URL" in guild.features:
                # guild has a vanity url so use it as the one to send
                return await guild.vanity_invite()
            invites = await guild.invites()
        else:
            invites = []
        for inv in invites:  # Loop through the invites for the guild
            if not (inv.max_uses or inv.max_age or inv.temporary):
                # Invite is for the guild's default channel,
                # has unlimited uses, doesn't expire, and
                # doesn't grant temporary membership
                # (i.e. they won't be kicked on disconnect)
                return inv
        else:  # No existing invite found that is valid
            channels_and_perms = zip(
                guild.text_channels, map(guild.me.permissions_in, guild.text_channels)
            )
            channel = next(
                (channel for channel, perms in channels_and_perms if perms.create_instant_invite),
                None,
            )
            if channel is None:
                return
            try:
                # Create invite that expires after max_age
                return await channel.create_invite(max_age=max_age)
            except discord.HTTPException:
                return

    async def ban_user(
        self,
        user: discord.Member,
        ctx: commands.Context,
        days: int = 0,
        reason: str = None,
        create_modlog_case=False,
    ) -> Union[str, bool]:
        author = ctx.author
        guild = ctx.guild

        if author == user:
            return _("I cannot let you do that. Self-harm is bad {}").format("\N{PENSIVE FACE}")
        elif not await is_allowed_by_hierarchy(self.bot, self.config, guild, author, user):
            return _(
                "I cannot let you do that. You are "
                "not higher than the user in the role "
                "hierarchy."
            )
        elif guild.me.top_role <= user.top_role or user == guild.owner:
            return _("I cannot do that due to Discord hierarchy rules.")
        elif not (0 <= days <= 7):
            return _("Invalid days. Must be between 0 and 7.")

        toggle = await self.config.guild(guild).dm_on_kickban()
        if toggle:
            with contextlib.suppress(discord.HTTPException):
                em = discord.Embed(
                    title=bold(_("You have been banned from {guild}.").format(guild=guild))
                )
                em.add_field(
                    name=_("**Reason**"),
                    value=reason if reason is not None else _("No reason was given."),
                    inline=False,
                )
                await user.send(embed=em)

        audit_reason = get_audit_reason(author, reason)

        queue_entry = (guild.id, user.id)
        try:
            await guild.ban(user, reason=audit_reason, delete_message_days=days)
            log.info(
                "{}({}) banned {}({}), deleting {} days worth of messages.".format(
                    author.name, author.id, user.name, user.id, str(days)
                )
            )
        except discord.Forbidden:
            return _("I'm not allowed to do that.")
        except Exception as e:
            log.exception(
                "{}({}) attempted to kick {}({}), but an error occurred.".format(
                    author.name, author.id, user.name, user.id
                )
            )
            return _("An unexpected error occurred.")

        if create_modlog_case:
            await modlog.create_case(
                self.bot,
                guild,
                ctx.message.created_at.replace(tzinfo=timezone.utc),
                "ban",
                user,
                author,
                reason,
                until=None,
                channel=None,
            )

        return True

    async def check_tempban_expirations(self):
        while self == self.bot.get_cog("Mod"):
            async for guild in AsyncIter(self.bot.guilds, steps=100):
                if not guild.me.guild_permissions.ban_members:
                    continue

                if await self.bot.cog_disabled_in_guild(self, guild):
                    continue

                async with self.config.guild(guild).current_tempbans() as guild_tempbans:
                    for uid in guild_tempbans.copy():
                        unban_time = datetime.fromtimestamp(
                            await self.config.member_from_ids(guild.id, uid).banned_until(),
                            timezone.utc,
                        )
                        if datetime.now(timezone.utc) > unban_time:  # Time to unban the user
                            queue_entry = (guild.id, uid)
                            try:
                                await guild.unban(
                                    discord.Object(id=uid), reason=_("Tempban finished")
                                )
                            except discord.NotFound:
                                # user is not banned anymore
                                guild_tempbans.remove(uid)
                            except discord.HTTPException as e:
                                # 50013: Missing permissions error code or 403: Forbidden status
                                if e.code == 50013 or e.status == 403:
                                    log.info(
                                        f"Failed to unban ({uid}) user from "
                                        f"{guild.name}({guild.id}) guild due to permissions."
                                    )
                                    break  # skip the rest of this guild
                                log.info(f"Failed to unban member: error code: {e.code}")
                            else:
                                # user unbanned successfully
                                guild_tempbans.remove(uid)
            await asyncio.sleep(60)

    @commands.command()
    @commands.guild_only()
    @commands.bot_has_permissions(kick_members=True)
    @checks.admin_or_permissions(kick_members=True)
    async def kick(self, ctx: commands.Context, user: discord.Member, *, reason: str = None):
        """Kick a user.

        If a reason is specified, it will be the reason that shows up
        in the audit log.
        """
        author = ctx.author
        guild = ctx.guild

        if author == user:
            await ctx.send(
                _("I cannot let you do that. Self-harm is bad {emoji}").format(
                    emoji="\N{PENSIVE FACE}"
                )
            )
            return
        elif not await is_allowed_by_hierarchy(self.bot, self.config, guild, author, user):
            await ctx.send(
                _(
                    "I cannot let you do that. You are "
                    "not higher than the user in the role "
                    "hierarchy."
                )
            )
            return
        elif ctx.guild.me.top_role <= user.top_role or user == ctx.guild.owner:
            await ctx.send(_("I cannot do that due to Discord hierarchy rules."))
            return
        audit_reason = get_audit_reason(author, reason)
        toggle = await self.config.guild(guild).dm_on_kickban()
        if toggle:
            with contextlib.suppress(discord.HTTPException):
                em = discord.Embed(
                    title=bold(_("You have been kicked from {guild}.").format(guild=guild))
                )
                em.add_field(
                    name=_("**Reason**"),
                    value=reason if reason is not None else _("No reason was given."),
                    inline=False,
                )
                await user.send(embed=em)
        try:
            await guild.kick(user, reason=audit_reason)
            log.info("{}({}) kicked {}({})".format(author.name, author.id, user.name, user.id))
        except discord.errors.Forbidden:
            await ctx.send(_("I'm not allowed to do that."))
        except Exception as e:
            log.exception(
                "{}({}) attempted to kick {}({}), but an error occurred.".format(
                    author.name, author.id, user.name, user.id
                )
            )
        else:
            await modlog.create_case(
                self.bot,
                guild,
                ctx.message.created_at.replace(tzinfo=timezone.utc),
                "kick",
                user,
                author,
                reason,
                until=None,
                channel=None,
            )
            await ctx.send(_("Done. That felt good."))

    @commands.command()
    @commands.guild_only()
    @commands.bot_has_permissions(ban_members=True)
    @checks.admin_or_permissions(ban_members=True)
    async def ban(
        self,
        ctx: commands.Context,
        user: discord.Member,
        days: Optional[int] = None,
        *,
        reason: str = None,
    ):
        """Ban a user from this server and optionally delete days of messages.

        If days is not a number, it's treated as the first word of the reason.

        Minimum 0 days, maximum 7. If not specified, defaultdays setting will be used instead."""
        author = ctx.author
        guild = ctx.guild
        if days is None:
            days = await self.config.guild(guild).default_days()

        result = await self.ban_user(
            user=user, ctx=ctx, days=days, reason=reason, create_modlog_case=True
        )

        if result is True:
            await ctx.send(_("Done. It was about time."))
        elif isinstance(result, str):
            await ctx.send(result)

    @commands.command()
    @commands.guild_only()
    @commands.bot_has_permissions(ban_members=True)
    @checks.admin_or_permissions(ban_members=True)
    async def hackban(
        self,
        ctx: commands.Context,
        user_ids: commands.Greedy[RawUserIds],
        days: Optional[int] = None,
        *,
        reason: str = None,
    ):
        """Preemptively bans user(s) from the server.

        User IDs need to be provided in order to ban
        using this command."""
        banned = []
        errors = {}
        upgrades = []

        async def show_results():
            text = _("Banned {num} users from the server.").format(
                num=humanize_number(len(banned))
            )
            if errors:
                text += _("\nErrors:\n")
                text += "\n".join(errors.values())
            if upgrades:
                text += _(
                    "\nFollowing user IDs have been upgraded from a temporary to a permanent ban:\n"
                )
                text += humanize_list(upgrades)

            for p in pagify(text):
                await ctx.send(p)

        def remove_processed(ids):
            return [_id for _id in ids if _id not in banned and _id not in errors]

        user_ids = list(set(user_ids))  # No dupes

        author = ctx.author
        guild = ctx.guild

        if not user_ids:
            await ctx.send_help()
            return

        if days is None:
            days = await self.config.guild(guild).default_days()

        if not (0 <= days <= 7):
            await ctx.send(_("Invalid days. Must be between 0 and 7."))
            return

        if not guild.me.guild_permissions.ban_members:
            return await ctx.send(_("I lack the permissions to do this."))

        tempbans = await self.config.guild(guild).current_tempbans()

        ban_list = await guild.bans()
        for entry in ban_list:
            for user_id in user_ids:
                if entry.user.id == user_id:
                    if user_id in tempbans:
                        # We need to check if a user is tempbanned here because otherwise they won't be processed later on.
                        continue
                    else:
                        errors[user_id] = _("User {user_id} is already banned.").format(
                            user_id=user_id
                        )

        user_ids = remove_processed(user_ids)

        if not user_ids:
            await show_results()
            return

        for user_id in user_ids:
            user = guild.get_member(user_id)
            if user is not None:
                if user_id in tempbans:
                    # We need to check if a user is tempbanned here because otherwise they won't be processed later on.
                    continue
                else:
                    # Instead of replicating all that handling... gets attr from decorator
                    try:
                        result = await self.ban_user(
                            user=user, ctx=ctx, days=days, reason=reason, create_modlog_case=True
                        )
                        if result is True:
                            banned.append(user_id)
                        else:
                            errors[user_id] = _("Failed to ban user {user_id}: {reason}").format(
                                user_id=user_id, reason=result
                            )
                    except Exception as e:
                        errors[user_id] = _("Failed to ban user {user_id}: {reason}").format(
                            user_id=user_id, reason=e
                        )

        user_ids = remove_processed(user_ids)

        if not user_ids:
            await show_results()
            return

        for user_id in user_ids:
            user = discord.Object(id=user_id)
            audit_reason = get_audit_reason(author, reason)
            queue_entry = (guild.id, user_id)
            async with self.config.guild(guild).current_tempbans() as tempbans:
                if user_id in tempbans:
                    tempbans.remove(user_id)
                    upgrades.append(str(user_id))
                    log.info(
                        "{}({}) upgraded the tempban for {} to a permaban.".format(
                            author.name, author.id, user_id
                        )
                    )
                    banned.append(user_id)
                else:
                    try:
                        await guild.ban(user, reason=audit_reason, delete_message_days=days)
                        log.info("{}({}) hackbanned {}".format(author.name, author.id, user_id))
                    except discord.NotFound:
                        errors[user_id] = _("User {user_id} does not exist.").format(
                            user_id=user_id
                        )
                        continue
                    except discord.Forbidden:
                        errors[user_id] = _(
                            "Could not ban {user_id}: missing permissions."
                        ).format(user_id=user_id)
                        continue
                    else:
                        banned.append(user_id)

            await modlog.create_case(
                self.bot,
                guild,
                ctx.message.created_at.replace(tzinfo=timezone.utc),
                "hackban",
                user_id,
                author,
                reason,
                until=None,
                channel=None,
            )
        await show_results()

    @commands.command()
    @commands.guild_only()
    @commands.bot_has_permissions(ban_members=True)
    @checks.admin_or_permissions(ban_members=True)
    async def tempban(
        self,
        ctx: commands.Context,
        user: discord.Member,
        duration: UserInputOptional[commands.TimedeltaConverter] = timedelta(days=1),
        days: Optional[int] = None,
        *,
        reason: str = None,
    ):
        """Temporarily ban a user from this server."""
        guild = ctx.guild
        author = ctx.author
        unban_time = datetime.now(timezone.utc) + duration

        if author == user:
            await ctx.send(
                _("I cannot let you do that. Self-harm is bad {}").format("\N{PENSIVE FACE}")
            )
            return
        elif not await is_allowed_by_hierarchy(self.bot, self.config, guild, author, user):
            await ctx.send(
                _(
                    "I cannot let you do that. You are "
                    "not higher than the user in the role "
                    "hierarchy."
                )
            )
            return
        elif guild.me.top_role <= user.top_role or user == guild.owner:
            await ctx.send(_("I cannot do that due to Discord hierarchy rules."))
            return

        if days is None:
            days = await self.config.guild(guild).default_days()

        if not (0 <= days <= 7):
            await ctx.send(_("Invalid days. Must be between 0 and 7."))
            return
        invite = await self.get_invite_for_reinvite(ctx, int(duration.total_seconds() + 86400))
        if invite is None:
            invite = ""

        queue_entry = (guild.id, user.id)
        await self.config.member(user).banned_until.set(unban_time.timestamp())
        async with self.config.guild(guild).current_tempbans() as current_tempbans:
            current_tempbans.append(user.id)

        with contextlib.suppress(discord.HTTPException):
            # We don't want blocked DMs preventing us from banning
            msg = _("You have been temporarily banned from {server_name} until {date}.").format(
                server_name=guild.name, date=unban_time.strftime("%m-%d-%Y %H:%M:%S")
            )
            if invite:
                msg += _(" Here is an invite for when your ban expires: {invite_link}").format(
                    invite_link=invite
                )
            await user.send(msg)
        try:
            await guild.ban(user, reason=reason, delete_message_days=days)
        except discord.Forbidden:
            await ctx.send(_("I can't do that for some reason."))
        except discord.HTTPException:
            await ctx.send(_("Something went wrong while banning."))
        else:
            await modlog.create_case(
                self.bot,
                guild,
                ctx.message.created_at.replace(tzinfo=timezone.utc),
                "tempban",
                user,
                author,
                reason,
                unban_time,
            )
            await ctx.send(_("Done. Enough chaos for now."))

    @commands.command()
    @commands.guild_only()
    @commands.bot_has_permissions(ban_members=True)
    @checks.admin_or_permissions(ban_members=True)
    async def softban(self, ctx: commands.Context, user: discord.Member, *, reason: str = None):
        """Kick a user and delete 1 day's worth of their messages."""
        guild = ctx.guild
        author = ctx.author

        if author == user:
            await ctx.send(
                _("I cannot let you do that. Self-harm is bad {emoji}").format(
                    emoji="\N{PENSIVE FACE}"
                )
            )
            return
        elif not await is_allowed_by_hierarchy(self.bot, self.config, guild, author, user):
            await ctx.send(
                _(
                    "I cannot let you do that. You are "
                    "not higher than the user in the role "
                    "hierarchy."
                )
            )
            return

        audit_reason = get_audit_reason(author, reason)

        invite = await self.get_invite_for_reinvite(ctx)
        if invite is None:
            invite = ""

        queue_entry = (guild.id, user.id)
        try:  # We don't want blocked DMs preventing us from banning
            msg = await user.send(
                _(
                    "You have been banned and "
                    "then unbanned as a quick way to delete your messages.\n"
                    "You can now join the server again. {invite_link}"
                ).format(invite_link=invite)
            )
        except discord.HTTPException:
            msg = None
        try:
            await guild.ban(user, reason=audit_reason, delete_message_days=1)
        except discord.errors.Forbidden:
            await ctx.send(_("My role is not high enough to softban that user."))
            if msg is not None:
                await msg.delete()
            return
        except discord.HTTPException as e:
            log.exception(
                "{}({}) attempted to softban {}({}), but an error occurred trying to ban them.".format(
                    author.name, author.id, user.name, user.id
                )
            )
            return
        try:
            await guild.unban(user)
        except discord.HTTPException as e:
            log.exception(
                "{}({}) attempted to softban {}({}), but an error occurred trying to unban them.".format(
                    author.name, author.id, user.name, user.id
                )
            )
            return
        else:
            log.info(
                "{}({}) softbanned {}({}), deleting 1 day worth "
                "of messages.".format(author.name, author.id, user.name, user.id)
            )
            await modlog.create_case(
                self.bot,
                guild,
                ctx.message.created_at.replace(tzinfo=timezone.utc),
                "softban",
                user,
                author,
                reason,
                until=None,
                channel=None,
            )
            await ctx.send(_("Done. Enough chaos."))

    @commands.command()
    @commands.guild_only()
    @commands.mod_or_permissions(move_members=True)
    async def voicekick(
        self, ctx: commands.Context, member: discord.Member, *, reason: str = None
    ):
        """Kick a member from a voice channel."""
        author = ctx.author
        guild = ctx.guild
        user_voice_state: discord.VoiceState = member.voice

        if await self._voice_perm_check(ctx, user_voice_state, move_members=True) is False:
            return
        elif not await is_allowed_by_hierarchy(self.bot, self.config, guild, author, member):
            await ctx.send(
                _(
                    "I cannot let you do that. You are "
                    "not higher than the user in the role "
                    "hierarchy."
                )
            )
            return
        case_channel = member.voice.channel
        # Store this channel for the case channel.

        try:
            await member.move_to(None)
        except discord.Forbidden:  # Very unlikely that this will ever occur
            await ctx.send(_("I am unable to kick this member from the voice channel."))
            return
        except discord.HTTPException:
            await ctx.send(_("Something went wrong while attempting to kick that member."))
            return
        else:
            await modlog.create_case(
                self.bot,
                guild,
                ctx.message.created_at.replace(tzinfo=timezone.utc),
                "vkick",
                member,
                author,
                reason,
                until=None,
                channel=case_channel,
            )

    @commands.command()
    @commands.guild_only()
    @commands.bot_has_permissions(ban_members=True)
    @checks.admin_or_permissions(ban_members=True)
    async def unban(self, ctx: commands.Context, user_id: RawUserIds, *, reason: str = None):
        """Unban a user from this server.

        Requires specifying the target user's ID. To find this, you may either:
         1. Copy it from the mod log case (if one was created), or
         2. enable developer mode, go to Bans in this server's settings, right-
        click the user and select 'Copy ID'."""
        guild = ctx.guild
        author = ctx.author
        audit_reason = get_audit_reason(ctx.author, reason)
        bans = await guild.bans()
        bans = [be.user for be in bans]
        user = discord.utils.get(bans, id=user_id)
        if not user:
            await ctx.send(_("It seems that user isn't banned!"))
            return
        queue_entry = (guild.id, user_id)
        try:
            await guild.unban(user, reason=audit_reason)
        except discord.HTTPException:
            await ctx.send(_("Something went wrong while attempting to unban that user."))
            return
        else:
            await modlog.create_case(
                self.bot,
                guild,
                ctx.message.created_at.replace(tzinfo=timezone.utc),
                "unban",
                user,
                author,
                reason,
                until=None,
                channel=None,
            )
            await ctx.send(_("Unbanned that user from this server."))

        if await self.config.guild(guild).reinvite_on_unban():
            user = ctx.bot.get_user(user_id)
            if not user:
                await ctx.send(
                    _("I don't share another server with this user. I can't reinvite them.")
                )
                return

            invite = await self.get_invite_for_reinvite(ctx)
            if invite:
                try:
                    await user.send(
                        _(
                            "You've been unbanned from {server}.\n"
                            "Here is an invite for that server: {invite_link}"
                        ).format(server=guild.name, invite_link=invite.url)
                    )
                except discord.Forbidden:
                    await ctx.send(
                        _(
                            "I failed to send an invite to that user. "
                            "Perhaps you may be able to send it for me?\n"
                            "Here's the invite link: {invite_link}"
                        ).format(invite_link=invite.url)
                    )
                except discord.HTTPException:
                    await ctx.send(
                        _(
                            "Something went wrong when attempting to send that user"
                            "an invite. Here's the link so you can try: {invite_link}"
                        ).format(invite_link=invite.url)
                    )
