import asyncio
import contextlib
from collections import namedtuple
from datetime import datetime, timedelta
from typing import cast, Optional, Union

import discord
from redbot.core import commands, i18n, checks, modlog
from redbot.core.utils.chat_formatting import pagify
from redbot.core.utils.mod import is_allowed_by_hierarchy, get_audit_reason
from .abc import MixinMeta
from .converters import RawUserIds
from .log import log

_ = 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.settings, 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.")

        audit_reason = get_audit_reason(author, reason)

        queue_entry = (guild.id, user.id)
        self.ban_queue.append(queue_entry)
        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:
            self.ban_queue.remove(queue_entry)
            return _("I'm not allowed to do that.")
        except Exception as e:
            self.ban_queue.remove(queue_entry)
            return e  # TODO: impproper return type? Is this intended to be re-raised?

        if create_modlog_case:
            try:
                await modlog.create_case(
                    self.bot,
                    guild,
                    ctx.message.created_at,
                    "ban",
                    user,
                    author,
                    reason,
                    until=None,
                    channel=None,
                )
            except RuntimeError as e:
                return _(
                    "The user was banned but an error occurred when trying to "
                    "create the modlog entry: {reason}"
                ).format(reason=e)

        return True

    async def check_tempban_expirations(self):
        member = namedtuple("Member", "id guild")
        while self == self.bot.get_cog("Mod"):
            for guild in self.bot.guilds:
                async with self.settings.guild(guild).current_tempbans() as guild_tempbans:
                    for uid in guild_tempbans.copy():
                        unban_time = datetime.utcfromtimestamp(
                            await self.settings.member(member(uid, guild)).banned_until()
                        )
                        now = datetime.utcnow()
                        if now > unban_time:  # Time to unban the user
                            user = await self.bot.fetch_user(uid)
                            queue_entry = (guild.id, user.id)
                            self.unban_queue.append(queue_entry)
                            try:
                                await guild.unban(user, reason=_("Tempban finished"))
                                guild_tempbans.remove(uid)
                            except discord.Forbidden:
                                self.unban_queue.remove(queue_entry)
                                log.info("Failed to unban member due to permissions")
                            except discord.HTTPException:
                                self.unban_queue.remove(queue_entry)
            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.settings, 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)
        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:
            print(e)
        else:
            try:
                await modlog.create_case(
                    self.bot,
                    guild,
                    ctx.message.created_at,
                    "kick",
                    user,
                    author,
                    reason,
                    until=None,
                    channel=None,
                )
            except RuntimeError as e:
                await ctx.send(e)
            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] = 0,
        *,
        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. Defaults to 0."""

        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] = 0,
        *,
        reason: str = None,
    ):
        """Preemptively bans user(s) from the server

        User IDs need to be provided in order to ban
        using this command"""
        days = cast(int, days)
        banned = []
        errors = {}

        async def show_results():
            text = _("Banned {num} users from the server.".format(num=len(banned)))
            if errors:
                text += _("\nErrors:\n")
                text += "\n".join(errors.values())

            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 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."))

        ban_list = await guild.bans()
        for entry in ban_list:
            for user_id in user_ids:
                if entry.user.id == user_id:
                    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:
                # 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)
            self.ban_queue.append(queue_entry)
            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:
                self.ban_queue.remove(queue_entry)
                errors[user_id] = _("User {user_id} does not exist.").format(user_id=user_id)
                continue
            except discord.Forbidden:
                self.ban_queue.remove(queue_entry)
                errors[user_id] = _("Could not ban {user_id}: missing permissions.").format(
                    user_id=user_id
                )
                continue
            else:
                banned.append(user_id)

            user_info = await self.bot.fetch_user(user_id)

            try:
                await modlog.create_case(
                    self.bot,
                    guild,
                    ctx.message.created_at,
                    "hackban",
                    user_info,
                    author,
                    reason,
                    until=None,
                    channel=None,
                )
            except RuntimeError as e:
                errors["0"] = _("Failed to create modlog case: {reason}").format(reason=e)
        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, days: int = 1, *, reason: str = None
    ):
        """Temporarily ban a user from this server."""
        guild = ctx.guild
        author = ctx.author
        days_delta = timedelta(days=int(days))
        unban_time = datetime.utcnow() + days_delta

        invite = await self.get_invite_for_reinvite(ctx, int(days_delta.total_seconds() + 86400))
        if invite is None:
            invite = ""

        queue_entry = (guild.id, user.id)
        await self.settings.member(user).banned_until.set(unban_time.timestamp())
        cur_tbans = await self.settings.guild(guild).current_tempbans()
        cur_tbans.append(user.id)
        await self.settings.guild(guild).current_tempbans.set(cur_tbans)

        with contextlib.suppress(discord.HTTPException):
            # We don't want blocked DMs preventing us from banning
            await user.send(
                _(
                    "You have been temporarily banned from {server_name} until {date}. "
                    "Here is an invite for when your ban expires: {invite_link}"
                ).format(
                    server_name=guild.name,
                    date=unban_time.strftime("%m-%d-%Y %H:%M:%S"),
                    invite_link=invite,
                )
            )
        self.ban_queue.append(queue_entry)
        try:
            await guild.ban(user)
        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:
            try:
                await modlog.create_case(
                    self.bot,
                    guild,
                    ctx.message.created_at,
                    "tempban",
                    user,
                    author,
                    reason,
                    unban_time,
                )
            except RuntimeError as e:
                await ctx.send(e)
            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.settings, 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
        self.ban_queue.append(queue_entry)
        try:
            await guild.ban(user, reason=audit_reason, delete_message_days=1)
        except discord.errors.Forbidden:
            self.ban_queue.remove(queue_entry)
            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:
            self.ban_queue.remove(queue_entry)
            print(e)
            return
        self.unban_queue.append(queue_entry)
        try:
            await guild.unban(user)
        except discord.HTTPException as e:
            self.unban_queue.remove(queue_entry)
            print(e)
            return
        else:
            log.info(
                "{}({}) softbanned {}({}), deleting 1 day worth "
                "of messages".format(author.name, author.id, user.name, user.id)
            )
            try:
                await modlog.create_case(
                    self.bot,
                    guild,
                    ctx.message.created_at,
                    "softban",
                    user,
                    author,
                    reason,
                    until=None,
                    channel=None,
                )
            except RuntimeError as e:
                await ctx.send(e)
            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.settings, 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(discord.Object(id=None))
            # Work around till we get D.py 1.1.0, whereby we can directly do 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:
            try:
                await modlog.create_case(
                    self.bot,
                    guild,
                    ctx.message.created_at,
                    "vkick",
                    member,
                    author,
                    reason,
                    until=None,
                    channel=case_channel,
                )
            except RuntimeError as e:
                await ctx.send(e)

    @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: int, *, 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
        try:
            user = await self.bot.fetch_user(user_id)
        except discord.errors.NotFound:
            await ctx.send(_("Couldn't find a user with that ID!"))
            return
        audit_reason = get_audit_reason(ctx.author, reason)
        bans = await guild.bans()
        bans = [be.user for be in bans]
        if user not in bans:
            await ctx.send(_("It seems that user isn't banned!"))
            return
        queue_entry = (guild.id, user.id)
        self.unban_queue.append(queue_entry)
        try:
            await guild.unban(user, reason=audit_reason)
        except discord.HTTPException:
            self.unban_queue.remove(queue_entry)
            await ctx.send(_("Something went wrong while attempting to unban that user"))
            return
        else:
            try:
                await modlog.create_case(
                    self.bot,
                    guild,
                    ctx.message.created_at,
                    "unban",
                    user,
                    author,
                    reason,
                    until=None,
                    channel=None,
                )
            except RuntimeError as e:
                await ctx.send(e)
            await ctx.send(_("Unbanned that user from this server"))

        if await self.settings.guild(guild).reinvite_on_unban():
            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)
                    )