import re

import discord

from redbot.core import checks, commands
from redbot.core.bot import Red
from redbot.core.i18n import Translator, cog_i18n
from redbot.core.utils.mod import slow_deletion, mass_purge
from redbot.cogs.mod.log import log

_ = Translator("Cleanup", __file__)


@cog_i18n(_)
class Cleanup:
    """Commands for cleaning messages"""

    def __init__(self, bot: Red):
        self.bot = bot

    @staticmethod
    async def check_100_plus(ctx: commands.Context, number: int) -> bool:
        """
        Called when trying to delete more than 100 messages at once

        Prompts the user to choose whether they want to continue or not
        """
        def author_check(message):
            return message.author == ctx.author

        await ctx.send(_('Are you sure you want to delete {} messages? (y/n)').format(number))
        response = await ctx.bot.wait_for('message', check=author_check)

        if response.content.lower().startswith('y'):
            return True
        else:
            await ctx.send(_('Cancelled.'))
            return False

    @staticmethod
    async def get_messages_for_deletion(
            ctx: commands.Context, channel: discord.TextChannel, number,
            check=lambda x: True, limit=100, before=None, after=None,
            delete_pinned=False
    ) -> list:
        """
        Gets a list of messages meeting the requirements to be deleted.

        Generally, the requirements are:
        - We don't have the number of messages to be deleted already
        - The message passes a provided check (if no check is provided,
          this is automatically true)
        - The message is less than 14 days old
        - The message is not pinned
        """
        to_delete = []
        too_old = False

        while not too_old and len(to_delete) - 1 < number:
            message = None
            async for message in channel.history(limit=limit,
                                                 before=before,
                                                 after=after):
                if (
                    (not number or len(to_delete) - 1 < number)
                    and check(message)
                    and (ctx.message.created_at - message.created_at).days < 14
                    and (delete_pinned or not message.pinned)
                ):
                    to_delete.append(message)
                elif (ctx.message.created_at - message.created_at).days >= 14:
                    too_old = True
                    break
                elif number and len(to_delete) >= number:
                    break
            if message is None:
                break
            else:
                before = message
        return to_delete

    @commands.group()
    @checks.mod_or_permissions(manage_messages=True)
    async def cleanup(self, ctx: commands.Context):
        """Deletes messages."""
        if ctx.invoked_subcommand is None:
            await ctx.send_help()

    @cleanup.command()
    @commands.guild_only()
    @commands.bot_has_permissions(manage_messages=True)
    async def text(self, ctx: commands.Context, text: str, number: int, delete_pinned: bool=False):
        """Deletes last X messages matching the specified text.

        Example:
        cleanup text \"test\" 5

        Remember to use double quotes."""

        channel = ctx.channel
        author = ctx.author
        is_bot = self.bot.user.bot

        if number > 100:
            cont = await self.check_100_plus(ctx, number)
            if not cont:
                return

        def check(m):
            if text in m.content:
                return True
            elif m == ctx.message:
                return True
            else:
                return False

        to_delete = await self.get_messages_for_deletion(
            ctx, channel, number, check=check, limit=1000, before=ctx.message,
            delete_pinned=delete_pinned)

        reason = "{}({}) deleted {} messages "\
                 " containing '{}' in channel {}.".format(author.name,
                                                         author.id, len(to_delete), text, channel.id)
        log.info(reason)

        if is_bot:
            await mass_purge(to_delete, channel)
        else:
            await slow_deletion(to_delete)

    @cleanup.command()
    @commands.guild_only()
    @commands.bot_has_permissions(manage_messages=True)
    async def user(self, ctx: commands.Context, user: str, number: int, delete_pinned: bool=False):
        """Deletes last X messages from specified user.

        Examples:
        cleanup user @\u200bTwentysix 2
        cleanup user Red 6"""

        try:
            member = await commands.converter.MemberConverter().convert(ctx, user)
        except commands.BadArgument:
            try:
                _id = int(user)
            except ValueError:
                raise commands.BadArgument()
        else:
            _id = member.id

        channel = ctx.channel
        author = ctx.author
        is_bot = self.bot.user.bot

        if number > 100:
            cont = await self.check_100_plus(ctx, number)
            if not cont:
                return

        def check(m):
            if m.author.id == _id:
                return True
            elif m == ctx.message:
                return True
            else:
                return False

        to_delete = await self.get_messages_for_deletion(
            ctx, channel, number, check=check, limit=1000, before=ctx.message,
            delete_pinned=delete_pinned
        )
        reason = "{}({}) deleted {} messages "\
                 " made by {}({}) in channel {}."\
                 "".format(author.name, author.id, len(to_delete),
                           member or '???', _id, channel.name)
        log.info(reason)

        if is_bot:
            # For whatever reason the purge endpoint requires manage_messages
            await mass_purge(to_delete, channel)
        else:
            await slow_deletion(to_delete)

    @cleanup.command()
    @commands.guild_only()
    @commands.bot_has_permissions(manage_messages=True)
    async def after(self, ctx: commands.Context, message_id: int, delete_pinned: bool=False):
        """Deletes all messages after specified message.

        To get a message id, enable developer mode in Discord's
        settings, 'appearance' tab. Then right click a message
        and copy its id.

        This command only works on bots running as bot accounts.
        """

        channel = ctx.channel
        author = ctx.author
        is_bot = self.bot.user.bot

        if not is_bot:
            await ctx.send(_("This command can only be used on bots with "
                             "bot accounts."))
            return

        after = await channel.get_message(message_id)

        if not after:
            await ctx.send(_("Message not found."))
            return

        to_delete = await self.get_messages_for_deletion(
            ctx, channel, 0, limit=None, after=after, delete_pinned=delete_pinned
        )

        reason = "{}({}) deleted {} messages in channel {}."\
                 "".format(author.name, author.id,
                           len(to_delete), channel.name)
        log.info(reason)

        await mass_purge(to_delete, channel)

    @cleanup.command()
    @commands.guild_only()
    @commands.bot_has_permissions(manage_messages=True)
    async def messages(self, ctx: commands.Context, number: int, delete_pinned: bool=False):
        """Deletes last X messages.

        Example:
        cleanup messages 26"""

        channel = ctx.channel
        author = ctx.author

        is_bot = self.bot.user.bot

        if number > 100:
            cont = await self.check_100_plus(ctx, number)
            if not cont:
                return

        to_delete = await self.get_messages_for_deletion(
            ctx, channel, number, limit=1000, before=ctx.message,
            delete_pinned=delete_pinned
        )

        reason = "{}({}) deleted {} messages in channel {}."\
                 "".format(author.name, author.id,
                           number, channel.name)
        log.info(reason)

        if is_bot:
            await mass_purge(to_delete, channel)
        else:
            await slow_deletion(to_delete)

    @cleanup.command(name='bot')
    @commands.guild_only()
    @commands.bot_has_permissions(manage_messages=True)
    async def cleanup_bot(self, ctx: commands.Context, number: int, delete_pinned: bool=False):
        """Cleans up command messages and messages from the bot."""

        channel = ctx.message.channel
        author = ctx.message.author
        is_bot = self.bot.user.bot

        if number > 100:
            cont = await self.check_100_plus(ctx, number)
            if not cont:
                return

        prefixes = await self.bot.get_prefix(ctx.message) # This returns all server prefixes
        if isinstance(prefixes, str):
            prefixes = [prefixes]

        # In case some idiot sets a null prefix
        if '' in prefixes:
            prefixes.remove('')

        def check(m):
            if m.author.id == self.bot.user.id:
                return True
            elif m == ctx.message:
                return True
            p = discord.utils.find(m.content.startswith, prefixes)
            if p and len(p) > 0:
                cmd_name = m.content[len(p):].split(' ')[0]
                return bool(self.bot.get_command(cmd_name))
            return False

        to_delete = await self.get_messages_for_deletion(
            ctx, channel, number, check=check, limit=1000, before=ctx.message,
            delete_pinned=delete_pinned
        )

        reason = "{}({}) deleted {} "\
                 " command messages in channel {}."\
                 "".format(author.name, author.id, len(to_delete),
                           channel.name)
        log.info(reason)

        if is_bot:
            await mass_purge(to_delete, channel)
        else:
            await slow_deletion(to_delete)

    @cleanup.command(name='self')
    async def cleanup_self(
            self, ctx: commands.Context, number: int,
            match_pattern: str = None, delete_pinned: bool=False):
        """Cleans up messages owned by the bot.

        By default, all messages are cleaned. If a third argument is specified,
        it is used for pattern matching: If it begins with r( and ends with ),
        then it is interpreted as a regex, and messages that match it are
        deleted. Otherwise, it is used in a simple substring test.

        Some helpful regex flags to include in your pattern:
        Dots match newlines: (?s); Ignore case: (?i); Both: (?si)
        """
        channel = ctx.channel
        author = ctx.message.author
        is_bot = self.bot.user.bot

        if number > 100:
            cont = await self.check_100_plus(ctx, number)
            if not cont:
                return

        # You can always delete your own messages, this is needed to purge
        can_mass_purge = False
        if type(author) is discord.Member:
            me = ctx.guild.me
            can_mass_purge = channel.permissions_for(me).manage_messages

        use_re = (match_pattern and match_pattern.startswith('r(') and
                  match_pattern.endswith(')'))

        if use_re:
            match_pattern = match_pattern[1:]  # strip 'r'
            match_re = re.compile(match_pattern)

            def content_match(c):
                return bool(match_re.match(c))
        elif match_pattern:
            def content_match(c):
                return match_pattern in c
        else:
            def content_match(_):
                return True

        def check(m):
            if m.author.id != self.bot.user.id:
                return False
            elif content_match(m.content):
                return True
            return False

        to_delete = await self.get_messages_for_deletion(
            ctx, channel, number, check=check, limit=1000, before=ctx.message,
            delete_pinned=delete_pinned
        )

        # Selfbot convenience, delete trigger message
        if author == self.bot.user:
            to_delete.append(ctx.message)

        if channel.name:
            channel_name = 'channel ' + channel.name
        else:
            channel_name = str(channel)

        reason = "{}({}) deleted {} messages "\
                 "sent by the bot in {}."\
                 "".format(author.name, author.id, len(to_delete),
                           channel_name)
        log.info(reason)

        if is_bot and can_mass_purge:
            await mass_purge(to_delete, channel)
        else:
            await slow_deletion(to_delete)