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.

        Tries its best to cleanup after itself if the response is positive.
        """
        def author_check(message):
            return message.author == ctx.author

        prompt = 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'):
            await prompt.delete()
            try:
                await response.delete()
            except:
                pass
            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"""

        member = None
        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
        )
        to_delete.append(ctx.message)

        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
        )
        to_delete.append(ctx.message)

        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)