# -*- coding: utf-8 -*-
"""
The MIT License (MIT)

Copyright (c) 2015-2016 Rapptz

Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and associated documentation files (the "Software"),
to deal in the Software without restriction, including without limitation
the rights to use, copy, modify, merge, publish, distribute, sublicense,
and/or sell copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
DEALINGS IN THE SOFTWARE.
"""

from .permissions import Permissions, PermissionOverwrite
from .enums import ChannelType, try_enum
from .mixins import Hashable
from .role import Role
from .user import User
from .member import Member
from . import utils

import discord.abc

import copy
import asyncio

__all__ = ('TextChannel', 'VoiceChannel', 'DMChannel', 'GroupChannel', '_channel_factory')

class TextChannel(discord.abc.Messageable, discord.abc.GuildChannel, Hashable):
    """Represents a Discord guild text channel.

    Supported Operations:

    +-----------+---------------------------------------+
    | Operation |              Description              |
    +===========+=======================================+
    | x == y    | Checks if two channels are equal.     |
    +-----------+---------------------------------------+
    | x != y    | Checks if two channels are not equal. |
    +-----------+---------------------------------------+
    | hash(x)   | Returns the channel's hash.           |
    +-----------+---------------------------------------+
    | str(x)    | Returns the channel's name.           |
    +-----------+---------------------------------------+

    Attributes
    -----------
    name: str
        The channel name.
    guild: :class:`Guild`
        The guild the channel belongs to.
    id: int
        The channel ID.
    topic: Optional[str]
        The channel's topic. None if it doesn't exist.
    position: int
        The position in the channel list. This is a number that starts at 0. e.g. the
        top channel is position 0.
    """

    __slots__ = ( 'name', 'id', 'guild', 'topic', '_state',
                  'position', '_overwrites' )

    def __init__(self, *, state, guild, data):
        self._state = state
        self.id = int(data['id'])
        self._update(guild, data)

    def __repr__(self):
        return '<TextChannel id={0.id} name={0.name!r} position={0.position}>'.format(self)

    def _update(self, guild, data):
        self.guild = guild
        self.name = data['name']
        self.topic = data.get('topic')
        self.position = data['position']
        self._fill_overwrites(data)

    @asyncio.coroutine
    def _get_channel(self):
        return self

    def _get_guild_id(self):
        return self.guild.id

    def permissions_for(self, member):
        base = super().permissions_for(member)

        # text channels do not have voice related permissions
        denied = Permissions.voice()
        base.value &= ~denied.value
        return base

    permissions_for.__doc__ = discord.abc.GuildChannel.permissions_for.__doc__

    @asyncio.coroutine
    def edit(self, **options):
        """|coro|

        Edits the channel.

        You must have the :attr:`Permissions.manage_channel` permission to
        use this.

        Parameters
        ----------
        name: str
            The new channel name.
        topic: str
            The new channel's topic.
        position: int
            The new channel's position.

        Raises
        ------
        InvalidArgument
            If position is less than 0 or greater than the number of channels.
        Forbidden
            You do not have permissions to edit the channel.
        HTTPException
            Editing the channel failed.
        """
        try:
            position = options.pop('position')
        except KeyError:
            pass
        else:
            yield from self._move(position)
            self.position = position

        if options:
            data = yield from self._state.http.edit_channel(self.id, **options)
            self._update(self.guild, data)

class VoiceChannel(discord.abc.GuildChannel, Hashable):
    """Represents a Discord guild voice channel.

    Supported Operations:

    +-----------+---------------------------------------+
    | Operation |              Description              |
    +===========+=======================================+
    | x == y    | Checks if two channels are equal.     |
    +-----------+---------------------------------------+
    | x != y    | Checks if two channels are not equal. |
    +-----------+---------------------------------------+
    | hash(x)   | Returns the channel's hash.           |
    +-----------+---------------------------------------+
    | str(x)    | Returns the channel's name.           |
    +-----------+---------------------------------------+

    Attributes
    -----------
    name: str
        The channel name.
    guild: :class:`Guild`
        The guild the channel belongs to.
    id: int
        The channel ID.
    position: int
        The position in the channel list. This is a number that starts at 0. e.g. the
        top channel is position 0.
    bitrate: int
        The channel's preferred audio bitrate in bits per second.
    user_limit: int
        The channel's limit for number of members that can be in a voice channel.
    """

    __slots__ = ('name', 'id', 'guild', 'bitrate',  'user_limit',
                 '_state', 'position', '_overwrites' )

    def __init__(self, *, state, guild, data):
        self._state = state
        self.id = int(data['id'])
        self._update(guild, data)

    def __repr__(self):
        return '<VoiceChannel id={0.id} name={0.name!r} position={0.position}>'.format(self)

    def _update(self, guild, data):
        self.guild = guild
        self.name = data['name']
        self.position = data['position']
        self.bitrate = data.get('bitrate')
        self.user_limit = data.get('user_limit')
        self._fill_overwrites(data)

    @property
    def voice_members(self):
        """Returns a list of :class:`Member` that are currently inside this voice channel."""
        ret = []
        for user_id, state in self.guild._voice_states.items():
            if state.channel.id == self.id:
                member = self.guild.get_member(user_id)
                if member is not None:
                    ret.append(member)
        return ret

    @asyncio.coroutine
    def edit(self, **options):
        """|coro|

        Edits the channel.

        You must have the :attr:`Permissions.manage_channel` permission to
        use this.

        Parameters
        ----------
        bitrate: int
            The new channel's bitrate.
        user_limit: int
            The new channel's user limit.
        position: int
            The new channel's position.

        Raises
        ------
        Forbidden
            You do not have permissions to edit the channel.
        HTTPException
            Editing the channel failed.
        """

        try:
            position = options.pop('position')
        except KeyError:
            pass
        else:
            yield from self._move(position)
            self.position = position

        if options:
            data = yield from self._state.http.edit_channel(self.id, **options)
            self._update(self.guild, data)

class DMChannel(discord.abc.Messageable, Hashable):
    """Represents a Discord direct message channel.

    Supported Operations:

    +-----------+-------------------------------------------------+
    | Operation |                   Description                   |
    +===========+=================================================+
    | x == y    | Checks if two channels are equal.               |
    +-----------+-------------------------------------------------+
    | x != y    | Checks if two channels are not equal.           |
    +-----------+-------------------------------------------------+
    | hash(x)   | Returns the channel's hash.                     |
    +-----------+-------------------------------------------------+
    | str(x)    | Returns a string representation of the channel  |
    +-----------+-------------------------------------------------+

    Attributes
    ----------
    recipient: :class:`User`
        The user you are participating with in the direct message channel.
    me: :class:`User`
        The user presenting yourself.
    id: int
        The direct message channel ID.
    """

    __slots__ = ('id', 'recipient', 'me', '_state')

    def __init__(self, *, me, state, data):
        self._state = state
        self.recipient = state.store_user(data['recipients'][0])
        self.me = me
        self.id = int(data['id'])

    @asyncio.coroutine
    def _get_channel(self):
        return self

    def _get_guild_id(self):
        return None

    def __str__(self):
        return 'Direct Message with %s' % self.recipient

    def __repr__(self):
        return '<DMChannel id={0.id} recipient={0.recipient!r}>'.format(self)

    @property
    def created_at(self):
        """Returns the direct message channel's creation time in UTC."""
        return utils.snowflake_time(self.id)

    def permissions_for(self, user=None):
        """Handles permission resolution for a :class:`User`.

        This function is there for compatibility with other channel types.

        Actual direct messages do not really have the concept of permissions.

        This returns all the Text related permissions set to true except:

        - send_tts_messages: You cannot send TTS messages in a DM.
        - manage_messages: You cannot delete others messages in a DM.

        Parameters
        -----------
        user: :class:`User`
            The user to check permissions for. This parameter is ignored
            but kept for compatibility.

        Returns
        --------
        :class:`Permissions`
            The resolved permissions.
        """

        base = Permissions.text()
        base.send_tts_messages = False
        base.manage_messages = False
        return base

class GroupChannel(discord.abc.Messageable, Hashable):
    """Represents a Discord group channel.

    Supported Operations:

    +-----------+-------------------------------------------------+
    | Operation |                   Description                   |
    +===========+=================================================+
    | x == y    | Checks if two channels are equal.               |
    +-----------+-------------------------------------------------+
    | x != y    | Checks if two channels are not equal.           |
    +-----------+-------------------------------------------------+
    | hash(x)   | Returns the channel's hash.                     |
    +-----------+-------------------------------------------------+
    | str(x)    | Returns a string representation of the channel  |
    +-----------+-------------------------------------------------+

    Attributes
    ----------
    recipients: list of :class:`User`
        The users you are participating with in the group channel.
    me: :class:`User`
        The user presenting yourself.
    id: int
        The group channel ID.
    owner: :class:`User`
        The user that owns the group channel.
    icon: Optional[str]
        The group channel's icon hash if provided.
    name: Optional[str]
        The group channel's name if provided.
    """

    __slots__ = ('id', 'recipients', 'owner', 'icon', 'name', 'me', '_state')

    def __init__(self, *, me, state, data):
        self._state = state
        self.recipients = [state.store_user(u) for u in data['recipients']]
        self.id = int(data['id'])
        self.me = me
        self._update_group(data)

    def _update_group(self, data):
        owner_id = utils._get_as_snowflake(data, 'owner_id')
        self.icon = data.get('icon')
        self.name = data.get('name')

        if owner_id == self.me.id:
            self.owner = self.me
        else:
            self.owner = utils.find(lambda u: u.id == owner_id, self.recipients)

    @asyncio.coroutine
    def _get_channel(self):
        return self

    def _get_guild_id(self):
        return None

    def __str__(self):
        if self.name:
            return self.name

        if len(self.recipients) == 0:
            return 'Unnamed'

        return ', '.join(map(lambda x: x.name, self.recipients))

    def __repr__(self):
        return '<GroupChannel id={0.id} name={0.name!r}>'.format(self)

    @property
    def icon_url(self):
        """Returns the channel's icon URL if available or an empty string otherwise."""
        if self.icon is None:
            return ''

        return 'https://cdn.discordapp.com/channel-icons/{0.id}/{0.icon}.jpg'.format(self)

    @property
    def created_at(self):
        """Returns the channel's creation time in UTC."""
        return utils.snowflake_time(self.id)

    def permissions_for(self, user):
        """Handles permission resolution for a :class:`User`.

        This function is there for compatibility with other channel types.

        Actual direct messages do not really have the concept of permissions.

        This returns all the Text related permissions set to true except:

        - send_tts_messages: You cannot send TTS messages in a DM.
        - manage_messages: You cannot delete others messages in a DM.

        This also checks the kick_members permission if the user is the owner.

        Parameters
        -----------
        user: :class:`User`
            The user to check permissions for.

        Returns
        --------
        :class:`Permissions`
            The resolved permissions for the user.
        """

        base = Permissions.text()
        base.send_tts_messages = False
        base.manage_messages = False
        base.mention_everyone = True

        if user.id == self.owner.id:
            base.kick_members = True

        return base

def _channel_factory(channel_type):
    value = try_enum(ChannelType, channel_type)
    if value is ChannelType.text:
        return TextChannel, value
    elif value is ChannelType.voice:
        return VoiceChannel, value
    elif value is ChannelType.private:
        return DMChannel, value
    elif value is ChannelType.group:
        return GroupChannel, value
    else:
        return None, value