Add support for system channel flags

4 files changed, 140 insertions, 3 deletions

diff --git a/discord/__init__.py b/discord/__init__.py
index 5a26c069..4586be59 100644
--- a/discord/__init__.py
+++ b/discord/__init__.py
@@ -26,7 +26,7 @@ from .user import User, ClientUser, Profile
 from .emoji import Emoji, PartialEmoji
 from .activity import *
 from .channel import *
-from .guild import Guild
+from .guild import Guild, SystemChannelFlags
 from .relationship import Relationship
 from .member import Member, VoiceState
 from .message import Message, Attachment
diff --git a/discord/guild.py b/discord/guild.py
index ae7140fa..fc8d22b9 100644
--- a/discord/guild.py
+++ b/discord/guild.py
@@ -48,6 +48,121 @@ from .asset import Asset
 BanEntry = namedtuple('BanEntry', 'reason user')
 _GuildLimit = namedtuple('_GuildLimit', 'emoji bitrate filesize')
 
+class _flag_descriptor:
+    def __init__(self, func):
+        self.flag = func(None)
+        self.__doc__ = func.__doc__
+
+    def __get__(self, instance, owner):
+        return instance._has_flag(self.flag)
+
+    def __set__(self, instance, value):
+        instance._set_flag(self.flag, value)
+
+def fill_with_flags(cls):
+    cls.VALID_FLAGS = {
+        name: value.flag
+        for name, value in cls.__dict__.items()
+        if isinstance(value, _flag_descriptor)
+    }
+
+    max_bits = max(cls.VALID_FLAGS.values()).bit_length()
+    cls.ALL_OFF_VALUE = -1 + (2 ** max_bits)
+    return cls
+
+@fill_with_flags
+class SystemChannelFlags:
+    r"""Wraps up a Discord system channel flag value.
+
+    Similar to :class:`Permissions`\, the properties provided are two way.
+    You can set and retrieve individual bits using the properties as if they
+    were regular bools. This allows you to edit the system flags easily.
+
+    To construct an object you can pass keyword arguments denoting the flags
+    to enable or disable.
+
+    .. container:: operations
+
+        .. describe:: x == y
+
+            Checks if two flags are equal.
+        .. describe:: x != y
+
+            Checks if two flags are not equal.
+        .. describe:: hash(x)
+
+               Return the flag's hash.
+        .. describe:: iter(x)
+
+               Returns an iterator of ``(name, value)`` pairs. This allows it
+               to be, for example, constructed as a dict or a list of pairs.
+
+    Attributes
+    -----------
+    value: :class`int`
+        The raw value. This value is a bit array field of a 53-bit integer
+        representing the currently available flags. You should query
+        flags via the properties rather than using this raw value.
+    """
+    __slots__ = ('value',)
+
+    def __init__(self, **kwargs):
+        self.value = self.ALL_OFF_VALUE
+        for key, value in kwargs.items():
+            if key not in self.VALID_FLAGS:
+                raise TypeError('%r is not a valid flag name.' % key)
+            setattr(self, key, value)
+
+    @classmethod
+    def _from_value(cls, value):
+        self = cls.__new__(cls)
+        self.value = value
+        return self
+
+    def __eq__(self, other):
+        return isinstance(other, SystemChannelFlags) and self.value == other.value
+
+    def __ne__(self, other):
+        return not self.__eq__(other)
+
+    def __hash__(self):
+        return hash(self.value)
+
+    def __repr__(self):
+        return '<SystemChannelFlags value=%s>' % self.value
+
+    def __iter__(self):
+        for name, value in self.__class__.__dict__.items():
+            if isinstance(value, _flag_descriptor):
+                yield (name, self._has_flag(value.flag))
+
+    # For some reason the flags in the Discord API are "inverted"
+    # ergo, if they're set then it means "suppress" (off in the GUI toggle)
+    # Since this is counter-intuitive from an API perspective and annoying
+    # these will be inverted automatically
+
+    def _has_flag(self, o):
+        return (self.value & o) != o
+
+    def _set_flag(self, o, toggle):
+        if toggle is True:
+            self.value &= ~o
+        elif toggle is False:
+            self.value |= o
+        else:
+            raise TypeError('Value to set for SystemChannelFlags must be a bool.')
+
+    @_flag_descriptor
+    def join_notifications(self):
+        """:class:`bool`: Returns True if the system channel is used for member join notifications."""
+        return 1
+
+    @_flag_descriptor
+    def premium_subscriptions(self):
+        """:class:`bool`: Returns True if the system channel is used for Nitro boosting notifications."""
+        return 2
+
+
 class Guild(Hashable):
     """Represents a Discord guild.
 
@@ -139,7 +254,7 @@ class Guild(Hashable):
                  'verification_level', 'explicit_content_filter', 'splash',
                  '_voice_states', '_system_channel_id', 'default_notifications',
                  'description', 'max_presences', 'max_members', 'premium_tier',
-                 'premium_subscription_count')
+                 'premium_subscription_count', '_system_channel_flags')
 
     _PREMIUM_GUILD_LIMITS = {
         None: _GuildLimit(emoji=50, bitrate=96e3, filesize=8388608),
@@ -259,6 +374,7 @@ class Guild(Hashable):
         self.max_members = guild.get('max_members')
         self.premium_tier = guild.get('premium_tier', 0)
         self.premium_subscription_count = guild.get('premium_subscription_count', 0)
+        self._system_channel_flags = guild.get('system_channel_flags', 0)
 
         for mdata in guild.get('members', []):
             member = Member(data=mdata, guild=self, state=state)
@@ -406,6 +522,11 @@ class Guild(Hashable):
         return channel_id and self._channels.get(channel_id)
 
     @property
+    def system_channel_flags(self):
+        """:class:`SystemChannelFlags`: Returns the guild's system channel settings."""
+        return SystemChannelFlags._from_value(self._system_channel_flags)
+
+    @property
     def emoji_limit(self):
         """:class:`int`: The maximum number of emoji slots this guild has."""
         more_emoji = 200 if 'MORE_EMOJI' in self.features else 50
@@ -869,6 +990,8 @@ class Guild(Hashable):
             The new vanity code for the guild.
         system_channel: Optional[:class:`TextChannel`]
             The new channel that is used for the system channel. Could be ``None`` for no system channel.
+        system_channel_flags: :class:`SystemChannelFlags`
+            The new system channel settings to use with the new system channel.
         reason: Optional[:class:`str`]
             The reason for editing this guild. Shows up on the audit log.
 
@@ -973,6 +1096,12 @@ class Guild(Hashable):
             raise InvalidArgument('explicit_content_filter field must be of type ContentFilter')
 
         fields['explicit_content_filter'] = explicit_content_filter.value
+
+        system_channel_flags = fields.get('system_channel_flags', self.system_channel_flags)
+        if not isinstance(system_channel_flags, SystemChannelFlags):
+            raise InvalidArgument('system_channel_flags field must be of type SystemChannelFlags')
+
+        fields['system_channel_flags'] = system_channel_flags.value
         await http.edit_guild(self.id, reason=reason, **fields)
 
     async def fetch_member(self, member_id):
diff --git a/discord/http.py b/discord/http.py
index bfbb4201..d3ef0b87 100644
--- a/discord/http.py
+++ b/discord/http.py
@@ -592,7 +592,8 @@ class HTTPClient:
         valid_keys = ('name', 'region', 'icon', 'afk_timeout', 'owner_id',
                       'afk_channel_id', 'splash', 'verification_level',
                       'system_channel_id', 'default_message_notifications',
-                      'description', 'explicit_content_filter', 'banner')
+                      'description', 'explicit_content_filter', 'banner',
+                      'system_channel_flags')
 
         payload = {
             k: v for k, v in fields.items() if k in valid_keys
diff --git a/docs/api.rst b/docs/api.rst
index 2464ffee..55ce36b2 100644
--- a/docs/api.rst
+++ b/docs/api.rst
@@ -2311,6 +2311,13 @@ PermissionOverwrite
 .. autoclass:: PermissionOverwrite
     :members:
 
+SystemChannelFlags
+~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: SystemChannelFlags
+    :members:
+
+
 Exceptions
 ------------