Rename the State to Cache

1 files changed, 853 insertions, 0 deletions

diff --git a/src/ext/cache/mod.rs b/src/ext/cache/mod.rs
new file mode 100644
index 0000000..484de1f
--- /dev/null
+++ b/src/ext/cache/mod.rs
@@ -0,0 +1,853 @@
+use std::collections::hash_map::Entry;
+use std::collections::HashMap;
+use std::default::Default;
+use std::mem;
+use ::model::*;
+
+/// A cache of all events received over a [`Connection`], where storing at least
+/// some data from the event is possible.
+///
+/// This acts as a cache, to avoid making requests over the REST API through the
+/// [`http`] module where possible. All fields are public, and do not have
+/// getters, to allow you more flexibility with the stored data. However, this
+/// allows data to be "corrupted", and _may or may not_ cause misfunctions
+/// within the library. Mutate data at your own discretion.
+///
+/// # Use by the Context
+///
+/// The [`Context`] will automatically attempt to pull from the cache for you.
+/// For example, the [`Context::get_channel`] method will attempt to find the
+/// channel in the cache. If it can not find it, it will perform a request
+/// through the REST API, and then insert a clone of the channel - if found -
+/// into the Cache.
+///
+/// This allows you to only need to perform the `Context::get_channel` call,
+/// and not need to first search through the cache - and if not found - _then_
+/// perform an HTTP request through the Context or `http` module.
+///
+/// Additionally, note that some information received through events can _not_
+/// be retrieved through the REST API. This is information such as [`Role`]s in
+/// [`LiveGuild`]s.
+///
+/// [`Connection`]: ../../client/struct.Connection.html
+/// [`Context`]: ../../client/struct.Context.html
+/// [`Context::get_channel`]: ../../client/struct.Context.html#method.get_channel
+/// [`LiveGuild`]: ../../model/struct.LiveGuild.html
+/// [`Role`]: ../../model/struct.Role.html
+/// [`http`]: ../../client/http/index.html
+#[derive(Debug, Clone)]
+pub struct Cache {
+    /// A map of the currently active calls that the current user knows about,
+    /// where the key is the Id of the [`PrivateChannel`] or [`Group`] hosting
+    /// the call.
+    ///
+    /// For bot users this will almost always be empty.
+    pub calls: HashMap<ChannelId, Call>,
+    /// A map of the groups that the current user is in.
+    ///
+    /// For bot users this will almost always be empty.
+    pub groups: HashMap<ChannelId, Group>,
+    /// Settings specific to a guild.
+    ///
+    /// This will always be empty for bot accounts.
+    pub guild_settings: HashMap<Option<GuildId>, UserGuildSettings>,
+    pub guilds: HashMap<GuildId, LiveGuild>,
+    /// A list of notes that a user has made for individual users.
+    ///
+    /// This will always be empty for bot accounts.
+    pub notes: HashMap<UserId, String>,
+    pub presences: HashMap<UserId, Presence>,
+    pub private_channels: HashMap<ChannelId, PrivateChannel>,
+    pub relationships: HashMap<UserId, Relationship>,
+    /// Account-specific settings for a user account.
+    pub settings: Option<UserSettings>,
+    pub unavailable_guilds: Vec<GuildId>,
+    pub user: CurrentUser,
+}
+
+impl Cache {
+    pub fn unknown_members(&self) -> u64 {
+        let mut total = 0;
+
+        for guild in self.guilds.values() {
+            let members = guild.members.len() as u64;
+
+            if guild.member_count > members {
+                total += guild.member_count - members;
+            }
+        }
+
+        total
+    }
+
+    pub fn all_private_channels(&self) -> Vec<ChannelId> {
+        self.groups
+            .keys()
+            .cloned()
+            .chain(self.private_channels.keys().cloned())
+            .collect()
+    }
+
+    pub fn all_guilds(&self) -> Vec<GuildId> {
+        self.guilds
+            .values()
+            .map(|s| s.id)
+            .chain(self.unavailable_guilds.iter().cloned())
+            .collect()
+    }
+
+    #[doc(hidden)]
+    pub fn __download_members(&mut self) -> Vec<GuildId> {
+        self.guilds
+            .values_mut()
+            .filter(|guild| guild.large)
+            .map(|ref mut guild| {
+                guild.members.clear();
+
+                guild.id
+            })
+            .collect::<Vec<_>>()
+    }
+
+    pub fn get_call<C: Into<ChannelId>>(&self, group_id: C) -> Option<&Call> {
+        self.calls.get(&group_id.into())
+    }
+
+    pub fn get_channel<C: Into<ChannelId>>(&self, id: C) -> Option<Channel> {
+        let id = id.into();
+
+        for guild in self.guilds.values() {
+            for channel in guild.channels.values() {
+                if channel.id == id {
+                    return Some(Channel::Public(channel.clone()));
+                }
+            }
+        }
+
+        None
+    }
+
+    pub fn get_guild<G: Into<GuildId>>(&self, id: G) -> Option<&LiveGuild> {
+        self.guilds.get(&id.into())
+    }
+
+    pub fn get_group<C: Into<ChannelId>>(&self, id: C) -> Option<&Group> {
+        self.groups.get(&id.into())
+    }
+
+    pub fn get_member<G, U>(&self, guild_id: G, user_id: U) -> Option<&Member>
+        where G: Into<GuildId>, U: Into<UserId> {
+        self.guilds
+            .get(&guild_id.into())
+            .map(|guild| {
+                guild.members.get(&user_id.into())
+            }).and_then(|x| match x {
+                Some(x) => Some(x),
+                _ => None,
+            })
+    }
+
+    pub fn get_role<G, R>(&self, guild_id: G, role_id: R) -> Option<&Role>
+        where G: Into<GuildId>, R: Into<RoleId> {
+        if let Some(guild) = self.guilds.get(&guild_id.into()) {
+            guild.roles.get(&role_id.into())
+        } else {
+            None
+        }
+    }
+
+    /// Update the cache according to the changes described in the given event.
+    #[allow(cyclomatic_complexity)]
+    #[allow(unneeded_field_pattern)]
+    pub fn update(&mut self, event: &Event) {
+        match *event {
+            Event::CallCreate(ref event) => {
+                self.update_with_call_create(event);
+            },
+            Event::CallDelete(ref event) => {
+                self.update_with_call_delete(event);
+            },
+            Event::CallUpdate(ref event) => {
+                self.update_with_call_update(event, false);
+            },
+            Event::ChannelCreate(ref event) => {
+                self.update_with_channel_create(event);
+            },
+            Event::ChannelDelete(ref event) => {
+                self.update_with_channel_delete(event);
+            },
+            Event::ChannelPinsUpdate(ref event) => {
+                self.update_with_channel_pins_update(event);
+            },
+            Event::ChannelRecipientAdd(ref event) => {
+                self.update_with_channel_recipient_add(event);
+            },
+            Event::ChannelRecipientRemove(ref event) => {
+                self.update_with_channel_recipient_remove(event);
+            },
+            Event::ChannelUpdate(ref event) => {
+                self.update_with_channel_update(event);
+            },
+            Event::GuildCreate(ref event) => {
+                self.update_with_guild_create(event);
+            },
+            Event::GuildDelete(ref event) => {
+                self.update_with_guild_delete(event);
+            },
+            Event::GuildEmojisUpdate(ref event) => {
+                self.update_with_guild_emojis_update(event);
+            },
+            Event::GuildMemberAdd(ref event) => {
+                self.update_with_guild_member_add(event);
+            },
+            Event::GuildMemberRemove(ref event) => {
+                self.update_with_guild_member_remove(event);
+            },
+            Event::GuildMemberUpdate(ref event) => {
+                self.update_with_guild_member_update(event);
+            },
+            Event::GuildMembersChunk(ref event) => {
+                self.update_with_guild_members_chunk(event);
+            },
+            Event::GuildRoleCreate(ref event) => {
+                self.update_with_guild_role_create(event);
+            },
+            Event::GuildRoleDelete(ref event) => {
+                self.update_with_guild_role_delete(event);
+            },
+            Event::GuildRoleUpdate(ref event) => {
+                self.update_with_guild_role_update(event);
+            },
+            Event::GuildSync(ref event) => {
+                self.update_with_guild_sync(event);
+            },
+            Event::GuildUnavailable(ref event) => {
+                self.update_with_guild_unavailable(event);
+            },
+            Event::GuildUpdate(ref event) => {
+                self.update_with_guild_update(event);
+            },
+            Event::PresencesReplace(ref event) => {
+                self.update_with_presences_replace(event);
+            },
+            Event::PresenceUpdate(ref event) => {
+                self.update_with_presence_update(event);
+            },
+            Event::Ready(ref event) => {
+                self.update_with_ready(event);
+            },
+            Event::RelationshipAdd(ref event) => {
+                self.update_with_relationship_add(event);
+            },
+            Event::RelationshipRemove(ref event) => {
+                self.update_with_relationship_remove(event);
+            },
+            Event::UserGuildSettingsUpdate(ref event) => {
+                self.update_with_user_guild_settings_update(event);
+            },
+            Event::UserNoteUpdate(ref event) => {
+                self.update_with_user_note_update(event);
+            },
+            Event::UserSettingsUpdate(ref event) => {
+                self.update_with_user_settings_update(event, false);
+            },
+            Event::UserUpdate(ref event) => {
+                self.update_with_user_update(event);
+            },
+            Event::VoiceStateUpdate(ref event) => {
+                self.update_with_voice_state_update(event);
+            },
+            Event::ChannelPinsAck(_) |
+            Event::FriendSuggestionCreate(_) |
+            Event::FriendSuggestionDelete(_) |
+            Event::GuildBanAdd(_) |
+            Event::GuildBanRemove(_) |
+            Event::GuildIntegrationsUpdate(_) |
+            Event::MessageAck(_) |
+            Event::MessageCreate(_) |
+            Event::MessageDelete(_) |
+            Event::MessageDeleteBulk(_) |
+            Event::MessageUpdate(_) |
+            Event::ReactionAdd(_) |
+            Event::ReactionRemove(_) |
+            Event::ReactionRemoveAll(_) |
+            Event::Resumed(_) |
+            Event::TypingStart(_) |
+            Event::VoiceServerUpdate(_) |
+            Event::WebhookUpdate(_) |
+            Event::Unknown(_) => {},
+        }
+    }
+
+    pub fn update_with_call_create(&mut self, event: &CallCreateEvent) {
+        match self.calls.entry(event.call.channel_id) {
+            Entry::Vacant(e) => {
+                e.insert(event.call.clone());
+            },
+            Entry::Occupied(mut e) => {
+                e.get_mut().clone_from(&event.call);
+            },
+        }
+    }
+
+    pub fn update_with_call_delete(&mut self, event: &CallDeleteEvent)
+        -> Option<Call> {
+        self.calls.remove(&event.channel_id)
+    }
+
+    pub fn update_with_call_update(&mut self, event: &CallUpdateEvent, old: bool)
+        -> Option<Call> {
+        let item = if old {
+            self.calls.get(&event.channel_id).cloned()
+        } else {
+            None
+        };
+
+        self.calls
+            .get_mut(&event.channel_id)
+            .map(|call| {
+                call.region.clone_from(&event.region);
+                call.ringing.clone_from(&event.ringing);
+            });
+
+        item
+    }
+
+    pub fn update_with_channel_create(&mut self, event: &ChannelCreateEvent)
+        -> Option<Channel> {
+        match event.channel {
+            Channel::Group(ref group) => {
+                let ch = self.groups.insert(group.channel_id, group.clone());
+
+                ch.map(Channel::Group)
+            },
+            Channel::Private(ref channel) => {
+                let ch = self.private_channels.insert(channel.id, channel.clone());
+
+                ch.map(Channel::Private)
+            },
+            Channel::Public(ref channel) => {
+                let ch = self.guilds
+                    .get_mut(&channel.guild_id)
+                    .map(|guild| {
+                        guild.channels.insert(channel.id, channel.clone())
+                    });
+
+                let ch = match ch {
+                    Some(Some(ch)) => Some(ch),
+                    _ => None,
+                };
+
+                ch.map(Channel::Public)
+            },
+        }
+    }
+
+    pub fn update_with_channel_delete(&mut self, event: &ChannelDeleteEvent)
+        -> Option<Channel> {
+        match event.channel {
+            Channel::Group(ref group) => {
+                self.groups.remove(&group.channel_id).map(Channel::Group)
+            },
+            Channel::Private(ref channel) => {
+                self.private_channels.remove(&channel.id)
+                    .map(Channel::Private)
+            },
+            Channel::Public(ref channel) => {
+                let ch = self.guilds
+                    .get_mut(&channel.guild_id)
+                    .map(|guild| guild.channels.remove(&channel.id));
+
+                match ch {
+                    Some(Some(ch)) => Some(Channel::Public(ch)),
+                    _ => None,
+                }
+            },
+        }
+    }
+
+    pub fn update_with_channel_pins_update(&mut self,
+                                           event: &ChannelPinsUpdateEvent) {
+        if let Some(channel) = self.private_channels.get_mut(&event.channel_id) {
+            channel.last_pin_timestamp = event.last_pin_timestamp.clone();
+
+            return;
+        }
+
+        if let Some(group) = self.groups.get_mut(&event.channel_id) {
+            group.last_pin_timestamp = event.last_pin_timestamp.clone();
+
+            return;
+        }
+
+        // Guild searching is last because it is expensive
+        // in comparison to private channel and group searching.
+        for guild in self.guilds.values_mut() {
+            for channel in guild.channels.values_mut() {
+                if channel.id == event.channel_id {
+                    channel.last_pin_timestamp = event.last_pin_timestamp.clone();
+
+                    return;
+                }
+            }
+        }
+    }
+
+    pub fn update_with_channel_recipient_add(&mut self,
+                                             event: &ChannelRecipientAddEvent) {
+        self.groups
+            .get_mut(&event.channel_id)
+            .map(|group| group.recipients.insert(event.user.id,
+                                                 event.user.clone()));
+    }
+
+    pub fn update_with_channel_recipient_remove(&mut self,
+                                                event: &ChannelRecipientRemoveEvent) {
+        self.groups
+            .get_mut(&event.channel_id)
+            .map(|group| group.recipients.remove(&event.user.id));
+    }
+
+    pub fn update_with_channel_update(&mut self, event: &ChannelUpdateEvent) {
+        match event.channel {
+            Channel::Group(ref group) => {
+                match self.groups.entry(group.channel_id) {
+                    Entry::Vacant(e) => {
+                        e.insert(group.clone());
+                    },
+                    Entry::Occupied(mut e) => {
+                        let dest = e.get_mut();
+
+                        if group.recipients.is_empty() {
+                            let recipients = mem::replace(&mut dest.recipients, HashMap::new());
+
+                            dest.clone_from(group);
+
+                            dest.recipients = recipients;
+                        } else {
+                            dest.clone_from(group);
+                        }
+                    },
+                }
+            },
+            Channel::Private(ref channel) => {
+                self.private_channels
+                    .get_mut(&channel.id)
+                    .map(|private| private.clone_from(channel));
+            },
+            Channel::Public(ref channel) => {
+                self.guilds
+                    .get_mut(&channel.guild_id)
+                    .map(|guild| guild.channels
+                        .insert(channel.id, channel.clone()));
+            },
+        }
+    }
+
+    pub fn update_with_guild_create(&mut self, event: &GuildCreateEvent) {
+        self.guilds.insert(event.guild.id, event.guild.clone());
+    }
+
+    pub fn update_with_guild_delete(&mut self, event: &GuildDeleteEvent)
+        -> Option<LiveGuild> {
+        self.guilds.remove(&event.guild.id)
+    }
+
+    pub fn update_with_guild_emojis_update(&mut self,
+                                           event: &GuildEmojisUpdateEvent) {
+        self.guilds
+            .get_mut(&event.guild_id)
+            .map(|guild| guild.emojis.extend(event.emojis.clone()));
+    }
+
+    pub fn update_with_guild_member_add(&mut self,
+                                        event: &GuildMemberAddEvent) {
+        self.guilds
+            .get_mut(&event.guild_id)
+            .map(|guild| {
+                guild.member_count += 1;
+                guild.members.insert(event.member.user.id,
+                                     event.member.clone());
+            });
+    }
+
+    pub fn update_with_guild_member_remove(&mut self,
+                                           event: &GuildMemberRemoveEvent)
+                                           -> Option<Member> {
+        let member = self.guilds
+            .get_mut(&event.guild_id)
+            .map(|guild| {
+                guild.member_count -= 1;
+                guild.members.remove(&event.user.id)
+            });
+
+        match member {
+            Some(Some(member)) => Some(member),
+            _ => None,
+        }
+    }
+
+    pub fn update_with_guild_member_update(&mut self,
+                                           event: &GuildMemberUpdateEvent)
+                                           -> Option<Member> {
+        if let Some(guild) = self.guilds.get_mut(&event.guild_id) {
+            let mut found = false;
+
+            let item = if let Some(member) = guild.members.get_mut(&event.user.id) {
+                let item = Some(member.clone());
+
+                member.nick.clone_from(&event.nick);
+                member.roles.clone_from(&event.roles);
+                member.user.clone_from(&event.user);
+
+                found = true;
+
+                item
+            } else {
+                None
+            };
+
+            if !found {
+                guild.members.insert(event.user.id, Member {
+                    deaf: false,
+                    joined_at: String::default(),
+                    mute: false,
+                    nick: event.nick.clone(),
+                    roles: event.roles.clone(),
+                    user: event.user.clone(),
+                });
+            }
+
+            item
+        } else {
+            None
+        }
+    }
+
+    pub fn update_with_guild_members_chunk(&mut self,
+                                           event: &GuildMembersChunkEvent) {
+        self.guilds
+            .get_mut(&event.guild_id)
+            .map(|guild| guild.members.extend(event.members.clone()));
+    }
+
+    pub fn update_with_guild_role_create(&mut self,
+                                         event: &GuildRoleCreateEvent) {
+        self.guilds
+            .get_mut(&event.guild_id)
+            .map(|guild| guild.roles.insert(event.role.id, event.role.clone()));
+    }
+
+    pub fn update_with_guild_role_delete(&mut self,
+                                         event: &GuildRoleDeleteEvent)
+                                         -> Option<Role> {
+        let role = self.guilds
+            .get_mut(&event.guild_id)
+            .map(|guild| guild.roles.remove(&event.role_id));
+
+        match role {
+            Some(Some(x)) => Some(x),
+            _ => None,
+        }
+    }
+
+    pub fn update_with_guild_role_update(&mut self,
+                                         event: &GuildRoleUpdateEvent)
+                                         -> Option<Role> {
+        let item = self.guilds
+            .get_mut(&event.guild_id)
+            .map(|guild| guild.roles
+                .get_mut(&event.role.id)
+                .map(|role| mem::replace(role, event.role.clone())));
+
+        match item {
+            Some(Some(x)) => Some(x),
+            _ => None,
+        }
+    }
+
+    pub fn update_with_guild_sync(&mut self, event: &GuildSyncEvent) {
+        self.guilds
+            .get_mut(&event.guild_id)
+            .map(|guild| {
+                guild.large = event.large;
+                guild.members.clone_from(&event.members);
+                guild.presences.clone_from(&event.presences);
+            });
+    }
+
+    pub fn update_with_guild_unavailable(&mut self,
+                                         event: &GuildUnavailableEvent) {
+        if !self.unavailable_guilds.contains(&event.guild_id) {
+            self.unavailable_guilds.push(event.guild_id);
+        }
+    }
+
+    pub fn update_with_guild_update(&mut self, event: &GuildUpdateEvent) {
+        self.guilds
+            .get_mut(&event.guild.id)
+            .map(|guild| {
+                guild.afk_timeout = event.guild.afk_timeout;
+                guild.afk_channel_id.clone_from(&event.guild.afk_channel_id);
+                guild.icon.clone_from(&event.guild.icon);
+                guild.name.clone_from(&event.guild.name);
+                guild.owner_id.clone_from(&event.guild.owner_id);
+                guild.region.clone_from(&event.guild.region);
+                guild.roles.clone_from(&event.guild.roles);
+                guild.verification_level = event.guild.verification_level;
+            });
+    }
+
+    pub fn update_with_presences_replace(&mut self, event: &PresencesReplaceEvent) {
+        self.presences.clone_from(&{
+            let mut p = HashMap::default();
+
+            for presence in &event.presences {
+                p.insert(presence.user_id, presence.clone());
+            }
+
+            p
+        });
+    }
+
+    pub fn update_with_presence_update(&mut self, event: &PresenceUpdateEvent) {
+        if let Some(guild_id) = event.guild_id {
+            if let Some(guild) = self.guilds.get_mut(&guild_id) {
+                // If the user was modified, update the member list
+                if let Some(user) = event.presence.user.as_ref() {
+                    guild.members
+                        .get_mut(&user.id)
+                        .map(|member| member.user.clone_from(user));
+                }
+
+                update_presence(&mut guild.presences, &event.presence);
+            }
+        }
+    }
+
+    pub fn update_with_ready(&mut self, ready: &ReadyEvent) {
+        let ready = ready.ready.clone();
+
+        for guild in ready.guilds {
+            match guild {
+                PossibleGuild::Offline(guild_id) => {
+                    self.unavailable_guilds.push(guild_id);
+                }
+                PossibleGuild::Online(guild) => {
+                    self.guilds.insert(guild.id, guild);
+                },
+            }
+        }
+
+        self.unavailable_guilds.sort();
+        self.unavailable_guilds.dedup();
+
+        // The private channels sent in the READY contains both the actual
+        // private channels, and the groups.
+        for (channel_id, channel) in ready.private_channels {
+            match channel {
+                Channel::Group(group) => {
+                    self.groups.insert(channel_id, group);
+                },
+                Channel::Private(channel) => {
+                    self.private_channels.insert(channel_id, channel);
+                },
+                Channel::Public(_) => {},
+            }
+        }
+
+        for guild in ready.user_guild_settings.unwrap_or_default() {
+            self.guild_settings.insert(guild.guild_id, guild);
+        }
+
+        for (user_id, presence) in ready.presences {
+            self.presences.insert(user_id, presence);
+        }
+
+        for (user_id, relationship) in ready.relationships {
+            self.relationships.insert(user_id, relationship);
+        }
+
+        self.notes.extend(ready.notes);
+
+        self.settings = ready.user_settings;
+        self.user = ready.user;
+    }
+
+    pub fn update_with_relationship_add(&mut self, event: &RelationshipAddEvent) {
+        self.relationships.insert(event.relationship.id,
+                                  event.relationship.clone());
+    }
+
+    pub fn update_with_relationship_remove(&mut self,
+                                           event: &RelationshipRemoveEvent) {
+        self.relationships.remove(&event.user_id);
+    }
+
+    pub fn update_with_user_guild_settings_update(&mut self,
+                                                  event: &UserGuildSettingsUpdateEvent)
+                                                  -> Option<UserGuildSettings> {
+        self.guild_settings
+            .get_mut(&event.settings.guild_id)
+            .map(|guild_setting| mem::replace(guild_setting, event.settings.clone()))
+    }
+
+    pub fn update_with_user_note_update(&mut self,
+                                        event: &UserNoteUpdateEvent)
+                                        -> Option<String> {
+        if event.note.is_empty() {
+            self.notes.remove(&event.user_id)
+        } else {
+            self.notes.insert(event.user_id, event.note.clone())
+        }
+    }
+
+    pub fn update_with_user_settings_update(&mut self,
+                                            event: &UserSettingsUpdateEvent,
+                                            old: bool)
+                                            -> Option<UserSettings> {
+        let item = if old {
+            self.settings.clone()
+        } else {
+            None
+        };
+
+        self.settings
+            .as_mut()
+            .map(|settings| {
+                opt_modify(&mut settings.enable_tts_command, &event.enable_tts_command);
+                opt_modify(&mut settings.inline_attachment_media, &event.inline_attachment_media);
+                opt_modify(&mut settings.inline_embed_media, &event.inline_embed_media);
+                opt_modify(&mut settings.locale, &event.locale);
+                opt_modify(&mut settings.message_display_compact, &event.message_display_compact);
+                opt_modify(&mut settings.render_embeds, &event.render_embeds);
+                opt_modify(&mut settings.show_current_game, &event.show_current_game);
+                opt_modify(&mut settings.theme, &event.theme);
+                opt_modify(&mut settings.convert_emoticons, &event.convert_emoticons);
+                opt_modify(&mut settings.friend_source_flags, &event.friend_source_flags);
+            });
+
+        item
+    }
+
+    pub fn update_with_user_update(&mut self, event: &UserUpdateEvent)
+        -> CurrentUser {
+        mem::replace(&mut self.user, event.current_user.clone())
+    }
+
+    pub fn update_with_voice_state_update(&mut self,
+                                          event: &VoiceStateUpdateEvent) {
+        if let Some(guild_id) = event.guild_id {
+            if let Some(guild) = self.guilds.get_mut(&guild_id) {
+                if event.voice_state.channel_id.is_some() {
+                    // Update or add to the voice state list
+                    {
+                        let finding = guild.voice_states
+                            .get_mut(&event.voice_state.user_id);
+
+                        if let Some(srv_state) = finding {
+                            srv_state.clone_from(&event.voice_state);
+
+                            return;
+                        }
+                    }
+
+                    guild.voice_states.insert(event.voice_state.user_id,
+                                              event.voice_state.clone());
+                } else {
+                    // Remove the user from the voice state list
+                    guild.voice_states.remove(&event.voice_state.user_id);
+                }
+            }
+
+            return;
+        }
+
+        if let Some(channel) = event.voice_state.channel_id {
+            // channel id available, insert voice state
+            if let Some(call) = self.calls.get_mut(&channel) {
+                {
+                    let finding = call.voice_states
+                        .get_mut(&event.voice_state.user_id);
+
+                    if let Some(grp_state) = finding {
+                        grp_state.clone_from(&event.voice_state);
+
+                        return;
+                    }
+                }
+
+                call.voice_states.insert(event.voice_state.user_id,
+                                         event.voice_state.clone());
+            }
+        } else {
+            // delete this user from any group call containing them
+            for call in self.calls.values_mut() {
+                call.voice_states.remove(&event.voice_state.user_id);
+            }
+        }
+    }
+}
+
+impl Default for Cache {
+    fn default() -> Cache {
+        Cache {
+            calls: HashMap::default(),
+            groups: HashMap::default(),
+            guild_settings: HashMap::default(),
+            guilds: HashMap::default(),
+            notes: HashMap::default(),
+            presences: HashMap::default(),
+            private_channels: HashMap::default(),
+            relationships: HashMap::default(),
+            settings: None,
+            unavailable_guilds: Vec::default(),
+            user: CurrentUser {
+                avatar: None,
+                bot: false,
+                discriminator: 0,
+                email: None,
+                id: UserId(0),
+                mfa_enabled: false,
+                mobile: None,
+                name: String::default(),
+                verified: false,
+            }
+        }
+    }
+}
+
+fn update_presence(presences: &mut HashMap<UserId, Presence>,
+                   presence: &Presence) {
+    if presence.status == OnlineStatus::Offline {
+        // Remove the user from the presence list
+        presences.remove(&presence.user_id);
+    } else {
+        // Update or add to the presence list
+        if let Some(ref mut guild_presence) = presences.get(&presence.user_id) {
+            if presence.user.is_none() {
+                guild_presence.clone_from(&presence);
+            }
+
+            return;
+        }
+        presences.insert(presence.user_id, presence.clone());
+    }
+}
+
+/// A reference to a private channel, public channel, or group.
+#[derive(Debug, Clone, Copy)]
+pub enum ChannelRef<'a> {
+    /// A private channel
+    Private(&'a PrivateChannel),
+    /// A group channel
+    Group(&'a Group),
+    /// A public channel and its guild
+    Public(&'a LiveGuild, &'a PublicChannel),
+}
+
+fn opt_modify<T: Clone>(dest: &mut T, src: &Option<T>) {
+    if let Some(val) = src.as_ref() {
+        dest.clone_from(val);
+    }
+}