Remove support for group calls and guild sync

Calls and guild sync are essentially leftovers from selfbot support
removal, the former moreso.

Removes the following `model::event` structs:

- CallCreateEvent
- CallDeleteEvent
- CallUpdateEvent
- GuildSyncEvent

which also removes the following `model::event::Event` variants:

`client::gateway::Shard::sync_calls` has been removed.

The following `client::Client` methods have been removed:

- `on_call_create`
- `on_call_delete`
- `on_call_update`
- `on_guild_sync`

Removes the following items on `ext::cache::Cache`:

```
ext::cache::Cache::{
    // fields
    calls,
    // methods
    get_call,
    update_with_call_create,
    update_with_call_delete,
    update_with_call_update,
    update_with_guild_sync,
}
```

Voice structs and methods now take solely a `guild_id` instead of a
`target`, due to the handling of 1-on-1 and group calls being removed.

This continues off commit d9118c0.<Paste>

4 files changed, 3 insertions, 176 deletions

diff --git a/src/client/dispatch.rs b/src/client/dispatch.rs
index 49dbdb0..fd46394 100644
--- a/src/client/dispatch.rs
+++ b/src/client/dispatch.rs
@@ -121,56 +121,6 @@ fn handle_event(event: Event,
                 data: &Arc<Mutex<ShareMap>>,
                 event_store: &Arc<RwLock<EventStore>>) {
     match event {
-        Event::CallCreate(event) => {
-            if let Some(handler) = handler!(on_call_create, event_store) {
-                update!(update_with_call_create, event);
-
-                let context = context(None, conn, data);
-
-                thread::spawn(move || (handler)(context, event.call));
-            } else {
-                update!(update_with_call_create, event);
-            }
-        },
-        Event::CallDelete(event) => {
-            if let Some(handler) = handler!(on_call_delete, event_store) {
-                let context = context(None, conn, data);
-
-                feature_cache! {{
-                    let call = update!(update_with_call_delete, event);
-
-                    thread::spawn(move || (handler)(context, event.channel_id, call));
-                } else {
-                    thread::spawn(move || (handler)(context, event.channel_id));
-                }}
-            } else {
-                update!(update_with_call_delete, event);
-            }
-        },
-        Event::CallUpdate(event) => {
-            if let Some(handler) = handler!(on_call_update, event_store) {
-                let context = context(None, conn, data);
-
-                feature_cache! {{
-                    let before = update!(update_with_call_update, event, true);
-                    let after = CACHE
-                        .read()
-                        .unwrap()
-                        .calls
-                        .get(&event.channel_id)
-                        .cloned();
-
-                    thread::spawn(move || (handler)(context, before, after));
-                } else {
-                    thread::spawn(move || (handler)(context, event));
-                }}
-            } else {
-                #[cfg(feature="cache")]
-                {
-                    update!(update_with_call_update, event, false);
-                }
-            }
-        },
         Event::ChannelCreate(event) => {
             if let Some(handler) = handler!(on_channel_create, event_store) {
                 update!(update_with_channel_create, event);
@@ -403,13 +353,6 @@ fn handle_event(event: Event,
                 }
             }
         },
-        Event::GuildSync(event) => {
-            if let Some(handler) = handler!(on_guild_sync, event_store) {
-                let context = context(None, conn, data);
-
-                thread::spawn(move || (handler)(context, event));
-            }
-        },
         Event::GuildUnavailable(event) => {
             update!(update_with_guild_unavailable, event);
 
diff --git a/src/client/event_store.rs b/src/client/event_store.rs
index cc74d63..9ec465c 100644
--- a/src/client/event_store.rs
+++ b/src/client/event_store.rs
@@ -2,24 +2,12 @@ use serde_json::Value;
 use std::collections::{BTreeMap, HashMap};
 use std::sync::Arc;
 use super::context::Context;
-use ::model::event::{
-    ChannelPinsAckEvent,
-    ChannelPinsUpdateEvent,
-    GuildSyncEvent,
-    MessageUpdateEvent,
-    PresenceUpdateEvent,
-    ResumedEvent,
-    TypingStartEvent,
-    VoiceServerUpdateEvent,
-};
+use ::model::event::*;
 use ::model::*;
 
 #[cfg(feature="cache")]
 use std::sync::RwLock;
 
-#[cfg(not(feature="cache"))]
-use ::model::event::{CallUpdateEvent, GuildMemberUpdateEvent};
-
 // This should use type macros when stable receives the type macro
 // stabilization patch.
 //
@@ -41,15 +29,6 @@ use ::model::event::{CallUpdateEvent, GuildMemberUpdateEvent};
 #[allow(type_complexity)]
 #[derive(Default)]
 pub struct EventStore {
-    pub on_call_create: Option<Arc<Fn(Context, Call) + Send + Sync + 'static>>,
-    #[cfg(feature="cache")]
-    pub on_call_delete: Option<Arc<Fn(Context, ChannelId, Option<Arc<RwLock<Call>>>) + Send + Sync + 'static>>,
-    #[cfg(not(feature="cache"))]
-    pub on_call_delete: Option<Arc<Fn(Context, ChannelId) + Send + Sync + 'static>>,
-    #[cfg(feature="cache")]
-    pub on_call_update: Option<Arc<Fn(Context, Option<Arc<RwLock<Call>>>, Option<Arc<RwLock<Call>>>) + Send + Sync + 'static>>,
-    #[cfg(not(feature="cache"))]
-    pub on_call_update: Option<Arc<Fn(Context, CallUpdateEvent) + Send + Sync + 'static>>,
     pub on_channel_create: Option<Arc<Fn(Context, Channel) + Send + Sync + 'static>>,
     pub on_channel_delete: Option<Arc<Fn(Context, Channel) + Send + Sync + 'static>>,
     pub on_channel_pins_ack: Option<Arc<Fn(Context, ChannelPinsAckEvent) + Send + Sync + 'static>>,
@@ -88,7 +67,6 @@ pub struct EventStore {
     pub on_guild_role_update: Option<Arc<Fn(Context, GuildId, Option<Role>, Role) + Send + Sync + 'static>>,
     #[cfg(not(feature="cache"))]
     pub on_guild_role_update: Option<Arc<Fn(Context, GuildId, Role) + Send + Sync + 'static>>,
-    pub on_guild_sync: Option<Arc<Fn(Context, GuildSyncEvent) + Send + Sync + 'static>>,
     pub on_guild_unavailable: Option<Arc<Fn(Context, GuildId) + Send + Sync + 'static>>,
     #[cfg(feature="cache")]
     pub on_guild_update: Option<Arc<Fn(Context, Option<Arc<RwLock<Guild>>>, PartialGuild) + Send + Sync + 'static>>,
diff --git a/src/client/gateway/shard.rs b/src/client/gateway/shard.rs
index f42c52a..627ba52 100644
--- a/src/client/gateway/shard.rs
+++ b/src/client/gateway/shard.rs
@@ -18,7 +18,7 @@ use ::constants::OpCode;
 use ::internal::prelude::*;
 use ::internal::ws_impl::{ReceiverExt, SenderExt};
 use ::model::event::{Event, GatewayEvent, ReadyEvent};
-use ::model::{ChannelId, Game, GuildId, OnlineStatus};
+use ::model::{Game, GuildId, OnlineStatus};
 
 #[cfg(feature="cache")]
 use ::client::CACHE;
@@ -483,22 +483,6 @@ impl Shard {
         Ok(())
     }
 
-    /// Syncs a number of [`Call`]s, given by their associated channel Ids. This
-    /// will allow the current user to know what calls are currently occurring,
-    /// as otherwise events will not be received.
-    pub fn sync_calls(&self, channels: &[ChannelId]) {
-        for &channel in channels {
-            let msg = ObjectBuilder::new()
-                .insert("op", OpCode::SyncCall.num())
-                .insert_object("d", |obj| obj
-                    .insert("channel_id", channel.0)
-                )
-                .build();
-
-            let _ = self.keepalive_channel.send(GatewayStatus::SendMessage(msg));
-        }
-    }
-
     /// Requests that one or multiple [`Guild`]s be synced.
     ///
     /// This will ask Discord to start sending member chunks for large guilds
diff --git a/src/client/mod.rs b/src/client/mod.rs
index 9286379..8c073b1 100644
--- a/src/client/mod.rs
+++ b/src/client/mod.rs
@@ -44,19 +44,7 @@ use websocket::result::WebSocketError;
 use websocket::stream::WebSocketStream;
 use ::internal::prelude::{Error, Result, Value};
 use ::internal::ws_impl::ReceiverExt;
-use ::model::event::{
-    ChannelPinsAckEvent,
-    ChannelPinsUpdateEvent,
-    Event,
-    GatewayEvent,
-    GuildSyncEvent,
-    MessageUpdateEvent,
-    PresenceUpdateEvent,
-    ReadyEvent,
-    ResumedEvent,
-    TypingStartEvent,
-    VoiceServerUpdateEvent,
-};
+use ::model::event::*;
 use ::model::*;
 
 #[cfg(feature="framework")]
@@ -65,9 +53,6 @@ use ::ext::framework::Framework;
 #[cfg(feature="cache")]
 use ::ext::cache::Cache;
 
-#[cfg(not(feature="cache"))]
-use ::model::event::{CallUpdateEvent, GuildMemberUpdateEvent};
-
 #[cfg(feature="cache")]
 lazy_static! {
     /// A mutable and lazily-initialized static binding. It can be accessed
@@ -326,16 +311,6 @@ impl Client {
         self.start_connection(Some([range[0], range[1], total_shards]), rest::get_gateway()?.url)
     }
 
-    /// Attaches a handler for when a [`CallCreate`] is received.
-    ///
-    /// [`CallCreate`]: ../model/event/enum.Event.html#variant.CallCreate
-    pub fn on_call_create<F>(&mut self, handler: F)
-        where F: Fn(Context, Call) + Send + Sync + 'static {
-        self.event_store.write()
-            .unwrap()
-            .on_call_create = Some(Arc::new(handler));
-    }
-
     /// Attaches a handler for when a [`ChannelCreate`] is received.
     ///
     /// [`ChannelCreate`]: ../model/event/enum.Event.html#variant.ChannelCreate
@@ -438,16 +413,6 @@ impl Client {
             .on_guild_role_create = Some(Arc::new(handler));
     }
 
-    /// Attaches a handler for when a [`GuildRoleSync`] is received.
-    ///
-    /// [`GuildRoleSync`]: ../model/event/enum.Event.html#variant.GuildRoleSync
-    pub fn on_guild_sync<F>(&mut self, handler: F)
-        where F: Fn(Context, GuildSyncEvent) + Send + Sync + 'static {
-        self.event_store.write()
-            .unwrap()
-            .on_guild_sync = Some(Arc::new(handler));
-    }
-
     /// Attaches a handler for when a [`GuildUnavailable`] is received.
     ///
     /// [`GuildUnavailable`]: ../model/event/enum.Event.html#variant.GuildUnavailable
@@ -809,29 +774,6 @@ impl Client {
 
 #[cfg(feature="cache")]
 impl Client {
-    /// Attaches a handler for when a [`CallDelete`] is received.
-    ///
-    /// The `ChannelId` is the Id of the channel hosting the call. Returns the
-    /// call from the cache - optionally - if the call was in it.
-    ///
-    /// [`CallDelete`]: ../model/event/enum.Event.html#variant.CallDelete
-    pub fn on_call_delete<F>(&mut self, handler: F)
-        where F: Fn(Context, ChannelId, Option<Arc<RwLock<Call>>>) + Send + Sync + 'static {
-        self.event_store.write()
-            .unwrap()
-            .on_call_delete = Some(Arc::new(handler));
-    }
-
-    /// Attaches a handler for when a [`CallUpdate`] is received.
-    ///
-    /// [`CallUpdate`]: ../model/event/enum.Event.html#variant.CallUpdate
-    pub fn on_call_update<F>(&mut self, handler: F)
-        where F: Fn(Context, Option<Arc<RwLock<Call>>>, Option<Arc<RwLock<Call>>>) + Send + Sync + 'static {
-        self.event_store.write()
-            .unwrap()
-            .on_call_update = Some(Arc::new(handler));
-    }
-
     /// Attaches a handler for when a [`ChannelUpdate`] is received.
     ///
     /// Optionally provides the version of the channel before the update.
@@ -936,26 +878,6 @@ impl Client {
 
 #[cfg(not(feature="cache"))]
 impl Client {
-    /// Attaches a handler for when a [`CallDelete`] is received.
-    ///
-    /// [`CallDelete`]: ../model/event/enum.Event.html#variant.CallDelete
-    pub fn on_call_delete<F>(&mut self, handler: F)
-        where F: Fn(Context, ChannelId) + Send + Sync + 'static {
-        self.event_store.write()
-            .unwrap()
-            .on_call_delete = Some(Arc::new(handler));
-    }
-
-    /// Attaches a handler for when a [`CallUpdate`] is received.
-    ///
-    /// [`CallUpdate`]: ../model/event/enum.Event.html#variant.CallUpdate
-    pub fn on_call_update<F>(&mut self, handler: F)
-        where F: Fn(Context, CallUpdateEvent) + Send + Sync + 'static {
-        self.event_store.write()
-            .unwrap()
-            .on_call_update = Some(Arc::new(handler));
-    }
-
     /// Attaches a handler for when a [`ChannelUpdate`] is received.
     ///
     /// [`ChannelUpdate`]: ../model/event/enum.Event.html#variant.ChannelUpdate