update guild on channel_* events [close #411]

cache.go

@@ -76,6 +76,40 @@ type guildCacheContainer struct {
 	Members    map[Snowflake]*Member
 }
 
+func (g *guildCacheContainer) addChannelID(id Snowflake) {
+	alreadyStored := func() bool {
+		for i := range g.ChannelIDs {
+			if g.ChannelIDs[i] == id {
+				return true
+			}
+		}
+		return false
+	}
+
+	if !alreadyStored() {
+		g.ChannelIDs = append(g.ChannelIDs, id)
+	}
+}
+
+func (g *guildCacheContainer) removeChannelID(id Snowflake) {
+	index := func() int {
+		for i := range g.ChannelIDs {
+			if g.ChannelIDs[i] == id {
+				return i
+			}
+		}
+		return -1
+	}
+
+	i := index()
+	if i == -1 {
+		return
+	}
+
+	g.ChannelIDs[i] = g.ChannelIDs[len(g.ChannelIDs)-1]
+	g.ChannelIDs = g.ChannelIDs[:len(g.ChannelIDs)-1]
+}
+
 func retrieveChannels(ids []Snowflake, repo *channelsCache) []*Channel {
 	channels := make([]*Channel, 0, len(ids))
 
@@ -209,10 +243,27 @@ func (c *BasicCache) ChannelCreate(data []byte) (*ChannelCreate, error) {
 	}
 	c.Patch(channel)
 
+	channel2 := DeepCopy(channel).(*Channel)
+
+	wg := &sync.WaitGroup{}
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		if channel2.GuildID.IsZero() {
+			return
+		}
+
+		c.Guilds.Lock()
+		c.Guilds.Store[channel2.GuildID].addChannelID(channel2.ID)
+		c.Guilds.Unlock()
+	}()
+
 	c.Channels.Lock()
-	defer c.Channels.Unlock()
 	_ = c.saveChannel(channel)
-	return &ChannelCreate{Channel: DeepCopy(channel).(*Channel)}, nil
+	c.Channels.Unlock()
+
+	wg.Wait()
+	return &ChannelCreate{Channel: channel2}, nil
 }
 
 func (c *BasicCache) saveChannel(channel *Channel) error {
@@ -245,6 +296,12 @@ func (c *BasicCache) ChannelUpdate(data []byte) (*ChannelUpdate, error) {
 	}
 	channelID := metadata.ID
 
+	if !metadata.GuildID.IsZero() {
+		c.Guilds.Lock()
+		c.Guilds.Store[metadata.GuildID].addChannelID(channelID)
+		c.Guilds.Unlock()
+	}
+
 	c.Channels.Lock()
 	defer c.Channels.Unlock()
 
@@ -280,10 +337,24 @@ func (c *BasicCache) ChannelDelete(data []byte) (*ChannelDelete, error) {
 	}
 	c.Patch(cd)
 
+	wg := &sync.WaitGroup{}
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		if cd.Channel.GuildID.IsZero() {
+			return
+		}
+
+		c.Guilds.Lock()
+		c.Guilds.Store[cd.Channel.GuildID].removeChannelID(cd.Channel.ID)
+		c.Guilds.Unlock()
+	}()
+
 	c.Channels.Lock()
-	defer c.Channels.Unlock()
 	delete(c.Channels.Store, cd.Channel.ID)
+	c.Channels.Unlock()
 
+	wg.Wait()
 	return cd, nil
 }
 

cache_test.go

@@ -917,6 +917,71 @@ func TestBasicCache_Guilds(t *testing.T) {
 		}
 	})
 
+	t.Run("channel-create", func(t *testing.T) {
+		const guildID = 1
+		const channelID = 20
+
+		cache := NewBasicCache()
+		cache.Guilds.Store[guildID] = &guildCacheContainer{Guild: &Guild{ID: guildID}}
+
+		data := []byte(fmt.Sprintf(`{"id":%d,"guild_id":%d}`, channelID, guildID))
+		_, err := cacheDispatcher(cache, EvtChannelCreate, data)
+		if err != nil {
+			t.Fatal("failed to create event", err)
+		}
+
+		channelIDs := cache.Guilds.Store[guildID].ChannelIDs
+		if len(channelIDs) != 1 {
+			t.Fatal("channel was not linked to guild")
+		}
+		if channelIDs[0] != Snowflake(channelID) {
+			t.Error("wrong channel id")
+		}
+	})
+
+	t.Run("channel-update", func(t *testing.T) {
+		const guildID = 1
+		const channelID = 20
+
+		cache := NewBasicCache()
+		cache.Guilds.Store[guildID] = &guildCacheContainer{Guild: &Guild{ID: guildID}}
+
+		data := []byte(fmt.Sprintf(`{"id":%d,"guild_id":%d}`, channelID, guildID))
+		_, err := cacheDispatcher(cache, EvtChannelUpdate, data)
+		if err != nil {
+			t.Fatal("failed to create event", err)
+		}
+
+		channelIDs := cache.Guilds.Store[guildID].ChannelIDs
+		if len(channelIDs) != 1 {
+			t.Fatal("channel was not linked to guild")
+		}
+		if channelIDs[0] != Snowflake(channelID) {
+			t.Error("wrong channel id")
+		}
+	})
+
+	t.Run("channel-delete", func(t *testing.T) {
+		const guildID = 1
+		const channelID = 20
+
+		cache := NewBasicCache()
+		cache.Guilds.Store[guildID] = &guildCacheContainer{
+			Guild:      &Guild{ID: guildID},
+			ChannelIDs: []Snowflake{channelID},
+		}
+
+		data := []byte(fmt.Sprintf(`{"id":%d,"guild_id":%d}`, channelID, guildID))
+		_, err := cacheDispatcher(cache, EvtChannelDelete, data)
+		if err != nil {
+			t.Fatal("failed to create event", err)
+		}
+
+		channelIDs := cache.Guilds.Store[guildID].ChannelIDs
+		if len(channelIDs) != 0 {
+			t.Error("there should be no channels")
+		}
+	})
 }
 
 func TestBasicCache_GuildMembers(t *testing.T) {