feature: add player

lavalink.go

@@ -12,11 +12,14 @@ type Lavalink struct {
 	UserID int
 
 	nodes   []Node
+	players map[string]*Player
 }
 
 var (
 	errNoNodes          = errors.New("No nodes present")
 	errNodeNotFound     = errors.New("Couldn't find that node")
+	errPlayerNotFound   = errors.New("Couldn't find a player for that guild")
+	errVolumeOutOfRange = errors.New("Volume is out of range, must be within [0, 1000]")
 	errInvalidVersion   = errors.New("This library requires Lavalink >= 3")
 	errUnknownPayload   = errors.New("Lavalink sent an unknown payload")
 )
@@ -74,3 +77,12 @@ func (lavalink *Lavalink) BestNode() (*Node, error) {
 	// TODO: lookup latency
 	return &lavalink.nodes[0], nil
 }
+
+// GetPlayer gets a player for a guild
+func (lavalink *Lavalink) GetPlayer(guild string) (*Player, error) {
+	p, ok := lavalink.players[guild]
+	if !ok {
+		return nil, errPlayerNotFound
+	}
+	return p, nil
+}

model.go

@@ -51,3 +51,46 @@ type TrackInfo struct {
 	Length     int    `json:"length"`
 	Position   int    `json:"position"`
 }
+
+const (
+	opVoiceUpdate  = "voiceUpdate"
+	opPlay         = "play"
+	opStop         = "stop"
+	opPause        = "pause"
+	opSeek         = "seek"
+	opVolume       = "volume"
+	opDestroy      = "destroy"
+	opPlayerUpdate = "playerUpdate"
+	opEvent        = "event"
+)
+
+type message struct {
+	Op          string             `json:"op"`
+	GuildID     string             `json:"guildId,omitempty"`
+	SessionID   string             `json:"sessionId,omitempty"`
+	Event       *VoiceServerUpdate `json:"event,omitempty"`
+	Track       string             `json:"track,omitempty"`
+	StartTime   string             `json:"startTime,omitempty"`
+	EndTime     string             `json:"endTime,omitempty"`
+	Pause       bool               `json:"pause,omitempty"`
+	Position    int                `json:"position,omitempty"`
+	Volume      int                `json:"volume,omitempty"`
+	State       *state             `json:"state,omitempty"`
+	Type        string             `json:"type,omitempty"`
+	Reason      string             `json:"reason,omitempty"`
+	Error       string             `json:"error,omitempty"`
+	ThresholdMs int                `json:"thresholdMs,omitempty"`
+	// TODO: stats
+}
+
+type state struct {
+	Time     int `json:"time"`
+	Position int `json:"position"`
+}
+
+// VoiceServerUpdate is a raw Discord VOICE_SERVER_UPDATE event
+type VoiceServerUpdate struct {
+	GuildID  int    `json:"guild_id"`
+	Endpoint string `json:"endpoint"`
+	Token    string `json:"token"`
+}

node.go

@@ -93,9 +93,50 @@ func (node *Node) onEvent(msgType int, msg []byte) error {
 	if msgType != websocket.TextMessage {
 		return errUnknownPayload
 	}
+
+	m := message{}
+	err := json.Unmarshal(msg, &m)
+	if err != nil {
+		return err
+	}
+
+	switch m.Op {
+	case opPlayerUpdate:
+		// todo
+	case opEvent:
+		// todo
+	default:
+		return errUnknownPayload
+	}
+
 	return nil
 }
 
+// CreatePlayer creates an audio player on this node
+func (node *Node) CreatePlayer(guildID string, sessionID string, event VoiceServerUpdate) (*Player, error) {
+	msg := message{
+		Op:        opVoiceUpdate,
+		GuildID:   guildID,
+		SessionID: sessionID,
+		Event:     &event,
+	}
+	data, err := json.Marshal(msg)
+	if err != nil {
+		return nil, err
+	}
+	err = node.wsConn.WriteMessage(websocket.TextMessage, data)
+	if err != nil {
+		return nil, err
+	}
+	player := &Player{
+		guildID: guildID,
+		manager: node.manager,
+		node:    node,
+	}
+	node.manager.players[guildID] = player
+	return player, nil
+}
+
 // LoadTracks queries lavalink to return a Tracks object
 //
 // query should be a valid Lavaplayer query, including but not limited to:

player.go

@@ -0,0 +1,124 @@
+package gavalink
+
+import (
+	"encoding/json"
+	"strconv"
+
+	"github.com/gorilla/websocket"
+)
+
+// Player is a Lavalink player
+type Player struct {
+	guildID string
+	manager *Lavalink
+	node    *Node
+}
+
+// Play will play the given track completely
+func (player *Player) Play(track string) error {
+	return player.PlayAt(track, 0, 0)
+}
+
+// PlayAt will play the given track at the specified start and end times
+//
+// Setting a time to 0 will omit it.
+func (player *Player) PlayAt(track string, startTime int, endTime int) error {
+	start := strconv.Itoa(startTime)
+	end := strconv.Itoa(endTime)
+
+	msg := message{
+		Op:        opPlay,
+		Track:     track,
+		StartTime: start,
+		EndTime:   end,
+	}
+	data, err := json.Marshal(msg)
+	if err != nil {
+		return err
+	}
+	err = player.node.wsConn.WriteMessage(websocket.TextMessage, data)
+	return err
+}
+
+// Stop will stop the currently playing track
+func (player *Player) Stop() error {
+	msg := message{
+		Op:      opStop,
+		GuildID: player.guildID,
+	}
+	data, err := json.Marshal(msg)
+	if err != nil {
+		return err
+	}
+	err = player.node.wsConn.WriteMessage(websocket.TextMessage, data)
+	return err
+}
+
+// Pause will pause or resume the player, depending on the pause parameter
+func (player *Player) Pause(pause bool) error {
+	msg := message{
+		Op:      opPause,
+		GuildID: player.guildID,
+		Pause:   pause,
+	}
+	data, err := json.Marshal(msg)
+	if err != nil {
+		return err
+	}
+	err = player.node.wsConn.WriteMessage(websocket.TextMessage, data)
+	return err
+}
+
+// Seek will seek the player to the speicifed position, in millis
+func (player *Player) Seek(position int) error {
+	msg := message{
+		Op:       opSeek,
+		GuildID:  player.guildID,
+		Position: position,
+	}
+	data, err := json.Marshal(msg)
+	if err != nil {
+		return err
+	}
+	err = player.node.wsConn.WriteMessage(websocket.TextMessage, data)
+	return err
+}
+
+// Volume will set the player's volume to the specified value
+//
+// volume must be within [0, 1000]
+func (player *Player) Volume(volume int) error {
+	if volume < 0 || volume > 1000 {
+		return errVolumeOutOfRange
+	}
+
+	msg := message{
+		Op:      opVolume,
+		GuildID: player.guildID,
+		Volume:  volume,
+	}
+	data, err := json.Marshal(msg)
+	if err != nil {
+		return err
+	}
+	err = player.node.wsConn.WriteMessage(websocket.TextMessage, data)
+	return err
+}
+
+// Destroy will destroy this player
+func (player *Player) Destroy() error {
+	msg := message{
+		Op:      opDestroy,
+		GuildID: player.guildID,
+	}
+	data, err := json.Marshal(msg)
+	if err != nil {
+		return err
+	}
+	err = player.node.wsConn.WriteMessage(websocket.TextMessage, data)
+	if err != nil {
+		return err
+	}
+	player.manager.players[player.guildID] = nil
+	return nil
+}