Implement per guild music queue and player

internal/music/manager.go

@@ -0,0 +1,53 @@
+package music
+
+import (
+	"context"
+	"log/slog"
+	"sync"
+
+	"github.com/disgoorg/disgolink/v4/disgolink"
+	"github.com/disgoorg/snowflake/v2"
+)
+
+type Manager struct {
+	lavalink *disgolink.Client
+	logger   *slog.Logger
+
+	mu     sync.Mutex
+	guilds map[snowflake.ID]*GuildPlayer
+}
+
+func NewManager(lavalinkClient *disgolink.Client, logger *slog.Logger) *Manager {
+	return &Manager{
+		lavalink: lavalinkClient,
+		logger:   logger,
+		guilds:   make(map[snowflake.ID]*GuildPlayer),
+	}
+}
+
+func (m *Manager) Guild(guildID snowflake.ID) *GuildPlayer {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	if gp, ok := m.guilds[guildID]; ok {
+		return gp
+	}
+
+	gp := newGuildPlayer(m.lavalink.Player(guildID))
+	m.guilds[guildID] = gp
+	return gp
+}
+
+func (m *Manager) OnTrackEnd(event *disgolink.PlayerTrackEndEvent) {
+	if !event.Reason.MayStartNext() {
+		return
+	}
+
+	ctx := context.Background()
+	if err := m.Guild(event.Player.GuildID).PlayNext(ctx, event.Track); err != nil {
+		m.logger.ErrorContext(ctx, "failed to play next queued track",
+			slog.String("guild_id", event.Player.GuildID.String()),
+			slog.Any("err", err),
+		)
+	}
+}