Implement slash commands for playback control

internal/commands/helpers.go

@@ -0,0 +1,109 @@
+package commands
+
+import (
+	"errors"
+	"fmt"
+	"strconv"
+	"strings"
+
+	"github.com/disgoorg/disgo/bot"
+	"github.com/disgoorg/disgo/discord"
+	"github.com/disgoorg/disgo/events"
+	"github.com/disgoorg/disgolink/v4/lavalink"
+	"github.com/disgoorg/snowflake/v2"
+)
+
+func guildID(event *events.ApplicationCommandInteractionCreate) (snowflake.ID, bool) {
+	id := event.GuildID()
+	if id == nil {
+		return 0, false
+	}
+	return *id, true
+}
+
+func memberVoiceChannel(discordClient *bot.Client, guild snowflake.ID, userID snowflake.ID) (snowflake.ID, bool) {
+	state, ok := discordClient.Caches.VoiceState(guild, userID)
+	if !ok || state.ChannelID == nil {
+		return 0, false
+	}
+	return *state.ChannelID, true
+}
+
+func ensureCanControlPlayback(discordClient *bot.Client, guild snowflake.ID, userID snowflake.ID) (bool, string) {
+	botChannelID, botConnected := memberVoiceChannel(discordClient, guild, discordClient.ApplicationID)
+	if !botConnected {
+		return true, ""
+	}
+
+	userChannelID, userConnected := memberVoiceChannel(discordClient, guild, userID)
+	if !userConnected || userChannelID != botChannelID {
+		return false, fmt.Sprintf("I'm currently active in <#%s>. Join that channel to control playback.", botChannelID)
+	}
+	return true, ""
+}
+
+func requirePlaybackAccess(discordClient *bot.Client, event *events.ApplicationCommandInteractionCreate) (snowflake.ID, error) {
+	gid, ok := guildID(event)
+	if !ok {
+		return 0, guildOnlyError(event)
+	}
+
+	if allowed, reason := ensureCanControlPlayback(discordClient, gid, event.User().ID); !allowed {
+		return 0, rejectEphemeral(event, reason)
+	}
+
+	return gid, nil
+}
+
+func reply(event *events.ApplicationCommandInteractionCreate, content string) error {
+	return event.CreateMessage(discord.NewMessageCreate().WithContent(content))
+}
+
+func replyEphemeral(event *events.ApplicationCommandInteractionCreate, content string) error {
+	return event.CreateMessage(discord.NewMessageCreate().WithContent(content).WithEphemeral(true))
+}
+
+func guildOnlyError(event *events.ApplicationCommandInteractionCreate) error {
+	return rejectEphemeral(event, "This command only works inside a server.")
+}
+
+func rejectEphemeral(event *events.ApplicationCommandInteractionCreate, content string) error {
+	if err := replyEphemeral(event, content); err != nil {
+		return err
+	}
+	return errors.New(content)
+}
+
+func replyWithError(event *events.ApplicationCommandInteractionCreate, userMessage string, cause error) error {
+	if err := replyEphemeral(event, userMessage); err != nil {
+		return err
+	}
+	return fmt.Errorf("%s: %w", userMessage, cause)
+}
+
+func intPtr(v int) *int {
+	return &v
+}
+
+func parsePosition(raw string) (lavalink.Duration, error) {
+	parts := strings.Split(raw, ":")
+	if len(parts) == 0 || len(parts) > 3 {
+		return 0, errors.New("expected seconds, mm:ss or hh:mm:ss")
+	}
+
+	segments := make([]int64, len(parts))
+	for i, part := range parts {
+		n, err := strconv.ParseInt(strings.TrimSpace(part), 10, 64)
+		if err != nil || n < 0 {
+			return 0, errors.New("expected seconds, mm:ss or hh:mm:ss")
+		}
+		segments[i] = n
+	}
+
+	var totalSeconds int64
+	for _, segment := range segments {
+		totalSeconds = totalSeconds*60 + segment
+	}
+
+	return lavalink.Duration(totalSeconds) * lavalink.Second, nil
+}