GMW/services/discord-gateway/src/modules/command-handler/media.handler.ts

import { randomUUID } from "node:crypto";
import type { CommandMessage, CommandReply } from "@bete/shared";
import { createChildLogger } from "@bete/shared/logger";
import { StreamType } from "@discordjs/voice";
import {
  extractMediaInfo,
  resolveMediaUrl,
} from "../voice-recording/mediaSource.js";
import type {
  MediaMode,
  MediaQueueItem,
} from "../voice-recording/mediaTypes.js";
import { discordPlayer } from "../voice-recording/player.js";

// ---------------------------------------------------------------------------
// Types
// ---------------------------------------------------------------------------

interface MediaStatusItem {
  id: string;
  source: string;
  title: string;
  mode: MediaMode;
  durationMs?: number | null;
  thumbnailUrl?: string | null;
}

export interface MediaStatusPayload {
  playing: boolean;
  musicVolume: number;
  current: MediaStatusItem | null;
  queue: MediaStatusItem[];
}

// ---------------------------------------------------------------------------
// Module-level queue
// ---------------------------------------------------------------------------

const mediaQueue: MediaQueueItem[] = [];
let currentTrackItem: MediaQueueItem | null = null;

// ---------------------------------------------------------------------------
// Helpers
// ---------------------------------------------------------------------------

function mapToStatusItem(item: MediaQueueItem): MediaStatusItem {
  return {
    id: item.id,
    source: item.source,
    title: item.title,
    mode: item.mode,
    durationMs: item.duration != null ? item.duration * 1000 : null,
    thumbnailUrl: item.thumbnailUrl ?? null,
  };
}

function buildStatusPayload(): MediaStatusPayload {
  return {
    playing:
      currentTrackItem !== null && discordPlayer.getStatus() === "playing",
    musicVolume: discordPlayer.getMusicVolume(),
    current: currentTrackItem ? mapToStatusItem(currentTrackItem) : null,
    queue: mediaQueue.map(mapToStatusItem),
  };
}

// ---------------------------------------------------------------------------
// MediaHandler
// ---------------------------------------------------------------------------

export class MediaHandler {
  private logger = createChildLogger("media-handler");

  constructor() {
    // Register auto-advance on natural track end
    discordPlayer.onIdle(() => {
      this.advanceQueue().catch((err) => {
        this.logger.error({ err }, "Auto-advance failed");
      });
    });
  }

  getCurrentMediaStatus(): MediaStatusPayload {
    return buildStatusPayload();
  }

  async handleMediaQueue(cmd: CommandMessage): Promise<CommandReply<unknown>> {
    const url = String(cmd.payload.url ?? "").trim();
    const mode: MediaMode = cmd.payload.mode === "screen" ? "screen" : "music";
    const requestedBy = String(cmd.payload.requestedBy ?? "unknown");

    if (!url) {
      this.logger.warn("media:queue received without a URL");
      return {
        id: cmd.id,
        success: false,
        data: null,
        error: "url is required",
      };
    }

    if (!discordPlayer.isConnected()) {
      this.logger.warn("media:queue attempted without active voice connection");
      return {
        id: cmd.id,
        success: false,
        data: null,
        error: "Not connected to a voice channel. Connect to voice first.",
      };
    }

    // Lightweight metadata fetch for display — the full resolve happens in playNext
    let title: string = url;
    let duration: number | undefined;
    let thumbnailUrl: string | undefined;
    try {
      const info = await extractMediaInfo(url);
      title = info.title ?? url;
      duration = info.duration;
      thumbnailUrl = info.thumbnail;
    } catch {
      this.logger.warn(
        { url },
        "Could not pre-resolve media metadata, queueing blind",
      );
    }

    const item: MediaQueueItem = {
      id: randomUUID(),
      source: url,
      title,
      kind: "url" as const,
      mode,
      requestedBy,
      addedAt: Date.now(),
      status: "queued",
      duration,
      thumbnailUrl,
    };

    mediaQueue.push(item);
    this.logger.info(
      { url, title, queueLength: mediaQueue.length },
      "Media queued",
    );

    // If nothing is playing, start immediately (next tick so status publishes)
    if (currentTrackItem === null) {
      setImmediate(() => {
        this.playNext().catch((err) => {
          this.logger.error({ err }, "playNext after queue failed");
        });
      });
    }

    return {
      id: cmd.id,
      success: true,
      data: buildStatusPayload(),
    };
  }

  async handleMediaSkip(cmd: CommandMessage): Promise<CommandReply<unknown>> {
    if (currentTrackItem) {
      discordPlayer.stop("music");
      currentTrackItem = null;
    }
    await this.playNext();
    return {
      id: cmd.id,
      success: true,
      data: buildStatusPayload(),
    };
  }

  async handleMediaStop(cmd: CommandMessage): Promise<CommandReply<unknown>> {
    discordPlayer.stop("music");
    currentTrackItem = null;
    mediaQueue.length = 0; // Clear entire queue
    return {
      id: cmd.id,
      success: true,
      data: buildStatusPayload(),
    };
  }

  async handleMediaVolume(cmd: CommandMessage): Promise<CommandReply<unknown>> {
    const volume = Number(cmd.payload.volume);
    if (!Number.isFinite(volume)) {
      return {
        id: cmd.id,
        success: false,
        data: null,
        error: "volume must be a number",
      };
    }
    discordPlayer.setMusicVolume(volume);
    return {
      id: cmd.id,
      success: true,
      data: buildStatusPayload(),
    };
  }

  // ---------------------------------------------------------------------------
  // Internal
  // ---------------------------------------------------------------------------

  /**
   * Advance to the next item in the queue. Called after natural track end
   * (via onIdle) or after manual skip.
   */
  private async playNext(): Promise<void> {
    // Stop any currently playing track (without triggering idle callback)
    if (currentTrackItem) {
      discordPlayer.stop("music");
      currentTrackItem = null;
    }

    const next = mediaQueue.shift();
    if (!next) {
      this.logger.info("Queue empty — nothing to play");
      return;
    }

    currentTrackItem = next;
    next.status = "playing";

    try {
      this.logger.info(
        { url: next.source, title: next.title },
        "Playing next from queue",
      );

      const resolution = await resolveMediaUrl(next.source);

      // Update title/duration with actual resolved values
      next.title = resolution.title ?? next.title;
      next.duration = resolution.duration ?? next.duration;

      discordPlayer.playStream(resolution.stream, "music", {
        inputType: StreamType.Arbitrary,
        inlineVolume: true,
        volume: discordPlayer.getMusicVolume(),
      });

      this.logger.info({ title: next.title }, "Playback started");
    } catch (err) {
      const message = err instanceof Error ? err.message : String(err);
      this.logger.error(
        { error: message, url: next.source, title: next.title },
        "Failed to play queued item, skipping to next",
      );

      currentTrackItem = null;
      next.status = "failed";

      // Try the next item in the queue
      setImmediate(() => {
        this.playNext().catch((err2) => {
          this.logger.error(
            { err: err2 },
            "playNext after error recovery failed",
          );
        });
      });
    }
  }

  /**
   * Called by the idle callback — delegates to playNext since the player is
   * already idle and currentTrackItem is already null.
   */
  private async advanceQueue(): Promise<void> {
    currentTrackItem = null;
    await this.playNext();
  }
}