import {
  AUDIO_EXTS,
  VIDEO_CONTAINER_EXTS,
} from "yt-dlp-transcript-common/lib/mediaFiles";

export type VideoFile = {
  name: string;
  // NULL for a tiered file (a link into `channels/<slug>/media/`, release 17)
  // whose media drive is unmounted or not answering: the file exists, its size
  // is not knowable now. Rendered "—", never 0.
  size: number | null;
  mtime: number;
};

export const WHISPER_FILENAME = "transcript.json";
export const CANONICAL_VTT = "transcript.en.vtt";
// lib/videoStatus.ts TRANSCRIPT_PIN_FILENAME (this module is client-side).
export const TRANSCRIPT_PIN_FILENAME = "transcript-pin.json";

export function isTranscriptVttName(name: string): boolean {
  return /^transcript\.[^.]+\.vtt$/.test(name);
}

// One list, shared with the detection predicates in lib/mediaFiles.ts — these
// were duplicated here and drifting. isAudioFile deliberately stays on
// AUDIO_EXTS alone: audio.mp4 is a wrong-format cleanup target, not something
// this panel offers a transcribe button for (editor/e2e/video-page.spec.ts:426).
const AUDIO_EXT_SET = new Set(AUDIO_EXTS);
const VIDEO_EXT_SET = new Set(VIDEO_CONTAINER_EXTS);

const TEXT_EXTS = new Set(["vtt", "json", "txt", "srt", "log"]);

export function fileExt(name: string): string {
  const dot = name.lastIndexOf(".");
  return dot >= 0 ? name.slice(dot + 1).toLowerCase() : "";
}

export function isAudioFile(name: string): boolean {
  return AUDIO_EXT_SET.has(fileExt(name));
}

// Files we can transcode FROM: any media file ffmpeg can demux to audio.
// Includes video containers so a kept source (e.g. audio.mp4 when
// keepSourceVideo=true) can be re-extracted to audio.<targetFormat> to
// overwrite a truncated or corrupt prior extraction.
export function isTranscodeSource(name: string): boolean {
  if (!name.startsWith("audio.")) return false;
  if (name.startsWith("audio.tmp-")) return false;
  const ext = fileExt(name);
  return AUDIO_EXT_SET.has(ext) || VIDEO_EXT_SET.has(ext);
}

export function audioExt(name: string): string {
  const dot = name.lastIndexOf(".");
  return dot >= 0 ? name.slice(dot + 1) : "";
}

export function mediaKind(name: string): "audio" | "video" | "text" | null {
  const ext = fileExt(name);
  if (AUDIO_EXT_SET.has(ext)) return "audio";
  if (VIDEO_EXT_SET.has(ext)) return "video";
  if (TEXT_EXTS.has(ext)) return "text";
  return null;
}

export function mediaUrl(slug: string, videoId: string, filename: string): string {
  return `/api/channels/${encodeURIComponent(slug)}/videos/${encodeURIComponent(videoId)}/files/${encodeURIComponent(filename)}`;
}