import { describe, it } from "node:test";
import assert from "node:assert/strict";
import {
  AUDIO_READ_PREFERENCE,
  audioFilesToRemove,
  findSourceMedia,
  isPartAudioFile,
  isRealAudioFile,
  isSourceMediaFile,
  isVideoContainer,
  pickPreferredAudio,
} from "./mediaFiles";

// These predicates decide what a DELETE sweep removes and what ffmpeg is handed
// as input, and they had never had a test. The fixtures below are not invented:
// every "junk" name is a real file surveyed out of the 78,963-video corpus, and
// audio.tmp-2760235.mp3 was observed live in a video dir while a transcode was
// running.

// Real, finalized audio in the corpus today (900 / 12 / 1 by count).
const REAL_AUDIO = ["audio.mp3", "audio.mp4", "audio.aac"];

// The four junk names that the old prefix-plus-denylist admitted as audio, plus
// this app's own transcode scratch, which an extension allowlist alone would
// re-admit (its extension is perfectly valid) and which the cleanup sweep would
// then race.
const NOT_AUDIO = [
  "audio.en-orig.vtt", // a SUBTITLE. No denylist rule excluded .vtt.
  "audio.live_chat.json.part-Frag114", // the .part rule used endsWith
  "audio.live_chat.json.part-Frag514",
  "audio.live_chat.json.part",
  "audio.live_chat.json",
  "audio.info.json",
  "audio.tmp-2760235.mp3", // controller/transcode.ts scratch, mid-transcode
  "audio.m4a.part", // an unfinished download, not a finalized file
  "audio.m4a.part.good", // audio-check snapshot
  "audio.m4a.part.testing",
  "audio.f251.webm.part", // yt-dlp per-format fragment
  "transcript.en.vtt",
  "metadata.info.json",
  "audio.", // degenerate
  "audio",
];

describe("isRealAudioFile", () => {
  it("accepts finalized audio.<ext> for every format on disk", () => {
    for (const name of REAL_AUDIO) {
      assert.equal(isRealAudioFile(name), true, name);
    }
  });

  it("accepts wrong-format containers, because those are cleanup targets", () => {
    // bulk-actions.spec.ts renames audio.m4a -> audio.webm and requires the
    // sweep to delete it, so webm/mp4 must stay in the list even though they
    // are containers rather than audio-only formats.
    for (const name of ["audio.webm", "audio.mkv", "audio.m4a", "audio.opus"]) {
      assert.equal(isRealAudioFile(name), true, name);
    }
  });

  it("rejects every non-media name that used to slip through", () => {
    for (const name of NOT_AUDIO) {
      assert.equal(isRealAudioFile(name), false, name);
    }
  });

  it("is case-insensitive on the extension", () => {
    assert.equal(isRealAudioFile("audio.MP3"), true);
  });
});

describe("isSourceMediaFile / findSourceMedia", () => {
  it("accepts a finalized container", () => {
    assert.equal(isSourceMediaFile("source-media.mp4"), true);
    assert.equal(isSourceMediaFile("source-media.mkv"), true);
  });

  it("rejects yt-dlp's postprocessor scratch", () => {
    // The ONLY source-media.* file in the whole corpus is this one, and it is
    // the corrupt 4 GiB truncated container. The old denylist had no .temp.
    // rule, so it read as finalized media — and finalizeAppExtraction would
    // transcode from it and then move it into the saved-video store as the
    // permanent copy.
    assert.equal(isSourceMediaFile("source-media.temp.mp4"), false);
    assert.equal(isSourceMediaFile("source-media.f137.mp4"), false);
    assert.equal(isSourceMediaFile("source-media.mp4.part"), false);
    assert.equal(isSourceMediaFile("source-media.info.json"), false);
  });

  it("never picks the scratch file over the real container", () => {
    assert.equal(
      findSourceMedia(["source-media.temp.mp4", "source-media.mp4"]),
      "source-media.mp4",
    );
    // Same answer whichever order readdir happened to return them in.
    assert.equal(
      findSourceMedia(["source-media.mp4", "source-media.temp.mp4"]),
      "source-media.mp4",
    );
  });

  it("returns null when only scratch is present", () => {
    assert.equal(findSourceMedia(["source-media.temp.mp4"]), null);
  });
});

describe("isPartAudioFile", () => {
  it("accepts a genuine interrupted audio download", () => {
    assert.equal(isPartAudioFile("audio.m4a.part"), true);
    assert.equal(isPartAudioFile("audio.webm.part"), true);
  });

  it("rejects live-chat sidecars and audio-check snapshots", () => {
    for (const name of [
      "audio.live_chat.json.part",
      "audio.live_chat.json.part-Frag114",
      "audio.m4a.part.good",
      "audio.m4a.part.testing",
      "audio.tmp-2760235.mp3.part",
      "audio.mp3",
    ]) {
      assert.equal(isPartAudioFile(name), false, name);
    }
  });
});

describe("audioFilesToRemove", () => {
  // The delete set. A real video dir mid-transcode, with a subtitle leak and a
  // live-chat fragment sitting next to the audio.
  const DIR = [
    "audio.mp3",
    "audio.m4a",
    "audio.en-orig.vtt",
    "audio.live_chat.json.part-Frag114",
    "audio.info.json",
    "audio.tmp-2760235.mp3",
    "metadata.info.json",
    "transcript.en.vtt",
  ];

  it("removes only the two real audio files", () => {
    assert.deepEqual(audioFilesToRemove(DIR), ["audio.mp3", "audio.m4a"]);
  });

  it("keeps the channel's target format under wrongFormatOnly", () => {
    assert.deepEqual(
      audioFilesToRemove(DIR, {
        targetAudioFile: "audio.mp3",
        wrongFormatOnly: true,
      }),
      ["audio.m4a"],
    );
  });

  it("is a subset of the raw entries for any input (monotonicity)", () => {
    const out = audioFilesToRemove(DIR);
    for (const name of out) assert.ok(DIR.includes(name), name);
  });
});

describe("isVideoContainer", () => {
  it("keys off the extension, not the base name", () => {
    assert.equal(isVideoContainer("source-media.mkv"), true);
    assert.equal(isVideoContainer("audio.mp4"), true);
    assert.equal(isVideoContainer("audio.mp3"), false);
    assert.equal(isVideoContainer("noext"), false);
  });
});

describe("pickPreferredAudio", () => {
  it("prefers mp3 when reading", () => {
    assert.equal(
      pickPreferredAudio(["audio.opus", "audio.mp3", "audio.m4a"]),
      "audio.mp3",
    );
  });

  it("falls back to a stable sort, not readdir order", () => {
    assert.equal(pickPreferredAudio(["audio.wav", "audio.aac"]), "audio.aac");
    assert.equal(pickPreferredAudio(["audio.aac", "audio.wav"]), "audio.aac");
  });

  it("returns null for no candidates", () => {
    assert.equal(pickPreferredAudio([]), null);
  });
});