feat(mux): add muxing.default_subtitle_type for the default subtitle

Name which subtitle type (forced, normal, sdh) gets the default flag. The forced default now follows the default audio track, not the first.

tests/tracks/test_mux_default_language.py

@@ -1,10 +1,14 @@
 from __future__ import annotations
 
-from typing import Optional
+import logging
+from pathlib import Path
+from typing import Callable, Optional
 
 import pytest
+from langcodes import Language
 
-from unshackle.core.tracks import Audio, Tracks
+from unshackle.core.config import config
+from unshackle.core.tracks import Audio, Subtitle, Tracks
 
 
 @pytest.mark.parametrize(
@@ -24,3 +28,84 @@ def test_first_match_index(languages: list[str], preferred: Optional[str], expec
         for i, lang in enumerate(languages)
     ]
     assert Tracks.first_match_index(tracks, preferred) == expected
+
+
+def subtitle(index: int, language: str, kind: str) -> Subtitle:
+    return Subtitle(
+        id_=f"s{index}",
+        url=f"https://x.example/{index}",
+        language=language,
+        codec=Subtitle.Codec.WebVTT,
+        forced=kind == "forced",
+        sdh=kind == "sdh",
+    )
+
+
+@pytest.mark.parametrize(
+    ("language", "types", "expected"),
+    [
+        ("pl", [], 0),
+        ("pl", ["normal", "sdh", "forced"], 1),
+        ("pl", ["forced"], 0),
+        ("en", ["sdh", "normal"], 3),
+        ("pl", ["sdh"], 0),
+        ("fr", ["normal"], None),
+        (None, ["normal"], 1),
+        (None, ["sdh", "normal"], 3),
+        (None, [], None),
+    ],
+)
+def test_default_subtitle_index(language: Optional[str], types: list[str], expected: Optional[int]) -> None:
+    kinds = [("pl", "forced"), ("pl", "normal"), ("en", "normal"), ("en", "sdh")]
+    subtitles = [subtitle(i, lang, kind) for i, (lang, kind) in enumerate(kinds)]
+    assert Tracks.default_subtitle_index(subtitles, language, types) == expected
+
+
+@pytest.mark.parametrize(
+    ("audio", "expected"),
+    [("en", 1), ("ar", 0), ("fr", 2), (None, 2)],
+)
+def test_a_forced_default_with_no_language_follows_the_audio(audio: Optional[str], expected: int) -> None:
+    kinds = [("ar", "forced"), ("en", "forced"), ("en", "normal")]
+    subtitles = [subtitle(i, lang, kind) for i, (lang, kind) in enumerate(kinds)]
+    audio_language = Language.get(audio) if audio else None
+    assert Tracks.default_subtitle_index(subtitles, None, ["forced", "normal"], audio_language) == expected
+
+
+def downloaded_tracks(tmp_path: Path, audio: list[tuple[str, bool]], subtitles: list[tuple[str, str]]) -> Tracks:
+    tracks = Tracks()
+    for i, (lang, original) in enumerate(audio):
+        track = Audio(id_=f"a{i}", url=f"https://x.example/a{i}", language=lang, is_original_lang=original)
+        tracks.add(track)
+    for i, (lang, kind) in enumerate(subtitles):
+        tracks.add(subtitle(i, lang, kind))
+    for track in tracks:
+        track.path = tmp_path / f"{track.id}.bin"
+        track.path.write_bytes(b"\x00")
+    return tracks
+
+
+def subtitle_defaults(args: list[str], count: int) -> list[str]:
+    return [args[i + 1] for i, arg in enumerate(args) if arg == "--default-track"][-count:]
+
+
+def test_mux_reads_default_subtitle_type(
+    tmp_path: Path,
+    monkeypatch: pytest.MonkeyPatch,
+    caplog: pytest.LogCaptureFixture,
+    mux_args: Callable[..., list[str]],
+) -> None:
+    monkeypatch.setattr(config, "muxing", {"default_subtitle_type": ["full", "CC", "Normal"]})
+    tracks = downloaded_tracks(tmp_path, [("en", True)], [("pl", "forced"), ("pl", "normal"), ("en", "sdh")])
+
+    with caplog.at_level(logging.WARNING):
+        args = mux_args(tracks)
+
+    assert subtitle_defaults(args, 3) == ["0:False", "0:False", "0:True"]
+    assert "'full' is not a subtitle type" in caplog.text
+
+
+def test_the_forced_default_follows_the_default_audio(tmp_path: Path, mux_args: Callable[..., list[str]]) -> None:
+    tracks = downloaded_tracks(tmp_path, [("en", False), ("pl", True)], [("en", "forced"), ("pl", "forced")])
+
+    assert subtitle_defaults(mux_args(tracks), 2) == ["0:False", "0:True"]