refactor(media): unify media identity and chain responsibilities

tests/test_anime_source_metainfo.py

@@ -69,3 +69,61 @@ def test_extended_ids_fall_back_when_installed_rust_is_old() -> None:
 
     assert metainfo["media_source"] == "anilist"
     assert metainfo["media_id"] == "154587"
+
+
+def test_generic_identity_falls_back_when_installed_rust_is_old() -> None:
+    """旧 Rust 扩展缺少通用字段时应直接使用 Python 解析器。"""
+    with patch(
+        "app.core.metainfo.rust_accel.supports_unified_media_identity",
+        return_value=False,
+    ), patch(
+        "app.core.metainfo.rust_accel.find_metainfo",
+        side_effect=AssertionError("旧 Rust 扩展不应处理通用媒体身份"),
+    ):
+        _, metainfo = find_metainfo(
+            "Frieren {[media_source=anilist;media_id=154587]}"
+        )
+
+    assert metainfo["media_source"] == "anilist"
+    assert metainfo["media_id"] == "154587"
+
+
+@pytest.mark.parametrize(
+    "title",
+    [
+        "Movie {[media_source=themoviedb;media_id=0;type=movies]}",
+        "Movie {[tmdbid=0;type=movies]}",
+        "Movie [tmdbid=0]",
+        "Anime [anilist=0]",
+    ],
+)
+def test_python_metainfo_rejects_zero_identity_and_removes_tag(title: str) -> None:
+    """Python 标签解析器应移除零值标签，但不得生成媒体身份。"""
+    with patch("app.core.metainfo.rust_accel.find_metainfo", return_value=None):
+        parsed_title, metainfo = find_metainfo(title)
+
+    assert metainfo["media_source"] is None
+    assert metainfo["media_id"] is None
+    assert "=0" not in parsed_title
+
+
+def test_metainfo_normalizes_zero_identity_from_old_rust_extension() -> None:
+    """旧 Rust 扩展返回零值身份时，主程序边界仍应将统一对清空。"""
+    rust_result = {
+        "title": "Movie",
+        "metainfo": {
+            "media_source": "themoviedb",
+            "media_id": "0",
+            "tmdbid": 0,
+        },
+    }
+    with patch(
+        "app.core.metainfo.rust_accel.find_metainfo",
+        return_value=rust_result,
+    ):
+        parsed_title, metainfo = find_metainfo("Movie [tmdbid=0]")
+
+    assert parsed_title == "Movie"
+    assert metainfo["media_source"] is None
+    assert metainfo["media_id"] is None
+    assert "tmdbid" not in metainfo