Package the capture-layer application into a CaptureImporter class

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

docs/decision_log.md

@@ -206,8 +206,10 @@
   （身分判定、拆解、正名）隨行入 class 作公開 staticmethod
   ／class 常數，「哪個函式屬哪個工作」由 class 歸屬直接
   表達。flush 定為匯入工作的完工契約——entry method 返回
-  時自身寫入已可查詢，不再由呼叫者補 flush。實測重構前後
-  工作儲存 dump 與衍生報表逐位元組相同。
+  時自身寫入已可查詢，不再由呼叫者補 flush。捕捉層套用
+  （歌詞、Wikidata 快照）隨後同型打包為 `CaptureImporter`
+  （單一入口收兩個可省略路徑）。實測重構前後工作儲存
+  dump 與衍生報表逐位元組相同。
 - **歌手型態刪去 mixed 值**：`ArtistType` 只留 solo／group。
   mixed 是先導研究「男／女／混合團體」單一欄位的殘留，
   正式設計拆成 gender＋type 後從未定義其指涉；署名一律

tools/src/pop_fem_audit_tools/build_db.py

@@ -425,13 +425,52 @@ class ArtistImporter:
         return folded, name
 
 
-def load_lyrics(session: Session, directory: Path) -> None:
+class CaptureImporter:
+    """The capture-import job: applies the optional capture-layer
+    inputs onto the stored songs and artists."""
+
+    def __init__(self, session: Session) -> None:
+        """Initialize the importer.
+
+        :param session: The database session.
+        """
+        self.__session: Session = session
+
+    def import_captures(self, lyrics_dir: Path | None,
+                        wikidata_csv: Path | None) -> None:
+        """Apply the optional capture-layer inputs onto the store.
+
+        A None input leaves its capture layer unloaded.  When
+        ``lyrics_dir`` is given, its cached lyrics files load into
+        the matching songs (see `__load_lyrics`).  When
+        ``wikidata_csv`` is given, it applies onto the artist rows
+        (see `__apply_artist_csv`).  When the method returns, the
+        applied changes are queryable in the session.
+
+        :param lyrics_dir: The lyrics cache directory to load, or
+            None to skip the lyrics capture layer.
+        :param wikidata_csv: The Wikidata artist snapshot CSV file
+            to apply, or None to skip the artist capture layer.
+        :return: None.
+        :raises BuildError: When ``lyrics_dir`` does not exist, or
+            a name in ``wikidata_csv`` matches no artist.
+        :raises OSError: When a capture file cannot be read.
+        """
+        if lyrics_dir is not None:
+            if not lyrics_dir.is_dir():
+                raise BuildError(
+                    f"{lyrics_dir}: no such directory")
+            self.__load_lyrics(lyrics_dir)
+        if wikidata_csv is not None:
+            self.__apply_artist_csv(wikidata_csv)
+        self.__session.flush()
+
+    def __load_lyrics(self, directory: Path) -> None:
         """Load the cached lyrics files into the matching songs.
 
-    A file whose stem is not an existing song ID is skipped with
-    a warning to the standard error.
+        A file whose stem is not an existing song ID is skipped
+        with a warning to the standard error.
 
-    :param session: The database session, with the songs flushed.
         :param directory: The existing lyrics cache directory with
             one ``<song_id>.txt`` file per song.
         :return: None.
@@ -440,24 +479,21 @@ def load_lyrics(session: Session, directory: Path) -> None:
         for path in sorted(directory.glob("*.txt")):
             song: Song | None = None
             if path.stem.isdigit():
-            song = session.get(Song, int(path.stem))
+                song = self.__session.get(Song, int(path.stem))
             if song is None:
                 print(f"warning: {path}: no song with ID"
                       f" \"{path.stem}\"", file=sys.stderr)
                 continue
             song.lyrics = path.read_text(encoding="utf-8")
 
-
-def apply_artist_csv(session: Session, path: Path) -> None:
+    def __apply_artist_csv(self, path: Path) -> None:
         """Apply an artist attribute CSV onto the artist rows.
 
         Artists match by exact name.  Only the non-empty cells are
         applied, field by field.  The note column is ignored.
 
-    :param session: The database session, with the artists
-        flushed.
-    :param path: The CSV file with the columns name, qid, gender,
-        type, genre, country, and note.
+        :param path: The CSV file with the columns name, qid,
+            gender, type, genre, country, and note.
         :return: None.
         :raises BuildError: When a name matches no artist.
         :raises OSError: When the file cannot be read.
@@ -465,12 +501,13 @@ def apply_artist_csv(session: Session, path: Path) -> None:
         with open(path, encoding="utf-8", newline="") as file:
             row: dict[str, str]
             for row in csv.DictReader(file):
-            artist: Artist | None = session.scalar(
+                artist: Artist | None = self.__session.scalar(
                     sa.select(Artist)
                     .where(Artist.name == row["name"]))
                 if artist is None:
                     raise BuildError(
-                    f"{path}: no artist named \"{row['name']}\"")
+                        f"{path}: no artist named"
+                        f" \"{row['name']}\"")
                 column: str
                 attribute: str
                 for column, attribute in ARTIST_FIELDS.items():
@@ -764,14 +801,8 @@ def main(argv: list[str] | None = None) -> int:
         reset_store(session)
         SongImporter(session).import_songs(args.chart_csv)
         ArtistImporter(session).import_artists()
-        if args.lyrics_dir is not None:
-            if not args.lyrics_dir.is_dir():
-                raise BuildError(
-                    f"{args.lyrics_dir}: no such directory")
-            load_lyrics(session, args.lyrics_dir)
-        if args.wikidata_csv is not None:
-            apply_artist_csv(session, args.wikidata_csv)
-        session.flush()
+        CaptureImporter(session).import_captures(
+            args.lyrics_dir, args.wikidata_csv)
         violations: list[str] = find_violations(
             session, YEARS, RANKS_PER_YEAR)
         if len(violations) > 0: