tagger: modulo mutagen per ID3 tag + cover art da URL

core/tagger.py

@@ -0,0 +1,109 @@
+"""Scrittura tag ID3 su file MP3 via mutagen, con cover art da URL."""
+
+from __future__ import annotations
+
+import re
+from pathlib import Path
+from typing import Optional
+
+import requests
+from mutagen.easyid3 import EasyID3
+from mutagen.id3 import ID3, APIC
+from mutagen.mp3 import MP3
+
+
+SAFE_FILENAME_RE = re.compile(r'[<>:"/\\|?*\x00-\x1f]')
+
+
+def sanitize_filename_stem(stem: str, max_len: int = 180) -> str:
+    """Rimuove caratteri non validi per un filename e limita lunghezza."""
+    s = SAFE_FILENAME_RE.sub("_", stem or "").strip()
+    s = re.sub(r"\s+", " ", s)
+    if len(s) > max_len:
+        s = s[:max_len].rstrip()
+    return s or "untitled"
+
+
+def build_filename_stem(artist: str, title: str) -> str:
+    """Compone 'Artista - Titolo' sanitizzato."""
+    artist = (artist or "").strip()
+    title = (title or "").strip()
+    if artist and title:
+        return sanitize_filename_stem(f"{artist} - {title}")
+    return sanitize_filename_stem(title or artist or "untitled")
+
+
+def _download_cover(url: str) -> Optional[bytes]:
+    """Scarica bytes cover, ritorna None su qualsiasi errore."""
+    try:
+        resp = requests.get(url, timeout=15)
+        if resp.status_code == 200:
+            return resp.content
+    except Exception:
+        pass
+    return None
+
+
+def _cover_mime(url: str, content: bytes) -> str:
+    """Deduci MIME dell'immagine da URL o magic bytes."""
+    u = url.lower()
+    if u.endswith(".png"):
+        return "image/png"
+    if u.endswith((".jpg", ".jpeg")):
+        return "image/jpeg"
+    # magic bytes
+    if content[:8] == b"\x89PNG\r\n\x1a\n":
+        return "image/png"
+    if content[:3] == b"\xff\xd8\xff":
+        return "image/jpeg"
+    return "image/jpeg"  # default
+
+
+def write_tags(filepath: str, metadata: dict) -> None:
+    """Scrive ID3 tag su file MP3 esistente.
+
+    metadata: dict con chiavi opzionali:
+        title, artist, album, date (YYYY o YYYY-MM-DD), genre,
+        tracknumber, cover_url
+
+    Errori non fatali (file mancante, tag non scrivibili): silenziosi
+    per non bloccare il download principale.
+    """
+    p = Path(filepath)
+    if not p.exists():
+        return
+
+    # 1. Tag testuali via EasyID3
+    try:
+        try:
+            audio = EasyID3(str(p))
+        except Exception:
+            # Se il file non ha header ID3, aggiungine uno vuoto
+            mp3 = MP3(str(p))
+            if mp3.tags is None:
+                mp3.add_tags()
+                mp3.save()
+            audio = EasyID3(str(p))
+        for key in ("title", "artist", "album", "date", "genre", "tracknumber"):
+            val = metadata.get(key)
+            if val:
+                audio[key] = str(val)
+        audio.save(str(p))
+    except Exception:
+        return  # ID3 broken, non provo la cover
+
+    # 2. Cover art via ID3 APIC
+    cover_url = (metadata.get("cover_url") or "").strip()
+    if not cover_url:
+        return
+    cover_bytes = _download_cover(cover_url)
+    if not cover_bytes:
+        return
+    try:
+        mime = _cover_mime(cover_url, cover_bytes)
+        tags = ID3(str(p))
+        tags.delall("APIC")
+        tags.add(APIC(encoding=3, mime=mime, type=3, desc="Cover", data=cover_bytes))
+        tags.save(str(p))
+    except Exception:
+        pass