feat(server): action dispatch with structured result and messages

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

server/actions.py

@@ -0,0 +1,59 @@
+"""Glue between a chosen Hit and a side-effecting download. Mirrors musicfetch's
+main() dispatch but returns a structured result dict and speakable messages."""
+import os
+from typing import Optional
+
+from . import mf
+
+
+def _source_label(hit) -> str:
+    return "YouTube Music" if hit.source == "youtube" else "Lidarr"
+
+
+def _title(hit) -> str:
+    return hit.album or hit.title or hit.artist
+
+
+def started_message(hit) -> str:
+    return f"Found '{_title(hit)}' by {hit.artist or 'unknown artist'} on {_source_label(hit)}. Downloading now."
+
+
+def done_message(hit) -> str:
+    return f"Finished downloading '{_title(hit)}' by {hit.artist or 'unknown artist'}."
+
+
+def failed_message(hit) -> str:
+    return f"Failed to download '{_title(hit)}' by {hit.artist or 'unknown artist'}."
+
+
+def _yt_path(hit, root: str) -> str:
+    artist_dir = (hit.artist.split(",")[0].strip() if hit.artist else "") or "Unknown Artist"
+    return os.path.join(root, artist_dir, "youtube")
+
+
+def _download_youtube(hit, quality: str, root: str) -> dict:
+    mf.act_youtube(hit, root, quality, False)
+    return {"path": _yt_path(hit, root), "lidarr_album_id": None}
+
+
+def perform_fetch(chosen, hits: list, quality: str, root: str) -> dict:
+    """Run the download for the chosen hit. Returns {"path", "lidarr_album_id"}.
+    Raises on unrecoverable failure (recorded by the job worker)."""
+    if chosen.source == "youtube":
+        return _download_youtube(chosen, quality, root)
+
+    if chosen.kind == "album":
+        handled = mf.act_lidarr_album(chosen, root, False, False)
+        if handled:
+            return {"path": None, "lidarr_album_id": chosen.payload.get("album", {}).get("id")}
+        # No indexer release -> fall through to the top YouTube hit, like the CLI.
+        yt = next((h for h in hits if h.source == "youtube"), None)
+        if yt is None:
+            raise RuntimeError("No Lidarr release and no YouTube fallback available.")
+        return _download_youtube(yt, quality, root)
+
+    # Lidarr artist pick.
+    ok = mf.act_lidarr_artist(chosen, root, False, False)
+    if not ok:
+        raise RuntimeError("Failed to add artist to Lidarr.")
+    return {"path": None, "lidarr_album_id": None}