[boardgames] Hash lrtl files and only import if changed

vrobbler/apps/scrobbles/importers/webdav.py

@@ -226,6 +226,32 @@ def scan_webdav_for_retroarch(webdav_client, user_id):
         if not downloaded:
             return 0
 
+        # Compute content hash of all downloaded files
+        import hashlib
+
+        hasher = hashlib.md5()
+        for basename in downloaded:
+            filepath = os.path.join(download_dir, basename)
+            hasher.update(basename.encode())
+            with open(filepath, "rb") as f:
+                hasher.update(f.read())
+        content_hash = hasher.hexdigest()
+
+        # Skip if the last completed import already has this hash
+        last_import = (
+            RetroarchImport.objects.filter(
+                user_id=user_id, processed_finished__isnull=False
+            )
+            .order_by("-processed_finished")
+            .first()
+        )
+        if last_import and last_import.files_hash == content_hash:
+            logger.info(
+                "Retroarch lrtl files unchanged for user, skipping",
+                extra={"user_id": user_id},
+            )
+            return 0
+
         zip_path = os.path.join(
             download_dir, f"retroarch-batch-{datetime.now().strftime('%Y%m%d%H%M%S')}.zip"
         )
@@ -236,6 +262,7 @@ def scan_webdav_for_retroarch(webdav_client, user_id):
         imp = RetroarchImport.objects.create(
             user_id=user_id,
             original_filename=f"batch-{len(downloaded)}-files",
+            files_hash=content_hash,
         )
         with open(zip_path, "rb") as f:
             imp.lrtl_file.save(
@@ -243,9 +270,10 @@ def scan_webdav_for_retroarch(webdav_client, user_id):
             )
         process_retroarch_import.delay(imp.id)
         logger.info(
-            "Queued retroarch import %s with %d file(s)",
+            "Queued retroarch import %s with %d file(s) (hash=%s)",
             imp.uuid,
             len(downloaded),
+            content_hash[:12],
         )
         return 1
     finally: