Preserve uploaded asset numbers

app.py

@@ -457,8 +457,8 @@ def index_bucket_models():
     return added
 
 
-def next_bucket_number(kind, anima):
-    numbers = []
+def bucket_numbers(kind, anima):
+    numbers = set()
     for item in list_bucket_tree(
         BUCKET_ID,
         prefix=f"{kind}/",
@@ -469,8 +469,8 @@ def next_bucket_number(kind, anima):
             continue
         match = MODEL_NUMBER.match(Path(item.path).name)
         if match and is_anima_asset(match.group(2)) == anima:
-            numbers.append(int(match.group(1)))
-    return max(numbers, default=0) + 1
+            numbers.add(int(match.group(1)))
+    return numbers
 
 
 def upload_bucket_assets(files, kind, anima, password):
@@ -484,24 +484,39 @@ def upload_bucket_assets(files, kind, anima, password):
     assets = []
     for file in files:
         source = Path(file)
-        name = source.name
-        match = MODEL_NUMBER.match(name)
-        name = match.group(2) if match else name
+        match = MODEL_NUMBER.match(source.name)
+        number, name = (int(match.group(1)), match.group(2)) \
+            if match else (None, source.name)
         if source.suffix.casefold() not in MODEL_SUFFIXES:
             raise gr.Error(f"Unsupported model file: {name}")
         if anima and not is_anima_asset(name):
             name = f"{ANIMA_PREFIX}_{name}"
-        assets.append((source, name))
+        assets.append((source, number, name))
 
     with model_upload_lock:
-        number = next_bucket_number(kind, anima)
-        paths = [
-            f"{kind}/{number + index}_{name}"
-            for index, (_, name) in enumerate(assets)
-        ]
+        used = bucket_numbers(kind, anima)
+        reserved = {
+            number for _, number, _ in assets
+            if number is not None and number not in used
+        }
+        next_number = max(used, default=0) + 1
+        additions = []
+        paths = []
+        for source, number, name in assets:
+            if number is not None and number in reserved:
+                reserved.remove(number)
+            else:
+                while next_number in used or next_number in reserved:
+                    next_number += 1
+                number = next_number
+                next_number += 1
+            used.add(number)
+            path = f"{kind}/{number}_{name}"
+            additions.append((source, path))
+            paths.append(path)
         batch_bucket_files(
             BUCKET_ID,
-            add=[(source, path) for (source, _), path in zip(assets, paths)],
+            add=additions,
             token=IMAGE_TOKEN,
         )
         index_bucket_models()