joy: don't load model when there is no work to do

joy

@@ -716,6 +716,21 @@ def main():
 
     setup_logging(args.verbose)
 
+    tasks = []
+    image_extensions = {".webp", ".png", ".jpeg", ".jpg", ".jxl"}
+    for image_path in Path(args.directory).rglob("*"):
+        if image_path.suffix.lower() in image_extensions:
+            caption_file = image_path.with_suffix(".caption")
+            # Skip if the caption file already exists
+            if caption_file.exists():
+                logging.info(f"Skipping {image_path}: Caption file already exists.")
+                continue
+            tasks.append((image_path, caption_file))
+
+    if not tasks:
+        logging.error('No input file found.')
+        return
+
     # Validate random-tags usage
     if args.random_tags is not None and args.feed_from_tags is None:
         parser.error("--random-tags can only be used when --feed-from-tags is enabled")
@@ -731,61 +746,52 @@ def main():
     else:
         logging.info("Running in dry-run mode. Models will not be loaded.")
 
-    image_extensions = {".webp", ".png", ".jpeg", ".jpg", ".jxl"}
-    for image_path in Path(args.directory).rglob("*"):
-        if image_path.suffix.lower() in image_extensions:
-            caption_file = image_path.with_suffix(".caption")
-
-            # Skip if the caption file already exists
-            if caption_file.exists():
-                logging.info(f"Skipping {image_path}: Caption file already exists.")
-                continue
+    for image_path, caption_file in tasks:
+        if not args.dry_run:
+            input_image = Image.open(image_path).convert("RGB")
 
-            if not args.dry_run:
-                input_image = Image.open(image_path).convert("RGB")
+        # Use custom prompt if specified
+        prompt = args.custom_prompt or JoyCaptionModel.get_prompt_string(
+            args.caption_type, args.caption_length
+        )
 
-            # Use custom prompt if specified
-            prompt = args.custom_prompt or JoyCaptionModel.get_prompt_string(
-                args.caption_type, args.caption_length
+        if args.feed_from_tags is not None and args.artist_from_folder:
+            raise ValueError(
+                "feed-from-tags and artist-from-folder can't be used together"
             )
+        if args.feed_from_tags is not None:
+            prompt = prompt_from_tags(args, image_path, tagset_normalizer, prompt)
+        elif args.artist_from_folder:
+            prompt = prompt_from_folder(prompt, image_path.resolve())
+
+        if args.dry_run:
+            logging.info(
+                f"Dry run: Skipping caption generation for {image_path} with prompt:\n\t{prompt}"
+            )
+            continue
+        else:
+            logging.info(f"Prompt for {image_path}:\n\t{prompt}")
 
-            if args.feed_from_tags is not None and args.artist_from_folder:
-                raise ValueError(
-                    "feed-from-tags and artist-from-folder can't be used together"
-                )
-            if args.feed_from_tags is not None:
-                prompt = prompt_from_tags(args, image_path, tagset_normalizer, prompt)
-            elif args.artist_from_folder:
-                prompt = prompt_from_folder(prompt, image_path.resolve())
-
-            if args.dry_run:
-                logging.info(
-                    f"Dry run: Skipping caption generation for {image_path} with prompt:\n\t{prompt}"
-                )
-                continue
-            else:
-                logging.info(f"Prompt for {image_path}:\n\t{prompt}")
-
-            caption = joy_caption_model.generate_valid_caption(input_image, prompt)
+        caption = joy_caption_model.generate_valid_caption(input_image, prompt)
 
-            # Strip commas if the --dont-strip-commas flag is not set
-            if not args.dont_strip_commas:
-                # Existing comma stripping logic
-                caption = re.sub(r",\s*([^\d])", r" \1", caption)
+        # Strip commas if the --dont-strip-commas flag is not set
+        if not args.dont_strip_commas:
+            # Existing comma stripping logic
+            caption = re.sub(r",\s*([^\d])", r" \1", caption)
 
-                # New feature: Add commas after periods if specified
-                if args.add_commas_to_sentence_ends:
-                    caption = re.sub(r"(\.)(\s+)([A-Z])", r"\1,\2\3", caption)
+            # New feature: Add commas after periods if specified
+            if args.add_commas_to_sentence_ends:
+                caption = re.sub(r"(\.)(\s+)([A-Z])", r"\1,\2\3", caption)
 
-            # Remove all newline characters
-            caption = caption.replace("\n", " ")
+        # Remove all newline characters
+        caption = caption.replace("\n", " ")
 
-            logging.info(f"Caption for {image_path}:\n\t{caption}\n\n")
+        logging.info(f"Caption for {image_path}:\n\t{caption}\n\n")
 
-            # Save the caption to a .caption file
-            with open(caption_file, "w", encoding="utf-8") as f:
-                f.write(caption)
-            logging.info(f"Caption saved to {caption_file}")
+        # Save the caption to a .caption file
+        with open(caption_file, "w", encoding="utf-8") as f:
+            f.write(caption)
+        logging.info(f"Caption saved to {caption_file}")
 
 
 RE_PARENS_SUFFIX = re.compile(r"_\([^)]+\)$")