app.py

import os
import gc
import torch
import shutil
import uuid
import gradio as gr
from huggingface_hub import HfApi, hf_hub_download
from safetensors.torch import load_file, save_file

def convert_and_upload(token, source_repo, target_repo, precision, target_components):
    if not token:
        yield "❌ Error: Please provide a valid Hugging Face Write Token."
        return
    if not target_repo.strip() or "your-username" in target_repo:
        yield "❌ Error: Please specify a valid Target Repository (e.g., your-username/repo-name)."
        return
    if not target_components:
        yield "❌ Error: Please select at least one component to quantize."
        return

    # Map precision string to PyTorch dtype
    if precision == "FP8":
        target_dtype = torch.float8_e4m3fn
    elif precision == "FP16":
        target_dtype = torch.float16
    elif precision == "BF16":
        target_dtype = torch.bfloat16
    else:
        target_dtype = None

    api = HfApi(token=token)
    yield f"🔄 Connecting to Hugging Face and verifying target repo: {target_repo}..."

    try:
        api.create_repo(repo_id=target_repo, exist_ok=True, private=False)
    except Exception as e:
        yield f"❌ Error checking/creating repo: {str(e)}\nMake sure your token has 'Write' permissions."
        return

    yield f"📋 Fetching file list from {source_repo}..."
    try:
        files = api.list_repo_files(source_repo)
    except Exception as e:
        yield f"❌ Error fetching files: {str(e)}"
        return

    # Create a unique cache directory for this specific run to prevent disk bloat
    cache_dir = f"./hf_cache_{uuid.uuid4().hex[:8]}"
    
    success_count = 0
    error_count = 0

    for file in files:
        # Detect large .safetensors files at the root level (just in case)
        is_root_safetensor = "/" not in file and file.endswith(".safetensors")
        
        if is_root_safetensor:
            yield f"🗑️ Auto-skipping massive root model: {file}..."
            try:
                api.delete_file(path_in_repo=file, repo_id=target_repo, token=token, commit_message=f"Auto-deleted root file {file}")
                yield f"✅ Ensured {file} is removed from target repository."
            except Exception:
                pass 
            continue

        yield f"⏳ Processing {file}..."

        try:
            os.makedirs(cache_dir, exist_ok=True)

            # Download using the token to ensure gated/large files don't fail silently
            local_path = hf_hub_download(
                repo_id=source_repo,
                filename=file,
                cache_dir=cache_dir,
                token=token 
            )

            in_target_component = any(f"{comp}/" in file for comp in target_components)

            if file.endswith(".safetensors") and in_target_component:
                yield f"🧠 Quantizing {file} to {precision} (This will take a few minutes)..."
                
                tensors = load_file(local_path)

                if target_dtype:
                    keys = list(tensors.keys())
                    for k in keys:
                        if tensors[k].is_floating_point():
                            # Cast the tensor to target precision
                            tensors[k] = tensors[k].to(target_dtype)

                converted_path = "converted.safetensors"
                save_file(tensors, converted_path)

                # Aggressive memory flush (Crucial for the 11.68GB transformer file)
                del tensors
                gc.collect()

                yield f"☁️ Uploading {precision} version of {file}..."
                api.upload_file(
                    path_or_fileobj=converted_path,
                    path_in_repo=file,
                    repo_id=target_repo,
                    commit_message=f"Upload {precision} quantized {file}"
                )
                
                os.remove(converted_path)

            else:
                yield f"☁️ Copying {file} as-is..."
                api.upload_file(
                    path_or_fileobj=local_path,
                    path_in_repo=file,
                    repo_id=target_repo,
                    commit_message=f"Copy {file} from original repo"
                )

            success_count += 1

            # EXTREME DISK CLEANUP: Nuke the cache directory after every file to prevent the 50GB Space Crash
            if os.path.exists(cache_dir):
                shutil.rmtree(cache_dir)
            
            gc.collect()

        except Exception as e:
            error_count += 1
            yield f"⚠️ Error processing {file}: {str(e)}\nSkipping to next file..."

    # Final cleanup sweep
    if os.path.exists(cache_dir):
        shutil.rmtree(cache_dir)

    yield f"✅ Finished! Successfully processed {success_count} files. Errors encountered: {error_count}."

# Dynamic UI Update for Target Repo Name
def update_target_repo(username, source, precision):
    user_prefix = username.strip() if username.strip() else "your-username"
    model_name = source.split("/")[-1] if "/" in source else source
    return f"{user_prefix}/{model_name}-{precision}"

# Build the Gradio UI
with gr.Blocks(theme=gr.themes.Soft()) as demo:
    gr.Markdown("# 🚀 LongCat Dedicated Quantizer")
    gr.Markdown(
        "Convert the **LongCat-Image** family of models to lower precisions (FP8, FP16, BF16).\n\n"
        "**Memory & Disk Protection:** This tool is specifically tuned to survive the massive 11.68 GB single-file `transformer` "
        "shard. It aggressively purges Hugging Face's download cache and PyTorch's RAM buffer after every single step to keep the free Space alive."
    )

    with gr.Row():
        with gr.Column(scale=2):
            hf_token = gr.Textbox(
                label="Hugging Face Token (Write Access Required)", 
                type="password",
                placeholder="hf_..."
            )
            hf_username = gr.Textbox(
                label="Your Hugging Face Username", 
                placeholder="e.g., rootlocalghost"
            )
            # Locked down to LongCat models
            source_repo = gr.Dropdown(
                choices=[
                    "meituan-longcat/LongCat-Image-Edit-Turbo",
                    "meituan-longcat/LongCat-Image-Edit",
                    "meituan-longcat/LongCat-Image"
                ], 
                value="meituan-longcat/LongCat-Image-Edit-Turbo", 
                label="Source Repository",
                allow_custom_value=False
            )
            
            target_components = gr.CheckboxGroup(
                choices=["text_encoder", "transformer", "vae"],
                value=["text_encoder", "transformer"],
                label="Components to Quantize",
                info="Select which folders should be cast to the new precision. Unselected folders will be copied as-is."
            )
            
            precision = gr.Dropdown(
                choices=["FP8", "FP16", "BF16"], 
                value="FP8", 
                label="Target Precision"
            )
            target_repo = gr.Textbox(
                label="Target Repository (Auto-generated)", 
                value="your-username/LongCat-Image-Edit-Turbo-FP8",
                interactive=True
            )
            start_btn = gr.Button("Start Quantization & Upload", variant="primary")
        
        with gr.Column(scale=3):
            output_log = gr.Textbox(
                label="Operation Logs", 
                lines=20, 
                interactive=False,
                max_lines=25
            )

    inputs_to_watch = [hf_username, source_repo, precision]
    for inp in inputs_to_watch:
        inp.change(
            fn=update_target_repo, 
            inputs=inputs_to_watch, 
            outputs=[target_repo]
        )

    start_btn.click(
        fn=convert_and_upload, 
        inputs=[hf_token, source_repo, target_repo, precision, target_components], 
        outputs=[output_log]
    )

if __name__ == "__main__":
    demo.launch()