import json
from pathlib import Path

def generate_metadata(base_path: Path, output_path: Path):
    """Generate metadata.jsonl for a split (e.g., data/sim/train)"""
    
    images_dir = base_path / "images"
    metadata = []
    
    for scene_dir in sorted(images_dir.iterdir()):
        if not scene_dir.is_dir():
            continue
        
        scene = scene_dir.name
        
        for img_file in sorted(scene_dir.glob("*.png")):
            fname = img_file.name
            
            image_path = f"images/{scene}/{fname}"
            seg_path = f"segmented/{scene}/{fname}"
            front_path = f"labels/{scene}/front/{fname}"
            back_path = f"labels/{scene}/back/{fname}"
            
            entry = {
                "file_name": image_path,
                "scene": scene,
            }
            
            if (base_path / seg_path).exists():
                entry["segmentation_mask_file_name"] = seg_path
            
            if (base_path / front_path).exists():
                entry["front_mask_file_name"] = front_path
            
            if (base_path / back_path).exists():
                entry["back_mask_file_name"] = back_path
            
            metadata.append(entry)
    
    output_path.parent.mkdir(parents=True, exist_ok=True)
    with open(output_path, "w") as f:
        for entry in metadata:
            f.write(json.dumps(entry) + "\n")
    
    print(f"Generated {output_path} with {len(metadata)} entries")


if __name__ == "__main__":
    dataset_root = Path(".")  
    
    splits = [
        ("sim", "train"),
        ("sim", "validation"),
        ("real", "train"),
        ("real", "validation"),
    ]
    
    for domain, split in splits:
        base_path = dataset_root / "data" / domain / split
        if base_path.exists():
            output_path = base_path / "metadata.jsonl"
            generate_metadata(base_path, output_path)
        else:
            print(f"Skipping {base_path} (not found)")