import os
import json

def generate_hf_metadata(dataset_dir):
    lq_dir = os.path.join(dataset_dir, 'lq')
    gt_dir = os.path.join(dataset_dir, 'gt')
    
    # Check if both directories exist
    if not os.path.exists(lq_dir) or not os.path.exists(gt_dir):
        print(f"Skipping {dataset_dir}, missing 'lq' or 'gt' folders.")
        return
        
    metadata_path = os.path.join(dataset_dir, 'metadata.jsonl')
    count = 0
    
    with open(metadata_path, 'w', encoding='utf-8') as f:
        # Traverse the lq folder
        for filename in sorted(os.listdir(lq_dir)):
            if filename.lower().endswith(('.png', '.jpg', '.jpeg', '.bmp', '.tif', '.webp')):
                gt_filename = filename
                if "_LR" in gt_filename:
                    # Common SR substitutions (e.g., _LR4 -> _HR, _LR -> _HR)
                    import re
                    gt_filename = re.sub(r'_LR\d*', '_HR', gt_filename)
                
                gt_file_path = os.path.join(gt_dir, gt_filename)
                
                # Check if GT exists
                if not os.path.exists(gt_file_path):
                    # Fallback to direct name if substitution was wrong
                    if os.path.exists(os.path.join(gt_dir, filename)):
                        gt_filename = filename
                        gt_file_path = os.path.join(gt_dir, gt_filename)

                if os.path.exists(gt_file_path):
                    record = {
                        "file_name": f"lq/{filename}",
                        "ground_truth": f"gt/{gt_filename}"
                    }
                    f.write(json.dumps(record) + '\n')
                    count += 1
                else:
                    print(f"Warning: Missing GT image for -> {gt_file_path}")
                    
    print(f"Successfully generated {metadata_path} for {dataset_dir}. Matched {count} image pairs.")

if __name__ == "__main__":
    datasets = ['imagenet512', 'RealSet80', 'RealSR']
    
    for ds in datasets:
        if os.path.exists(ds):
            generate_hf_metadata(ds)
        else:
            print(f"Directory not found: {ds}")