import argparse
import glob
import os
from pyiqa import create_metric
from tqdm import tqdm
import csv
from time import time

import torch


def main():
    """Inference demo for pyiqa.
    """
    parser = argparse.ArgumentParser()
    parser.add_argument('-t', '--target', type=str, default=None, help='input image/folder path.')
    parser.add_argument('-r', '--ref', type=str, default=None, help='reference image/folder path if needed.')
    parser.add_argument('--device', type=str, default=None, help='reference image/folder path if needed.')
    parser.add_argument(
        '--metric_mode',
        type=str,
        default='FR',
        help='metric mode Full Reference or No Reference. options: FR|NR.')
    parser.add_argument('-m', '--metric_name', type=str, default='PSNR', help='IQA metric name, case sensitive.')
    parser.add_argument('--save_file', type=str, default=None, help='path to save results.')

    # Add a --verbose flag
    parser.add_argument(
        '-v', '--verbose',
        action='store_true',  # This makes it a flag (True when used, False otherwise)
        help='Enable verbose output'
    )

    args = parser.parse_args()

    metric_name = args.metric_name.lower()

    # set up IQA model
    iqa_model = create_metric(metric_name, metric_mode=args.metric_mode, device=args.device)
    metric_mode = iqa_model.metric_mode

    if os.path.isfile(args.target):
        input_paths = [args.target]
        if args.ref is not None:
            ref_paths = [args.ref]
    else:
        input_paths = sorted(glob.glob(os.path.join(args.target, '*')))
        if args.ref is not None:
            ref_paths = sorted(glob.glob(os.path.join(args.ref, '*')))

    if args.save_file:
        sf = open(args.save_file, 'a')
        sfwriter = csv.writer(sf)

    avg_score = 0
    test_img_num = len(input_paths)
    if metric_name != 'fid':
        pbar = tqdm(total=test_img_num, unit='image')
        for idx, img_path in enumerate(input_paths):
            img_name = os.path.basename(img_path)
            if metric_mode == 'FR':
                ref_img_path = ref_paths[idx]
            else:
                ref_img_path = None

            start_time = time()
            score = iqa_model(img_path, ref_img_path).cpu().item()
            end_time = time()
            avg_score += score
            pbar.update(1)
            pbar.set_description(f'{metric_name} of {img_name}: {score}')
            pbar.write(f'{metric_name} of {img_name}: {score}\tTime: {end_time - start_time:.2f}s')
            if args.save_file:
                sfwriter.writerow([img_path, score])
            
        pbar.close()
        avg_score /= test_img_num
    else:
        assert os.path.isdir(args.target), 'input path must be a folder for FID.'
        avg_score = iqa_model(args.target, args.ref)
    
    if args.verbose and torch.cuda.is_available():
        print(torch.cuda.memory_summary())

    msg = f'Average {metric_name} score of {args.target} with {test_img_num} images is: {avg_score}'
    print(msg)
    if args.save_file:
        sf.close()

    if args.save_file:
        print(f'Done! Results are in {args.save_file}.')
    else:
        print(f'Done!')

    return avg_score


if __name__ == '__main__':
    main()