import argparse
import csv
import fnmatch
import os


def list_input_csvs(input_dir, output_path):
    files = []
    for n in os.listdir(input_dir):
        if n.startswith('.'):
            continue
        if not fnmatch.fnmatch(n, 'splits_*.csv'):
            continue
        files.append(os.path.join(input_dir, n))
    files = sorted(files)
    if output_path:
        out_abs = os.path.abspath(output_path)
        files = [p for p in files if os.path.abspath(p) != out_abs]
    return files


def collect_columns(paths):
    trains, vals, tests = [], [], []
    for path in paths:
        if not os.path.exists(path):
            continue
        with open(path, newline='') as f:
            reader = csv.DictReader(f)
            for r in reader:
                t = (r.get('train') or '').strip()
                v = (r.get('val') or '').strip()
                te = (r.get('test') or '').strip()
                if t:
                    trains.append(t)
                if v:
                    vals.append(v)
                if te:
                    tests.append(te)
    return trains, vals, tests


def write_parallel(trains, vals, tests, output):
    n = max(len(trains), len(vals), len(tests))
    with open(output, 'w', newline='') as f:
        writer = csv.writer(f)
        writer.writerow(['', 'train', 'val', 'test'])
        for i in range(n):
            t = trains[i] if i < len(trains) else ''
            v = vals[i] if i < len(vals) else ''
            te = tests[i] if i < len(tests) else ''
            writer.writerow([i, t, v, te])


def main():
    parser = argparse.ArgumentParser()
    base = os.path.dirname(os.path.abspath(__file__))
    default_output = os.path.join(base, 'splits_ALL_MERGED.csv')
    parser.add_argument('--input_dir', default='/mnt/datadisk0/data_process')
    parser.add_argument('--inputs', nargs='*', default=None)
    parser.add_argument('--output', default='/mnt/datadisk0/data_process/splits_ALL_MERGED.csv')
    args = parser.parse_args()

    if args.inputs:
        inputs = args.inputs
    else:
        inputs = list_input_csvs(args.input_dir, args.output)

    trains, vals, tests = collect_columns(inputs)
    write_parallel(trains, vals, tests, args.output)

    print('Input CSVs:', len(inputs))
    print('Train items:', len(trains))
    print('Val items:', len(vals))
    print('Test items:', len(tests))
    print('Output CSV:', args.output)


if __name__ == '__main__':
    main()