import csv
import os


def read_files(base_dir):
    data = []
    for file in os.listdir(base_dir):
        print(f'reading file \'{file}\'')
        with open(os.path.join('data', file), 'r') as input_file:
            data.extend(list(csv.DictReader(input_file)))
    return data


def main():
    data = read_files('data')
    print(data[0])
    print("Sorting")
    data = sorted(data, key=lambda entry: int(entry['SERIAL_NUMBER']))
    print(data[0])
    print(f'final length of data {len(data)}')

    with open('test.csv', 'w') as out_file:
        writer = csv.DictWriter(out_file, data[0].keys())
        writer.writeheader()
        writer.writerows(data)


if __name__ == '__main__':
    main()


#
# with open('test.csv') as again_in:
#     reader2 = csv.DictReader(again_in)
#     data2 = list(reader2)
#
# print(data2[0])
#
# print(f"Is same? {data[0] == data2[0]}")