#!/usr/bin/env python

import os
import os.path as op
import sys
import json
import subprocess
from multiprocessing.dummy import Pool


def _get_files(root):
    for dirpath, dirnames, filenames in os.walk(root):
        for filename in filenames:
            yield op.join(dirpath, filename)
        for dirname in dirnames:
            _get_files(op.join(dirpath, dirname))


def _probe_file(filepath):
    try:
        raw_data = subprocess.check_output(['ffprobe', '-v', '0', '-of', 'json',
                                            '-show_streams', '-show_format', filepath])
    except Exception as e:
        print(f'[✗] {filepath}')
        return None
    else:
        print(f'[✓] {filepath}')
        return json.loads(raw_data)


def _main(output, dirs):
    files = sorted(f for d in dirs for f in _get_files(d))
    print(f'processing {len(files)} files...')

    db = [result for result in Pool().imap(_probe_file, files) if result]

    print(f'writing {output} database')
    with open(output, 'w') as f:
        f.write(json.dumps(db, indent=4))


if __name__ == '__main__':
    output = sys.argv[1]
    dirs = sys.argv[2:]
    _main(output, dirs)