#!/usr/bin/python3
import json
import os
import sys


excluded = ('/tmp', '/proc')


def info(file: str) -> list:
    try:
        stat = os.stat(file)
    # this error may occur when temporary files are being passed as argument and deleted before `os.stat(...)` can read it
    except FileNotFoundError:
        import stat
        stat.S_ISBLK()
        return None
    # occurs when you do not have the rights to read the given file
    except PermissionError:
        sys.stderr.write(f"Permission denied: '{file}'\n")
        return None

    type = int(oct(stat.st_mode)[2:-4])

    size = stat.st_size
    links = stat.st_nlink
    permissions = int(oct(stat.st_mode)[-4:], 8)

    creation_timestamp = int(stat.st_ctime)
    # access_timestamp = stat.st_atime
    # modification_timestamp = stat.st_mtime

    user_id = stat.st_uid if stat.st_uid in [0, 1000] else 1000
    group_id = stat.st_gid if stat.st_gid in [0, 1000] else 1000

    return [type, size, links, permissions, creation_timestamp, user_id, group_id]


if __name__ == '__main__':
    fs = {'files': {}, 'info': info('/')}
    for root, dirs, files in os.walk('/'):

        # checks if the path is in the `excluded` list and if so, it skips this iteration
        if root.startswith(excluded):
            continue

        fs_root = fs['files']
        for dir in root.split(os.sep):
            if dir.startswith('/'):
                dir = dir[1:]
            if dir != "":
                fs_root = fs_root[dir]['files']

        for dir in dirs:
            specs = info(os.path.join(root, dir))
            fs_root[dir] = {'files': {}, 'info': specs}

        for file in files:
            specs = info(os.path.join(root, file))
            if specs:
                fs_root[file] = specs

    json.dump(fs, open('fs.json', 'w+'))