#!/usr/bin/env python3

# Copyright (c) 2017 Computer Vision Center (CVC) at the Universitat Autonoma de
# Barcelona (UAB).
#
# This work is licensed under the terms of the MIT license.
# For a copy, see <https://opensource.org/licenses/MIT>.

"""Download big files from Google Drive."""

import argparse
import shutil
import sys

import requests

def sizeof_fmt(num, suffix='B'):
    # https://stackoverflow.com/a/1094933/5308925
    for unit in ['','K','M','G','T','P','E','Z']:
        if abs(num) < 1000.0:
            return "%3.2f%s%s" % (num, unit, suffix)
        num /= 1000.0
    return "%.2f%s%s" % (num, 'Yi', suffix)


def print_status(destination, progress):
    message = "Downloading %s...    %s" % (destination, sizeof_fmt(progress))
    empty_space = shutil.get_terminal_size((80, 20)).columns - len(message)
    sys.stdout.write('\r' + message + empty_space * ' ')
    sys.stdout.flush()


def download_file_from_google_drive(id, destination):
    # https://stackoverflow.com/a/39225039/5308925

    def save_response_content(response, destination):
        chunk_size = 32768
        written_size = 0

        with open(destination, "wb") as f:
            for chunk in response.iter_content(chunk_size):
                if chunk: # filter out keep-alive new chunks
                    f.write(chunk)
                    written_size += chunk_size
                    print_status(destination, written_size)
        print('Done.')

    def get_confirm_token(response):
        for key, value in response.cookies.items():
            if key.startswith('download_warning'):
                return value

        return None

    url = "https://docs.google.com/uc?export=download"

    session = requests.Session()

    response = session.get(url, params={'id': id}, stream=True)
    token = get_confirm_token(response)

    if token:
        params = {'id': id, 'confirm': token}
        response = session.get(url, params=params, stream=True)

    save_response_content(response, destination)


if __name__ == "__main__":

    try:

        argparser = argparse.ArgumentParser(description=__doc__)
        argparser.add_argument(
            'id',
            help='Google Drive\'s file id')
        argparser.add_argument(
            'destination',
            help='destination file path')
        args = argparser.parse_args()

        download_file_from_google_drive(args.id, args.destination)

    except KeyboardInterrupt:
        print('\nCancelled by user. Bye!')