# Copyright 2022 The Chromium Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
"""Generates checksums for URLs in the Pervasive Payload list."""

import argparse
import csv
import requests
import urllib.parse
import pervasive_checksum


def generate_list_with_checksums(data):
  pairs_list = []
  flat_list = []
  for i, url_info in enumerate(data):
    url = url_info[0]
    print(f"[{i}/{len(data)}] Fetching {url}")

    with requests.get(url,
                      headers={"Accept-Encoding": "gzip, deflate, br"},
                      stream=True) as response:

      headers = list(response.headers.items())
      raw_body = response.raw.data

    checksum = pervasive_checksum.calculate_checksum(headers, raw_body)
    pairs_list.append([url, checksum])
    flat_list.append(str(url))
    flat_list.append(str(checksum))

  return pairs_list, flat_list


def main():
  parser = argparse.ArgumentParser(
      description=__doc__, formatter_class=argparse.RawTextHelpFormatter)

  parser.add_argument(
      "input",
      type=str,
      nargs=1,
      help="path for input csv file containing pervasive payloads list")

  parser.add_argument("-v",
                      "--list-version",
                      "--version",
                      dest="list_version",
                      default="1",
                      help="version of pervasive payloads list")

  parser.add_argument("-f",
                      "--format",
                      dest="format",
                      default="csv",
                      choices=["csv", "comma_separated", "url_encoded"],
                      help="output format to use. Default: csv")

  parser.add_argument("output",
                      type=str,
                      nargs=1,
                      help="path for output file for URLs and checksums")

  args = parser.parse_args()

  filename = args.input[0]

  data = []
  with open(filename, mode="r", newline="") as csvfile:
    datareader = csv.reader(csvfile)
    data = list(datareader)

  pairs_list, flat_list = generate_list_with_checksums(data)

  if args.format == "csv":
    with open(args.output[0], mode="w", newline="") as f:
      writer = csv.writer(f)
      writer.writerows(pairs_list)

  elif args.format == "comma_separated":
    flat_list.insert(0, str(args.list_version))
    with open(args.output[0], mode="w") as file:
      file.write(",\n".join(flat_list))

  elif args.format == "url_encoded":
    concatenated = str(args.list_version) + ","
    concatenated += ",".join(flat_list)
    url_encoded_list = urllib.parse.quote_plus(concatenated)
    with open(args.output[0], mode="w") as file:
      file.write(url_encoded_list)
    print(
        "NOTE: To run the feature via commandline, use the following command:\n"
        "out/Default/chrome --enable-features='PervasivePayloadsList:pervasive-payloads/(url_encoded_list),CacheTransparency,SplitCacheByNetworkIsolationKey'"
    )


if __name__ == "__main__":
  main()