#!/usr/bin/env python3
# Copyright 2015 The Chromium Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

"""Windows ICO file crusher.

Optimizes the PNG images within a Windows ICO icon file. This extracts all of
the sub-images within the file, runs any PNG-formatted images through
optimize-png-files.sh, then packs them back into an ICO file.

NOTE: ICO files can contain both raw uncompressed BMP files and PNG files. This
script does not touch the BMP files, which means if you have a huge uncompressed
image, it will not get smaller. 256x256 icons should be PNG-formatted first.
(Smaller icons should be BMPs for compatibility with Windows XP.)
"""

import argparse
import io
import logging
import os
import sys

import ico_tools


def main(args=None):
  if args is None:
    args = sys.argv[1:]

  parser = argparse.ArgumentParser(description='Crush Windows ICO files.')
  parser.add_argument(
    'files',
    metavar='ICO',
    type=argparse.FileType('r+b'),
    nargs='+',
    help='.ico files to be crushed',
  )
  parser.add_argument(
    '-o',
    dest='optimization_level',
    metavar='OPT',
    type=int,
    help='optimization level',
  )
  parser.add_argument(
    '--lint',
    dest='lint',
    action='store_true',
    help='test the ICO file without modifying (set status to 1 on error)',
  )
  parser.add_argument(
    '-d',
    '--debug',
    dest='debug',
    action='store_true',
    help='enable debug logging',
  )

  args = parser.parse_args()

  if args.debug:
    logging.getLogger().setLevel(logging.DEBUG)

  failed = False
  for file in args.files:
    buf = io.BytesIO()
    file.seek(0, os.SEEK_END)
    old_length = file.tell()
    file.seek(0, os.SEEK_SET)

    if args.lint:
      for error in ico_tools.LintIcoFile(file):
        logging.warning('%s: %s', file.name, error)
        # Any errors should cause this process to exit with a status of 1.
        failed = True
      continue

    ico_tools.OptimizeIcoFile(file, buf, args.optimization_level)

    new_length = len(buf.getvalue())

    # Always write (even if file size not reduced), because we make other fixes
    # such as regenerating the AND mask.
    file.truncate(new_length)
    file.seek(0)
    file.write(buf.getvalue())

    if new_length >= old_length:
      logging.info('%s : Could not reduce file size.', file.name)
    else:
      saving = old_length - new_length
      saving_percent = float(saving) / old_length
      logging.info(
        '%s : %d => %d (%d bytes : %d %%)',
        file.name,
        old_length,
        new_length,
        saving,
        int(saving_percent * 100),
      )

  return failed


if __name__ == '__main__':
  sys.exit(main())