#!/usr/bin/env python3

"""Script to roll Abseil into chromium."""

import argparse
import convert_bazel_to_gn
import generate_def_files
import logging
import os
import re
import subprocess
import tempfile
from datetime import datetime

ABSL_URI = 'https://github.com/abseil/abseil-cpp.git'

def _PullAbseil(abseil_dir, revision):
    logging.info('Updating abseil...')
    args = ['git', 'clone', ABSL_URI]
    if revision:
        args.extend(['--revision', revision])
    subprocess.check_call(args, cwd=abseil_dir)

def _SyncChromium(chromium_dir):
    logging.info('Updating chromium...')
    subprocess.check_call(['git', 'pull', '--rebase'], cwd=chromium_dir)
    subprocess.check_call(['gclient', 'sync'], cwd=chromium_dir)


def _UpdateChromiumReadme(readme_filename, abseil_dir):
    logging.info('Updating ' + readme_filename)

    stdout = subprocess.check_output(['git', 'log', '-n1', '--pretty=short'],
                                     cwd=abseil_dir)
    new_revision = re.search('commit\\s(.{40})', str(stdout)).group(1)

    with open(readme_filename, 'r+') as f:
        content = f.read()
        prefix = 'Revision: '
        pos = content.find(prefix)
        assert (pos > 0)
        pos = pos + len(prefix)
        old_revision = content[pos:pos + 40]
        f.seek(pos)
        f.write(new_revision)

    logging.info('Abseil old revision is ' + old_revision)
    logging.info('Abseil new revision is ' + new_revision)
    return old_revision[0:10] + '..' + new_revision[0:10]


def _UpdateAbseilInChromium(abseil_dir, chromium_dir):
    logging.info('Syncing abseil in chromium/src/third_party...')
    exclude = [
        '*BUILD.gn',
        'DIR_METADATA',
        'README.chromium',
        'OWNERS',
        '.clang-format-ignore',
        '.git',
        '.gitignore',
        '.style.yapf',
        '*.gni',
        '*clang-format',
        'patches/*',
        'patches',
        'absl_hardening_test.cc',
        'roll_abseil.py',
        'generate_def_files.py',
        'convert_bazel_to_gn.py',
        '*.def',
    ]
    params = [
        'rsync', '-aP', abseil_dir,
        os.path.join(chromium_dir, 'third_party'), '--delete'
    ]
    for e in exclude:
        params.append('--exclude={}'.format(e))
    subprocess.check_call(params, cwd=chromium_dir)


def _PatchAbseil(abseil_in_chromium_dir):
    logging.info('Patching abseil...')
    for patch in os.listdir(os.path.join(abseil_in_chromium_dir, 'patches')):
        subprocess.check_call([
            'patch', '--strip', '1', '-i',
            os.path.join(abseil_in_chromium_dir, 'patches', patch)
        ])

    os.remove(
        os.path.join(abseil_in_chromium_dir, 'absl', 'base', 'internal',
                     'dynamic_annotations.h'))


def _Commit(chromium_dir, hash_diff, should_upload):
    logging.info('Commit...')
    desc = """Roll abseil_revision {0}

Change Log:
https://chromium.googlesource.com/external/github.com/abseil/abseil-cpp/+log/{0}
Full diff:
https://chromium.googlesource.com/external/github.com/abseil/abseil-cpp/+/{0}
Bug: None""".format(hash_diff)

    subprocess.check_call(['git', 'add', 'third_party/abseil-cpp'],
                          cwd=chromium_dir)
    proc = subprocess.run(
        ['git', 'diff', '--staged', '--quiet', 'third_party/abseil-cpp'],
        cwd=chromium_dir)
    if proc.returncode == 0:
        logging.info('Abseil is up-to-date, nothing to commit!')
        return

    subprocess.check_call(['git', 'commit', '-m', desc], cwd=chromium_dir)

    if should_upload:
        logging.info('Upload...')
        subprocess.check_call([
            'git', 'cl', 'upload', '--commit-description=' + desc,
            '--bypass-hooks'
        ],
                              cwd=chromium_dir)


def _Roll(should_branch, should_pull, should_generate_def, should_upload,
          revision):
    chromium_dir = os.getcwd()
    abseil_in_chromium_dir = os.path.join(chromium_dir, 'third_party',
                                          'abseil-cpp')
    if should_branch:
        branch_name = datetime.today().strftime('rolling-absl-%Y%m%d')
        logging.info('Creating branch ' + branch_name + ' for the roll...')
        subprocess.check_call(['git', 'new-branch', branch_name],
                              cwd=chromium_dir)

    if should_pull:
        _SyncChromium(chromium_dir)

    with tempfile.TemporaryDirectory() as abseil_root:
        _PullAbseil(abseil_root, revision)
        abseil_dir = os.path.join(abseil_root, 'abseil-cpp')
        _UpdateAbseilInChromium(abseil_dir, chromium_dir)
        hash_diff = _UpdateChromiumReadme(
            os.path.join(abseil_in_chromium_dir, 'README.chromium'),
            abseil_dir)

    _PatchAbseil(abseil_in_chromium_dir)
    convert_bazel_to_gn.convert_all(abseil_in_chromium_dir)
    if should_generate_def:
        generate_def_files.generate_all(chromium_dir)

    _Commit(chromium_dir, hash_diff, should_upload)


if __name__ == '__main__':
    logging.getLogger().setLevel(logging.INFO)

    parser = argparse.ArgumentParser()
    parser.add_argument(
        '--no-branch',
        action='store_true',
        help='Skip creating a new branch, use the current one.')
    parser.add_argument('--no-pull',
                        action='store_true',
                        help='Skip pulling the latest Chromium revision.')
    parser.add_argument('--no-def',
                        action='store_true',
                        help='Skip regenerating def files.')
    parser.add_argument('--no-upload',
                        action='store_true',
                        help='Skip uploading the change.')
    parser.add_argument('--revision',
                        default=None,
                        help='Revision to roll to. The default is the latest.')
    args = parser.parse_args()

    if os.getcwd().endswith('src') and os.path.exists('chrome/browser'):
        _Roll(not args.no_branch, not args.no_pull, not args.no_def,
              not args.no_upload, args.revision)
    else:
        logging.error('Run this script from a chromium/src/ directory.')