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

import argparse
import collections
import logging
import os
import re
import subprocess
import sys
import time


SCRIPT_DIR = os.path.dirname(os.path.realpath(__file__))
SRC_DIR = os.path.abspath(os.path.join(SCRIPT_DIR, os.pardir))
sys.path.insert(0, os.path.join(SRC_DIR, 'build'))
import find_depot_tools
find_depot_tools.add_depot_tools_to_path()
import roll_dep_svn
from third_party import upload

# Avoid depot_tools/third_party/upload.py print verbose messages.
upload.verbosity = 0  # Errors only.

CHROMIUM_GIT_URL = 'https://chromium.googlesource.com/chromium/src.git'
COMMIT_POSITION_RE = re.compile('^Cr-Commit-Position: .*#([0-9]+).*$')
CL_ISSUE_RE = re.compile('^Issue number: ([0-9]+) \((.*)\)$')
REVIEW_URL_RE = re.compile('^https?://(.*)/(.*)')
ROLL_BRANCH_NAME = 'special_webrtc_roll_branch'
TRYJOB_STATUS_SLEEP_SECONDS = 30

# Use a shell for subcommands on Windows to get a PATH search.
IS_WIN = sys.platform.startswith('win')
WEBRTC_PATH = os.path.join('third_party', 'webrtc')
# Run these CQ trybots in addition to the default ones in infra/config/cq.cfg.
EXTRA_TRYBOTS = (
    'master.tryserver.chromium.linux:linux_chromium_archive_rel_ng;'
    'master.tryserver.chromium.mac:mac_chromium_archive_rel_ng'
)

# Result codes from build/third_party/buildbot_8_4p1/buildbot/status/results.py
# plus the -1 code which is used when there's no result yet.
TRYJOB_STATUS = {
  -1: 'RUNNING',
  0: 'SUCCESS',
  1: 'WARNINGS',
  2: 'FAILURE',
  3: 'SKIPPED',
  4: 'EXCEPTION',
  5: 'RETRY',
}
SUCCESS_STATUS = (0, 1, 3)
FAILURE_STATUS = (2, 4, 5)

CommitInfo = collections.namedtuple('CommitInfo', ['commit_position',
                                                   'git_commit',
                                                   'git_repo_url'])
CLInfo = collections.namedtuple('CLInfo', ['issue', 'url', 'review_server'])


def _VarLookup(local_scope):
  return lambda var_name: local_scope['vars'][var_name]


def _PosixPath(path):
  """Convert a possibly-Windows path to a posix-style path."""
  (_, path) = os.path.splitdrive(path)
  return path.replace(os.sep, '/')


def _ParseGitCommitPosition(description):
  for line in reversed(description.splitlines()):
    m = COMMIT_POSITION_RE.match(line.strip())
    if m:
      return m.group(1)
  logging.error('Failed to parse svn revision id from:\n%s\n', description)
  sys.exit(-1)


def _ParseGitCommitHash(description):
  for line in description.splitlines():
    if line.startswith('commit '):
      return line.split()[1]
  logging.error('Failed to parse git commit id from:\n%s\n', description)
  sys.exit(-1)
  return None


def _ParseDepsFile(filename):
  with open(filename, 'rb') as f:
    deps_content = f.read()
  return _ParseDepsDict(deps_content)


def _ParseDepsDict(deps_content):
  local_scope = {}
  global_scope = {
    'Var': _VarLookup(local_scope),
    'deps_os': {},
  }
  exec(deps_content, global_scope, local_scope)
  return local_scope


def _PrintTrybotsStatus(tryjob_results):
  status_to_name = {}
  for trybot_result in tryjob_results:
    status = TRYJOB_STATUS.get(trybot_result['result'], 'UNKNOWN')
    status_to_name.setdefault(status, [])
    status_to_name[status].append(trybot_result['builder'])

  print '\n========== TRYJOBS STATUS =========='
  for status,name_list in status_to_name.iteritems():
    print '%s: %s' % (status, ','.join(sorted(name_list)))


class AutoRoller(object):
  def __init__(self, chromium_src):
    self._chromium_src = chromium_src

  def _RunCommand(self, command, working_dir=None, ignore_exit_code=False,
                  extra_env=None):
    """Runs a command and returns the stdout from that command.

    If the command fails (exit code != 0), the function will exit the process.
    """
    working_dir = working_dir or self._chromium_src
    logging.debug('cmd: %s cwd: %s', ' '.join(command), working_dir)
    env = os.environ.copy()
    if extra_env:
      logging.debug('extra env: %s', extra_env)
      env.update(extra_env)
    p = subprocess.Popen(command, stdout=subprocess.PIPE,
                         stderr=subprocess.PIPE, shell=IS_WIN, env=env,
                         cwd=working_dir, universal_newlines=True)
    output = p.stdout.read()
    p.wait()
    p.stdout.close()
    p.stderr.close()

    if not ignore_exit_code and p.returncode != 0:
      logging.error('Command failed: %s\n%s', str(command), output)
      sys.exit(p.returncode)
    return output

  def _GenerateCLDescriptionCommand(self, webrtc_current, webrtc_new):
    commit_range = '%s..%s' % (webrtc_current.git_commit[:7],
                               webrtc_new.git_commit[:7])

    webrtc_changelog_url = '%s/+log/%s' % (webrtc_current.git_repo_url,
                                           commit_range)

    git_log_cmd = ['git', 'log', commit_range, '--date=short', '--no-merges',
                   '--format=%ad %ae %s']

    working_dir = os.path.join(self._chromium_src, WEBRTC_PATH)
    git_log = self._RunCommand(git_log_cmd, working_dir=working_dir)

    nb_commits = git_log.count('\n')
    webrtc_header = 'Roll WebRTC %s:%s (%d commit%s)' % (
        webrtc_current.commit_position, webrtc_new.commit_position,
        nb_commits, 's' if nb_commits > 1 else '')
    git_author = self._RunCommand(
        ['git', 'config', 'user.email'],
        working_dir=self._chromium_src).splitlines()[0]
    description = ('%s\n\n'
                   'Changes: %s\n\n'
                   '$ %s\n'
                   '%s\n'
                   'TBR=%s\n'
                   'CQ_INCLUDE_TRYBOTS=%s\n') % (
                       webrtc_header,
                       webrtc_changelog_url,
                       ' '.join(git_log_cmd),
                       git_log,
                       git_author,
                       EXTRA_TRYBOTS)

    return description

  def _GetCommitInfo(self, path_below_src, git_hash=None, git_repo_url=None):
    working_dir = os.path.join(self._chromium_src, path_below_src)
    self._RunCommand(['git', 'fetch', 'origin'], working_dir=working_dir)
    revision_range = git_hash or 'origin'
    ret = self._RunCommand(
        ['git', '--no-pager', 'log', revision_range,
         '--no-abbrev-commit', '--pretty=full', '-1'],
        working_dir=working_dir)
    return CommitInfo(_ParseGitCommitPosition(ret), _ParseGitCommitHash(ret),
                      git_repo_url)

  def _GetDepsCommitInfo(self, deps_dict, path_below_src):
    entry = deps_dict['deps'][_PosixPath('src/%s' % path_below_src)]
    at_index = entry.find('@')
    git_repo_url = entry[:at_index]
    git_hash = entry[at_index + 1:]
    return self._GetCommitInfo(path_below_src, git_hash, git_repo_url)

  def _GetCLInfo(self):
    cl_output = self._RunCommand(['git', 'cl', 'issue'])
    m = CL_ISSUE_RE.match(cl_output.strip())
    if not m:
      logging.error('Cannot find any CL info. Output was:\n%s', cl_output)
      sys.exit(-1)
    issue_number = int(m.group(1))
    url = m.group(2)

    # Parse the codereview host from the URL.
    m = REVIEW_URL_RE.match(url)
    if not m:
      logging.error('Cannot parse codereview host from URL: %s', url)
      sys.exit(-1)
    review_server = m.group(1)
    return CLInfo(issue_number, url, review_server)

  def _GetCurrentBranchName(self):
    return self._RunCommand(
        ['git', 'rev-parse', '--abbrev-ref', 'HEAD']).splitlines()[0]

  def _IsTreeClean(self):
    lines = self._RunCommand(['git', 'status', '--porcelain']).splitlines()
    if len(lines) == 0:
      return True

    logging.debug('Dirty/unversioned files:\n%s', '\n'.join(lines))
    return False

  def _UpdateReadmeFile(self, readme_path, new_revision):
    readme = open(os.path.join(self._chromium_src, readme_path), 'r+')
    txt = readme.read()
    m = re.sub(re.compile('.*^Revision\: ([0-9]*).*', re.MULTILINE),
        ('Revision: %s' % new_revision), txt)
    readme.seek(0)
    readme.write(m)
    readme.truncate()

  def PrepareRoll(self, dry_run, ignore_checks, no_commit, close_previous_roll,
                  revision):
    # TODO(kjellander): use os.path.normcase, os.path.join etc for all paths for
    # cross platform compatibility.

    if not ignore_checks:
      if self._GetCurrentBranchName() != 'master':
        logging.error('Please checkout the master branch.')
        return -1
      if not self._IsTreeClean():
        logging.error('Please make sure you don\'t have any modified files.')
        return -1

    logging.debug('Checking for a previous roll branch.')
    if close_previous_roll:
      self.Abort()

    logging.debug('Pulling latest changes')
    if not ignore_checks:
      self._RunCommand(['git', 'pull'])

    self._RunCommand(['git', 'checkout', '-b', ROLL_BRANCH_NAME])

    # Modify Chromium's DEPS file.

    # Parse current hashes.
    deps_filename = os.path.join(self._chromium_src, 'DEPS')
    deps = _ParseDepsFile(deps_filename)
    webrtc_current = self._GetDepsCommitInfo(deps, WEBRTC_PATH)

    # Get the commit info for the given revision. If it's None, get the commit
    # info for ToT.
    revision_info = self._GetCommitInfo(WEBRTC_PATH, revision)

    if IS_WIN:
      # Make sure the roll script doesn't use Windows line endings.
      self._RunCommand(['git', 'config', 'core.autocrlf', 'true'])

    self._UpdateDep(deps_filename, WEBRTC_PATH, revision_info)

    if self._IsTreeClean():
      print 'The latest revision is already rolled for WebRTC.'
      self._DeleteRollBranch()
    else:
      description = self._GenerateCLDescriptionCommand(
        webrtc_current, revision_info)
      logging.debug('Committing changes locally.')
      self._RunCommand(['git', 'add', '--update', '.'])
      self._RunCommand(['git', 'commit', '-m', description])
      logging.debug('Uploading changes...')
      upload_cmd = ['git', 'cl', 'upload']
      if not dry_run and not no_commit:
        logging.debug('Sending the CL to the CQ...')
        upload_cmd.extend(['--use-commit-queue', '--send-mail'])
      self._RunCommand(upload_cmd, extra_env={'EDITOR': 'true'})
      cl_info = self._GetCLInfo()
      logging.debug('Issue: %d URL: %s', cl_info.issue, cl_info.url)

    # TODO(kjellander): Checkout masters/previous branches again.
    return 0

  def _UpdateDep(self, deps_filename, dep_relative_to_src, commit_info):
    dep_name = os.path.join('src', dep_relative_to_src)
    comment = 'commit position %s' % commit_info.commit_position

    # roll_dep_svn.py relies on cwd being the Chromium checkout, so let's
    # temporarily change the working directory and then change back.
    cwd = os.getcwd()
    os.chdir(os.path.dirname(deps_filename))
    roll_dep_svn.update_deps(deps_filename, dep_relative_to_src, dep_name,
                         commit_info.git_commit, comment)
    os.chdir(cwd)

  def _DeleteRollBranch(self):
    self._RunCommand(['git', 'checkout', 'master'])
    self._RunCommand(['git', 'branch', '-D', ROLL_BRANCH_NAME])
    logging.debug('Deleted the local roll branch (%s)', ROLL_BRANCH_NAME)


  def _GetBranches(self):
    """Returns a tuple of active,branches.

    The 'active' is the name of the currently active branch and 'branches' is a
    list of all branches.
    """
    lines = self._RunCommand(['git', 'branch']).split('\n')
    branches = []
    active = ''
    for l in lines:
      if '*' in l:
        # The assumption is that the first char will always be the '*'.
        active = l[1:].strip()
        branches.append(active)
      else:
        b = l.strip()
        if b:
          branches.append(b)
    return (active, branches)

  def Abort(self):
    active_branch, branches = self._GetBranches()
    if active_branch == ROLL_BRANCH_NAME:
      active_branch = 'master'
    if ROLL_BRANCH_NAME in branches:
      print 'Aborting pending roll.'
      self._RunCommand(['git', 'checkout', ROLL_BRANCH_NAME])
      # Ignore an error here in case an issue wasn't created for some reason.
      self._RunCommand(['git', 'cl', 'set_close'], ignore_exit_code=True)
      self._RunCommand(['git', 'checkout', active_branch])
      self._RunCommand(['git', 'branch', '-D', ROLL_BRANCH_NAME])
    return 0


def main():
  parser = argparse.ArgumentParser(
      description='Find webrtc revisions for roll.')
  parser.add_argument('--abort',
    help=('Aborts a previously prepared roll. '
          'Closes any associated issues and deletes the roll branches'),
    action='store_true')
  parser.add_argument('--no-commit',
    help=('Don\'t send the CL to the CQ. This is useful if additional changes '
          'are needed to the CL (like for API changes).'),
    action='store_true')
  parser.add_argument('--close-previous-roll', action='store_true',
                      help='Abort a previous roll if one exists.')
  parser.add_argument('--dry-run', action='store_true', default=False,
      help='Create branches and CLs but doesn\'t send tryjobs or commit.')
  parser.add_argument('--ignore-checks', action='store_true', default=False,
      help=('Skips checks for being on the master branch, dirty workspaces and '
            'the updating of the checkout. Will still delete and create local '
            'Git branches.'))
  parser.add_argument('-r', '--revision', default=None,
                      help='WebRTC revision to roll. If not specified,'
                           'the latest version will be used')
  parser.add_argument('-v', '--verbose', action='store_true', default=False,
      help='Be extra verbose in printing of log messages.')
  args = parser.parse_args()

  if args.verbose:
    logging.basicConfig(level=logging.DEBUG)
  else:
    logging.basicConfig(level=logging.ERROR)

  autoroller = AutoRoller(SRC_DIR)
  if args.abort:
    return autoroller.Abort()
  else:
    return autoroller.PrepareRoll(args.dry_run, args.ignore_checks,
                                  args.no_commit, args.close_previous_roll,
                                  args.revision)

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