#!/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 rietveld
import roll_dep_svn
from gclient import GClientKeywords
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-Original-Commit-Position: .*#([0-9]+).*$')
CL_ISSUE_RE = re.compile('^Issue number: ([0-9]+) \((.*)\)$')
RIETVELD_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 = ('tryserver.chromium.linux:linux_chromium_archive_rel_ng;'
                 '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', 'rietveld_server'])


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 = {}
  var = GClientKeywords.VarImpl({}, local_scope)
  global_scope = {
    'File': GClientKeywords.FileImpl,
    'From': GClientKeywords.FromImpl,
    'Var': var.Lookup,
    'deps_os': {},
  }
  exec(deps_content, global_scope, local_scope)
  return local_scope


def _WaitForTrybots(issue, rietveld_server):
  """Wait until all trybots have passed or at least one have failed.

  Returns:
    An exit code of 0 if all trybots passed or non-zero otherwise.
  """
  assert type(issue) is int
  print 'Trybot status for https://%s/%d:' % (rietveld_server, issue)
  remote = rietveld.Rietveld('https://' + rietveld_server, None, None)

  attempt = 0
  max_tries = 60*60/TRYJOB_STATUS_SLEEP_SECONDS # Max one hour
  while attempt < max_tries:
    # Get patches for the issue so we can use the latest one.
    data = remote.get_issue_properties(issue, messages=False)
    patchsets = data['patchsets']

    # Get trybot status for the latest patch set.
    data = remote.get_patchset_properties(issue, patchsets[-1])

    tryjob_results = data['try_job_results']
    if len(tryjob_results) == 0:
      logging.debug('No trybots have yet been triggered for https://%s/%d' ,
                    rietveld_server, issue)
    else:
      _PrintTrybotsStatus(tryjob_results)
      if any(r['result'] in FAILURE_STATUS for r in tryjob_results):
        logging.error('Found failing tryjobs (see above)')
        return 1
      if all(r['result'] in SUCCESS_STATUS for r in tryjob_results):
        return 0

    logging.debug('Waiting for %d seconds before next check...',
                  TRYJOB_STATUS_SLEEP_SECONDS)
    time.sleep(TRYJOB_STATUS_SLEEP_SECONDS)
    attempt += 1


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)))


def _GenerateCLDescriptionCommand(webrtc_current, webrtc_new):
  def GetChangeLogURL(git_repo_url, current_hash, new_hash):
    return '%s/+log/%s..%s' % (git_repo_url, current_hash[0:7], new_hash[0:7])

  webrtc_str = 'WebRTC %s:%s' % (webrtc_current.commit_position,
                                 webrtc_new.commit_position)
  webrtc_changelog_url = GetChangeLogURL(webrtc_current.git_repo_url,
                                         webrtc_current.git_commit,
                                         webrtc_new.git_commit)

  description = [ '-m', 'Roll ' + webrtc_str ]
  description.extend(['-m', 'Changes: %s' % webrtc_changelog_url])
  description.extend(['-m', 'TBR='])
  description.extend(['-m', 'CQ_EXTRA_TRYBOTS=%s' % EXTRA_TRYBOTS])
  return description


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 _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, '--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 Rietveld host from the URL.
    m = RIETVELD_URL_RE.match(url)
    if not m:
      logging.error('Cannot parse Rietveld host from URL: %s', url)
      sys.exit(-1)
    rietveld_server = m.group(1)
    return CLInfo(issue_number, url, rietveld_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):
    # 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)

    # Find ToT revisions.
    webrtc_latest = self._GetCommitInfo(WEBRTC_PATH)

    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, webrtc_latest)

    if self._IsTreeClean():
      print 'The latest revision is already rolled for WebRTC.'
      self._DeleteRollBranch()
    else:
      description = _GenerateCLDescriptionCommand(
        webrtc_current, webrtc_latest)
      logging.debug('Committing changes locally.')
      self._RunCommand(['git', 'add', '--update', '.'])
      self._RunCommand(['git', 'commit'] + description)
      logging.debug('Uploading changes...')
      self._RunCommand(['git', 'cl', 'upload'],
                       extra_env={'EDITOR': 'true'})
      cl_info = self._GetCLInfo()
      logging.debug('Issue: %d URL: %s', cl_info.issue, cl_info.url)

      if not dry_run and not no_commit:
        logging.debug('Sending the CL to the CQ...')
        self._RunCommand(['git', 'cl', 'set_commit'])
        logging.debug('Sent the CL to the CQ. Monitor here: %s', 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 WaitForTrybots(self):
    active_branch, _ = self._GetBranches()
    if active_branch != ROLL_BRANCH_NAME:
      self._RunCommand(['git', 'checkout', ROLL_BRANCH_NAME])
    cl_info = self._GetCLInfo()
    return _WaitForTrybots(cl_info.issue, cl_info.rietveld_server)


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('--wait-for-trybots',
    help=('Waits until all trybots from a previously created roll are either '
          'successful or at least one has failed. This is useful to be able to '
          'continuously run this script but not initiating new rolls until a '
          'previous one is known to have passed or failed.'),
    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('-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()
  elif args.wait_for_trybots:
    return autoroller.WaitForTrybots()
  else:
    return autoroller.PrepareRoll(args.dry_run, args.ignore_checks,
                                  args.no_commit, args.close_previous_roll)

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