#!/usr/bin/python

# Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

"""This module uprevs a given package's ebuild to the next revision."""

import optparse
import os
import subprocess
import sys

import constants
if __name__ == '__main__':
  sys.path.insert(0, constants.SOURCE_ROOT)

from chromite.buildbot import portage_utilities
from chromite.lib import cros_build_lib


# TODO(sosa): Remove during OO refactor.
VERBOSE = False

# Dictionary of valid commands with usage information.
COMMAND_DICTIONARY = {
                        'commit':
                          'Marks given ebuilds as stable locally',
                        'push':
                          'Pushes previous marking of ebuilds to remote repo',
                      }


# ======================= Global Helper Functions ========================


def _Print(message):
  """Verbose print function."""
  if VERBOSE:
    cros_build_lib.Info(message)


def CleanStalePackages(boards, package_atoms):
  """Cleans up stale package info from a previous build.
  Args:
    boards: Boards to clean the packages from.
    package_atoms: The actual package atom to unmerge.
  """
  if package_atoms:
    cros_build_lib.Info('Cleaning up stale packages %s.' % package_atoms)
    for board in boards:
      unmerge_board_cmd = ['emerge-%s' % board, '--unmerge']
      unmerge_board_cmd.extend(package_atoms)
      cros_build_lib.RunCommand(unmerge_board_cmd)

    unmerge_host_cmd = ['emerge', '--unmerge']
    unmerge_host_cmd.extend(package_atoms)
    cros_build_lib.SudoRunCommand(unmerge_host_cmd)

  for board in boards:
    cros_build_lib.RunCommand(['eclean-%s' % board, '-d', 'packages'],
                              redirect_stderr=True)
  cros_build_lib.SudoRunCommand(['eclean', '-d', 'packages'],
                            redirect_stderr=True)


def _DoWeHaveLocalCommits(stable_branch, tracking_branch):
  """Returns true if there are local commits."""
  current_branch = _SimpleRunCommand('git branch | grep \*').split()[1]
  if current_branch == stable_branch:
    current_commit_id = _SimpleRunCommand('git rev-parse HEAD')
    tracking_commit_id = _SimpleRunCommand('git rev-parse %s' % tracking_branch)
    return current_commit_id != tracking_commit_id
  else:
    return False


def _CheckSaneArguments(package_list, command, options):
  """Checks to make sure the flags are sane.  Dies if arguments are not sane."""
  if not command in COMMAND_DICTIONARY.keys():
    _PrintUsageAndDie('%s is not a valid command' % command)
  if not options.packages and command == 'commit' and not options.all:
    _PrintUsageAndDie('Please specify at least one package')
  if not options.boards and command == 'commit':
    _PrintUsageAndDie('Please specify a board')
  if not os.path.isdir(options.srcroot):
    _PrintUsageAndDie('srcroot is not a valid path')
  options.srcroot = os.path.abspath(options.srcroot)


def _PrintUsageAndDie(error_message=''):
  """Prints optional error_message the usage and returns an error exit code."""
  command_usage = 'Commands: \n'
  # Add keys and usage information from dictionary.
  commands = sorted(COMMAND_DICTIONARY.keys())
  for command in commands:
    command_usage += '  %s: %s\n' % (command, COMMAND_DICTIONARY[command])
  commands_str = '|'.join(commands)
  cros_build_lib.Warning('Usage: %s FLAGS [%s]\n\n%s' % (
      sys.argv[0], commands_str, command_usage))
  if error_message:
    cros_build_lib.Die(error_message)
  else:
    sys.exit(1)


def _SimpleRunCommand(command):
  """Runs a shell command and returns stdout back to caller."""
  _Print('  + %s' % command)
  proc_handle = subprocess.Popen(command, stdout=subprocess.PIPE, shell=True)
  stdout = proc_handle.communicate()[0]
  retcode = proc_handle.wait()
  if retcode != 0:
    _Print(stdout)
    raise subprocess.CalledProcessError(retcode, command)
  return stdout


# ======================= End Global Helper Functions ========================


def PushChange(stable_branch, tracking_branch, dryrun, cwd='.'):
  """Pushes commits in the stable_branch to the remote git repository.

  Pushes local commits from calls to CommitChange to the remote git
  repository specified by current working directory. If changes are
  found to commit, they will be merged to the merge branch and pushed.
  In that case, the local repository will be left on the merge branch.

  Args:
    stable_branch: The local branch with commits we want to push.
    tracking_branch: The tracking branch of the local branch.
    dryrun: Use git push --dryrun to emulate a push.
  Raises:
      OSError: Error occurred while pushing.
  """
  if not _DoWeHaveLocalCommits(stable_branch, tracking_branch):
    cros_build_lib.Info('No work found to push.  Exiting')
    return

  # For the commit queue, our local branch may contain commits that were
  # just tested and pushed during the CommitQueueCompletion stage. Sync
  # and rebase our local branch on top of the remote commits.
  remote, push_branch = cros_build_lib.GetPushBranch(cwd)
  cros_build_lib.SyncPushBranch(cwd, remote, push_branch)

  # Check whether any local changes remain after the sync.
  if not _DoWeHaveLocalCommits(stable_branch, '%s/%s' % (remote, push_branch)):
    cros_build_lib.Info('All changes already pushed. Exiting')
    return

  description = _SimpleRunCommand('git log --format=format:%s%n%n%b ' +
      '%s/%s..%s' % (remote, push_branch, stable_branch))
  description = 'Marking set of ebuilds as stable\n\n%s' % description
  cros_build_lib.Info('Using description %s' % description)
  cros_build_lib.CreatePushBranch(constants.MERGE_BRANCH, cwd)
  _SimpleRunCommand('git merge --squash %s' % stable_branch)
  cros_build_lib.RunCommand(['git', 'commit', '-m', description])
  _SimpleRunCommand('git config push.default tracking')
  cros_build_lib.GitPushWithRetry(constants.MERGE_BRANCH, cwd=cwd,
                                  dryrun=dryrun)


class GitBranch(object):
  """Wrapper class for a git branch."""

  def __init__(self, branch_name, tracking_branch):
    """Sets up variables but does not create the branch."""
    self.branch_name = branch_name
    self.tracking_branch = tracking_branch

  def CreateBranch(self):
    GitBranch.Checkout(self)

  @classmethod
  def Checkout(cls, target):
    """Function used to check out to another GitBranch."""
    if target.branch_name == target.tracking_branch or target.Exists():
      git_cmd = 'git checkout %s -f' % target.branch_name
    else:
      git_cmd = 'repo start %s .' % target.branch_name
    _SimpleRunCommand(git_cmd)

  def Exists(self):
    """Returns True if the branch exists."""
    branch_cmd = 'git branch'
    branches = _SimpleRunCommand(branch_cmd)
    return self.branch_name in branches.split()

  def Delete(self):
    """Deletes the branch and returns the user to the master branch.

    Returns True on success.
    """
    tracking_branch = GitBranch(self.tracking_branch, self.tracking_branch)
    GitBranch.Checkout(tracking_branch)
    delete_cmd = 'repo abandon %s' % self.branch_name
    _SimpleRunCommand(delete_cmd)


def main():
  parser = optparse.OptionParser('cros_mark_as_stable OPTIONS packages')
  parser.add_option('--all', action='store_true',
                    help='Mark all packages as stable.')
  parser.add_option('-b', '--boards',
                    help='Colon-separated list of boards')
  parser.add_option('--drop_file',
                    help='File to list packages that were revved.')
  parser.add_option('--dryrun', action='store_true',
                    help='Passes dry-run to git push if pushing a change.')
  parser.add_option('-o', '--overlays',
                    help='Colon-separated list of overlays to modify.')
  parser.add_option('-p', '--packages',
                    help='Colon separated list of packages to rev.')
  parser.add_option('-r', '--srcroot',
                    default='%s/trunk/src' % os.environ['HOME'],
                    help='Path to root src directory.')
  parser.add_option('--verbose', action='store_true',
                    help='Prints out debug info.')
  (options, args) = parser.parse_args()

  global VERBOSE
  VERBOSE = options.verbose
  portage_utilities.EBuild.VERBOSE = options.verbose

  if len(args) != 1:
    _PrintUsageAndDie('Must specify a valid command [commit, push]')

  command = args[0]
  package_list = None
  if options.packages:
    package_list = options.packages.split(':')

  _CheckSaneArguments(package_list, command, options)
  if options.overlays:
    overlays = {}
    for path in options.overlays.split(':'):
      if not os.path.isdir(path):
        cros_build_lib.Die('Cannot find overlay: %s' % path)
      overlays[path] = []
  else:
    cros_build_lib.Warning('Missing --overlays argument')
    overlays = {
      '%s/private-overlays/chromeos-overlay' % options.srcroot: [],
      '%s/third_party/chromiumos-overlay' % options.srcroot: []
    }

  if command == 'commit':
    portage_utilities.BuildEBuildDictionary(
      overlays, options.all, package_list)

  tracking_branch = cros_build_lib.GetManifestDefaultBranch(options.srcroot)
  tracking_branch = 'remotes/m/' + tracking_branch

  # Contains the array of packages we actually revved.
  revved_packages = []
  new_package_atoms = []

  for overlay, ebuilds in overlays.items():
    if not os.path.isdir(overlay):
      cros_build_lib.Warning("Skipping %s" % overlay)
      continue

    # TODO(davidjames): Currently, all code that interacts with git depends on
    # the cwd being set to the overlay directory. We should instead pass in
    # this parameter so that we don't need to modify the cwd globally.
    os.chdir(overlay)

    if command == 'push':
      PushChange(constants.STABLE_EBUILD_BRANCH, tracking_branch,
                 options.dryrun)
    elif command == 'commit' and ebuilds:
      existing_branch = cros_build_lib.GetCurrentBranch('.')
      work_branch = GitBranch(constants.STABLE_EBUILD_BRANCH, tracking_branch)
      work_branch.CreateBranch()
      if not work_branch.Exists():
        cros_build_lib.Die('Unable to create stabilizing branch in %s' %
                           overlay)

      # In the case of uprevving overlays that have patches applied to them,
      # include the patched changes in the stabilizing branch.
      if existing_branch:
        _SimpleRunCommand('git rebase %s' % existing_branch)

      for ebuild in ebuilds:
        try:
          _Print('Working on %s' % ebuild.package)
          new_package = ebuild.RevWorkOnEBuild(options.srcroot)
          if new_package:
            revved_packages.append(ebuild.package)
            new_package_atoms.append('=%s' % new_package)
        except (OSError, IOError):
          cros_build_lib.Warning('Cannot rev %s\n' % ebuild.package +
                  'Note you will have to go into %s '
                  'and reset the git repo yourself.' % overlay)
          raise

  if command == 'commit':
    CleanStalePackages(options.boards.split(':'), new_package_atoms)
    if options.drop_file:
      fh = open(options.drop_file, 'w')
      fh.write(' '.join(revved_packages))
      fh.close()


if __name__ == '__main__':
  main()