#!/usr/bin/python
#
# Copyright (C) 2010 Ksplice, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
# Author: Greg Price <price@ksplice.com>

## CC_EMAIL: All review requests will be CC'd here.
CC_EMAIL = 'code-review@humbughq.com'

## DOMAIN: Reviewers without an '@' will be assumed to be localparts here.
DOMAIN = 'humbughq.com'

##### END CONFIG #####
## But you might want to change behavior below.

import sys
import os
import optparse
import posixpath
import subprocess
import tempfile
import git
import shlex
import codecs
from StringIO import StringIO
from email.message import Message
from email.header import Header

usage = """
%%prog -r <reviewer> [-r <another-reviewer>] [-s <summary>] [-m <message>] [options] {<since>|<revision-range>}

Send a patch series for review.  Sends mail to the reviewer,
CC %s, identifying the commits to be reviewed.

Name a range of commits, or name a single commit (e.g., 'HEAD^' or
'origin/master') to identify all commits on HEAD since that commit.

If you set REVIEW_USE_SENDMAIL to be nonempty, /usr/bin/sendmail will
be used to mail the review request. Otherwise, msmtp will be used by
default.
""".strip() % CC_EMAIL


def check_unicode(option, opt, value):
  try:
    return unicode(value, 'utf-8', 'strict')
  except UnicodeDecodeError:
    raise optparse.OptionValueError('option %s: invalid UTF-8 string' % opt)

class MyOption(optparse.Option):
  TYPES = optparse.Option.TYPES + ('unicode',)
  TYPE_CHECKER = dict(optparse.Option.TYPE_CHECKER, unicode=check_unicode)


def parse_options(args):
  parser = optparse.OptionParser(usage, option_class=MyOption)
  parser.add_option('--first-parent', action='store_true', dest='first_parent',
                    help='follow first parents only')
  parser.add_option('-r', '--reviewer', type='unicode', dest='reviewers', action="append",
                    help='the person you are asking to do the review')
  parser.add_option('--stdout', action='store_true', dest='stdout',
                    help='send to standard output rather than send mail')
  parser.add_option('--format', type='choice', dest='format',
                    choices=['oneline', 'message', 'patch'],
                    help="'patch' (default for one commit), 'message' (default for more), or 'oneline'")
  parser.add_option('-s', '--summary', type='unicode', dest='summary',
                    help='summary for subject line')
  parser.add_option('-m', '--message', type='unicode', dest='message',
                    help='message for body of email')
  parser.add_option('-t', '--testing', type='unicode', dest='testing',
                    help='extent and methods of testing employed')
  parser.add_option('-e', '--edit', action='store_true', dest='edit',
                    help='spawn $EDITOR and edit review request')
  options, args = parser.parse_args(args)
  if not options.reviewers:
    parser.error('reviewer required')
  reviewers_fixed = []
  for reviewer in options.reviewers:
    if '@' not in reviewer:
      reviewers_fixed.append(reviewer + '@' + DOMAIN)
    else:
      reviewers_fixed.append(reviewer)
  options.reviewers = reviewers_fixed
  if len(args) < 2:
    parser.error('must specify revision(s) to be reviewed')
  return options, args


def get_default_remote(repo):
  try:
    return repo.git.config('--get', 'remotes.default')
  except git.exc.GitCommandError:
    try:
      branch = repo.active_branch
      return repo.git.config('--get', 'branch.%s.remote' % branch)
    except git.exc.GitCommandError:
      return 'origin'


def get_reponame(repo):
  remote = get_default_remote(repo)

  try:
    url = repo.git.config('--get', 'remote.%s.url' % remote)
  except git.exc.GitCommandError:
    url = repo.wd

  name = posixpath.basename(posixpath.normpath(url.split(':', 1)[-1]))
  if name.endswith('.git'):
    name = name[:-len('.git')]
  return name


def parse_revs(repo, opts, args):
  args = repo.git.rev_parse(*args).splitlines()
  if len(args) == 1:
      args = ['^' + args[0].lstrip('^'), 'HEAD']
  if opts.first_parent:
      args[:0] = ['--first-parent']
  return [repo.commit(c) for c in repo.git.rev_list('--reverse', *args).split()]


def get_current_user(repo):
  ident = unicode(repo.git.var('GIT_AUTHOR_IDENT'), 'utf-8', 'replace')
  return ident[:ident.rindex('>') + 1]

def make_header(repo, opts, revs):
  me = get_current_user(repo)
  reponame = get_reponame(repo)

  remote = get_default_remote(repo)
  (sha, name) = repo.git.name_rev(revs[-1].hexsha,
                                  refs='refs/remotes/%s/*' % (remote,),
                                  always=True).split()
  prefix = 'remotes/' + remote + "/"
  if name.startswith(prefix):
      name = name[len(prefix):]
      tip_name = '%s (%s)' % (name, revs[-1].hexsha[:7])
  else:
      print >>sys.stderr, "WARNING: Can't find this commit in remote -- did you push?"
      tip_name = revs[-1].hexsha[:7]

  objective_summary = '%d commit(s) to %s' % (len(revs), tip_name)
  summary = ('%s (%s)' % (opts.summary, objective_summary) if opts.summary
             else objective_summary)

  return [('From', Header(me)),
          ('To', Header(', '.join(opts.reviewers))),
          ('Cc', Header(CC_EMAIL)),
          ('Subject', Header('%s review: %s' % (reponame, summary)))]


def write_template(target, repo, opts):
  me = get_current_user(repo)

  print >>target, 'Dear %s,' % ", ".join(opts.reviewers)
  print >>target
  print >>target, 'At your convenience, please review the following commits.'
  print >>target, 'Reply with any comments, or advance master when you are satisfied.'
  print >>target
  if opts.message:
    print >>target, opts.message
    print >>target
  print >>target, 'Testing:',
  if opts.testing:
    print >>target, opts.testing
  else:
    print >>target, '(No formal testing done, or none specified.)'
  print >>target
  print >>target, 'Thanks,'
  print >>target, me


def write_commitmsg(target, repo, opts, revs):

  if opts.format == 'oneline':
    for r in revs:
      print >>target, unicode(repo.git.log('-n1', '--oneline', r), 'utf-8', 'replace')
  elif opts.format == 'message' or opts.format is None and len(revs) > 1:
    for r in revs:
      if opts.first_parent:
        print >>target, unicode(repo.git.log('-n1', r), 'utf-8', 'replace')
        print >>target, unicode(repo.git.diff('--stat', str(r)+'^', r), 'utf-8', 'replace')
      else:
        print >>target, unicode(repo.git.log('-n1', '--stat', r), 'utf-8', 'replace')
      print >>target
  elif opts.format == 'patch' or opts.format is None and len(revs) == 1:
    for r in revs:
      if opts.first_parent:
        print >>target, unicode(repo.git.log('-n1', r), 'utf-8', 'replace')
        print >>target, unicode(repo.git.diff('--stat', '-p', str(r)+'^', r), 'utf-8', 'replace')
      else:
        print >>target, unicode(repo.git.log('-n1', '--stat', '-p', r), 'utf-8', 'replace')
      print >>target
  else:
    raise Exception("Bad format option.")


def edit(repo, opts, revs):
  headers = make_header(repo, opts, revs)

  template = StringIO()
  commitmsg = StringIO()

  write_template(template, repo, opts)
  write_commitmsg(commitmsg, repo, opts, revs)

  temp = codecs.getwriter('utf-8')(tempfile.NamedTemporaryFile(prefix="review-"))

  # Prepare editable buffer.

  print >>temp, """# This is an editable review request.  All lines beginning with # will
# be ignored.  To abort the commit, remove all lines from this buffer."""
  print >>temp, "#"
  for (key, value) in headers:
    print >>temp, u"# %s: %s" % (key, value)
  print >>temp
  print >>temp, template.getvalue()
  for line in commitmsg.getvalue().splitlines():
    print >>temp, "# " + line
  temp.flush()

  # Open EDITOR to edit buffer.

  editor = os.getenv('EDITOR','emacs')
  subprocess.check_call(shlex.split(editor) + [temp.name])

  # Check if buffer is empty, and if so abort.

  if (os.path.getsize(temp.name) == 0):
    print >>sys.stderr, "Aborting due to empty buffer."
    sys.exit(2)

  # Reopen temp file, slurp it in, and reconstruct mail.

  final = codecs.open(temp.name, 'r', 'utf-8')
  msg = Message()
  for (key, value) in headers:
    msg[key] = value
  msg.set_payload(
    ("".join(line for line in final if not line.startswith("#")).strip() +
     "\n\n" + commitmsg.getvalue()).encode('utf-8'),
    'utf-8')

  # Clean up.

  temp.close()
  final.close()
  try:
    os.unlink(temp.name)
  except OSError:
    pass
  return msg


def main(args):
  opts, args = parse_options(args)
  repo = git.Repo()
  revs = parse_revs(repo, opts, args[1:])
  if not revs:
    print >>sys.stderr, '%s: no revisions specified' % os.path.basename(args[0])
    return 2

  if opts.edit:
    msg = edit(repo, opts, revs)

  else:
    # Just build the message.
    msg = Message()
    for (key, value) in make_header(repo, opts, revs):
      msg[key] = value

    template = StringIO()
    commitmsg = StringIO()

    write_template(template, repo, opts)
    write_commitmsg(commitmsg, repo, opts, revs)
    msg.set_payload(
      (template.getvalue() + "\n" + commitmsg.getvalue()).encode('utf-8'),
      'utf-8')

  # Send or print the message, as appropriate.
  if opts.stdout:
    for (key, value) in msg.items():
      print >>sys.stdout, u"%s: %s" % (key, value)
    print >>sys.stdout
    print >>sys.stdout, msg.get_payload(decode=True),
  else:
    sys.path.append(os.path.dirname(os.path.dirname(__file__)))
    import api.common
    me = get_current_user(repo)
    api_key_file = os.path.join(os.environ["HOME"], '.humbug-api-key')
    if not os.path.exists(api_key_file):
      print >>sys.stderr, "You need to place your Humbug API key at %s" % (api_key_file,)
      sys.exit(1)
    client = api.common.HumbugAPI(email=me[me.index("<") + 1:me.index('>')],
                                  site="https://staging.humbughq.com",
                                  api_key=file(api_key_file).read().strip(),
                                  verbose=True)
    client.send_message({'type': "private",
                         'recipient': [opts.reviewers],
                         'content': "I just sent you a review request!  Check your email for details."})

    if os.environ.get('REVIEW_USE_SENDMAIL', ''):
      command = ['/usr/sbin/sendmail', '-bm', '-t']
    else:
      command = ['msmtp', '-t']
    subprocess.Popen(command,
                     stdin=subprocess.PIPE).communicate(msg.as_string())

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