#!/usr/bin/env python

# This script is typically used by Mesos committers to push a locally applied
# review chain to ASF git repo and mark the reviews as submitted on ASF
# ReviewBoard.
#
# Example Usage:
#
# > git checkout master
# > git pull origin
# > ./support/apply-reviews.py -c -r 1234
# > ./support/push-commits.py
#
# TODO(vinod): Also post the commit message to the corresponding ASF JIRA
# tickets and resolve them if necessary.

import argparse
import os
import re
import sys

from subprocess import check_output

REVIEWBOARD_URL =  'https://reviews.apache.org'


def get_reviews(revision_range):
    """Returns the list of reviews found in the commits in the revision range.
    """
    log = check_output(['git',
                        '--no-pager',
                        'log',
                        '--no-color',
                        '--reverse',
                        revision_range]).strip()

    review_ids = []
    for line in log.split('\n'):
        pos = line.find('Review: ')
        if pos != -1:
            pattern = re.compile('Review: ({url})$'.format(
                url=os.path.join(REVIEWBOARD_URL, 'r', '[0-9]+')))
            match = pattern.search(line.strip().strip('/'))
            if match is None:
                print "\nInvalid ReviewBoard URL: '{}'".format(line[pos:])
                sys.exit(1)

            url = match.group(1)
            review_ids.append(os.path.basename(url))

    return review_ids


def close_reviews(reviews, options):
    """ Marks the given reviews as submitted on ReviewBoard."""
    # Close the reviews on ReviewBoard.
    for review_id in reviews:
       print 'Closing review', review_id
       if not options['dry_run']:
           # TODO(vinod): Include the commit message as '--description'.
           check_output(['rbt', 'close', review_id])


def parse_options():
    """Returns a dictionary of options parsed from command line arguments."""
    parser = argparse.ArgumentParser()

    parser.add_argument('-n',
                        '--dry-run',
                        action='store_true',
                        help='Perform a dry run.')

    args = parser.parse_args()

    options = {}
    options['dry_run'] = args.dry_run

    return options


if __name__ == '__main__':
    options = parse_options()

    current_branch_ref = check_output(['git', 'symbolic-ref', 'HEAD']).strip()
    current_branch = current_branch_ref.replace('refs/heads/', '', 1)

    if current_branch != 'master':
        print 'Please run this script from master branch'
        sys.exit(1)

    remote_tracking_branch = check_output(['git',
                                           'rev-parse',
                                           '--abbrev-ref',
                                           'master@{upstream}']).strip()

    merge_base = check_output(['git',
			       'merge-base',
			       remote_tracking_branch,
			       'master']).strip()

    if merge_base == current_branch_ref:
        print 'No new commits found to push'
        sys.exit(1)

    reviews = get_reviews(merge_base + ".." + current_branch_ref)

    print 'Found reviews', reviews

    # Push the current branch to remote master.
    remote = check_output(['git',
                           'config',
                           '--get',
                           'branch.master.remote']).strip()

    print 'Pushing commits to', remote

    if not options['dry_run']:
        check_output(['git',
                      'push',
                      remote,
                      'master:master'])

    # Now mark the reviews as submitted.
    close_reviews(reviews, options)