##############################################################################
# Copyright (c) 2017 Feng Pan (fpan@redhat.com) and others.
#
# All rights reserved. This program and the accompanying materials
# are made available under the terms of the Apache License, Version 2.0
# which accompanies this distribution, and is available at
# http://www.apache.org/licenses/LICENSE-2.0
##############################################################################

import argparse
import git
import logging
import os
from pygerrit2.rest import GerritRestAPI
import re
import shutil
import sys

from apex.common import constants as con
from urllib.parse import quote_plus


def get_change(url, repo, branch, change_id):
    """
    Fetches a change from upstream repo
    :param url: URL of upstream gerrit
    :param repo: name of repo
    :param branch: branch of repo
    :param change_id: SHA change id
    :return: change if found and not abandoned, closed
    """
    rest = GerritRestAPI(url=url)
    change_path = "{}~{}~{}".format(quote_plus(repo), quote_plus(branch),
                                    change_id)
    change_str = "changes/{}?o=CURRENT_REVISION".format(change_path)
    change = rest.get(change_str)
    try:
        assert change['status'] not in 'ABANDONED' 'CLOSED', \
            'Change {} is in {} state'.format(change_id, change['status'])
        logging.debug('Change found: {}'.format(change))
        return change

    except KeyError:
        logging.error('Failed to get valid change data structure from url '
                      '{}/{}, data returned: \n{}'
                      .format(change_id, change_str, change))
        raise


def clone_fork(args):
    ref = None
    logging.info("Cloning {}".format(args.repo))

    try:
        cm = git.Repo(search_parent_directories=True).commit().message
    except git.exc.InvalidGitRepositoryError:
        logging.debug('Current Apex directory is not a git repo: {}'
                      .format(os.getcwd()))
        cm = ''

    logging.info("Current commit message: {}".format(cm))
    m = re.search('{}:\s*(\S+)'.format(args.repo), cm)

    if m:
        change_id = m.group(1)
        logging.info("Using change ID {} from {}".format(change_id, args.repo))
        change = get_change(args.url, args.repo, args.branch, change_id)
        if change:
            current_revision = change['current_revision']
            ref = change['revisions'][current_revision]['ref']
            logging.info('setting ref to {}'.format(ref))

    # remove existing file or directory named repo
    if os.path.exists(args.repo):
        if os.path.isdir(args.repo):
            shutil.rmtree(args.repo)
        else:
            os.remove(args.repo)

    ws = git.Repo.clone_from("{}/{}".format(args.url, args.repo),
                             args.repo, b=args.branch)
    if ref:
        git_cmd = ws.git
        git_cmd.fetch("{}/{}".format(args.url, args.repo), ref)
        git_cmd.checkout('FETCH_HEAD')
        logging.info('Checked out commit:\n{}'.format(ws.head.commit.message))


def strip_patch_sections(patch, sections=['releasenotes', 'tests']):
    """
    Removes patch sections from a diff which contain a file path
    :param patch:  patch to strip
    :param sections: list of keywords to use to strip out of the patch file
    :return: stripped patch
    """

    append_line = True
    tmp_patch = []
    for line in patch.split("\n"):
        if re.match('diff\s', line):
            for section in sections:
                if re.search(section, line):
                    logging.debug("Stripping {} from patch: {}".format(
                        section, line))
                    append_line = False
                    break
                else:
                    append_line = True
        if append_line:
            tmp_patch.append(line)
    return '\n'.join(tmp_patch)


def is_path_in_patch(patch, path):
    """
    Checks if a particular path is modified in a patch diff
    :param patch: patch diff
    :param path: path to check for in diff
    :return: Boolean
    """
    for line in patch.split("\n"):
        if re.match('^diff.*{}'.format(path), line):
            return True
    return False


def get_patch(change_id, repo, branch, url=con.OPENSTACK_GERRIT):
    logging.info("Fetching patch for change id {}".format(change_id))
    change = get_change(url, repo, branch, change_id)
    if change:
        current_revision = change['current_revision']
        rest = GerritRestAPI(url=url)
        change_path = "{}~{}~{}".format(quote_plus(repo), quote_plus(branch),
                                        change_id)
        patch_url = "changes/{}/revisions/{}/patch".format(change_path,
                                                           current_revision)
        return strip_patch_sections(rest.get(patch_url))


def get_parser():
    parser = argparse.ArgumentParser()
    parser.add_argument('--debug', action='store_true', default=False,
                        help="Turn on debug messages")
    subparsers = parser.add_subparsers()
    fork = subparsers.add_parser('clone-fork',
                                 help='Clone fork of dependent repo')
    fork.add_argument('-r', '--repo', required=True, help='Name of repository')
    fork.add_argument('-u', '--url',
                      default='https://gerrit.opnfv.org/gerrit',
                      help='Gerrit URL of repository')
    fork.add_argument('-b', '--branch',
                      default='master',
                      help='Branch to checkout')
    fork.set_defaults(func=clone_fork)
    return parser


def main():
    parser = get_parser()
    args = parser.parse_args(sys.argv[1:])
    if args.debug:
        logging_level = logging.DEBUG
    else:
        logging_level = logging.INFO

    logging.basicConfig(format='%(asctime)s %(levelname)s: %(message)s',
                        datefmt='%m/%d/%Y %I:%M:%S %p',
                        level=logging_level)
    if hasattr(args, 'func'):
        args.func(args)
    else:
        parser.print_help()
        exit(1)


if __name__ == "__main__":
    main()