# vim: set fileencoding=utf-8 :
#
# (C) 2010,2012,2015,2016 Guido Günther <agx@sigxcpu.org>
#    This program is free software; you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation; either version 2 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program; if not, please see
#    <http://www.gnu.org/licenses/>
#
# Based on the aa-create-git-repo and dom-new-git-repo shell scripts
"""Create a remote Git repository based on the current one"""

import sys
import os
import urllib.parse
import subprocess
import tty
import termios
import re
import configparser

from gbp.deb.changelog import ChangeLog, NoChangeLogError
from gbp.command_wrappers import (CommandExecFailed, GitCommand)
from gbp.config import (GbpOptionParserDebian, GbpOptionGroup)
from gbp.errors import GbpError
from gbp.git import GitRepositoryError
from gbp.deb.git import DebianGitRepository
from gbp.scripts.common import ExitCodes

import gbp.log


def print_config(remote, branches):
    """
    Print out the git config to push to the newly created repo.

    >>> print_config({'name': 'name', 'url': 'url'}, ['foo', 'bar'])
    [remote "name"]
            url = url
            fetch = +refs/heads/*:refs/remotes/name/*
            push = foo
            push = bar
    [branch "foo"]
            remote = name
            merge = refs/heads/foo
    [branch "bar"]
            remote = name
            merge = refs/heads/bar
    """

    print("""[remote "%(name)s"]
        url = %(url)s
        fetch = +refs/heads/*:refs/remotes/%(name)s/*""" % remote)

    for branch in branches:
        print("        push = %s" % branch)

    for branch in branches:
        print("""[branch "%s"]
        remote = %s
        merge = refs/heads/%s""" % (branch, remote['name'], branch))


def parse_url(remote_url, name, pkg, template_dir=None, bare=True):
    """
    Sanity check our remote URL

    """
    frags = urllib.parse.urlparse(remote_url)
    if frags.scheme in ['ssh', 'git+ssh', '']:
        scheme = frags.scheme
    else:
        raise GbpError("URL must use ssh protocol.")

    if '%(pkg)s' not in remote_url and not remote_url.endswith(".git"):
        raise GbpError("URL needs to contain either a repository name or '%(pkg)s'")

    if ":" in frags.netloc:
        (host, port) = frags.netloc.split(":", 1)
        if not re.match(r"^[0-9]+$", port):
            raise GbpError("URL contains invalid port.")
    else:
        host = frags.netloc
        port = None

    if frags.path.startswith("/~"):
        m = re.match(r"/(~[a-zA-Z0-9_-]*/)(.*)", frags.path)
        if not m:
            raise GbpError("URL contains invalid ~username expansion.")
        base = m.group(1)
        path = m.group(2)
    else:
        base = ""
        path = frags.path

    remote = {'pkg': pkg,
              'url': remote_url % {'pkg': pkg},
              'dir': path % {'pkg': pkg},
              'base': base,
              'host': host,
              'port': port,
              'name': name,
              'scheme': scheme,
              'template-dir': template_dir,
              'bare': bare}
    return remote


def build_remote_script(remote, branch):
    """
    Create the script that will be run on the remote side
    """
    args = remote
    args['branch'] = branch
    args['git-init-args'] = '--shared'
    if args['bare']:
        args['git-init-args'] += ' --bare'
        args['checkout_cmd'] = ''
        args['git_dir'] = '.'
    else:
        args['checkout_cmd'] = 'git checkout -f'
        args['git_dir'] = '.git'
    if args['template-dir']:
        args['git-init-args'] += (' --template=%s'
                                  % args['template-dir'])
    remote_script_pattern = \
        ['',
         'set -e',
         'umask 002',
         'if [ -d %(base)s"%(dir)s" ]; then',
         '  echo "Repository at \"%(base)s%(dir)s\" already exists - giving up."',
         '  exit 1',
         'fi',
         'mkdir -p %(base)s"%(dir)s"',
         'cd %(base)s"%(dir)s"',
         'git init %(git-init-args)s',
         'echo "%(pkg)s packaging" > %(git_dir)s/description',
         'echo "ref: refs/heads/%(branch)s" > %(git_dir)s/HEAD',
         '']
    remote_script = '\n'.join(remote_script_pattern) % args
    return remote_script


def build_cmd(remote):
    """
    Build the command we pass the script to

    >>> build_cmd({'scheme': ''})
    ['sh']
    >>> build_cmd({'scheme': 'ssh', 'host': 'host', 'port': 80})
    ['ssh', '-p', 80, 'host', 'sh']
    """
    cmd = []
    if remote["scheme"]:
        cmd.append('ssh')
        if remote["port"]:
            cmd.extend(['-p', remote['port']])
        cmd.append(remote["host"])
    cmd.append('sh')
    return cmd


def read_yn():
    fd = sys.stdin.fileno()
    try:
        old_settings = termios.tcgetattr(fd)
    except termios.error:
        old_settings = None

    try:
        if old_settings:
            tty.setraw(sys.stdin.fileno())
        ch = sys.stdin.read(1)
    finally:
        if old_settings:
            termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)

    if ch in ('y', 'Y'):
        return True
    else:
        return False


def setup_branch_tracking(repo, remote, branches):
    repo.add_remote_repo(name=remote['name'], url=remote['url'], fetch=True)
    gitTrackRemote = GitCommand('branch', ['--set-upstream-to'])
    for branch in branches:
        gitTrackRemote(['%s/%s' % (remote['name'], branch), branch])


def push_branches(remote, branches):
    gitPush = GitCommand('push')
    gitPush([remote['url']] + branches)
    gitPush([remote['url'], '--tags'])


def usage_msg():
    return """%prog [options] - create a remote git repository
Actions:
  create         create the repository. This is the default when no action is
                 given.
  list           list available configuration templates for remote repositories"""


def build_parser(name, sections=[]):
    try:
        parser = GbpOptionParserDebian(command=os.path.basename(name), prefix='',
                                       usage=usage_msg(),
                                       sections=sections)
    except (GbpError, configparser.NoSectionError) as err:
        gbp.log.err(err)
        return None

    branch_group = GbpOptionGroup(parser,
                                  "branch options",
                                  "branch layout and tracking options")
    branch_group.add_config_file_option(option_name="remote-url-pattern",
                                        dest="remote_url")
    parser.add_option_group(branch_group)
    branch_group.add_config_file_option(option_name="upstream-branch",
                                        dest="upstream_branch")
    branch_group.add_config_file_option(option_name="debian-branch",
                                        dest="debian_branch")
    branch_group.add_boolean_config_file_option(option_name="pristine-tar",
                                                dest="pristine_tar")
    branch_group.add_boolean_config_file_option(option_name="track",
                                                dest='track')
    branch_group.add_boolean_config_file_option(option_name="bare",
                                                dest='bare')
    parser.add_option("-v", "--verbose",
                      action="store_true",
                      dest="verbose",
                      default=False,
                      help="verbose command execution")
    parser.add_config_file_option(option_name="color",
                                  dest="color",
                                  type='tristate')
    parser.add_config_file_option(option_name="color-scheme",
                                  dest="color_scheme")
    parser.add_option("--remote-name",
                      dest="name",
                      default="origin",
                      help="The name of the remote, default is 'origin'")
    parser.add_config_file_option(option_name="template-dir",
                                  dest="template_dir")
    parser.add_config_file_option(option_name="remote-config",
                                  dest="remote_config")
    return parser


def parse_args(argv):
    """
    Parse the command line arguments and config files.

    @param argv: the command line arguments
    @type argv: C{list} of C{str}
    """
    sections = []
    # We handle the template section as an additional config file
    # section to parse, this makes e.g. --help work as expected:
    for arg in argv:
        if arg.startswith('--remote-config='):
            sections = ['remote-config %s' % arg.split('=', 1)[1]]
            break

    parser = build_parser(argv[0], sections)
    if not parser:
        return None, None, None

    return list(parser.parse_args(argv)) + [parser.config_file_sections]


def do_create(options):
    retval = 0
    changelog = 'debian/changelog'
    cmd = []

    try:
        repo = DebianGitRepository(os.path.curdir)
    except GitRepositoryError:
        gbp.log.err("%s is not a git repository" % (os.path.abspath('.')))
        return 1

    try:
        branches = []

        for branch in [options.debian_branch, options.upstream_branch]:
            if repo.has_branch(branch):
                branches += [branch]

        if repo.has_pristine_tar_branch() and options.pristine_tar:
            branches += [repo.pristine_tar_branch]

        try:
            cp = ChangeLog(filename=changelog)
            pkg = cp['Source']
        except NoChangeLogError:
            pkg = None

        if not pkg:
            gbp.log.warn("Couldn't parse changelog, will use directory name.")
            pkg = os.path.basename(os.path.abspath(os.path.curdir))
            pkg = os.path.splitext(pkg)[0]

        remote = parse_url(options.remote_url,
                           options.name,
                           pkg,
                           options.template_dir,
                           options.bare)
        if repo.has_remote_repo(options.name):
            raise GbpError("You already have a remote name '%s' defined for this repository." % options.name)

        gbp.log.info("Shall I create a repository for '%(pkg)s' at '%(url)s' now? (y/n)?" % remote)
        if not read_yn():
            raise GbpError("Aborted.")

        remote_default = branches[0] if branches else options.debian_branch
        remote_script = build_remote_script(remote, remote_default)
        if options.verbose:
            print(remote_script)

        cmd = build_cmd(remote)
        if options.verbose:
            print(cmd)

        proc = subprocess.Popen(cmd, stdin=subprocess.PIPE)
        proc.communicate(remote_script.encode())
        if proc.returncode:
            raise GbpError("Error creating remote repository")

        if branches:
            push_branches(remote, branches)
        if options.track:
            setup_branch_tracking(repo, remote, branches)
        else:
            gbp.log.info("You can now add:")
            print_config(remote, branches)
            gbp.log.info("to your .git/config to 'gbp pull' and 'git push' in the future.")
    except KeyboardInterrupt:
        retval = 1
        gbp.log.err("Interrupted. Aborting.")
    except CommandExecFailed:
        retval = 1
    except (GbpError, GitRepositoryError) as err:
        if str(err):
            gbp.log.err(err)
        retval = 1
    return retval


def get_config_names(sections):
    config_names = []
    for section in sections:
        if section.startswith("remote-config "):
            config_names.append(section.split(' ', 1)[1])
    return config_names


def do_list(sections):
    names = get_config_names(sections)
    if names:
        gbp.log.info("Available remote config templates:")
        for n in names:
            print("    %s" % n)
    else:
        gbp.log.info("No remote config templates found.")
    return 0


def main(argv):
    retval = 1

    options, args, sections = parse_args(argv)
    if not options:
        return ExitCodes.parse_error

    gbp.log.setup(options.color, options.verbose, options.color_scheme)

    if len(args) == 1:
        args.append('create')  # the default
    elif len(args) > 2:
        gbp.log.err("Only one action allowed")
        return 1

    action = args[1]
    if action == 'create':
        retval = do_create(options)
    elif action == 'list':
        retval = do_list(sections)
    else:
        gbp.log.err("Unknown action '%s'" % action)
    return retval


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

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