#! /usr/bin/python

# Copyright (C) 2012  Canonical Ltd.
# Author: Colin Watson <cjwatson@ubuntu.com>

# 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; version 3 of the License.
#
# 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, see <http://www.gnu.org/licenses/>.

"""Branch a set of Ubuntu seeds for the next release."""

from __future__ import print_function

from optparse import OptionParser
import os
import re
import subprocess
try:
    from urllib.parse import urlparse
except ImportError:
    from urlparse import urlparse

from launchpadlib.launchpad import Launchpad
from enum import Enum

class VCS(Enum):
    Git = 1
    Bazaar = 2

    @staticmethod
    def detect_vcs(source):
        if os.path.exists(os.path.join(source, ".git")):
            return VCS.Git
        elif os.path.exists(os.path.join(source, ".bzr")):
            return VCS.Bazaar
        else:
            return None


def remote_bzr_branch(source):
    # TODO: should really use bzrlib instead
    info = subprocess.check_output(
        ["bzr", "info", source], universal_newlines=True)
    for line in info.splitlines():
        if "checkout of branch:" in line:
            return line.split(": ")[1].rstrip("/")
    else:
        raise Exception("Unable to find remote branch for %s" % source)


def remote_git_repository(source, srcbranch):
    fullbranch = subprocess.check_output(
        ["git", "rev-parse", "--symbolic-full-name",
         srcbranch + "@{upstream}"],
        universal_newlines=True, cwd=source)
    return subprocess.check_output(
        ["git", "ls-remote", "--get-url", fullbranch.split("/")[2]],
        universal_newlines=True, cwd=source).rstrip("\n")


def lp_branch(options, url):
    return options.launchpad.branches.getByUniqueName(
        unique_name=urlparse(url).path.lstrip("/"))


def branch(options, collection):
    source = "%s.%s" % (collection, options.source_series)
    dest = "%s.%s" % (collection, options.dest_series)
    vcs = VCS.detect_vcs(source)
    if vcs:
        if vcs is VCS.Bazaar:
            subprocess.check_call(["bzr", "up", source])
            remote_source = remote_bzr_branch(source)
            remote_dest = os.path.join(os.path.dirname(remote_source), dest)
            subprocess.check_call(["bzr", "branch", source, dest])
            subprocess.check_call(["bzr", "push", "-d", dest, remote_dest])
            subprocess.check_call(["bzr", "bind", ":push"], cwd=dest)

            lp_source = lp_branch(options, remote_source)
            lp_source.lifecycle_status = "Mature"
            lp_source.lp_save()

            lp_dest = lp_branch(options, remote_dest)
            lp_dest.lifecycle_status = "Development"
            lp_dest.lp_save()
        elif vcs is VCS.Git:
            subprocess.check_call(["git", "fetch"], cwd=source)
            subprocess.check_call(["git", "reset", "--hard", "FETCH_HEAD"], cwd=source)
            os.rename(source, dest)
            subprocess.check_call(["git", "checkout", "-b", options.dest_series], cwd=dest)

        re_include_source = re.compile(
            r"^(include )(.*)\.%s" % options.source_series)
        new_lines = []
        message = []
        with open(os.path.join(dest, "STRUCTURE")) as structure:
            for line in structure:
                match = re_include_source.match(line)
                if match:
                    new_lines.append(re_include_source.sub(
                        r"\1\2.%s" % options.dest_series, line))
                    message.append(
                        "%s.%s -> %s.%s" %
                        (match.group(2), options.source_series,
                         match.group(2), options.dest_series))
                else:
                    new_lines.append(line)
        if message:
            with open(os.path.join(dest, "STRUCTURE.new"), "w") as structure:
                for line in new_lines:
                    print(line, end="", file=structure)
            os.rename(
                os.path.join(dest, "STRUCTURE.new"),
                os.path.join(dest, "STRUCTURE"))
            if vcs is VCS.Bazaar:
                subprocess.check_call(
                    ["bzr", "commit", "-m", "; ".join(message)], cwd=dest)
            elif vcs is VCS.Git:
                subprocess.check_call(["git", "add", "STRUCTURE"], cwd=dest)
                subprocess.check_call(
                    ["git", "commit", "-m", "; ".join(message)], cwd=dest)
                subprocess.check_call(
                    ["git", "push", "origin", options.dest_series], cwd=dest)

                remote = remote_git_repository(dest, options.source_series)
                if "git.launchpad.net" in remote:
                    lp_git_repo = options.launchpad.git_repositories.getByPath(
                        path=urlparse(remote).path.lstrip("/"))
                    lp_git_repo.default_branch = options.dest_series
                    lp_git_repo.lp_save()
                else:
                    raise Exception(
                        "Git remote URL must be on git.launchpad.net.")


def main():
    parser = OptionParser(usage="usage: %prog [options] collection ...")
    parser.add_option(
        "-l", "--launchpad", dest="launchpad_instance", default="production")
    parser.add_option(
        "--source-series",
        help="source series (default: current stable release)")
    parser.add_option(
        "--dest-series",
        help="destination series (default: series in pre-release freeze)")
    options, args = parser.parse_args()
    if not args:
        parser.error("You must specify at least one seed collection.")

    options.launchpad = Launchpad.login_with(
        "branch-seeds", options.launchpad_instance, version="devel")

    distro = options.launchpad.distributions["ubuntu"]
    if options.source_series is None:
        options.source_series = [
            series.name for series in distro.series
            if series.status == "Current Stable Release"][0]
    if options.dest_series is None:
        options.dest_series = [
            series.name for series in distro.series
            if series.status == "Pre-release Freeze"][0]

    for collection in args:
        branch(options, collection)


main()