#!/usr/bin/python3
#
# Copyright (C) 2011, Stefano Rivera <stefanor@ubuntu.com>
#
# Permission to use, copy, modify, and/or distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

from collections import defaultdict
import optparse
import re
import sys

import apt
from distro_info import UbuntuDistroInfo

from ubuntutools.config import UDTConfig
from ubuntutools.lp.lpapicache import Launchpad, Distribution
from ubuntutools.lp.udtexceptions import PackageNotFoundException
from ubuntutools.question import (YesNoQuestion, EditBugReport,
                                  confirmation_prompt)
from ubuntutools.rdepends import query_rdepends, RDependsException

from ubuntutools import getLogger
Logger = getLogger(__name__)


class DestinationException(Exception):
    pass


def determine_destinations(source, destination):
    ubuntu_info = UbuntuDistroInfo()
    if destination is None:
        destination = ubuntu_info.stable()

    if source not in ubuntu_info.all:
        raise DestinationException("Source release %s does not exist" % source)
    if destination not in ubuntu_info.all:
        raise DestinationException("Destination release %s does not exist"
                                   % destination)
    if destination not in ubuntu_info.supported():
        raise DestinationException("Destination release %s is not supported"
                                   % destination)

    found = False
    destinations = []
    support_gap = False
    for release in ubuntu_info.all:
        if release == destination:
            found = True
        if release == source:
            break
        if found:
            if support_gap:
                if ubuntu_info.is_lts(release):
                    support_gap = False
                else:
                    continue
            if release not in ubuntu_info.supported():
                support_gap = True
                continue
            destinations.append(release)

    assert found
    assert len(destinations) > 0

    return destinations


def disclaimer():
    print("Ubuntu's backports are not for fixing bugs in stable releases, "
          "but for bringing new features to older, stable releases.\n"
          "See https://wiki.ubuntu.com/UbuntuBackports for the Ubuntu "
          "Backports policy and processes.\n"
          "See https://wiki.ubuntu.com/StableReleaseUpdates for the process "
          "for fixing bugs in stable releases.")
    confirmation_prompt()


def check_existing(package, destinations):
    """Search for possible existing bug reports"""
    # The LP bug search is indexed, not substring:
    query = re.findall(r'[a-z]+', package)
    bugs = []
    for release in destinations:
        project_name = '{}-backports'.format(release)
        try:
            project = Launchpad.projects[project_name]
        except KeyError:
            Logger.error("The backports tracking project '%s' doesn't seem to "
                         "exist.  Please check the situation with the "
                         "backports team.", project_name)
            sys.exit(1)
        bugs += project.searchTasks(omit_duplicates=True,
                                    search_text=query,
                                    status=["Incomplete", "New", "Confirmed",
                                            "Triaged", "In Progress",
                                            "Fix Committed"])
    if not bugs:
        return

    Logger.info("There are existing bug reports that look similar to your "
                "request. Please check before continuing:")

    for bug in sorted(set(bug_task.bug for bug_task in bugs)):
        Logger.info(" * LP: #%-7i: %s  %s", bug.id, bug.title, bug.web_link)

    confirmation_prompt()


def find_rdepends(releases, published_binaries):
    intermediate = defaultdict(lambda: defaultdict(list))

    # We want to display every pubilshed binary, even if it has no rdepends
    for binpkg in published_binaries:
        intermediate[binpkg]

    for arch in ('any', 'source'):
        for release in releases:
            for binpkg in published_binaries:
                try:
                    raw_rdeps = query_rdepends(binpkg, release, arch)
                except RDependsException:
                    # Not published? TODO: Check
                    continue
                for relationship, rdeps in raw_rdeps.items():
                    for rdep in rdeps:
                        # Ignore circular deps:
                        if rdep['Package'] in published_binaries:
                            continue
                        # arch==any queries return Reverse-Build-Deps:
                        if arch == 'any' and rdep.get('Architectures', []) == ['source']:
                            continue
                        intermediate[binpkg][rdep['Package']].append((release, relationship))

    output = []
    for binpkg, rdeps in intermediate.items():
        output += ['', binpkg, '-' * len(binpkg)]
        for pkg, appearences in rdeps.items():
            output += ['* %s' % pkg]
            for release, relationship in appearences:
                output += ['  [ ] %s (%s)' % (release, relationship)]

    found_any = sum(len(rdeps) for rdeps in intermediate.values())
    if found_any:
        output = [
            "Reverse dependencies:",
            "=====================",
            "The following reverse-dependencies need to be tested against the "
            "new version of %(package)s. "
            "For reverse-build-dependencies (-Indep), please test that the "
            "package still builds against the new %(package)s. "
            "For reverse-dependencies, please test that the version of the "
            "package currently in the release still works with the new "
            "%(package)s installed. "
            "Reverse- Recommends, Suggests, and Enhances don't need to be "
            "tested, and are listed for completeness-sake."
           ] + output
    else:
        output = ["No reverse dependencies"]

    return output


def locate_package(package, distribution):
    archive = Distribution('ubuntu').getArchive()
    for pass_ in ('source', 'binary'):
        try:
            package_spph = archive.getSourcePackage(package, distribution)
            return package_spph
        except PackageNotFoundException as e:
            if pass_ == 'binary':
                Logger.error(str(e))
                sys.exit(1)

        try:
            apt_pkg = apt.Cache()[package]
        except KeyError:
            continue
        package = apt_pkg.candidate.source_name
        Logger.info("Binary package specified, considering its source "
                    "package instead: %s", package)


def request_backport(package_spph, source, destinations):

    published_binaries = set()
    for bpph in package_spph.getBinaries():
        published_binaries.add(bpph.getPackageName())

    if not published_binaries:
        Logger.error("%s (%s) has no published binaries in %s. ",
                     package_spph.getPackageName(), package_spph.getVersion(),
                     source)
        Logger.info("Is it stuck in bin-NEW? It can't be backported until "
                    "the binaries have been accepted.")
        sys.exit(1)

    testing = []
    testing += ["You can test-build the backport in your PPA with "
                "backportpackage:"]
    testing += ["$ backportpackage -u ppa:<lp username>/<ppa name> "
                "-s %s -d %s %s"
                % (source, dest, package_spph.getPackageName())
                for dest in destinations]
    testing += [""]
    for dest in destinations:
        testing += ['* %s:' % dest]
        testing += ["[ ] Package builds without modification"]
        testing += ["[ ] %s installs cleanly and runs" % binary
                    for binary in published_binaries]

    subst = {
        'package': package_spph.getPackageName(),
        'version': package_spph.getVersion(),
        'component': package_spph.getComponent(),
        'source': package_spph.getSeriesAndPocket(),
        'destinations': ', '.join(destinations),
    }
    subject = ("Please backport %(package)s %(version)s (%(component)s) "
               "from %(source)s" % subst)
    body = ('\n'.join(
            [
             "Please backport %(package)s %(version)s (%(component)s) "
             "from %(source)s to %(destinations)s.",
             "",
             "Reason for the backport:",
             "========================",
             ">>> Enter your reasoning here <<<",
             "",
             "Testing:",
             "========",
             "Mark off items in the checklist [X] as you test them, "
             "but please leave the checklist so that backporters can quickly "
             "evaluate the state of testing.",
             ""
            ]
            + testing
            + [""]
            + find_rdepends(destinations, published_binaries)
            + [""]) % subst)

    editor = EditBugReport(subject, body)
    editor.edit()
    subject, body = editor.get_report()

    Logger.info('The final report is:\nSummary: %s\nDescription:\n%s\n',
                subject, body)
    if YesNoQuestion().ask("Request this backport", "yes") == "no":
        sys.exit(1)

    targets = [Launchpad.projects['%s-backports' % destination]
               for destination in destinations]
    bug = Launchpad.bugs.createBug(title=subject, description=body,
                                   target=targets[0])
    for target in targets[1:]:
        bug.addTask(target=target)

    Logger.info("Backport request filed as %s", bug.web_link)


def main():
    parser = optparse.OptionParser('%prog [options] package')
    parser.add_option('-d', '--destination', metavar='DEST',
                      help='Backport to DEST release and necessary '
                           'intermediate releases '
                           '(default: current stable release)')
    parser.add_option('-s', '--source', metavar='SOURCE',
                      help='Backport from SOURCE release '
                           '(default: current devel release)')
    parser.add_option('-l', '--lpinstance', metavar='INSTANCE', default=None,
                      help='Launchpad instance to connect to '
                           '(default: production).')
    parser.add_option('--no-conf', action='store_true',
                      dest='no_conf', default=False,
                      help="Don't read config files or environment variables")
    options, args = parser.parse_args()

    if len(args) != 1:
        parser.error("One (and only one) package must be specified")
    package = args[0]

    config = UDTConfig(options.no_conf)

    if options.lpinstance is None:
        options.lpinstance = config.get_value('LPINSTANCE')
    Launchpad.login(options.lpinstance)

    if options.source is None:
        options.source = Distribution('ubuntu').getDevelopmentSeries().name

    try:
        destinations = determine_destinations(options.source,
                                              options.destination)
    except DestinationException as e:
        Logger.error(str(e))
        sys.exit(1)

    disclaimer()

    check_existing(package, destinations)

    package_spph = locate_package(package, options.source)
    request_backport(package_spph, options.source, destinations)


if __name__ == '__main__':
    main()