# vim: set fileencoding=utf-8 :
#
# (C) 2011 Guido Günther <agx@sigxcpu.org>
# (C) 2012-2014 Intel Corporation <markus.lehtonen@linux.intel.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; 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/>
#
"""manage patches in a patch queue"""

from six.moves import configparser
import bz2
import errno
import gzip
import os
import re
import shutil
import sys

import gbp.log
import gbp.tmpfile as tempfile
from gbp.config import GbpOptionParserRpm
from gbp.rpm.git import GitRepositoryError, RpmGitRepository
from gbp.git.modifier import GitModifier
from gbp.command_wrappers import GitCommand, CommandExecFailed
from gbp.errors import GbpError
from gbp.patch_series import PatchSeries, Patch
from gbp.pkg import parse_archive_filename
from gbp.rpm import (SpecFile, NoSpecError, guess_spec, guess_spec_repo,
                     spec_from_repo)
from gbp.scripts.common.pq import (is_pq_branch, pq_branch_name, pq_branch_base,
            parse_gbp_commands, format_patch, format_diff,
            switch_to_pq_branch, apply_single_patch, apply_and_commit_patch,
            drop_pq, switch_pq)
from gbp.scripts.common.buildpackage import dump_tree


def is_ancestor(repo, parent, child):
    """Check if commit is ancestor of another"""
    parent_sha1 = repo.rev_parse("%s^0" % parent)
    child_sha1 = repo.rev_parse("%s^0" % child)
    try:
        merge_base = repo.get_merge_base(parent_sha1, child_sha1)
    except GitRepositoryError:
        merge_base = None
    return merge_base == parent_sha1

def generate_patches(repo, start, end, outdir, options):
    """
    Generate patch files from git
    """
    gbp.log.info("Generating patches from git (%s..%s)" % (start, end))
    patches = []
    commands = {}
    for treeish in [start, end]:
        if not repo.has_treeish(treeish):
            raise GbpError('Invalid treeish object %s' % treeish)

    start_sha1 = repo.rev_parse("%s^0" % start)
    try:
        end_commit = end
    except GitRepositoryError:
        # In case of plain tree-ish objects, assume current branch head is the
        # last commit
        end_commit = "HEAD"
    end_commit_sha1 = repo.rev_parse("%s^0" % end_commit)

    start_sha1 = repo.rev_parse("%s^0" % start)

    if not is_ancestor(repo, start_sha1, end_commit_sha1):
        raise GbpError("Start commit '%s' not an ancestor of end commit "
                       "'%s'" % (start, end_commit))
    # Check for merge commits, squash if merges found
    merges = repo.get_commits(start, end_commit, options=['--merges'])
    if merges:
        # Shorten SHA1s
        start_sha1 = repo.rev_parse(start, short=7)
        merge_sha1 = repo.rev_parse(merges[0], short=7)
        patch_fn = format_diff(outdir, None, repo, start_sha1, merge_sha1)
        if patch_fn:
            gbp.log.info("Merge commits found! Diff between %s..%s written "
                         "into one monolithic diff" % (start_sha1, merge_sha1))
            patches.append(patch_fn)
            start = merge_sha1

    # Generate patches
    for commit in reversed(repo.get_commits(start, end_commit)):
        info = repo.get_commit_info(commit)
        (cmds, info['body']) = parse_gbp_commands(info,
                                                  'gbp-rpm',
                                                  ('ignore'),
                                                  ('if', 'ifarch'))
        if not 'ignore' in cmds:
            patch_fn = format_patch(outdir, repo, info, patches,
                                    options.patch_numbers)
            if patch_fn:
                commands[os.path.basename(patch_fn)] = cmds
        else:
            gbp.log.info('Ignoring commit %s' % info['id'])

    # Generate diff to the tree-ish object
    if end_commit != end:
        gbp.log.info("Generating diff file %s..%s" % (end_commit, end))
        patch_fn = format_diff(outdir, None, repo, end_commit, end,
                               options.patch_export_ignore_path)
        if patch_fn:
            patches.append(patch_fn)

    return patches, commands


def rm_patch_files(spec):
    """
    Delete the patch files listed in the spec file. Doesn't delete patches
    marked as not maintained by gbp.
    """
    # Remove all old patches from the spec dir
    for patch in spec.patchseries(unapplied=True):
        gbp.log.debug("Removing '%s'" % patch.path)
        try:
            os.unlink(patch.path)
        except OSError as err:
            if err.errno != errno.ENOENT:
                raise GbpError("Failed to remove patch: %s" % err)
            else:
                gbp.log.debug("Patch %s does not exist." % patch.path)


def update_patch_series(repo, spec, start, end, options):
    """
    Export patches to packaging directory and update spec file accordingly.
    """
    # Unlink old patch files and generate new patches
    rm_patch_files(spec)

    patches, commands = generate_patches(repo, start, end,
                                         spec.specdir, options)
    spec.update_patches(patches, commands)
    spec.write_spec_file()
    return patches


def parse_spec(options, repo, treeish=None):
    """
    Find and parse spec file.

    If treeish is given, try to find the spec file from that. Otherwise, search
    for the spec file in the working copy.
    """
    try:
        if options.spec_file:
            options.packaging_dir = os.path.dirname(options.spec_file)
            if not treeish:
                spec = SpecFile(options.spec_file)
            else:
                spec = spec_from_repo(repo, treeish, options.spec_file)
        else:
            preferred_name = os.path.basename(repo.path) + '.spec'
            if not treeish:
                spec = guess_spec(options.packaging_dir, True, preferred_name)
            else:
                spec = guess_spec_repo(repo, treeish, options.packaging_dir,
                                       True, preferred_name)
    except NoSpecError as err:
        raise GbpError("Can't parse spec: %s" % err)
    relpath = spec.specpath if treeish else os.path.relpath(spec.specpath,
                                                            repo.path)
    gbp.log.debug("Using '%s' from '%s'" % (relpath, treeish or 'working copy'))
    return spec


def find_upstream_commit(repo, spec, upstream_tag):
    """Find commit corresponding upstream version"""
    tag_str_fields = {'upstreamversion': spec.upstreamversion,
                      'version': spec.upstreamversion}
    upstream_commit = repo.find_version(upstream_tag, tag_str_fields)
    if not upstream_commit:
        raise GbpError("Couldn't find upstream version %s" %
                       spec.upstreamversion)
    return upstream_commit


def export_patches(repo, options):
    """Export patches from the pq branch into a packaging branch"""
    current = repo.get_branch()
    if is_pq_branch(current):
        base = pq_branch_base(current)
        gbp.log.info("On branch '%s', switching to '%s'" % (current, base))
        repo.set_branch(base)
        pq_branch = current
    else:
        pq_branch = pq_branch_name(current)
    spec = parse_spec(options, repo)
    upstream_commit = find_upstream_commit(repo, spec, options.upstream_tag)
    export_treeish = pq_branch

    update_patch_series(repo, spec, upstream_commit, export_treeish, options)

    GitCommand('status')(['--', spec.specdir])


def safe_patches(queue, tmpdir_base):
    """
    Safe the current patches in a temporary directory
    below 'tmpdir_base'. Also, uncompress compressed patches here.

    @param queue: an existing patch queue
    @param tmpdir_base: base under which to create tmpdir
    @return: tmpdir and a safed queue (with patches in tmpdir)
    @rtype: tuple
    """

    tmpdir = tempfile.mkdtemp(dir=tmpdir_base, prefix='patchimport_')
    safequeue = PatchSeries()

    if len(queue) > 0:
        gbp.log.debug("Safeing patches '%s' in '%s'" %
                        (os.path.dirname(queue[0].path), tmpdir))
    for patch in queue:
        base, _archive_fmt, comp = parse_archive_filename(patch.path)
        uncompressors = {'gzip': gzip.open, 'bzip2': bz2.BZ2File}
        if comp in uncompressors:
            gbp.log.debug("Uncompressing '%s'" % os.path.basename(patch.path))
            src = uncompressors[comp](patch.path, 'r')
            dst_name = os.path.join(tmpdir, os.path.basename(base))
        elif comp:
            raise GbpError("Unsupported patch compression '%s', giving up"
                           % comp)
        else:
            src = open(patch.path, 'r')
            dst_name = os.path.join(tmpdir, os.path.basename(patch.path))

        dst = open(dst_name, 'w')
        dst.writelines(src)
        src.close()
        dst.close()

        safequeue.append(patch)
        safequeue[-1].path = dst_name

    return safequeue


def get_packager(spec):
    """Get packager information from spec"""
    if spec.packager:
        match = re.match(r'(?P<name>.*[^ ])\s*<(?P<email>\S*)>',
                         spec.packager.strip())
        if match:
            return GitModifier(match.group('name'), match.group('email'))
    return GitModifier()


def import_spec_patches(repo, options):
    """
    apply a series of patches in a spec/packaging dir to branch
    the patch-queue branch for 'branch'

    @param repo: git repository to work on
    @param options: command options
    """
    current = repo.get_branch()
    # Get spec and related information
    if is_pq_branch(current):
        base = pq_branch_base(current)
        if options.force:
            spec = parse_spec(options, repo, base)
            spec_treeish = base
        else:
            raise GbpError("Already on a patch-queue branch '%s' - doing "
                           "nothing." % current)
    else:
        spec = parse_spec(options, repo)
        spec_treeish = None
        base = current
    upstream_commit = find_upstream_commit(repo, spec, options.upstream_tag)
    packager = get_packager(spec)
    pq_branch = pq_branch_name(base)

    # Create pq-branch
    if repo.has_branch(pq_branch) and not options.force:
        raise GbpError("Patch-queue branch '%s' already exists. "
                       "Try 'switch' instead." % pq_branch)
    try:
        if repo.get_branch() == pq_branch:
            repo.force_head(upstream_commit, hard=True)
        else:
            repo.create_branch(pq_branch, upstream_commit, force=True)
    except GitRepositoryError as err:
        raise GbpError("Cannot create patch-queue branch '%s': %s" %
                        (pq_branch, err))

    # Put patches in a safe place
    if spec_treeish:
        packaging_tmp = tempfile.mkdtemp(prefix='dump_', dir=options.tmp_dir)
        packaging_tree = '%s:%s' % (spec_treeish, options.packaging_dir)
        dump_tree(repo, packaging_tmp, packaging_tree, with_submodules=False,
                  recursive=False)
        spec.specdir = packaging_tmp
    in_queue = spec.patchseries()
    queue = safe_patches(in_queue, options.tmp_dir)
    # Do import
    try:
        gbp.log.info("Switching to branch '%s'" % pq_branch)
        repo.set_branch(pq_branch)

        if not queue:
            return
        gbp.log.info("Trying to apply patches from branch '%s' onto '%s'" %
                        (base, upstream_commit))
        for patch in queue:
            gbp.log.debug("Applying %s" % patch.path)
            apply_and_commit_patch(repo, patch, packager)
    except (GbpError, GitRepositoryError) as err:
        repo.set_branch(base)
        repo.delete_branch(pq_branch)
        raise GbpError('Import failed: %s' % err)

    gbp.log.info("Patches listed in '%s' imported on '%s'" % (spec.specfile,
                                                              pq_branch))


def rebase_pq(repo, options):
    """Rebase pq branch on the correct upstream version (from spec file)."""
    current = repo.get_branch()
    if is_pq_branch(current):
        base = pq_branch_base(current)
        spec = parse_spec(options, repo, base)
    else:
        base = current
        spec = parse_spec(options, repo)
    upstream_commit = find_upstream_commit(repo, spec, options.upstream_tag)

    switch_to_pq_branch(repo, base)
    GitCommand("rebase")([upstream_commit])


def build_parser(name):
    """Construct command line parser"""
    try:
        parser = GbpOptionParserRpm(command=os.path.basename(name),
                                    prefix='', usage=
"""%prog [options] action - maintain patches on a patch queue branch
tions:
export         Export the patch queue / devel branch associated to the
               current branch into a patch series in and update the spec file
import         Create a patch queue / devel branch from spec file
               and patches in current dir.
rebase         Switch to patch queue / devel branch associated to the current
               branch and rebase against upstream.
drop           Drop (delete) the patch queue /devel branch associated to
               the current branch.
apply          Apply a patch
switch         Switch to patch-queue branch and vice versa.""")

    except configparser.ParsingError as err:
        gbp.log.err('Invalid config file: %s' % err)
        return None

    parser.add_boolean_config_file_option(option_name="patch-numbers",
            dest="patch_numbers")
    parser.add_option("-v", "--verbose", action="store_true", dest="verbose",
            default=False, help="Verbose command execution")
    parser.add_option("--force", dest="force", action="store_true",
            default=False,
            help="In case of import even import if the branch already exists")
    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_config_file_option(option_name="tmp-dir", dest="tmp_dir")
    parser.add_config_file_option(option_name="upstream-tag",
            dest="upstream_tag")
    parser.add_config_file_option(option_name="spec-file", dest="spec_file")
    parser.add_config_file_option(option_name="packaging-dir",
            dest="packaging_dir")
    return parser


def parse_args(argv):
    """Parse command line arguments"""
    parser = build_parser(argv[0])
    if not parser:
        return None, None
    return parser.parse_args(argv)


def main(argv):
    """Main function for the gbp pq-rpm command"""
    retval = 0

    (options, args) = parse_args(argv)
    if not options:
        return 1

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

    if len(args) < 2:
        gbp.log.err("No action given.")
        return 1
    else:
        action = args[1]

    if args[1] in ["export", "import", "rebase", "drop", "switch", "convert"]:
        pass
    elif args[1] in ["apply"]:
        if len(args) != 3:
            gbp.log.err("No patch name given.")
            return 1
        else:
            patchfile = args[2]
    else:
        gbp.log.err("Unknown action '%s'." % args[1])
        return 1

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

    try:
        # Create base temporary directory for this run
        options.tmp_dir = tempfile.mkdtemp(dir=options.tmp_dir,
                                           prefix='gbp-pq-rpm_')
        current = repo.get_branch()
        if action == "export":
            export_patches(repo, options)
        elif action == "import":
            import_spec_patches(repo, options)
        elif action == "drop":
            drop_pq(repo, current)
        elif action == "rebase":
            rebase_pq(repo, options)
        elif action == "apply":
            patch = Patch(patchfile)
            apply_single_patch(repo, current, patch, fallback_author=None)
        elif action == "switch":
            switch_pq(repo, current)
    except CommandExecFailed:
        retval = 1
    except GitRepositoryError as err:
        gbp.log.err("Git command failed: %s" % err)
        retval = 1
    except GbpError as err:
        if str(err):
            gbp.log.err(err)
        retval = 1
    finally:
        shutil.rmtree(options.tmp_dir, ignore_errors=True)

    return retval

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

