#! /usr/bin/perl
# Copyright (C) 2015 The Qt Company Ltd.
# Contact: http://www.qt.io/licensing/
#
# You may use this file under the terms of the 3-clause BSD license.
# See the file LICENSE from this package for details.
#

use warnings;
use strict;

my @repos = (
    [ "projects.pro", "qt" ],
    [ "qlalr.pro", "qt5/qlalr" ],
    [ "qtactiveqt.pro", "qt5/qtactiveqt" ],
    [ "qtbase.pro", "qt5/qtbase" ],
    [ "qtdeclarative.pro", "qt5/qtdeclarative" ],
    [ "qtdoc.pro", "qt5/qtdoc" ],
    [ "qtphonon.pro", "qt5/qtphonon" ],
    [ "qtquick1.pro", "qt5/qtquick1" ],
    [ "qtscript.pro", "qt5/qtscript" ],
    [ "qtsvg.pro", "qt5/qtsvg" ],
    [ "qttools.pro", "qt5/qttools" ],
    [ "qttranslations.pro", "qt5/qttranslations" ],
    [ "qtxmlpatterns.pro", "qt5/qtxmlpatterns" ],
    [ "qtcreator.pro", "qtcreator" ],

    [ "git-hooks/sanitize-commit", "qt5/qtrepotools" ],
    [ "shell/sanitize-commit", "devtools" ],
);

my @mappings = (
    [ [ "qt", "qt5/qlalr" ], [
        [ 'util/qlalr//[^/]+$', 'src//[^/]+$' ],
        [ 'util/qlalr', '' ]
    ] ],
    [ [ "qt", "qt5/qtactiveqt" ], [
        [ 'tools/activeqt', 'tools' ],
        [ 'doc/src/examples/activeqt', 'doc/src/examples' ],
        [ 'doc/src/development//[^/]+$', 'doc/src//[^/]+$' ]
    ] ],
    [ [ "qt", "qt5/qtbase" ], [
        [ 'doc/src/development', 'qmake/doc/src' ],
    ] ],
    [ [ "qt", "qt5/qtdeclarative" ], [
        [ 'tools/qml', 'tools/qmlviewer' ]
    ] ],
    [ [ "qt", "qt5/qtdoc" ], [
        [ 'tools/qdoc3/test', 'doc/config' ]
    ] ],
    [ [ "qt", "qt5/qtphonon" ], [
    ] ],
    [ [ "qt", "qt5/qtquick1" ], [
    ] ],
    [ [ "qt", "qt5/qtscript" ], [
    ] ],
    [ [ "qt", "qt5/qtsvg" ], [
    ] ],
    [ [ "qt", "qt5/qttools" ], [
        [ 'tools', 'src' ]
    ] ],
    [ [ "qt", "qt5/qttranslations" ], [
    ] ],
    [ [ "qt", "qt5/qtxmlpatterns" ], [
    ] ],
    [ [ "devtools", "qt5/qtrepotools" ], [
        [ 'shell/git-', 'bin/git-' ],
        [ 'shell/git_post_commit_hook', 'git-hooks/git_post_commit_hook' ],
        [ 'shell/sanitize-commit', 'git-hooks/sanitize-commit' ]
    ] ],
    [ [ "qtcreator", "qt5/qttools" ], [
        [ 'src/shared/proparser', 'src/linguist/shared' ],
    ], 1 ],
    [ [ "qtcreator", "qt5/qtbase" ], [
        [ 'src/shared/proparser', 'qmake/library' ],
    ], 1 ],
    [ [ "qt5/qtbase", "qt5/qttools" ], [
        [ 'qmake/library', 'src/linguist/shared' ],
    ], 1 ],
    [ [ "qt5/qtbase", "qt5/qtdoc" ], [
        [ 'qmake/doc/src/snippets', 'doc/src/snippets' ],
        [ 'qmake/doc/src', 'doc/src/development' ],
    ], 1 ]
);

my ($cand, $inv);
sub map_name($)
{
    my ($fn) = @_;
    for my $ptha (@{$$cand[1]}) {
        my ($pthi, $ptho) = ($$ptha[$inv], $$ptha[1 - $inv]);
        $pthi .= "(.*)" if (!($pthi =~ s,//(.*),/($1),));
        $ptho =~ s,//.*,/,;
        last if ($fn =~ s/^$pthi/$ptho$1/);
    }
    return $fn;
}

sub get_arg()
{
    if (@ARGV < 2) {
        die $ARGV[0]." requires an argument.\n";
    }
    shift @ARGV;
    return $ARGV[0];
}

sub get_repo_arg()
{
    my $arg = $ARGV[0];
    my $val = get_arg();
    for my $rp (@repos) {
        if ($$rp[1] eq $val) {
            return $val;
        }
        if ($$rp[1] =~ /\/\Q$val\E$/) {
            return $$rp[1];
        }
    }
    die "Fatal: Unknown repository passed to $arg.\n";
}

my ($src_repo, $dst_repo, $other_path) = ("", "", "");
my @commits = ();
my $push = 0;
my $noop = 0;
while (@ARGV) {
    my $arg = $ARGV[0];
    if ($arg eq '-h' or $arg eq '-help' or $arg eq '--help') {
        print <<EOF ;
Usage: $0 [options] [SHA1/-range]

Options:
  -l, --pull <repo>   Specify repo to pull from instead of guessing it.
  -s, --push [<repo>] Push [to specified repo] instead of pulling.
  -p, --path <path>   Specify path of other repo instead of guessing it.
  -n, --dry-run       Dump patch to stdout instead of applying it.
  --                  Only SHA1s follow this option (use with -s without repo).

By default, the HEAD commit of the source repo is cherry-picked.
EOF
        exit 0;
    } elsif ($arg eq '-l' or $arg eq '--pull') {
        $src_repo = get_repo_arg();
    } elsif ($arg eq '-s' or $arg eq '--push') {
        $dst_repo = get_repo_arg() if (@ARGV >= 2 && $ARGV[1] !~ /^-/);
        $push = 1;
    } elsif ($arg eq '-p' or $arg eq '--path') {
        $other_path = get_arg();
    } elsif ($arg eq '-n' or $arg eq '--dry-run') {
        $noop = 1;
    } elsif ($arg eq "--") {
        shift @ARGV;
        push @commits, @ARGV;
        last;
    } elsif ($arg =~ /^-/) {
        die "Unrecognized option $arg.\n";
    } else {
        push @commits, $arg;
    }
    shift @ARGV;
}

die "-s and -l are mutually exclusive.\n" if ($src_repo ne "" and $dst_repo ne "");

push @commits, "HEAD" if (!@commits);

my $cdup = `git rev-parse --show-cdup` or exit 1;
chomp $cdup;
if (length($cdup)) {
    chdir $cdup or die "Cannot enter $cdup: $!\n";
}

my $this_repo = "";
for my $rp (@repos) {
    if (-f $$rp[0]) {
        $this_repo = $$rp[1];
        last;
    }
}
die "Fatal: This Git repository is not known to this script.\n" if ($this_repo eq "");

if (!$push) {
    $dst_repo = $this_repo;
} else {
    $src_repo = $this_repo;
}

die "Fatal: source and target repository are the same.\n" if ($src_repo eq $dst_repo);

my @candidates = ();
my $mincand = 10;
for my $cand (@mappings) {
    my $mcand = $$cand[2] // 0;
    if ($mcand <= $mincand) {
        for my $inv (0, 1) {
            if (("" eq $src_repo or $$cand[0][$inv] eq $src_repo) and
                ("" eq $dst_repo or $$cand[0][1 - $inv] eq $dst_repo)) {
                if ($mcand < $mincand) {
                    $mincand = $mcand;
                    @candidates = ();
                }
                push @candidates, [ $cand, $inv ];
                last;
            }
        }
    }
}
if (@candidates == 0) {
    die "Fatal: found no mapping between source and target repository.\n";
} elsif (@candidates > 1) {
    die "Fatal: found multiple mappings between source and target repository. Try -l/-p.\n";
}
($cand, $inv) = @{$candidates[0]};
print "Porting from ".$$cand[0][$inv]." to ".$$cand[0][1 - $inv]."\n";
if ($other_path eq "") {
    my $this_path = $$cand[0][1 - ($push ^ $inv)];
    my $cnt = 1;
    while ($this_path =~ /\//g) { $cnt++ }
    $other_path = "../"x$cnt . $$cand[0][$push ^ $inv];
}
print "Other path is ".$other_path."\n";
my $cd_other = "cd \"".$other_path."\" && ";
my ($src_cd, $dst_cd) = ("", "");
if (!$push) {
    $src_cd = $cd_other;
} else {
    $dst_cd = $cd_other;
}

my $short_src = $$cand[0][$inv];
$short_src =~ s,^.*/,,;
my $needid = -1;
for my $commit (@commits) {
    my @revs;
    if ($commit =~ /\.\./) {
        @revs = `${src_cd}git rev-list --reverse $commit`;
    } else {
        @revs = ($commit);
    }
    for my $rev (@revs) {
        my ($first, $empty, $sha1, $patch, $haveid) = (1, 0, "", "", 0);
        open DIFF, $src_cd."git format-patch --stdout -1 --src-prefix=\@old\@/ --dst-prefix=\@new\@/ ".$rev." |" or die "cannot run git: $!";
        while (<DIFF>) {
            if ($first) {
                $first = 0;
                /^From (.{40}) / and $sha1 = $1;
            } elsif ($_ eq "\n" || /^[-\w]+: /) {
                $haveid = 1 if (/^Change-Id:/);
                $empty = 1;
            } else {
                if (s/^(diff --git \@old\@\/)(.*)( \@new\@\/)(.*)\n/$1.map_name($2).$3.map_name($4)."\n"/e) {
                } elsif (s/^(--- \@old\@|\+\+\+ \@new\@)\/([^\n]+)/$1."\/".map_name($2)/e) {
                } elsif ($_ eq "---\n") {
                    $patch .= "\n" if (!$empty);
                    $patch .= "(cherry picked from ".$short_src."/".$sha1.")\n";
                    if (!$haveid) {
                        $needid = int(grep /codereview/, `${dst_cd}git remote -v`) if ($needid < 0);
                        $patch .= "Change-Id: I".$sha1."\n" if ($needid);
                    }
                }
                $empty = 0;
            }
            $patch .= $_;
        }
        close DIFF or die "Aborting at ".$rev."\n";
        if ($noop) {
            print $patch;
        } else {
            open PATCH, "| ".$dst_cd."git am -3" or die "cannot run git: $!";
            print PATCH $patch;
            close PATCH or die "Aborting at ".$rev."\n";
        }
    }
}
exit 0;