#!/bin/env perl
use strict;

my $repos =
{
    'op-build' => { REPO => "http://github.com/open-power/op-build" },
    'hostboot' => { REPO => "http://github.com/open-power/hostboot" ,
                    DIR => "openpower/package/hostboot",
                    PACKAGE => "HOSTBOOT" },
    'skiboot'  => { REPO => "http://github.com/open-power/skiboot" ,
                    DIR => "openpower/package/skiboot",
                    PACKAGE => "SKIBOOT" },
    'occ'      => { REPO => "http://github.com/open-power/occ" ,
                    DIR => "openpower/package/occ",
                    PACKAGE => "OCC" },
    'pnor'     => { REPO => "http://github.com/open-power/pnor" ,
                    DIR => "openpower/package/openpower-pnor",
                    PACKAGE => "OPENPOWER_PNOR" },
    'palmetto-xml' => { REPO => "http://github.com/open-power/palmetto-xml" ,
                    DIR => "openpower/package/palmetto-xml",
                    PACKAGE => "PALMETTO_XML" },
    'habanero-xml' => { REPO => "http://github.com/open-power/habanero-xml" ,
                    DIR => "openpower/package/habanero-xml",
                    PACKAGE => "HABANERO_XML" },
    'firestone-xml' => { REPO => "http://github.com/open-power/firestone-xml" ,
                    DIR => "openpower/package/firestone-xml",
                    PACKAGE => "FIRESTONE_XML" },
    'garrison-xml'  => { REPO => "http://github.com/open-power/garrison-xml" ,
                    DIR => "openpower/package/garrison-xml",
                    PACKAGE => "GARRISON_XML" },
    'barreleye-xml'  => { REPO => "http://github.com/open-power/barreleye-xml" ,
                    DIR => "openpower/package/barreleye-xml",
                    PACKAGE => "BARRELEYE_XML" },
    'witherspoon-xml'  => { REPO => "http://github.com/open-power/witherspoon-xml" ,
                    DIR => "openpower/package/witherspoon-xml",
                    PACKAGE => "WITHERSPOON_XML" },
    'zaius-xml'  => { REPO => "http://github.com/open-power/zaius-xml" ,
                    DIR => "openpower/package/zaius-xml",
                    PACKAGE => "ZAIUS_XML" },
    'petitboot'     => { REPO => "http://github.com/open-power/petitboot" ,
                    DIR => "openpower/package/petitboot",
                    PACKAGE => "PETITBOOT" },
};

my $begin_release = shift;
my $end_release = shift;

foreach my $repo (keys %{$repos})
{
    if (-e $repo)
    {
        system("cd $repo; git fetch") && die "Could not fetch $repo";
    }
    else
    {
        system("git clone $repos->{$repo}->{REPO} $repo") &&
            die "Could not clone $repo";
    }
}

system("cd op-build; git checkout $end_release --force; git reset HEAD --hard");


open(OP_SUMMARY, "cd op-build; ".
        "git diff $begin_release...$end_release --name-only |".
        "grep -e \"\.mk\" -e \"Config.in\" |".
        "xargs git diff $begin_release...$end_release -- |".
        "grep -e '^[+-][^[:space:]]*_VERSION' ".
        "-e'^[+-][[:space:]]*default.*if.*LATEST_VERSION' |") || die;

my $old_level = {};
my $new_level = {};

while(my $line = <OP_SUMMARY>)
{
    chomp $line;
    if ($line =~ m/\$/) # Sanity check there are not variables here.
    {
        next;
    }
    if ($line =~ m/-([^[:space:]]*)_VERSION([[:space:]]*\?*=[[:space:]]*)(.*)/)
    {
        print "Old $1:$3\n";
        $old_level->{$1} = $3;
    }
    if ($line =~ m/-([^[:space:]]*)_VERSION_BRANCH_MASTER([[:space:]]*\?*=[[:space:]]*)(.*)/)
    {
        print "Old $1:$3\n";
        $old_level->{$1} = $3;
    }
    if ($line =~ m/\+([^[:space:]]*)_VERSION([[:space:]]*\?*=[[:space:]]*)(.*)/)
    {
        print "New $1:$3\n";
        $new_level->{$1} = $3;
    }
    if ($line =~ m/\+([^[:space:]]*)_VERSION_BRANCH_MASTER([[:space:]]*\?*=[[:space:]]*)(.*)/)
    {
        print "New $1:$3\n";
        $new_level->{$1} = $3;
    }

    if ($line =~ m/-[[:space:]]*default[[:space:]]*"([^[:space:]]*)"[[:space:]]*if[[:space:]]BR2_([^[:space:]]*)_LATEST_VERSION/)
    {
        print "Old $2:$1\n";
        $old_level->{$2} = $1;
    }
    if ($line =~ m/\+[[:space:]]*default[[:space:]]*"([^[:space:]]*)"[[:space:]]*if[[:space:]]BR2_([^[:space:]]*)_LATEST_VERSION/)
    {
        print "New $2:$1\n";
        $new_level->{$2} = $1;
    }
}

open(OUTPUT, "> RELEASE.md") || die "Failed to open RELEASE.md";

print OUTPUT "# Release Notes for OpenPower Firmware $end_release\n";

my $op_url = $repos->{'op-build'}->{REPO};

foreach my $repo (sort keys %{$repos})
{
    next if (not exists $repos->{$repo}->{PACKAGE});

    my $package = $repos->{$repo}->{PACKAGE};
    my $url = $repos->{$repo}->{REPO};
    my $dir = $repos->{$repo}->{DIR};

    print OUTPUT "## Package: $repo\n";
    print OUTPUT "[Repository]($url)\n";
    print OUTPUT "\n";

    my $package = $repos->{$repo}->{PACKAGE};

    # Display patches.
    if (open(LSLOG, "ls op-build/$dir/*.patch | ".
                    "xargs -n1 --no-run-if-empty basename |"))
    {
        print OUTPUT "### Patches\n";
        while (my $logline = <LSLOG>)
        {
            chomp $logline;
            print OUTPUT "* [$logline]".
                "($op_url/tree/$end_release/$dir/$logline)\n";
        }
        close LSLOG;
        print OUTPUT "\n";
    }
    else
    {
        print OUTPUT "None.\n";
    }

    # Display changes.
    print OUTPUT "### Commits\n";
    if ((not exists $old_level->{$package}) &&
        (not exists $new_level->{$package}))
    {
        # No change identified.
        print "No changes: $repo\n";
        print OUTPUT "No changes.\n";
        next;
    }

    if ((exists $old_level->{$package}) &&
        (exists $new_level->{$package}))
    {
        print "Changes in $repo...\n";

        open(GITLOG, "cd $repo; git shortlog $old_level->{$package}...".
                     "$new_level->{$package} --no-merges --format=".
                     "\"* [%h]($url/commit/%h) %s\" |");

        while (my $logline = <GITLOG>)
        {
            chomp $logline;
            $logline =~ s/^[[:space:]]*//;
            print OUTPUT "$logline\n";
        }
        close GITLOG;
        print OUTPUT "\n";
        next;
    }

    if (not exists $old_level->{$package})
    {
        print "New package $repo.\n";
        print OUTPUT "New package.\n";
        next;
    }

    if (not exists $new_level->{$package})
    {
        print "Deleted package $repo.\n";
        print OUTPUT "Package removed.\n";
        next;
    }
}