#!/usr/bin/perl -w
#
# Helper script for debian-cd EFI CD creation
#
# Parse the Isolinux boot menus and create matching grub menus and submenus
#
# Complicated by the way grub theming works - we need to create a
# separate grub theme per submenu simply so that we can describe the
# current (sub)menu appropriately.

use strict;
use File::Path qw(make_path);

my $isolinuxdir = shift or die "Need to know where the isolinux directory is!\n";
my $outdir = shift or die "Need to know where to write output!\n";
my $grub_theme = shift or die "Need input file location for base grub theme!\n";
my $tl_distro= shift or die "Need a top-level distro name (e.g. Debian)\n";
my $tl_kernel= shift or die "Need a top-level kernel (e.g. GNU/Linux)\n";
my $tl_version= shift or die "Need a top-level version (e.g. 7.0)\n";
my $theme_dir = "$outdir/boot/grub/theme";
my @cpp_and_opts = ('cpp',
		    '-traditional',
		    '-undef',
		    '-P',
		    '-C',
		    '-Wall',
		    '-nostdinc');

my @lines;
my @menus;
my $incdepth = 0;
my @menu_number = (1,0,0,0,0);
my @menu_title = ('', '', '', '', '');
my $menudepth = 0;
my $pre = "";
my $in_ifcpu = 0;
my $amd64_label = "";
my %menu;

sub parse_file {
    my $file = shift;

    $incdepth++;
#    for(my $i = 0; $i < $incdepth ; $i++) {
#	print STDERR " ";
#    }
#    print STDERR "parsing $isolinuxdir/$file\n";
    open(my $fh, "< $isolinuxdir/$file") or return;
    while (my $line = <$fh>) {
	chomp $line;
	if ($line =~ /^\s*include\ (.*\.cfg)/) {
	    parse_file($1);
	} elsif ($line =~ /label archdetect/) {
	    # We don't have support for arch detection in Grub, so only
	    # show the amd64 options
	    $in_ifcpu = 1;
	} elsif ($line =~ /kernel (.*c32)/) {
	    # This tells us that the matching "append" data will have
	    # the label we need to look for. Ugh!
	    if ($1 =~ /ifcpu64/) {
		$in_ifcpu = 2;
	    }
	} elsif ($line =~ /^\s*label (.*)/ && $1 =~ /$amd64_label/) {
	    $in_ifcpu = 3;
	} elsif ($line =~ /^\s*append\ (.*\.cfg)/) {
	    if ($in_ifcpu == 3) {
		parse_file($1);
		$in_ifcpu = 1;
	    }
	} elsif ($line =~ /append (.*)$/ && $in_ifcpu == 2) {
	    # Parse out the first entry - that's what we want to use
	    # as a label elsewhere. Ugh!
	    my @list = split(/ /, $1);
	    $amd64_label = $list[0];
	    $in_ifcpu = 1;
	} elsif ($line =~ /default archdetect/) {
	    $in_ifcpu = 0;
	} else {
	    push(@lines, $line);
	}
    }
    close $fh;
    $incdepth--;
}

sub print_indent {
    my $text = shift;
    my $i = 1;
    while ($i++ < $menudepth) {
	print "    ";
    }
    print $text;
}

sub print_kernel {
    my $t = shift;
    my %k = %{$t};
    my $initrd;
    my $hotkey = "";

    if ($k{"label"} =~ m,\^(\S),) {
	$hotkey = lc "--hotkey=$1 ";
	$k{"label"} =~ s/\^//;
    }
    if ($k{"append"} =~ s? (initrd=\S+)??) {
	$initrd = $1;
	$initrd =~ s?^.*initrd=??;
    }
    print_indent "menuentry $hotkey'$pre" . $k{"label"} . "' {\n";
    print_indent "    set background_color=black\n";
    print_indent "    linux    " . $k{"kernel"} . " " . $k{"append"} . "\n";
    print_indent "    initrd   $initrd\n";
    print_indent "}\n";
}

sub debug {
#    print_indent $menudepth . " " . $menu{"number"} . ": " . $menu{"label"} . 
#	" '" . $menu{"title"} . "'\n";
}

sub create_theme_file {
    my $filename = shift;
    my @args;
    push(@args, @cpp_and_opts);
    push(@args, "-DTITLE=\"$tl_distro $tl_kernel $tl_version\"");
    for (my $i = 0; $i < $menudepth; $i++) {
	push(@args, "-DMENU$i=\"" . $menu_title[$i] . "\"");
    }
    push(@args, "$grub_theme");
    open(IN, "-|", @args) or die "Can't open cpp input: $!\n";
    open(OUT, ">", "$theme_dir/$filename")
	or die "Can't create theme file $theme_dir/$filename: $!\n";
    while (<IN>) {
	print OUT "$_";
    }
    close(IN);
    close(OUT);
}

make_path($theme_dir);
if (! -d $theme_dir) {
    die "Can't make theme dir $theme_dir: $!\n";
}
parse_file("isolinux.cfg");

$menu{"number"} = "1";
$menu{"label"} = "top";
$menu{"title"} = "$tl_distro $tl_kernel UEFI Installer menu";
$menu_title[$menudepth] = $menu{"title"};

my %kernel;
my $in_kernel = 0;
my $new_menu = 0;

$menudepth++;
debug();
print_indent "set theme=/boot/grub/theme/" . $menu{"number"} . "\n";
create_theme_file($menu{"number"});

foreach my $line(@lines) {
    if ($line =~ /^\s*menu begin\ (\S+)/) {
	$menu_number[$menudepth]++;
	$new_menu = 1;
	my $mn_string = "";
	for(my $i = 0; $i <= $menudepth ; $i++) {
	    $mn_string .= "$menu_number[$i]";
	    if ($i < $menudepth) {
		$mn_string .= "-";
	    }
	}
	$menu{"number"} = $mn_string;
	$menu{"label"} = $1;
	if ($in_kernel) {
	    print_kernel(\%kernel);
	    undef %kernel;
	    $in_kernel = 0;
	}
    } elsif ($line =~ /^\s*menu end/) {
	if ($in_kernel) {
	    print_kernel(\%kernel);
	    undef %kernel;
	    $in_kernel = 0;
	}
	$menu_number[$menudepth] = 0;
	$menudepth--;
	if ($menudepth) {
	    print_indent "}\n";
	}
	if ($menudepth > 1) {
	    $pre = "... ";
	} else {
	    $pre = "";
	}	    
    } elsif ($line =~ /^\s*menu title (.*$)/) {
	if ($in_kernel) {
	    print_kernel(\%kernel);
	    undef %kernel;
	    $in_kernel = 0;
	}
	$menu{"title"} = $1;
	if ($new_menu) {
	    my $hotkey = "";
	    if ($menu{"label"} =~ m,\^(\S),) {
		$hotkey = lc "--hotkey=$1 ";
		$menu{"label"} =~ s/\^//;
	    }
	    print_indent "submenu $hotkey'$pre" . $menu{"label"} . " ...' {\n";
	    $menu_title[$menudepth] = $menu{"title"};
	    $menudepth++;
	    if ($menudepth > 1) {
		$pre = "... ";
	    } else {
		$pre = "";
	    }	    
	    debug();
	    print_indent "set menu_color_normal=cyan/blue\n";
	    print_indent "set menu_color_highlight=white/blue\n";
	    print_indent "set theme=/boot/grub/theme/" . $menu{"number"} . "\n";
	    create_theme_file($menu{"number"});
	    $new_menu = 0;
	}
    } elsif ($line =~ /^label (\S*(rescue|install|auto|expert)\S*)/) {
	if ($in_kernel) {
	    print_kernel(\%kernel);
	    undef %kernel;
	}
	$kernel{"ref"} = $1;
	$in_kernel = 1;
    } elsif ($line =~ /menu label (.*)$/ && $in_kernel) {
	$kernel{"label"} = $1;
    } elsif ($line =~ /menu label (.*)$/) {
	$menu{"label"} = $1;
    } elsif ($line =~ /menu default/ && $in_kernel) {
	$kernel{"default"} = 1;
    } elsif ($line =~ /kernel (.*)$/ && $in_kernel) {
	$kernel{"kernel"} = $1;
    } elsif ($line =~ /append (.*)$/ && $in_kernel) {
	$kernel{"append"} = $1;
    } else {
	#print "$line\n";
    }
}
if ($in_kernel) {
    print_kernel(\%kernel);
    undef %kernel;
}