#!/usr/bin/perl

my @CVT_ratios = qw(5/4 4/3 3/2 16/10 15/9 16/9);
my @known_ratios = @CVT_ratios;

my @edid_info = group_by2(
    a8 => '_header',
    a2  => 'manufacturer_name',

    v => 'product_code',
    V => 'serial_number',
    C => 'week',
    C => 'year',
    C => 'edid_version',
    C => 'edid_revision',
    a => 'video_input_definition',

    C => 'max_size_horizontal', # in cm, 0 on projectors
    C => 'max_size_vertical', # in cm, 0 on projectors
    C => 'gamma',
    a => 'feature_support',
    a10 => '_color_characteristics',
    a3  => 'established_timings',
    a16 => 'standard_timings',
    a72 => 'monitor_details',

    C => 'extension_flag',
    C => 'checksum',
);

my %subfields = (
    manufacturer_name => [ group_by2(
	1 => '',
	5 => '1',
	5 => '2',
	5 => '3',
    ) ],

    video_input_definition => [ group_by2(
	1 => 'digital',
	1 => 'separate_sync',
	1 => 'composite_sync',
	1 => 'sync_on_green',
	2 => '',
	2 => 'voltage_level',
    ) ],

    feature_support => [ group_by2(
	1 => 'DPMS_standby',
	1 => 'DPMS_suspend',
	1 => 'DPMS_active_off',        
	1 => 'rgb',

	1 => '',
        1 => 'sRGB_compliance',
	1 => 'has_preferred_timing',
        1 => 'GTF_compliance',
    ) ],

    established_timings => [ group_by2(
	1 => '720x400_70',
	1 => '720x400_88',
	1 => '640x480_60',
	1 => '640x480_67',
	1 => '640x480_72',
	1 => '640x480_75',
	1 => '800x600_56',
	1 => '800x600_60',
	1 => '800x600_72',
	1 => '800x600_75',
	1 => '832x624_75',
	1 => '1024x768_87i',
	1 => '1024x768_60',
	1 => '1024x768_70',
	1 => '1024x768_75',
	1 => '1280x1024_75',
    ) ],

    detailed_timing => [ group_by2(
	8 => 'horizontal_active',
	8 => 'horizontal_blanking',
	4 => 'horizontal_active_hi',
	4 => 'horizontal_blanking_hi',
	8 => 'vertical_active',
	8 => 'vertical_blanking',
	4 => 'vertical_active_hi',
	4 => 'vertical_blanking_hi',
	8 => 'horizontal_sync_offset',
	8 => 'horizontal_sync_pulse_width',
	4 => 'vertical_sync_offset',
	4 => 'vertical_sync_pulse_width',
	2 => 'horizontal_sync_offset_hi',
	2 => 'horizontal_sync_pulse_width_hi',
	2 => 'vertical_sync_offset_hi',
	2 => 'vertical_sync_pulse_width_hi',
	8 => 'horizontal_image_size', # in mm
	8 => 'vertical_image_size', # in mm
	4 => 'horizontal_image_size_hi',
	4 => 'vertical_image_size_hi',
	8 => 'horizontal_border',
	8 => 'vertical_border',

	1 => 'interlaced',
	2 => 'stereo',      
	2 => 'digital_composite',
	1 => 'horizontal_sync_positive',
	1 => 'vertical_sync_positive',
	1 => '',
    ) ],

    standard_timing => [ group_by2(
	8 => 'X',
	2 => 'aspect',
	6 => 'vfreq',
    ) ],
    monitor_range => [ group_by2(
	8 => 'vertical_min',
	8 => 'vertical_max',
	8 => 'horizontal_min',
	8 => 'horizontal_max',
	8 => 'pixel_clock_max',
    ) ],

    manufacturer_specified_range_timing => [ group_by2(
	# http://www.spwg.org/salisbury_march_19_2002.pdf
	# for the glossary: http://www.vesa.org/Public/PSWG/PSWG15v1.pdf
	8 => 'horizontal_sync_pulse_width_min', # HSPW (Horizontal Sync Pulse Width)
	8 => 'horizontal_sync_pulse_width_max',
	8 => 'horizontal_back_porch_min', # t_hbp
	8 => 'horizontal_back_porch_max',
	8 => 'vertical_sync_pulse_width_min', # VSPW (Vertical Sync Pulse Width)
	8 => 'vertical_sync_pulse_width_max',
	8 => 'vertical_back_porch_min', # t_vbp (Vertical Back Porch)
	8 => 'vertical_back_porch_max',
	8 => 'horizontal_blanking_min', # t_hp (Horizontal Period)
	8 => 'horizontal_blanking_max',
	8 => 'vertical_blanking_min', # t_vp
	8 => 'vertical_blanking_max',
	8 => 'module_revision',
    ) ],
);

sub get_many_bits {
    my ($s, $field_name) = @_;
    my @bits = split('', unpack('B*', $s));
    my %h;
    foreach (@{$subfields{$field_name}}) {
	my ($size, $field) = @$_;
	my @l = ('0' x (8 - $size), splice(@bits, 0, $size));
	$h{$field} = unpack("C", pack('B*', join('', @l))) if $field && $field !~ /^_/;
    }
    \%h;
}

sub check_parsed_edid {
    my ($edid) = @_;

    $edid->{manufacturer_name} ne '@@@' or return 'bad manufacturer_name';
    $edid->{edid_version} != 0xff && $edid->{edid_revision} != 0xff or return 'bad edid_version';

    if ($edid->{monitor_range}) {
	$edid->{monitor_range}{horizontal_min} && 
	  $edid->{monitor_range}{horizontal_min} <= $edid->{monitor_range}{horizontal_max} 
	    or return 'bad HorizSync';
	$edid->{monitor_range}{vertical_min} &&
	  $edid->{monitor_range}{vertical_min} <= $edid->{monitor_range}{vertical_max} 
	    or return 'bad VertRefresh';
    }

    '';
}

sub parse_edid {
    my ($raw_edid, $verbose) = @_;

    my %edid;
    my @vals = unpack(join('', map { $_->[0] } @edid_info), $raw_edid);
    my $i;
    foreach (@edid_info) {
	my ($field, $v) = ($_->[1], $vals[$i++]);

	if ($field eq 'year') {
	    $v += 1990;
	} elsif ($field eq 'manufacturer_name') {
	    my $h = get_many_bits($v, 'manufacturer_name');
	    $v = join('', map { chr(ord('A') + $h->{$_} - 1) } 1 .. 3);
	} elsif ($field eq 'video_input_definition') {
	    $v = get_many_bits($v, 'video_input_definition');
	} elsif ($field eq 'feature_support') {
	    $v = get_many_bits($v, 'feature_support');
	} elsif ($field eq 'established_timings') {
	    my $h = get_many_bits($v, 'established_timings');
	    $v = [
		sort { $a->{X} <=> $b->{X} || $a->{vfreq} <=> $b->{vfreq} }
		map { /(\d+)x(\d+)_(\d+)(i?)/ ? { X => $1, Y => $2, vfreq => $3, $4 ? (interlace => 1) : () } : () }
		grep { $h->{$_} } keys %$h ];
	} elsif ($field eq 'standard_timings') {
	    my @aspect2ratio = (
		$edid{edid_version} > 1 || $edid{edid_revision} > 2 ? '16/10' : '1/1',
		'4/3', '5/4', '16/9',
	    );
	    $v = [ map {
		my $h = get_many_bits($_, 'standard_timing');
		$h->{X} = ($h->{X} + 31) * 8;
		if ($_ ne "\x20\x20" && $h->{X} > 256) { # cf VALID_TIMING in Xorg edid.h
		    $h->{vfreq} += 60;
		    if ($h->{ratio} = $aspect2ratio[$h->{aspect}]) {
			delete $h->{aspect};
			$h->{Y} = $h->{X} / eval($h->{ratio});
		    }
		    $h;
		} else { () }
	    } unpack('a2' x 8, $v) ];
	} elsif ($field eq 'monitor_details') {
	    while ($v) {
		(my $pixel_clock, my $vv, $v) = unpack("v a16 a*", $v);

		if ($pixel_clock) {
		    # detailed timing
		    my $h = get_many_bits($vv, 'detailed_timing');
		    $h->{pixel_clock} = $pixel_clock / 100; # to have it in MHz

		    my %detailed_timing_field_size = map { $_->[1], $_->[0] } @{$subfields{detailed_timing}};
		    foreach my $field (keys %detailed_timing_field_size) {
			$field =~ s/_hi$// or next;
			my $hi = delete($h->{$field . '_hi'});
			$h->{$field} += $hi << $detailed_timing_field_size{$field};
		    }
		    push @{$edid{detailed_timings}}, $h
		      if $h->{horizontal_active} > 0 && $h->{vertical_active} > 0;
		} else {
		    (my $flag, $vv) = unpack("n x a*", $vv);

		    if ($flag == 0xfd) {
			# range
			$edid{monitor_range} = get_many_bits($vv, 'monitor_range');
			if ($edid{monitor_range}{pixel_clock_max} == 0xff) {
			    delete $edid{monitor_range}{pixel_clock_max};
			} else {
			    $edid{monitor_range}{pixel_clock_max} *= 10; #- to have it in MHz
			}
		    } elsif ($flag == 0xf) {
			my $range = get_many_bits($vv, 'manufacturer_specified_range_timing');

			my $e = $edid{detailed_timings}[0];
			my $valid = 1;
			foreach my $m ('min', 'max') {
			    my %total;
			    foreach my $dir ('horizontal', 'vertical') {
				$range->{$dir . '_sync_pulse_width_' . $m} *= 2;
				$range->{$dir . '_back_porch_' . $m} *= 2;
				$range->{$dir . '_blanking_' . $m} *= 2;
				if ($e && $e->{$dir . '_active'}) {
				    $total{$dir} = $e->{$dir . '_active'} + $range->{$dir . '_blanking_' . $m};
				}
			    }
			    if ($total{horizontal} && $total{vertical}) {
				my $hfreq = $e->{pixel_clock} * 1000 / $total{horizontal};
				my $vfreq = $hfreq * 1000 / $total{vertical};
				$range->{'horizontal_' . ($m eq 'min' ? 'max' : 'min')} = round($hfreq);
				$range->{'vertical_' . ($m eq 'min' ? 'max' : 'min')} = round($vfreq);
			    } else {
				$valid = 0;
			    }
			}
			$edid{$valid ? 'monitor_range' : 'manufacturer_specified_range_timing'} = $range;

		    } elsif ($flag == 0xfc) {
			my $prev = $edid{monitor_name};
			$edid{monitor_name} = ($prev ? "$prev " : '') . unpack('A13', $vv);
		    } elsif ($flag == 0xfe) {
			push @{$edid{monitor_text}}, unpack('A13', $vv);
		    } elsif ($flag == 0xff) {
			push @{$edid{serial_number2}}, unpack('A13', $vv);
		    } else {
		       $verbose && $vv ne "\0" x 13 && $vv ne " " x 13 and
			 warn "parse_edid: unknown flag $flag\n";
		    }
		}
	    }
	}

	$edid{$field} = $v if $field && $field !~ /^_/;
    }

    $edid{max_size_precision} = 'cm';
    $edid{EISA_ID} = $edid{manufacturer_name} . sprintf('%04x', $edid{product_code}) if $edid{product_code};

    if ($edid{monitor_range}) {
	$edid{HorizSync} = $edid{monitor_range}{horizontal_min} . '-' . $edid{monitor_range}{horizontal_max};
	$edid{VertRefresh} = $edid{monitor_range}{vertical_min} . '-' . $edid{monitor_range}{vertical_max};
    }

    if ($edid{max_size_vertical}) {
	$edid{ratio} = $edid{max_size_horizontal} / $edid{max_size_vertical};
	$edid{ratio_name} = ratio_name($edid{max_size_horizontal}, $edid{max_size_vertical}, 'cm');
	$edid{ratio_precision} = 'cm';
    }

    foreach my $h (@{$edid{detailed_timings}}) {

	# if the mm size given in the detailed_timing is not far from the cm size
	# put it as a more precise cm size
	my %in_cm = map { $_ => $h->{$_ . '_image_size'} / 10 } ('horizontal', 'vertical');
	my ($error) = sort { $b <=> $a } map { abs($edid{'max_size_' . $_} - $in_cm{$_}) } keys %in_cm;
	if ($error <= 0.5) {
	    $edid{'max_size_' . $_} = $in_cm{$_} foreach keys %in_cm;
	    $edid{max_size_precision} = 'mm';
	}
	if ($error < 1 && $in_cm{vertical}) {
	    # using it for the ratio
	    $edid{ratio} = $in_cm{horizontal} / $in_cm{vertical};
	    $edid{ratio_name} = ratio_name($in_cm{horizontal}, $in_cm{vertical}, 'mm');
	    $edid{ratio_precision} = 'mm';
	}

	$h->{bad_ratio} = 1 if abs($edid{ratio} - $h->{horizontal_active} / $h->{vertical_active}) > ($edid{ratio_precision} eq 'mm' ? 0.02 : 0.2);

	if ($edid{max_size_vertical}) {
	    $h->{vertical_dpi} = $h->{vertical_active} / $edid{max_size_vertical} * 2.54;
	}
	if ($edid{max_size_horizontal}) {
	    $h->{horizontal_dpi} = $h->{horizontal_active} / $edid{max_size_horizontal} * 2.54;
	}
	my $dpi_string = '';
	if ($h->{vertical_dpi} && $h->{horizontal_dpi}) {
	    $dpi_string = 
	      abs($h->{vertical_dpi} / $h->{horizontal_dpi} - 1) < 0.05 ? 
		sprintf("%d dpi", $h->{horizontal_dpi}) :
		sprintf("%dx%d dpi", $h->{horizontal_dpi}, $h->{vertical_dpi});
	}

	my $horizontal_total = $h->{horizontal_active} + $h->{horizontal_blanking};
	my $vertical_total = $h->{vertical_active} + $h->{vertical_blanking};

	$h->{ModeLine_comment} = sprintf qq(# Monitor preferred modeline (%.1f Hz vsync, %.1f kHz hsync, ratio %s%s)),
	  $h->{pixel_clock} / $horizontal_total / $vertical_total * 1000 * 1000,
	  $h->{pixel_clock} / $horizontal_total * 1000,
	  nearest_ratio($h->{horizontal_active} / $h->{vertical_active}, 0.01) || sprintf("%.2f", $h->{horizontal_active} / $h->{vertical_active}),
	  $dpi_string ? ", $dpi_string" : '';
	  
	$h->{ModeLine} = sprintf qq("%dx%d" $h->{pixel_clock} %d %d %d %d %d %d %d %d %shsync %svsync),
	  $h->{horizontal_active}, $h->{vertical_active},

	  $h->{horizontal_active},
	  $h->{horizontal_active} + $h->{horizontal_sync_offset}, 
	  $h->{horizontal_active} + $h->{horizontal_sync_offset} + $h->{horizontal_sync_pulse_width},
	  $horizontal_total,

	  $h->{vertical_active},
	  $h->{vertical_active} + $h->{vertical_sync_offset}, 
	  $h->{vertical_active} + $h->{vertical_sync_offset} + $h->{vertical_sync_pulse_width},
	  $vertical_total,

	  $h->{horizontal_sync_positive} ? '+' : '-',
	  $h->{vertical_sync_positive} ? '+' : '-';
    }

    $edid{diagonal_size} = sqrt(sqr($edid{max_size_horizontal}) + 
				sqr($edid{max_size_vertical})) / 2.54;

    \%edid;
}

sub nearest_ratio {
    my ($ratio, $max_error) = @_;
    my @sorted = 
      sort { $a->[1] <=> $b->[1] }
	map { 
	    my $error = abs($ratio - eval($_));
	    $error > $max_error ? () : [ $_, $error ];
	} @known_ratios;
    $sorted[0][0];
}

sub ratio_name {
    my ($horizontal, $vertical, $precision) = @_;
    
    if ($precision eq 'mm') {
	nearest_ratio($horizontal / $vertical, 0.1);
    } else {
	my $error = 0.5;
	my $ratio1 = nearest_ratio(($horizontal + $error) / ($vertical - $error), 0.2);
	my $ratio2 = nearest_ratio(($horizontal - $error) / ($vertical + $error), 0.2);
	$ratio1 && $ratio2 or return;
	if ($ratio1 eq $ratio2) {
	    $ratio1;
	} else {
	    my $ratio = nearest_ratio($horizontal / $vertical, 0.2);
	    join(' or ', $ratio, $ratio eq $ratio1 ? $ratio2 : $ratio1);
	}
    }
}

sub to_MonitorsDB {
    my ($edid) = @_;

    $edid->{monitor_range} && $edid->{EISA_ID} or return;

    my $detailed_timings = $edid->{detailed_timings} || [];
    my @preferred_resolutions = map { 
	join('x', $_->{horizontal_active}, $_->{vertical_active});
    } grep { !$_->{bad_ratio} } @$detailed_timings;

    (my $monitor_name = $edid->{monitor_name}) =~ s/;/,/g;
    my ($raw_vendor, $raw_model) = $edid->{EISA_ID} =~ /(...)(.*)/;
    my ($VendorName, $only_Model) =
      $monitor_name =~ /(\S+)\s(.*)/ ? 
	($1, $2) :
	($raw_vendor, $monitor_name || $raw_model);

    join('; ', 
	 $VendorName, "$VendorName $only_Model", $edid->{EISA_ID},
	 sprintf("%u-%u", $edid->{monitor_range}{horizontal_min}, $edid->{monitor_range}{horizontal_max}),
	 sprintf("%u-%u", $edid->{monitor_range}{vertical_min}, $edid->{monitor_range}{vertical_max}),
	 @$detailed_timings == 1 ? @preferred_resolutions : (),
     );
}

sub print_edid {
    my ($edid, $verbose) = @_;

    print "Name: $edid->{monitor_name}\n" if $edid->{monitor_name};
    print "EISA ID: $edid->{EISA_ID}\n" if $edid->{EISA_ID};
    printf "Screen size: %.1f cm x %.1f cm (%3.2f inches%s)\n",
      $edid->{max_size_horizontal},
      $edid->{max_size_vertical},
      $edid->{diagonal_size},
      $edid->{ratio_name} ? sprintf(", aspect ratio %s = %.2f", $edid->{ratio_name}, $edid->{ratio}) :
	$edid->{ratio} ? sprintf(", aspect ratio %.2f", $edid->{ratio}) : '';
    
    print "Gamma: ", $edid->{gamma} / 100 + 1, "\n";
    printf "%s signal\n", $edid->{video_input_definition}{digital} ? 'Digital' : 'Analog';

    if ($verbose) {
	foreach (@{$edid->{established_timings} || []}) {
	    print "Standard resolution: $_->{X}x$_->{Y} @ $_->{vfreq} Hz (established timing)\n" if !$_->{interlace};
	}
	foreach (@{$edid->{standard_timings} || []}) {
	    print "Standard resolution: $_->{X}x$_->{Y} @ $_->{vfreq} Hz, ratio $_->{ratio}",
	      $edid->{ratio_name} && index($edid->{ratio_name}, $_->{ratio}) == -1 ? ' (!)' : '',
	      "\n";
	}
    }

    if ($edid->{monitor_range}) {
	printf "Max video bandwidth: %u MHz\n", $edid->{monitor_range}{pixel_clock_max} if $edid->{monitor_range}{pixel_clock_max};
	print "\n";
	printf "\tHorizSync %u-%u\n", $edid->{monitor_range}{horizontal_min}, $edid->{monitor_range}{horizontal_max};
	printf "\tVertRefresh %u-%u\n", $edid->{monitor_range}{vertical_min}, $edid->{monitor_range}{vertical_max};
    }

    foreach my $h (@{$edid->{detailed_timings}}) {
	print "\n";
	print "\t", $h->{ModeLine_comment}, $h->{bad_ratio} ? ' (bad ratio)' : '', "\n";
	print "\tModeLine ", $h->{ModeLine}, "\n";	
    }
}

sub usage() {
    die "usage: monitor-parse-edid [-v] [--perl] [<edid file>]\n";
}

use Getopt::Long;
GetOptions(
    'v' => \ (my $verbose),
    'perl' => \ (my $raw_perl),
    'MonitorsDB' => \ (my $MonitorsDB),
) or usage();

my ($file, $F);
if (@ARGV == 0) {
    $F = *STDIN;
} elsif (@ARGV == 1) {
    open($F, $file = $ARGV[0]) or usage();
} else {
    usage();
}

my $raw_edid = join('', <$F>);

sub error {
    my ($msg) = @_;
    print STDERR ($file ? "$file: " : ''), $msg, "\n";
    exit 1;
}

length($raw_edid) == 128 || length($raw_edid) == 256 or error("bad edid");

my $edid = parse_edid($raw_edid, $verbose);
if (my $err = check_parsed_edid($edid)) {
    die "$err\n";
}
$edid->{file} = $file if $file;

if ($raw_perl) {
    use Data::Dumper;
    $Data::Dumper::Sortkeys = 1;
    my $s = Dumper($edid);
    $s =~ s/.*? = {/+{/; # remove variable name we don't want
    $s =~ s/};$/}/m;
    print $s;
} elsif ($MonitorsDB) {
    my $s = to_MonitorsDB($edid);
    print "$s\n" if $s;
} else {
    print_edid($edid, $verbose);
}


sub sqr { $_[0] * $_[0] }
sub round { int($_[0] + 0.5) }
sub group_by2 {
    my @l;
    for (my $i = 0; $i < @_; $i += 2) {
	push @l, [ $_[$i], $_[$i+1] ];
    }
    @l;
}