#!/usr/bin/env perl
#
# Figure out which subsystems are in use and suggest --disable-SUBSYSTEM switch
# for those not in use.
#
# Copyright (c) 2016-2024, Jani Salonen <salojan@goto10.co>
# All rights reserved.
#

use utf8;
use warnings;

#
%DEFS = (
	'engine/menu_defs.h' => 'menu',
	'engine/widget_defs.h' => 'widget'
);

%FUNC = ();
%USES = ();
%PROG = ();

# Get the main source file to be parsed later
#
binmode(STDOUT, ":utf8");

open(FILE, '<:encoding(UTF-8)', "engine/dsl_ano.h") ||
	die("Failed to open engine/dsl_ano.h: " . $!);

my @f = <FILE>;

close(FILE);

# Construct subsystem hash table from function names
#
open(FILE, '<:encoding(UTF-8)', "engine/dynload_ret.h") ||
	die("Failed to open engine/dynload_ret.h: " . $!);

my @g = <FILE>;

close(FILE);

foreach my $g (@g) {
	$g =~ s/\r|\n//g;

	next unless($g);

	if($g =~ /"\w+",.*?\/\*\s+\w+\s+\*\//) {
		my $h = $g;

		$g =~ s/^.*?"//;
		$g =~ s/".*$//;
		$h =~ s/^.*\/\*\s+//;
		$h =~ s/\s+.*$//;

		$FUNC{$g} = $h;
		$USES{$h} = 1;
	}
}

# Get disableable subsystems from configure.ac
#
open(FILE, '<:encoding(UTF-8)', "configure.ac") ||
	die("Failed to open configure.ac: " . $!);

my @h = <FILE>;

close(FILE);

foreach my $h (@h) {
	$h =~ s/\r|\n//g;

	next unless($h);

	if($h =~ /-DPROG_DISABLE_/) {
		$h =~ s/^.*-DPROG_DISABLE_//;
		$h =~ s/".*$//;

		$PROG{lc($h)} = 1;
	}
}

# Get subsystem out from to-be-disabled-hash if its _defs.h file has something useful
#
while((my $k, $v) = each %DEFS) {
	open(FILE, '<:encoding(UTF-8)', "$k") ||
		die("Failed to open " . $k . ": " . $!);

	my @t = <FILE>;

	close(FILE);

	my @c = grep(/^\/\*.*\s+items\s+processed.*\*\//, @t);

	if($c[0] && $c[0] ne "") {
		$c[0] =~ s/\r|\n//g;
		$c[0] =~ s/^\/\*\s+//;
		$c[0] =~ s/\s.*$//;

		if($c[0] != 0) {
			$USES{$v} = 0 if($USES{$v});
		}
	}
}

# Figure out which subsystems can be disabled...
#
my $k = 0;

for(my $i = 0; $i < @f; $i++) {
	$f[$i] =~ s/\r|\n//g;

	next unless($f[$i]);

	if(($k == 0 || $k == 2) && $f[$i] =~ /^static\s+struct\s+dsl_cmd_func_s\s+.*?\s+=\s+{$/) {
		$k = 1;
	}
	elsif($k == 1 && $f[$i] =~ /^};$/) {
		$k = 0;
	}
	elsif($k == 1) {
		$f[$i] =~ s/^.*?"//;
		$f[$i] =~ s/".*$//;

		$USES{$FUNC{$f[$i]}} = 0 if($FUNC{$f[$i]});

		$k = 2;
	}
}

# ...and output list of subsystems
#
my $c = 0;
my $d = 0;

while((my $k, $v) = each %USES) {
	$d++ if(($PROG{$k} && $PROG{$k} == 1) && $v == 1);
}

foreach my $k (sort { lc($a) cmp lc($b) } keys %USES) {
	if(($PROG{$k} && $PROG{$k} == 1) && $USES{$k} == 1) {
		if($c == 0) {
			print STDOUT "" .
			"According to source files, there is some unused subsystems. You may consider" . "\n" .
			"disabling those subsystems to reduce executable size. Please supply following" . "\n" .
			"options to configure script if you haven't done so yet:" . "\n\n";

		}

		print STDOUT " --disable-" . $k;

		if(($c + 1) != $d) {
			print STDOUT " \\" . "\n";
		}
		else {
			print STDOUT "\n";
		}

		$c++;
	}
}

print STDOUT "\n" if($c != 0);

exit(0);