#
# This stub of perl assumes that the following two
# variables are prepended:
#
# TMPDIR CPP
#
# ToDo: strip out all the .h junk
#
($Pgm = $0) =~ s/.*\/([^\/]+)$/\1/;
$Usage  = "usage: $Pgm: not done yet\n";

$Status  = 0; # just used for exit() status
$Verbose = 0;
$Dashdashes_seen = 0;

$Begin_magic_str = "# DO NOT DELETE: Beginning of C dependencies\n";
$End_magic_str = "# DO NOT DELETE: End of C dependencies\n";
$Obj_suffix = '.o';
@Defines = ();
$Include_dirs = '';
$Makefile = '';
@Src_files = ();

if ( $ENV{'TMPDIR'} ) { # where to make tmp file names
    $Tmp_prefix = $ENV{'TMPDIR'} . "/mkdependC$$";
} else {
    $Tmp_prefix ="${TMPDIR}/mkdependC$$";
    $ENV{'TMPDIR'} = "${TMPDIR}"; # set the env var as well
}

$tempfile = '';

sub quit_upon_signal { 
  if (-f $tempfile) {
	print STDERR "Deleting $tempfile .. \n"; 
	unlink $tempfile;
   }
}
$SIG{'INT'}  = 'quit_upon_signal';
$SIG{'QUIT'} = 'quit_upon_signal';

&mangle_command_line_args();

if ( ! $Makefile && -f 'makefile' ) {
    $Makefile = 'makefile';
} elsif ( ! $Makefile && -f 'Makefile') {
    $Makefile = 'Makefile';
} elsif ( ! $Makefile) {
    die "$Pgm: no makefile or Makefile found\n";
}

@Depend_lines = ();
%Depend_seen = ();

print STDERR "Include_dirs=$Include_dirs\n" if $Verbose;

foreach $sf (@Src_files) {
    # just like lit-inputter
    # except it puts each file through CPP and
    # a de-commenter (not implemented);
    # builds up @Depend_lines
    print STDERR "Here we go for source file: $sf\n" if $Verbose;
    ($of = $sf) =~ s/\.(c|hc)$/$Obj_suffix/;

    &slurp_file($sf, 'fh00');
}

# OK, mangle the Makefile
unlink("$Makefile.bak");
rename($Makefile,"$Makefile.bak");
# now copy Makefile.bak into Makefile, rm'ing old dependencies
# and adding the new
open(OMKF,"< $Makefile.bak") || die "$Pgm: can't open $Makefile.bak: $!\n";
open(NMKF,"> $Makefile") || die "$Pgm: can't open $Makefile: $!\n";
select(NMKF);
$_ = <OMKF>;
while ($_ && $_ ne $Begin_magic_str) { # copy through, 'til Begin_magic_str
    print $_;
    $_ = <OMKF>;
}
while ($_ && $_ ne $End_magic_str) { # delete 'til End_magic_str
    $_ = <OMKF>;
}
# insert dependencies
print $Begin_magic_str;
print @Depend_lines;
print $End_magic_str;
while (<OMKF>) { # copy the rest through
    print $_;
}
close(NMKF);
close(OMKF);
exit 0;

sub mangle_command_line_args {
    while($_ = $ARGV[0]) {
	shift(@ARGV);

	if ( /^--$/ ) {
	    $Dashdashes_seen++;

	} elsif ( /^-D(.*)/ ) { # recognized wherever they occur
	    push(@Defines, $_);
	} elsif ( /^-I/ ) {
	    $Include_dirs .= " $_";

	} elsif ($Dashdashes_seen != 1) { # not between -- ... --
	    if ( /^-v$/ ) {
		$Verbose++;
	    } elsif ( /^-f/ ) {
		$Makefile	= &grab_arg_arg($_);
	    } elsif ( /^-o/ ) {
		$Obj_suffix	= &grab_arg_arg($_);
	    } elsif ( /^-bs/ ) {
		$Begin_magic_str = &grab_arg_arg($_) . "\n";
	    } elsif ( /^-es/ ) {
		$End_magic_str = &grab_arg_arg($_) . "\n";
	    } elsif ( /^-w/ ) {
		$Width	= &grab_arg_arg($_);
	    } elsif ( /^-/ ) {
		print STDERR "$Pgm: unknown option ignored: $_\n";
	    } else {
		push(@Src_files, $_);
	    }

	} elsif ($Dashdashes_seen == 1) { # where we ignore unknown options
	    push(@Src_files,$_) if ! /^-/;
	}
    }
}

sub grab_arg_arg {
    local($option) = @_;
    local($rest_of_arg);
    
    ($rest_of_arg = $option) =~ s/^-.//;

    if ($rest_of_arg) {
	return($rest_of_arg);
    } elsif ($#ARGV >= 0) {
	local($temp) = $ARGV[0]; shift(@ARGV); 
	return($temp);
    } else {
	die "$Pgm: no argument following $option option\n";
    }
}

sub slurp_file { # follows an example in the `open' item in perl man page
    local($fname,$fhandle) = @_;
    local($depend); # tmp
    $fhandle++; # a string increment

    $fname = &tidy_dir_names($fname);

    $tempfile = "$Tmp_prefix.i";

    # ${CPP} better be 'gcc -E', or the -x option will fail...
    $result = system("${CPP} $Include_dirs @Defines -x c $fname -o $tempfile");
    if ($result != 0) {
	unlink($tempfile);
	exit($result);
    };

    open($fhandle, $tempfile) || die "$Pgm: Can't open $tempfile: $!\n";

    line: while (<$fhandle>) {
	next line if ! /^#/;
	next line if /^#(ident|pragma)/;
	chop; # rm trailing newline

	$_ = &tidy_dir_names($_);

	# strip junk off the front and back
	$_ =~ s/^#\s+\d+\s+//;
	$_ =~ s/[ 0-9]*$//;
	
	# a little bit of ad-hoc fiddling now:
	# don't bother w/ dependencies on /usr/include stuff
	# don't bother if it looks like a GCC built-in hdr file
	# don't bother with funny yacc-ish files
    	# don't bother with "literate" .h files (.lh); we'll just
	# depend on the de-litified versions (which have better info)
	# don't let a file depend on itself
	next line if /^\/usr\/include/;
	# Hack - the cygwin32 dir structure is odd!
	next line if /H-i386-cygwin32\/i386-cygwin32/;
	next line if /H-i386-cygwin32\/lib\/gcc-lib\/i386-cygwin32/;
	next line if /\/gcc-lib\/[^\/\n]+\/[\.0-9]+\/include\//;
	next line if /\/gnu\/[^-\/]+-[^-\/]+-[^-\/]+\/include\//;
	next line if /\/yaccpar/;
    	next line if /\/bison\.(simple|hairy)/;
	next line if /\.lh$/;
	next line if $_ eq $fname;

	print STDERR "$fname :: $_\n" if $Verbose;

	# ToDo: some sanity checks that we still have something reasonable?

	$depend = "$of : $_\n";
	next line if $Depend_seen{$depend};  # already seen this one...

	# OK, it's a new one.
	push (@Depend_lines, $depend);
	$Depend_seen{$depend} = 1;
    }
    close($fhandle);
    unlink($tempfile);
    $tempfile = '';  # for quit_upon_signal
}

sub tidy_dir_names { # rm various pernicious dir-name combinations...
    local($str) = @_;

    $str =~ s|/[^/.][^/]*/\.\.||g;	# nuke: /<dir>/..
    $str =~ s|/\.[^.][^/]*/\.\.||g;	# nuke: /./.. (and others)
    $str =~ s|"||g;
    $str =~ s| \./| |;
    $str;
}