# *** MSUB does some substitutions here ***
# *** grep for $( ***
#
# tries to work like mkdependC
#
# ToDo: strip out all the .h junk
#
($Pgm = $0) =~ s/.*\/([^\/]+)$/\1/;
$Usage  = <<EOUSAGE;
Usage: $Pgm [mkdependHS options] [-- GHC options --] srcfile1 [srcfile2 ...]

Options recognised wherever they occur (mkdependHS or GHC):

    -D<blah>	A cpp #define; usual meaning
    -i<dirs>	Add <dirs> (colon-separated) to list of directories
		to search for "import"ed modules
    -I<dir>	Add <dir> to list of directories to search for
		.h files (i.e., usual meaning)
    -syslib <blah> This program uses this GHC system library; take
		appropriate action (e.g., recognise when they are
		"import"ing a module from that library).
    -fhaskell1.[2-9] Deal with the oddities associated with a
		particular version of Haskell 1.
    -ignore <mod>

mkdependHS-specific options (not between --'s):

    -v		Be verbose.
    -v -v	Be very verbose.
    -f blah	Use "blah" as the makefile, rather than "makefile"
		or "Makefile".
    -o <osuf>	Use <osuf> as the "object file" suffix ( default: .o)
    -s <suf>	Make extra dependencies for files with
		suffix <suf><osuf>; thus, "-o .hc -s _a" will
		make dependencies both for .hc files and for _a.hc
		files.  (Useful in conjunction with NoFib "ways".)
    -x <file>   Regard <file> as "stable"; i.e., eXclude it from having
		dependencies on it.
EOUSAGE

$Status  = 0; # just used for exit() status
$Verbose = 0; # 1 => verbose, 2 => very verbose
$Dashdashes_seen = 0;

# Try to guess how to run gcc's CPP directly -------------

$OrigCpp = '$(RAWCPP)';
if ( $OrigCpp !~ /(\S+)\s+(.*)/ ) {
    $Cpp = $OrigCpp;
} else {
    $cmd  = $1;
    $rest = $2;
    if ( -x $cmd ) { # cool
	$Cpp = $OrigCpp;
    } else { # oops; try to guess
	$GccV = `gcc -v 2>&1`;
	if ( $GccV =~ /Reading specs from (.*)\/specs/ ) {
	    $Cpp = "$1/cpp $rest";
	} else {
	    die "hscpp: don't know how to run cpp: $OrigCpp\n";
	}
    }
}

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

#------------------------------------------------------------------------
# If you are adjusting paths by hand for a binary GHC distribution,
# de-commenting the line to set GLASGOW_HASKELL_ROOT should do.
# Or you can leave it as is, and set the environment variable externally.
#------------------------------------------------------------------------
# $ENV{'GLASGOW_HASKELL_ROOT'} = '/some/absolute/path/name';

if (! $ENV{'GLASGOW_HASKELL_ROOT'}) { # good -- death to environment variables
    $TopPwd	    = '$(TOP_PWD)';
    $InstLibDirGhc  = '$(INSTLIBDIR_GHC)';
    $InstDataDirGhc = '$(INSTDATADIR_GHC)';
} else {
    $TopPwd = $ENV{'GLASGOW_HASKELL_ROOT'};

    if ('$(INSTLIBDIR_GHC)' =~ /.*(\/lib\/ghc\/\d\.\d\d\/[^-]-[^-]-[^-]\/.*)/) {
	$InstLibDirGhc	= $ENV{'GLASGOW_HASKELL_ROOT'} . $1;
    } else {
	print STDERR "GLASGOW_HASKELL_ROOT environment variable is set;\nBut can't untangle $(INSTLIBDIR_GHC).\n(Installation error)\n";
	exit(1);
    }

    if ('$(INSTDATADIR_GHC)' =~ /.*(\/lib\/ghc\/\d\.\d\d\/.*)/) {
	$InstDataDirGhc	= $ENV{'GLASGOW_HASKELL_ROOT'} . $2;
    } else {
	print STDERR "GLASGOW_HASKELL_ROOT environment variable is set;\nBut can't untangle $(INSTDATADIR_GHC).\n(Installation error)\n";
	exit(1);
    }
}

$Unlit = ( $(INSTALLING) ) ? "$InstLibDirGhc/unlit"
			     : "$TopPwd/$(CURRENT_DIR)/$(GHC_UNLIT)";

$Begin_magic_str = "# DO NOT DELETE: Beginning of Haskell dependencies\n";
$End_magic_str = "# DO NOT DELETE: End of Haskell dependencies\n";
$Obj_suffix = '.o';
$ghc_version_info = int ( $(PROJECTVERSION) * 100 );

$Import_dirs = '.';
%Syslibs = ();
%LibIfaces  = (); # known prelude/syslib ifaces; read from a file
%IgnoreMe = ();

$Haskell_1 = 3; # assume Haskell 1.3. Changed by -fhaskell-1.?
$Include_dirs = '-I.';
$Makefile = '';
@Src_files = ();

&mangle_command_line_args();

# load up LibIfaces tables:
&read_MODULES('prelude', 'prelude');
foreach $lib ( @Syslibs ) {
    &read_MODULES('syslib', $lib);
}
#print STDERR "libs provide:",(keys %LibIfaces),"\n";

if ( $Status ) {
    print stderr $Usage;
    exit(1);
}

push(@Defines,
     ("-D__HASKELL1__=$Haskell_1",
      "-D__GLASGOW_HASKELL__=$ghc_version_info"));

@Import_dirs  = split(/:/,$Import_dirs);
@Include_dirs = split(/\s+/,$Include_dirs); # still has -I's in it
# NB: We keep the scalar-variable equivalents to use in error messages

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

print STDERR "CPP defines=@Defines\n" if $Verbose;
print STDERR "Import_dirs=@Import_dirs\n" if $Verbose;
print STDERR "Include_dirs=@Include_dirs\n" if $Verbose;

&preprocess_import_dirs();

@Depend_lines = ();

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 $Verbose;
    ($bf = $sf) =~ s/\.l?hs$//;
    push(@Depend_lines, "$bf$Obj_suffix $bf.hi : $sf\n");
    foreach $suff (@File_suffix) {
        push(@Depend_lines, "$bf$suff$Obj_suffix : $sf\n");
    }

    # if it's a literate file, .lhs, then we de-literatize it:
    if ( $sf !~ /\.lhs$/ ) {
	$file_to_read = $sf;
    } else {
    	$file_to_read = "$Tmp_prefix.hs";
	local($to_do) = "$Unlit $sf $file_to_read";
	&run_something($to_do, 'unlit');
    }
    &slurp_file_for_imports($file_to_read, $sf);

    if ( $sf =~ /\.lhs$/ ) {
	unlink "$Tmp_prefix.hs";
    }
}

# 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) || exit(1);
close(OMKF) || exit(1);
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(.*)/ ) {
	    $Import_dirs .= ":$1";
	} elsif ( /^-I/ ) {
	    $Include_dirs .= " $_";
	} elsif ( /^-syslib$/ ) {
	    push(@Syslibs, &grab_arg_arg($_,''));
	} elsif ( /^-fhaskell-1\.([2-9])/ ) {
	    $Haskell_1 = $1;
	} elsif ($Dashdashes_seen != 1) { # not between -- ... --
	    if ( /^-v$/ ) {
		$Verbose++;
	    } elsif ( /^-f(.*)/ ) {
		$Makefile	= &grab_arg_arg('-f',$1);
	    } elsif ( /^-o(.*)/ ) {
		$Obj_suffix	= &grab_arg_arg('-o',$1);
	    } elsif ( /^-x(.*)/ ) { 
		local($thing) = &grab_arg_arg($_,$1);
		$IgnoreMe{$thing} = 'y';
	    } elsif ( /^-s(.*)/ ) {
		local($suff)	=  &grab_arg_arg('-s',$1);
		push(@File_suffix, $suff);
	    } elsif ( /^-/ ) {
		print STDERR "$Pgm: unknown option ignored: $_\n";
		$Status++;
	    } else {
		push(@Src_files, $_);
	    }

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

sub read_MODULES {
    local($flavor,$lib) = @_;

    local($m_dir) = '';
    if ($flavor eq 'prelude') {    
	$m_dir = ( $(INSTALLING) ) ? "$InstDataDirGhc/imports" : "$TopPwd/$(CURRENT_DIR)/$(GHC_LIBSRC)";
    } else {
	$m_dir = ( $(INSTALLING) ) ? "$InstSysLibDir/$lib"     : "$TopPwd/hslibs/$lib";
    }
    local($m_file) = "$m_dir/MODULES";

    open(MFILE, "< $m_file") || die "$Pgm: can't open $m_file to read\n";
    while (<MFILE>) {
	chop;
	# strip comments and leading/trailing whitespace
	s/#.*//;
	s/^\s+//;
	s/\s+$//;
	next if /^$/; # nothing left!
	
	$LibIfaces{"$lib:$_"} = 1; # record that this library provides this iface
    }
    close(MFILE);
}

sub grab_arg_arg {
    local($option, $rest_of_arg) = @_;
    
    if ($rest_of_arg) {
	return($rest_of_arg);
    } elsif ($#ARGV >= 0) {
	local($temp) = $ARGV[0]; shift(@ARGV); 
	return($temp);
    } else {
	print STDERR "$Pgm: no argument following $option option\n";
	$Status++;
    }
}

sub preprocess_import_dirs {
    # it's probably cheaper to find out what's in all
    # the @Import_dirs before we start processing.
    local($d, $thing);
    local($_);
    %ModuleIn = ();

    foreach $d ( @Import_dirs ) {
	opendir(DIR, $d) || die "$Pgm: can't open directory $d\n";

	for ($_ = readdir(DIR); $_; $_ = readdir(DIR)) {
	    next unless /(.*)\.hi$/;
	    $thing = $1;
	    if ($ModuleIn{$thing} && $ModuleIn{$thing} ne $d) {
		print STDERR "$Pgm: warning: $thing.hi appears in both $ModuleIn{$thing} and $d!\n";
	    } else {
		$ModuleIn{$thing} = $d;
	    }
	}
	closedir(DIR); # No, don't check the error code
    }
}

sub slurp_file_for_imports {
    local($file_to_read, $orig_src_file) = @_;
    local($follow_file);

    local($last_seen_dir) = $orig_src_file;
    $last_seen_dir =~ s/\/[^\/]+$//; # strip to dir name
    $last_seen_dir = '.' if ($last_seen_dir eq $orig_src_file);

    # we mangle #include's so they will also leave something
    # behind to indicate the dependency on _them_

    print STDERR "/usr/bin/sed -e '/^# *include/{p;s/^# *include/!include/;};s/'\\''//g;s/\"//g' $file_to_read | $Cpp $Include_dirs -I$last_seen_dir @Defines |\n" if $Verbose;

    open(SRCFILE, "/usr/bin/sed -e '/^# *include/{p;s/^# *include/!include/;};s/'\\''//g;s/\"//g' $file_to_read | $Cpp $Include_dirs -I$last_seen_dir @Defines |")
	|| die "$Pgm: Can't open $file_to_read: $!\n";

    while (<SRCFILE>) {
	next unless (/^>?\s*(import)(\s+qualified)?\s+([A-Z][A-Za-z0-9_']*)/ || /^!(include)(\s+)"(\S+)"/);
	$todo    = $1;
	$modname = $3;

	if ($todo eq 'import') {
	    if ( $IgnoreMe{$modname} eq 'y' ) {
		$follow_file = '__ignore__';
	    } elsif ( $ModuleIn{$modname} ) {
		$follow_file = "$ModuleIn{$modname}/$modname.hi";
	    } else { # hard way
		$follow_file
		  = &find_in_Import_dirs($orig_src_file, $modname, $last_seen_dir);
	    }
	} else {
	    if ( $IgnoreMe{$modname} eq 'y' ) {
		$follow_file = '__ignore__';
	    } else {
		$follow_file
		  = &find_in_Include_dirs($orig_src_file, $modname, $last_seen_dir);
	    }
	}

	if (! $follow_file) { # it didnae find anything
	    die "$orig_src_file: Couldn't handle: $_\n";

	} else { # it found something
	    if ($follow_file ne '__ignore__') {
		local($int_file);
		$int_file = $follow_file;

		if ( $int_file !~ /\.(l?hs|hi)$/ ) {
		    push(@Depend_lines, "$bf$Obj_suffix : $int_file\n");
		    foreach $suff (@File_suffix) {
			push(@Depend_lines, "$bf$suff$Obj_suffix : $int_file\n");
		    }

		} else {
		    $int_file =~ s/\.l?hs$//;
		    $int_file =~ s/\.hi$//;

		    push(@Depend_lines, "$bf$Obj_suffix : $int_file.hi\n");
		    foreach $suff (@File_suffix) {
			push(@Depend_lines, "$bf$suff$Obj_suffix : $int_file$suff.hi\n");
		    }
		}
	    }
	}
    }
    close(SRCFILE) || exit(1);
}

# when we see something, we cache that fact ('y').
# also, when we get a miss, we cache that (so we don't try later); ('n')
%FileExists = ();

sub find_in_Import_dirs {
    local($orig_src_file, $modname, $last_seen_dir) = @_;
    local($import_dir);
    local($do_magical_check) = 0;
    local($name_to_check);

    # do it the old hard way: hop along Import_dir list
    foreach $import_dir (@Import_dirs) {
	# handle . magically
	if ($import_dir eq '.') {
	    # record that we should do a SPECIAL try for a file in last_seen_dir (LAST)
	    $do_magical_check = 1;
	}

	$name_to_check = "$import_dir/$modname.hi";
	if ( $FileExists{$name_to_check} ne 'n' ) { # either 'y' or nothing
	    print STDERR "trying $name_to_check...\n" if $Verbose >= 2; # very verbose
	    return($name_to_check) if $FileExists{$name_to_check} eq 'y';
	    if (-f $name_to_check) {
		$FileExists{$name_to_check} = 'y';
		return($name_to_check) ;
	    } else {
		$FileExists{$name_to_check} = 'n';
	    }
    	}

	$name_to_check = "$import_dir/$modname.hs";
	print STDERR "trying... $name_to_check\n" if $Verbose >= 2; # very verbose
	return($name_to_check) if -f $name_to_check;

	$name_to_check = "$import_dir/$modname.lhs";
	print STDERR "trying... $name_to_check\n" if $Verbose >= 2; # very verbose
	return($name_to_check) if -f $name_to_check;
    }
    if ($do_magical_check == 1) {
	$name_to_check = "$last_seen_dir/$modname.hi";

	if ( $FileExists{$name_to_check} ne 'n' ) { # either 'y' or nothing
	    print STDERR "trying $name_to_check...\n" if $Verbose >= 2; # very verbose
	    return($name_to_check) if $FileExists{$name_to_check} eq 'y';
	    if (-f $name_to_check) {
		$FileExists{$name_to_check} = 'y';
		return($name_to_check) ;
	    } else {
		$FileExists{$name_to_check} = 'n';
	    }
    	}

	$name_to_check = "$last_seen_dir/$modname.lhs";
	print STDERR "trying... $name_to_check\n" if $Verbose >= 2; # very verbose
	return($name_to_check) if -f $name_to_check;

	$name_to_check = "$last_seen_dir/$modname.hs";
	print STDERR "trying... $name_to_check\n" if $Verbose >= 2; # very verbose
	return($name_to_check) if -f $name_to_check;
    }

    # OK, maybe it's referring to something in a system library
    foreach $lib ( @Syslibs ) {
	return('__ignore__') if $LibIfaces{"$lib:$modname"};
    }

    # Last hope: referring to a Prelude interface
    return('__ignore__') if $LibIfaces{"prelude:$modname"};

    die "No file `$modname.hi', `$modname.lhs' or `$modname.hs' (reqd from file `$orig_src_file')\namong import directories:\n\t$Import_dirs\n";
}

sub find_in_Include_dirs {
    local($orig_src_file, $name, $last_seen_dir) = @_;
    local($include_dir);
    local($do_magical_check) = 0;

    # no funny name guessing here

    # hop along Include_dir list
    foreach $include_dir (@Include_dirs) {
	$include_dir =~ s/^-I//;

	# handle . magically
	if ($include_dir eq '.') {
	    # record that we should do a SPECIAL try for a file in last_seen_dir (LAST)
	    $do_magical_check = 1;
	}
	print STDERR "trying $include_dir/$name...\n" if $Verbose >= 2; # very verbose
	if (-f "$include_dir/$name") {
	    return("$include_dir/$name");
	}
    }
    if ($do_magical_check == 1) {
	print STDERR "trying $last_seen_dir/$name...\n" if $Verbose >= 2; # very verbose
	if (-f "$last_seen_dir/$name") {
	    return("$last_seen_dir/$name");
	}
    }
    die "No file `$name' (reqd from file `$orig_src_file') among include directories: $Include_dirs\n";
}

# out of the driver, actually
sub run_something {
    local($str_to_do, $tidy_name) = @_;

    print STDERR "\n$tidy_name:\n\t" if $Verbose;
    print STDERR "$str_to_do\n" if $Verbose;

    local($return_val) = system($str_to_do) >> 8;

    if ($return_val != 0) {
	local($die_msg) = "$Pgm: execution of the $tidy_name had trouble";
	$die_msg .= " (program not found)" if $return_val == 255;
	$die_msg .= " ($!)" if $Verbose && $! != 0;
	$die_msg .= "\n";
	print STDERR $die_msg;
	exit $return_val;
    }
}