#!/usr/bin/perl

use English;
use Getopt::Declare; 

######################
# ARGUMENT PROCESSING
######################

#$inFilename = $ARGV[0];

use vars qw ($inFilename $POSTSCRIPT_OUTPUT $PDF_OUTPUT $ALLOW_EMBEDDED_CODE);

#test4


$argSpecification = q(
		      -ps	              Create a postscript output file (by calling latex, and then dvips)
		      {$POSTSCRIPT_OUTPUT = 1;} 

		      -pdf	              Create a pdf output file (by calling latex, and then dvipdf)
		      {$PDF_OUTPUT = 1;}

		      -e		 Allow execution of embedded code (advanced feature)
		      {$ALLOW_EMBEDDED_CODE = 1;}

		      <input>	     The input file
		      {$inFilename = $input;}
		      );



$args = new Getopt::Declare($argSpecification);

#print "ARG: $inFilename\n $j\nPO: $POSTSCRIPT_OUTPUT, PDF: $PDF_OUTPUT";


######################
# DEFINE GLOBAL CONSTANTS
######################

use vars qw($EASYLATEX_DIR, @TRANSFORM_PATHS, $PS_OUTPUT_COMMANDS, $PDF_OUTPUT_COMMANDS, $outFilename, $stripFilename);

# doing both ways; todo; clean up global var declr

$PS_OUTPUT_COMMANDS = <<'EOF' ;
system('latex',$outFilename);
system('dvips',"${stripFilename}.dvi", "-o${stripFilename}.ps");
EOF

$PDF_OUTPUT_COMMANDS = <<'EOF' ;
system('latex',$outFilename);
system('dvipdf',"${stripFilename}.dvi");
EOF



######################
# MAIN
######################

init();

$in = readFile($inFilename);
$stripFilename = stripFilename($inFilename); 
$outFilename = $stripFilename . '.tex';

### preprocess the file: if it doesn't end with a newline, add one
if (substr($in,-1) ne "\n") {$in = $in . "\n";}

## first, make a copy of the input
open(OUT, '>'.$outFilename);
print OUT $in;
close(OUT);

## now, run the transforms on it
foreach $transform (@TRANSFORM_PATHS) {
    system("$transform", "$outFilename", "$EASYLATEX_DIR");
#    print "\n\nJUST DID $transform\n\n";
#    system('cat', "$outFilename");
}

## do post-processing if requested
postProcess();


######################
# end of MAIN
######################



sub init
{
    findEasylatexDir();
    initListOfTransforms();
}

sub postProcess {
    if ($POSTSCRIPT_OUTPUT)
    {
	eval $PS_OUTPUT_COMMANDS;
    }

    if ($PDF_OUTPUT)
    {
	eval $PDF_OUTPUT_COMMANDS;
    }
}


###########################################################################
# findEasylatexDir
#   looks through a searchpath for the easylatex directory.
#   die if it can't find it.
###########################################################################
sub findEasylatexDir {
   my @easylatex_dir_searchpath;

    push(@easylatex_dir_searchpath,"$ENV{HOME}/.easylatex");
    push(@easylatex_dir_searchpath,'/usr/lib/easylatex');

    $EASYLATEX_DIR = '';
    foreach $path (@easylatex_dir_searchpath)
    {
	if (( -e $path && -d $path)) {
	    $EASYLATEX_DIR = $path;
	}
    }

    errorCheckEasylatexDir();
}

####################################################
# errorCheckEasylatexDir
#    if the easylatex or the transform directories
#    don't exist or aren't directories, then die
####################################################
sub errorCheckEasylatexDir {    
    if (! $EASYLATEX_DIR)
    {
	die "Can't find easylatex directory. The program probably isn't installed correctly; please see documentation. Aborting (looked for the directory in " . join(', ', @easylatex_dir_searchpath) . ")";
	
    }
    
    if (! ( -e "$EASYLATEX_DIR/transforms" && -d "$EASYLATEX_DIR/transforms"))
    {
	die "I found the easylatex directory at $EASYLATEX_DIR, but didn't find the directory $EASYLATEX_DIR/transforms. The program probably isn't installed correctly; please see documentation. Aborting.";
	
    }

# TODO: add to docs
}

###########################################################################
# initListOfTransforms
#   makes a list of the paths of the transforms to run
#     (1) lists the files in the transform directory,
#     (2) filters out files starting with '.' or '#' or ending with '~',
#     (3) sorts the resulting list,
#     (4) prepends the path to each file,
#     (5) leaves the result in the global variable @TRANSFORM_PATHS
###########################################################################
sub initListOfTransforms {

    my %fullPath;

##### list the files in the transform directory
    opendir(TRANSFORMDIR, "$EASYLATEX_DIR/transforms") || die "can't opendir $EASYLATEX_DIR/transforms. The program probably isn't installed correctly; please see documentation. Aborting.";
    @TRANSFORM_PATHS = readdir(TRANSFORMDIR);
    closedir(TRANSFORMDIR);

#### remember the path
    foreach $path  (@TRANSFORM_PATHS)
    {
	$fullPath{$path} = "$EASYLATEX_DIR/transforms/"  . $path;
    }


##### if allowed, add the embedded code transforms
    if ($ALLOW_EMBEDDED_CODE) {
	opendir(EMBEDDED_CODE_TRANSFORMDIR,"$EASYLATEX_DIR/embed_transforms");
	@EMBEDDED_CODE_TRANSFORM_PATHS = readdir(EMBEDDED_CODE_TRANSFORMDIR);
	closedir(EMBEDDED_CODE_TRANSFORMDIR);

	foreach $path  (@EMBEDDED_CODE_TRANSFORM_PATHS)
	{
	    $fullPath{$path} = "$EASYLATEX_DIR/embed_transforms/"  . $path;
	}

	push(@TRANSFORM_PATHS, @EMBEDDED_CODE_TRANSFORM_PATHS); 
	# add this to the @TRANSFORM_PATHS list
}



##### filter
    @TRANSFORM_PATHS = grep(!/^\./,@TRANSFORM_PATHS);
    @TRANSFORM_PATHS = grep(!/^\#/,@TRANSFORM_PATHS);
    @TRANSFORM_PATHS = grep(!/~$/,@TRANSFORM_PATHS);
    @TRANSFORM_PATHS = grep(!/math_mode_symbol_list.txt/,@TRANSFORM_PATHS);
    @TRANSFORM_PATHS = grep(!/config.txt/,@TRANSFORM_PATHS);

#### sort
    @TRANSFORM_PATHS = sort(@TRANSFORM_PATHS);


#### prepend the path
    foreach $path  (@TRANSFORM_PATHS)
    {
	$path = $fullPath{$path};
    }


#    use Data::Dumper; print Dumper(@TRANSFORM_PATHS);



}

######################
# UTILITY SUBROUTINES
######################

######################
# string readFile($fileName)
#   reads in and returns the contents of file $fileName
######################

sub readFile {
    my ($fileName) = @_;
    my $file;

    local undef $INPUT_RECORD_SEPARATOR;
    open(INFILE, $fileName);
    $file = <INFILE>;
    close INFILE;

    return $file;
}

######################
# string calculateOutFilename($inFilename)
######################

sub stripFilepath {
        my ($inFilename) = @_;
	my $stripFilepath;

	$stripFilename = $inFilename;
	
	$stripFilename =~ s/.txt//;

	return $stripFilepath;
	
}


sub stripFilename {
        my ($inFilename) = @_;
	my $stripFilename;

	$stripFilename = $inFilename;
	
	$stripFilename =~ s/.txt//;
	
	$stripFilename =~ s/.*\///;

	return $stripFilename;
	
}