#!/usr/bin/perl -w

#
# asfmt.pl
#
# Simple 65C02 assembler source formatter.
#
# 20181219 LSH
#

use strict;

sub usage {
  print "Usage:\n";
  print "$0 [-h] <input_file>\n";
  print " -h : This help\n";
}

# Process command line arguments.
while (defined $ARGV[0] && $ARGV[0] =~ /^-/) {
  # Help.
  if ($ARGV[0] eq '-h') {
    usage();
    exit;
  } else {
    die "Invalid argument $ARGV[0]\n";
  }
}

my $input_file = shift;

die "Must supply input filename\n" unless defined $input_file && $input_file;

sub parse_line {
  my ($line, $lineno) = @_;

  my ($label, $mnemonic, $operand, $comment) = ('', '', '', '');
  if ($line =~ /^(\S+)\s+(\S+)\s+(\S+)\s+(;.*)$/) {
    $label = $1;
    $mnemonic = $2;
    $operand = $3;
    $comment = $4;
  } elsif ($line =~ /^(\S+)\s+(\S+)\s+(\S+)\s*$/) {
    $label = $1;
    $mnemonic = $2;
    $operand = $3;
    $comment = '';
  } elsif ($line =~ /^\s+(\S+)\s+(\S+)\s+(;.*)$/) {
    $label = '';
    $mnemonic = $1;
    $operand = $2;
    $comment = $3;
  } elsif ($line =~ /^\s+(\S+)\s+(\S+)\s*$/) {
    $label = '';
    $mnemonic = $1;
    $operand = $2;
    $comment = '';
  } elsif ($line =~ /^\s+(\S+)\s+(;.*)$/) {
    $label = '';
    $mnemonic = $1;
    $operand = '';
    $comment = $2;
  } elsif ($line =~ /^\s+(\S+)\s*$/) {
    $label = '';
    $mnemonic = $1;
    $operand = '';
    $comment = '';
  } elsif ($line =~ /^(\S+)\s*$/) {
    $label = $1;
    $mnemonic = '';
    $operand = '';
    $comment = '';
  } elsif ($line =~ /^(\S+)\s+(\S+)\s*$/) {
    $label = $1;
    $mnemonic = $2;
    $operand = '';
    $comment = '';
  } elsif ($line =~ /^\s+(\S+)\s+(;.*)$/) {
    $label = '';
    $mnemonic = $1;
    $operand = '';
    $comment = $2;
  } elsif ($line =~ /^(\S+)\s+(\S+)\s+(;.*)$/) {
    $label = $1;
    $mnemonic = $2;
    $operand = '';
    $comment = $3;
  } elsif ($line =~ /^(\S+)\s+([Aa][Ss][Cc])\s+(".+")\s+(;.*)$/) {
    $label = $1;
    $mnemonic = $2;
    $operand = $3;
    $comment = $4;
  } elsif ($line =~ /^\s+([Aa][Ss][Cc])\s+(".+")\s+(;.*)$/) {
    $label = '';
    $mnemonic = $1;
    $operand = $2;
    $comment = $3;
  } elsif ($line =~ /^(\S+)\s+([Aa][Ss][Cc])\s+(".+")\s*$/) {
    $label = $1;
    $mnemonic = $2;
    $operand = $3;
    $comment = '';
  } elsif ($line =~ /^\s+([Aa][Ss][Cc])\s+(".+")\s*$/) {
    $label = '';
    $mnemonic = $1;
    $operand = $2;
    $comment = '';
  } else {
    print "SYNTAX ERROR!  $lineno : $line\n";
  }

  $label = '' unless defined $label;
  $comment = '' unless defined $comment;
  $mnemonic = '' unless defined $mnemonic;
  $operand = '' unless defined $operand;

  return ($label, $mnemonic, $operand, $comment);
}

my $ifh;

# Open the input file.
if (open($ifh, "<$input_file")) {
  my $lineno = 0;

  while (my $line = readline $ifh) {
    chomp $line;

    $lineno++;

    if ($line =~ /^\s*\*|^\s*;/) {
      print "$line\n";
      next;
    }

    # Parse input lines.
    my ($label, $mnemonic, $operand, $comment) = parse_line($line, $lineno);

    print sprintf("%-8s %-4s %-12s %s\n", $label, $mnemonic, $operand, $comment);
  }

  close $ifh;
} else {
  die "Can't open $input_file\n";
}

1;