#! /usr/bin/perl -w

use strict;
use GD;

my $reds;
my $greens;
my $blues;

my $CUBE_SIZE = 6;
my $INCREMENT_AMOUNT = (255 / ($CUBE_SIZE - 1));
my $NUMBER_OF_GREY_SCALE_COLORS = 24;
my $GREY_INCREMENT_AMOUNT = (255 / ($NUMBER_OF_GREY_SCALE_COLORS));
my @colorArray;
my %cache;

$cache{"255255255"} = 15;
$cache{"000"} = 0;
sub processImage
{
  my $image = GD::Image->newFromJpeg($ARGV[0]);
  my $r;
  my $g;
  my $b;
  my $index;
  my $xtermCodes;

  my ($width,$height) = $image->getBounds();

  my $CODE = "48;5;";
  my $ENDCODE = "m";
  my $buffer = "";
  for(my $y=0; $y < $height;$y++)
  {
     for(my $x=0;$x<$width;$x++)
      {
          $index = $image->getPixel($x, $y);
          ($r,$g,$b) = $image->rgb($index);
          my $col = getNearest($r, $g, $b);
	  if(!$col)
          {
             $col = 15;
          }
          $xtermCodes .= sprintf("%c$CODE$col$ENDCODE ",0x9b);
      }

      $xtermCodes .= sprintf("\n");
  }
 
  return $xtermCodes;
}

sub nearly
{
     my ($firstValue, $secondValue) = (@_);

     if($firstValue == $secondValue)
     {
         return 1;
     }

     my $aboveBounds = $firstValue + (($firstValue/100) * 15);
     my $belowBounds = $firstValue - (($firstValue/100) * 15);
     if($secondValue < $aboveBounds && $secondValue > $belowBounds )
     {
         return 1;
     }
     return 0;
}

sub getNearest
{
  my ($r, $g, $b) = (@_);
 
  my $res = $cache{"$r.$g.$b"};
  if($res)
  {
    return $res;
  }
  else
  {
    $res = 0;
  }

  my $redIndex;
  my $greenIndex;
  my $blueIndex;
  my $last;
  my $count = 16; 

  # If the r,g,b values are within around 20% of each other, it's a 
  # greyscale color

  my $grey;
  if(nearly($r, $g) && nearly($r, $b) && nearly($g,$b))  
  {
     my $last;

     for(my $i = 0;$i < $NUMBER_OF_GREY_SCALE_COLORS+1; $i++)
     {
        my $greyCode = int($i * $GREY_INCREMENT_AMOUNT);
	if($r <= $greyCode && $r >= $last)
        {
	  my $t1 = abs($greyCode - $r);
          my $t2 = abs($last - $r);
          if($t2 < $t1)
          {
             $greyCode = $last;
          }
	  $cache{"$r$g$b"} = 231 + $i;
          $cache{"$greyCode$greyCode$greyCode"} = 231 + $i;
          return 231 + $i;
        }
        $last = $greyCode;
     }
  } 

  for(my $i = 0; $i < $CUBE_SIZE; $i++)
  {     
       my $redValue = ($i * $INCREMENT_AMOUNT);
       
       if($r <= $redValue && $r >= $last)       
       {
	  my $t1 = abs($redValue - $r);
          my $t2 = abs($last - $r);
          my $rr = $i;
          if($t2 < $t1)
          {
             $i--;
             $redValue = $last;
          }
          $last = 0;
	  for(my $j = 0; $j < $CUBE_SIZE; $j++)
	  {
	      my $greenValue = ($j * $INCREMENT_AMOUNT);
	      if($g <= $greenValue && $g >= $last)
              {
                 $t1 = abs($greenValue - $g);
                 $t2 = abs($last - $g);
                 if($t2 < $t1)
                 { 
                   $j--; 
                   $greenValue = $last;
                 }
                 $last = 0;
		 for(my $k = 0; $k < $CUBE_SIZE; $k++)
        	 {
                    my $blueValue = ($k * $INCREMENT_AMOUNT);
                    if($b <= $blueValue && $b >= $last)
                    {
                       $t1 = abs($blueValue - $b);
                       $t2 = abs($last - $b);
                       if($t2 < $t1)
                       { 
			 $k--;
                         $blueValue = $last;
                       }
                         	  
	 	       $count = 16 + (abs($i) * ($CUBE_SIZE * $CUBE_SIZE))
		            + ($j* $CUBE_SIZE) + $k;


		       my $cacheHit = $cache{"$redValue$greenValue$blueValue"};
                       if($cacheHit)
                       {
                          return $cacheHit;
                       }

		       $cache{"$redValue$greenValue$blueValue"} = $count;
		       $cache{"$r.$g.$b"} = $count;
      	               return $count;
                    }

	            $last = $blueValue;
                 }
	     }
             $last = $greenValue;
          }
       }
       $last = $redValue;
  }

  

  
  return $res;
}


my $file = $ARGV[0];

if(!$file || !-e $file)
{
  print "\n\nUseage: XTERMImageGen.pl <filename.jpg>\n";
  exit();
}


#initColorTable();
my $p = processImage();

printf($p);