#!/usr/bin/perl -w

use strict;
use constant BUFFER_SIZE => 128;

if( $#ARGV != 0 )
{
   die "$0 <line count>\n";
}
my $line_count = $ARGV[0];
my $mode = $line_count % 2;

my $pi = atan2(0, -1);
my @buffer = ();
for(my $i = 0; $i < BUFFER_SIZE; $i++)
{
   push @buffer, (("X" x 79) . "\n");
}
my $head = 0;
my $tail = 40;

my $char = 0;
my $last_x = 40;
my $last_y = 80;
for(; $line_count > 0; $line_count--)
{
   $buffer[$tail] = ("X" x 79) . "\n";
   $tail = ($tail + 1) % BUFFER_SIZE;
   $head != $tail or die;

   # Generate star
   my $cx = rand(70) + 5;
   my $distance = sqrt(($cx - $last_x) * ($cx - $last_x) + $last_y * $last_y);
   if( $last_y > 30 && $distance > 40 )
   {
      my $size0 = 1 + rand(2);
      my $size1 = 12 - $size0 + rand(8);
      my $phase = rand(2 * $pi);
      my $v0 = 0.5;
      my $v1 = 0.5;
      if( $mode )
      {
         $size0 = 17 + rand(5);
         $size1 = 0;
         $v0 = 0.2;
         $v1 = 0.4;
      }

      for(my $ta = 0; $ta < 10 * $pi; $ta += 0.05)
      {
         my $r = $size0 + $size1 + $size1 * 0.5 * sin($ta + $phase);
         for(my $tr = 0; $tr < $r; $tr += 0.1)
         {
            my $x = $cx + $tr * cos($ta / 5);
            my $dy = $tr * sin($ta / 5);
            my $y = ($tail + BUFFER_SIZE - 20) +
                    ($dy > 0 ? $v0 * $dy : $v1 * $dy);
            $y = int($y + 0.5) % BUFFER_SIZE;
            $x = int($x + 0.5);
            if( $x >= 0 && $x < length($buffer[$y]) )
            {
               substr($buffer[int($y + 0.5)], int($x + 0.5), 1) = ' ';
            }
         }
      }
      $last_x = $cx;
      $last_y = 0;

      if( $mode )
      {
         $cx += rand($size0) - $size0 / 2;
         my $y1 = int($tail + BUFFER_SIZE - 21) % BUFFER_SIZE;
         my $y2 = int($tail + BUFFER_SIZE - 22) % BUFFER_SIZE;
         if( $cx - 3 > 2 )
         {
            substr($buffer[$y1], int($cx) - 3, 1) = '#';
            substr($buffer[$y2], int($cx) - 3, 1) = '#';
         }
         if( $cx + 2 < 77 )
         {
            substr($buffer[$y1], int($cx) + 2, 1) = '#';
            substr($buffer[$y2], int($cx) + 2, 1) = '#';
         }
      }
   }
   else
   {
      $last_y += 2;
   }

   # Output text following template
   my $template = $buffer[$head];
   $head = ($head + 1) % BUFFER_SIZE;
   foreach my $c (unpack 'C*', $template)
   {
      $c = chr($c);
      if( $c =~ /\s/s )
      {
         print $c;
      }
      else
      {
         print chr($char + ord('a'));
         $char = ($char + 1) % 26;
      }
   }
}