<?php 

	Class MarkovChains
	{
		var $prepared = array();
								
		function MarkovChains($source)
		{
			$source = strtolower($source);
  			$source = str_replace(array ("? ", "! "), ".", $source);
  			$source = str_replace(array (" -", "- ", "\t", "\r", "\n", "|",  "&", '\\', '/',  " :", " ;", "©", "·"), ' ', $source);
  			$source = str_replace(array (")", "(", "]", "[", "'", "\"", '*', '•', '~', '{', '}'), '', $source);
  			$source = str_replace(" ,", ",", $source);
  			$source = preg_replace("~(\s+\d{1,2}\s+)|(\w*\.\w+)~", " ", $source);
  			$source = preg_replace("~\s+~", " ", $source);
  				
			$sentens = explode('. ', $source); 
  			$count_sentens = count($sentens);
  			for ($j=0; $j<$count_sentens; ++$j)
  			{
    				$sentens[$j] = explode(' ', $sentens[$j]); 
    				$count_words = count($sentens[$j]) - 1;
    				for ($i=0; $i < $count_words; ++$i)
    				{
      					$prefix = $sentens[$j][$i];
      					$this->prepared[$prefix][] = $sentens[$j][$i+1];
    				}
  			}
  		
			$keys = array_keys($this->prepared);
  			foreach ($keys as $key)
  			{
    				$this->prepared[$key] = array_unique($this->prepared[$key]);
  			}
		}
			
		function GenerateText($size)
		{
			$result_count = 0;
  			for ($j=0; $result_count < $size; ++$j)
  			{
    				$prev = array_rand($this->prepared); 
    				$num  = mt_rand(5, 12); 
    				for ($i=0; $i<$num; ++$i)
    				{	
					$sents[$j][$i] = $prev;
      					++$result_count;
      					$p = $this->prepared[$prev][mt_rand(0, count($this->prepared[$prev]) - 1)];
      					if ($p == '') $p = array_rand($this->prepared);
      					$prev = $p;
      					if ($prev == '') break 2;
    				}
  			}
  	
			foreach ($sents as $sent)
  			{
    				$count_word=count($sent);
    				if ($count_word<=2) continue;
    				
    				if (strlen($sent[$count_word-1]) < 4) unset($sent[$count_word-1]);
    				
    				$sent[$count_word-2] = rtrim($sent[$count_word-2], ",:;");
    				$sent[$count_word-1] = rtrim($sent[$count_word-1], ",:;");
    				$output .= ucfirst(implode(' ', $sent)).'. ';
  			}
  	
			$output = str_replace(' .', '.', $output);
			
			return $output;
		}
	
	}

	
	//Example
	//$source = file_get_contents("text.txt");
	//$markov = new MarkovChains($source);
	//$result = $markov->GenerateText(500);
	//echo $result;
	
?>