/**
 * PHPredict
 * 
 * A word predictor class
 * 
 */
class phpredict {
    var $_predictionTable = array();
    function phpredict() {
    	
    }
    function parse($line) {
        $words = explode(' ', $line);
        if(count($words) > 2) {
        	$current3WordList = array(array_shift($words), array_shift($words), array_shift($words));
            $this->parse3WordList($current3WordList);
            if(count($words) > 0) {
        	    foreach($words as $word) {
            	   array_shift($current3WordList);
                   array_push($current3WordList, $word);
                   $this->parse3WordList($current3WordList);
                }
            }
        }
    }
    function parse3WordList($words)
    {
    	if(!isset($this->_predictionTable[$words[0]])) {
            $this->_predictionTable[$words[0]] = array();
        }
        if(!isset($this->_predictionTable[$words[0]][$words[1]])) {
            $this->_predictionTable[$words[0]][$words[1]] = array();
        }
        if(!isset($this->_predictionTable[$words[0]][$words[1]][$words[2]])) {
            $this->_predictionTable[$words[0]][$words[1]][$words[2]] = 1;
        } else {
            $this->_predictionTable[$words[0]][$words[1]][$words[2]]++;
        }
    }
    function predict($line) {
        $words = explode(' ', $line);
        if(count($words) < 2) {
        	return 'I need two words to predict';
        }
        $words = array_slice($words, -2, 2);
        if(isset($this->_predictionTable[$words[0]])) {
            if(isset($this->_predictionTable[$words[0]][$words[1]])) {
                $maxCount = 0;
                foreach($this->_predictionTable[$words[0]][$words[1]] as $word => $count) {
                	if($count > $maxCount) {
                		$predictedWord = $word;
                        $maxCount = $count;
                	}
                }
                return $predictedWord;
            } else {
            	return 'I dont know';
            }
        } else {
            return 'I dont know';
        }
    }
    function console() {
    	
    	$line = '';
        while($line != 'exit') {
            echo 'PHPredict console# ';
        	$line = trim(fgets(STDIN));
            if($line == 'debug') {
            	print_r($this);
            } elseif($line == 'predict') {
            	
            	echo 'Predict: ';
                $lineIn = trim(fgets(STDIN));
                echo 'Predicted: ' . $lineIn . ' ' . $this->predict($lineIn);
                echo "\n";
            } else {
            	$this->parse($line);
            }
            
        }
    }
}
$phpredict = new phpredict();
$phpredict->console();