<?php

/**
 * @class IHMExpressionParserClass
 * @brief Parser for IHM expression
 * @details
 */
class IHMExpressionParserClass
{
	//constants
	private static $constantTag     = '@';
	private static $constantNode    = 'constant';
	private static $constantNameAtt = 'name';

	//aliases
	private static $aliasTag     = '#';
	private static $aliasNode    = 'alias';
	private static $aliasNameAtt = 'name';

	//functions
	private static $functionsNode    = 'function';
	private static $functionsNameAtt = 'name';
	private static $functionsArgsAtt = 'args';
	private static $functionsNewKernelNode = 'new_kernel';

	//operator
	private static $operators = array(
			//standard operators
			"+" => array("type" => "operator"),
			"-" => array("type" => "operator"),
			"*" => array("type" => "operator"),
			"/" => array("type" => "operator"),
			//operators that's need to be translate by a function for the kernel
			"^" => array("type" => "function", "function" => "pow"),
			"<" => array("type" => "function", "function" => "lower_than"),
			">" => array("type" => "function", "function" => "greater_than"),
			"&" => array("type" => "function", "function" => "And"),
			"|" => array("type" => "function", "function" => "Or")
	);

	private $constantsArray;

	private $aliasesArray;

	private $functionsArray;

	/*
	 * @brief Constructor
	*/
	function __construct()
	{
	}

	/*
	 * @brief test function
	*/
	public function test()
	{
		//tests
		$tests = array(
				"dst>3" => array ("expression" => "greater_than(\$dst,3)", "params" => array("dst")),
				"@const_1<dst" => array("expression" => "(lower_than(1.0E-10,\$dst))", "params" => array("dst")),
				"dst^#alias_2" => array("expression" => "(pow(\$dst,\$imf[1]))", "params" => array("dst","imf")),
				"dst^2+@const_2" => array("expression" => "(pow(\$dst,2))+-2.8", "params" => array("dst")),
				"atan(imf(2)/imf(1))+speed/100.0" => array("expression" => "atan((\$imf[2]/\$imf[1]))+(\$speed/100.0)", "params" => array("imf","speed")),
				"shiftT_(clust1_hia_pad,60)" => array("expression" => "#timeShift(\$clust1_hia_pad;60)", "params" => array("clust1_hia_pad")),
				"smooth_(density,1200)" => array("expression" => "#boxcar(\$density;1200)", "params" => array("density")),
				"shiftT_(density,-600)" => array("expression" => "#timeShift(\$density;-600)", "params" => array("density")),
				"deriv(density)" => array("expression" => "#deriv(\$density)", "params" => array("density")),
				"abs(dst)" =>array("expression" => "abs(\$dst)", "params" => array("dst")),
				"density*speed+(density^2-1.0)/speed" => array("expression" => "(\$density*\$speed)+((pow(\$density,2))-1.0)/\$speed", "params" => array("density","speed")),
				"(-7<dst)&(dst<-3)" => array("expression" => "And((lower_than(-7,\$dst)),(lower_than(\$dst,-3)))", "params" => array("dst"))
		);

		//init constants, aliases and functions for test
		$this->constantsArray = array(
				"@const_1" => 1e-10,
				"@const_2" => -2.8
		);

		$this->aliasesArray = array(
				"#alias_1" => "dst",
				"#alias_2" => "imf(1)"
		);

		$this->functionsArray = array(
				"func_old" => array("kernel_name" => "func_new", "nb_args" => 0),
				"atan" => array("kernel_name" => "atan", "nb_args" => 0),
				"shiftT_" => array("kernel_name" => "#timeShift", "nb_args" => 1),
				"smooth_" => array("kernel_name" => "#boxcar", "nb_args" => 1),
				"deriv" => array("kernel_name" => "#deriv", "nb_args" => 0),
				"abs" => array("kernel_name" => "abs", "nb_args" => 0)
		);

		//add operator to change in function
		foreach (self::$operators as $operator)
		{
			if ($operator["type"] == "function")
				$this->functionsArray[$operator["function"]] = 
					array("kernel_name" => $operator["function"], "nb_args" => 0);
		}

		//
		foreach ($tests as $key => $value)
		{
			echo "==> Test : ".$key.PHP_EOL;

			$res = $this->parse($key);
				
			echo "Result : ".$res["expression"].PHP_EOL;
				
			echo json_encode($value).PHP_EOL.json_encode($res).PHP_EOL;
				
			if (json_encode($value) == json_encode($res))
				echo "OK !".PHP_EOL;
			else
				echo "ERROR !".PHP_EOL;
		}
	}

	/*
	 * @brief main method to parse a IHM expression
	*/
	public function parse($expression)
	{
		//echo "Source expression : ".$expression.PHP_EOL;
		//clean expression and replace constants and aliases by associated value
		$this->clean($expression);
		$this->replaceConstants($expression);
		$this->replaceAliases($expression);
		$this->clean($expression);

		//explode expression
		$elements = $this->explodeExpression($expression);
		
		//group elements in tree
		$tree = $this->buildTreeElements($elements);
		
		//translate
		$params_full = array();
		$translated = $this->translate($tree,$params_full);
		
		//keep only params id
		$params = array();
		foreach ($params_full as $param_full)
			$params[] = $param_full["id"];

		return array("expression" => $translated, "params" => $params);
	}

	/*
	 * @brief clean expression
	*/
	private function clean(&$expression)
	{
		//remove all " "
		$expression = str_replace(" ", "", $expression);

		//replace [ and { by (
		$expression = str_replace(array("[","{"), "(", $expression);

		//replace ] and } by )
		$expression = str_replace(array("]","}"), ")", $expression);
	}

	/*
	 * @brief detect if some constants are defined in the expression
	*/
	private function isConstantDetected($expression)
	{
		return preg_match('/'.self::$constantTag.'/', $expression);
	}

	/*
	 * @brief replace constants by real values in expression
	*/
	private function replaceConstants(&$expression)
	{
		if (!$this->isConstantDetected($expression))
			return;

		if (!isset($this->constantsArray))
		{
			//load constants array
			$dom = new DomDocument("1.0");
			$constantsXMLFile = IHMConfigClass::getConstantsFilePath();
			if (!$dom->load($constantsXMLFile))
				throw new Exception('Cannot load constants file');
				
			$this->constantsArray = array();
				
			$constants_ = $dom->getElementsByTagName(self::$constantNode);
			for ($i = 1; $i <  $constants_->length; $i++)
				$this->constantsArray[self::$constantTag.$constants_->item($i)->getAttribute(self::$constantNameAtt)] = $constants_->item($i)->nodeValue;
		}

		//replace
		$expression = strtr($expression, $this->constantsArray);

		//be sure that all constants are replaced
		if ($this->isConstantDetected($expression))
			throw new Exception('Cannot replace some constants : '.$expression);
	}

	/*
	 * @brief detect if at least one aliases is defined in the expression
	*/
	private function isAliasDetected($expression)
	{
		return preg_match('/'.self::$aliasTag.'/', $expression);
	}

	/*
	 * @brief replace aliases by real parameter id in expression
	*/
	private function replaceAliases(&$expression)
	{
		if (!$this->isAliasDetected($expression))
			return;

		if (!isset($this->aliasesArray))
		{
			//load aliases array
			$dom = new DomDocument("1.0");
			$aliasesXMLFile = IHMConfigClass::getUserAliasesFilePath();
			if (!$dom->load($aliasesXMLFile))
				throw new Exception('Cannot load aliases file');
				
			$this->aliasesArray = array();
				
			$aliases_ = $dom->getElementsByTagName(self::$aliasNode);
			for ($i = 1; $i <  $aliases_->length; $i++)
				$this->aliasesArray[self::$alias_tag.$aliases_->item($i)->getAttribute(self::$aliasNameAtt)] = $aliases_->item($i)->nodeValue;
		}

		//replace
		$expression = strtr($expression, $this->aliasesArray);

		//be sure that all aliases are replaced
		if ($this->isAliasDetected($expression))
			throw new Exception('Cannot replace some aliases : '.$expression);
	}

	/*
	 * @brief load list of available functions
	*/
	private function loadFunctions()
	{
		if (isset($this->functionsArray))
			return;
			
		$dom = new DomDocument("1.0");
		$functionsXMLFile = IHMConfigClass::getFunctionsFilePath();

		if (!$dom->load($functionsXMLFile))
			throw new Exception('Cannot load functions file');
			
		$this->functionsArray = array();

		$functions_ = $dom->getElementsByTagName(self::$functionsNode);
		 
		for ($i = 0; $i < $functions_->length; $i++)
		{
			$tempArr =  explode('(', $functions_->item($i)->getAttribute(self::$functionsNameAtt));
			$nbArgs  =  $functions_->item($i)->getAttribute(self::$functionsArgsAtt);
			$kernelFunctions_ = $functions_->item($i)->getElementsByTagName(self::$functionsNewKernelNode);
			if ($kernelFunctions_->length == 0)
				$kernelFunction = "";
			else
				$kernelFunction = $kernelFunctions_->item(0)->nodeValue;
			$this->functionsArray[$tempArr[0]] = array(
				"kernel_name" => $kernelFunction,
				"nb_args"     => intval($nbArgs),
				"isOperator"  => false
			);
		}

		//add operator to change in function
		foreach (self::$operators as $operator)
		{
			if ($operator["type"] == "function")
				$this->functionsArray[$operator["function"]] = array(
					"kernel_name" => $operator["function"],
					"nb_args"     => 0,
					"isOperator"  => true
			);
		}
	}

	/*
	 * @brief detect if the element is a function
	*/
	private function isFunction($element)
	{
		$this->loadFunctions();
		return array_key_exists($element,$this->functionsArray);
	}

	/*
	 * @brief detect if the element is an operator
	*/
	private function isOperator($c)
	{
		foreach (self::$operators as $key => $value)
		if ($key == $c)
			return true;
	}

	/*
	 * @brief get the function associated to an operator
	*/
	private function getOperatorAssociatedFunction($c)
	{
		foreach (self::$operators as $key => $value)
		if ($key == $c)
		if ($value["type"] == "function")
			return $value["function"];
		return "";
	}

	/*
	 * @brief detect if the operator needed to be replace by a function
	*/
	private function isOperatorToFunction($c)
	{
		return ($this->getOperatorAssociatedFunction($c) != "");
	}

	/*
	 * @brief detect if the element is a separator
	*/
	private function isSeparator($c)
	{
		return ($this->isOperator($c) || $c == "(" || $c == ")" || $c == ",");
	}

	/*
	 * @brief detect a decimal value
	*/
	private function isDecimal($element)
	{
		return preg_match("/^[+\-]?(?:0|[1-9]\d*)(?:\.?\d*)?(?:[eE][+\-]?\d+)?/",$element);
		//return preg_match("/[+\-]?(?:0|[1-9]\d*)(?:\.?\d*)?(?:[eE][+\-]?\d+)/",$element);
	}

	/*
	 * @brief detect an integer value
	*/
	private function isInteger($element)
	{
		return preg_match("/^\d+$/",$element);
	}

	/*
	 * @brief explode expression for parsing
	*/
	private function explodeExpression($expression)
	{
		$crt = "";
		$elements = array();
		for ($i = 0; $i < strlen($expression); ++$i)
		{
			$c = $expression[$i];
			if ($this->isSeparator($c))
			{
				if ((($c == "+") || ($c == "-")) &&
				preg_match('/^\d*\.?\d*[eE]$/',$crt))
				{
					//scientific decimal element => false positive separator
					$crt .= $c;
					continue;
				}
				//push in elements list
				if ($crt != "")
					$elements[] = $crt;
				$elements[] = $c;
				$crt = "";
				continue;
			}
			$crt .= $c;
		}
		if ($crt != "")
			$elements[] = $crt;
		
		//regroup parameters and components before to add brackets for operators priority
		$els = array();
		$i = 0;
		for ($i; $i < count($elements)-3; ++$i)
		{
			if (($elements[$i+1] == "(")          &&
				$this->isParameter($elements[$i]) &&
				$this->isInteger($elements[$i+2]) &&
				($elements[$i+3] == ")"))
			{
				$els[] = ($elements[$i].$elements[$i+1].$elements[$i+2].$elements[$i+3]);
				$i = $i+3;
				continue;
			}
			$els[] = $elements[$i];
		}

		for ($j = $i; $j < count($elements); ++$j)
			$els[] = $elements[$j];
		
		$elements = $els;
		
		//regroup negative number
		$els = array();
		$i = 0;
		for ($i; $i < count($elements)-1; ++$i)
		{
			if (($elements[$i] == "-") && (
					$this->isDecimal($elements[$i+1]) || $this->isInteger($elements[$i+1])))
			{
				if (($i == 0) || (!$this->isDecimal($elements[$i-1]) && !$this->isInteger($elements[$i-1]) && !$this->isParameter($elements[$i-1])))
				{
					$els[] = ($elements[$i].$elements[$i+1]);
					$i = $i+1;
					continue;
				}
			}
			$els[] = $elements[$i];
		}
		
		for ($j = $i; $j < count($elements); ++$j)
			$els[] = $elements[$j];
		
		$elements = $els;
		
		//add brackets for operators priority
		
		$els = array();
		$i = 0;
		for ($i; $i < count($elements)-2; ++$i)
		{
			if ($elements[$i+1] == "*" || $elements[$i+1] == "/" || $elements[$i+1] == "^" || $elements[$i+1] == "<")
			{
				if ($elements[$i] != ")")
				{
					$els[] = "(";
					$els[] = $elements[$i];
					$els[] = $elements[$i+1];
					$els[] = $elements[$i+2];
					$els[] = ")";
					$i += 2;
				}
				else
					$els[] = $elements[$i];
			}
			else
				$els[] = $elements[$i];
		}
		for ($j = $i; $j < count($elements); ++$j)
			$els[] = $elements[$j];

		//split parameters and components
		$elements = $els;
		
		$els = array();
		$i = 0;
		for ($i; $i < count($elements); ++$i)
		{
			$tmpArray = explode('(',$elements[$i]);
			if ((count($tmpArray) == 2) && ($tmpArray[0] != "") && ($tmpArray[1] != ""))
			{
				$tmpArray2 = explode(')',$tmpArray[1]);
				if ((count($tmpArray2) == 2) && ($tmpArray2[0] != "") && ($tmpArray2[1] == ""))
				{
					$els[] = "(";
					$els[] = $tmpArray[0];
					$els[] = "(";
					$els[] = $tmpArray2[0];
					$els[] = ")";
					$els[] = ")";
					continue;
				}
			}
			$els[] = $elements[$i];
		}
			
		return $els;
	}

	/*
	 * @brief build a tree of the expression
	*/
	private function buildTreeElements($elements)
	{
		$expression_group = array();
		$crt_group = &$expression_group;
		$opened_groups = array($expression_group);
		for($i = 0; $i < count($elements); ++$i)
		{
			if ($elements[$i] == "(")
			{
				array_push($opened_groups,array());
				continue;
			}
			if ($elements[$i] == ")")
			{
				$group_to_close = $opened_groups[count($opened_groups)-1];
				array_pop($opened_groups);
				if (count($opened_groups) <= 0)
					throw new Exception('Expression error - Brackets definition');
				array_push($opened_groups[count($opened_groups)-1],$group_to_close);
				continue;
			}
			if (count($opened_groups) <= 0)
				throw new Exception('Expression error - Brackets definition');
			array_push($opened_groups[count($opened_groups)-1],$elements[$i]);
		}

		if (count($opened_groups) != 1)
			throw new Exception('Expression error - Brackets definition');
		$expression_group = $opened_groups[0];

		return $expression_group;
	}

	/*
	 * @brief detect if the element is a parameter
	*/
	private function isParameter($element)
	{
		return (!is_array($element) &&
				!$this->isDecimal($element) &&
				!$this->isOperator($element) &&
				!$this->isFunction($element) &&
				($element != ",") && ($element != ";") && ($element != "(") && ($element != ")"));
	}

	/*
	 * @brief detect if the element is a component for a parameter
	*/
	private function isParameterComponent($tree, $i)
	{
		$paramId = "";
		if ($i <= 0)
			return false;
		if (!$this->isParameter($tree[$i-1]))
			return false;
		return (is_array($tree[$i]) &&
				(count($tree[$i] == 1)) &&
				$this->isInteger($tree[$i][0]));
	}

	/*
	 * @brief add a parameter
	*/
	private function addParameterIdInParameterArray($paramId, &$params)
	{
		foreach ($params as $param)
		if ($param["id"] == $paramId)
			return;
		$params[] = array("id" => $paramId, "indexes" => array(), "calib_infos" => array());
	}

	/*
	 * @brief add a parameter component
	*/
	private function addParameterComponentInParameterArray($paramId, $component, &$params)
	{
		foreach ($params as &$param)
		if ($param["id"] == $paramId)
		{
			array_push($param["indexes"],$component);
			return;
		}
	}

	/*
	 * @brief process used to treat parameter components
	*/
	private function regroupParameterAndComponent($tree,&$params,&$result)
	{
		for ($i = 0; $i < count($tree); ++$i)
		{
			if (is_array($tree[$i]) && (count($tree[$i]) > 0))
			{
				$res = array();
				$this->regroupParameterAndComponent($tree[$i],$params,$res);
				$result[] = $res;
			}
			else if ($this->isParameter($tree[$i]))
			{
				$param = $tree[$i];
				$this->addParameterIdInParameterArray($param,$params);
				if ($i < count($tree) - 1)
				{
					if ($this->isParameterComponent($tree,$i+1))
					{
						$this->addParameterComponentInParameterArray($param, $tree[$i+1][0], $params);
						$param .= ("[".$tree[$i+1][0]."]");
						++$i;
					}
				}
				$result[] = $param;
			}
			else
			{
				$result[] = $tree[$i];
			}
		}
	}

	/*
	 * @brief replace all operators that's needed to be replace by a function
	*/
	private function fixOperatorToFunction($tree,&$result)
	{
		$i = 0;
		for ($i; $i < count($tree)-1; ++$i)
		{
			if ($this->isOperatorToFunction($tree[$i+1]))
			{
				if ($i >= count($tree)-2)
					throw new Exception('Expression error - Error in operator definition');
				
				if (is_array($tree[$i]))
				{
					$left = array();
					$this->fixOperatorToFunction($tree[$i],$left);
				}
				else
					$left     = $tree[$i];
				$function = $this->getOperatorAssociatedFunction($tree[$i+1]);
				if (is_array($tree[$i+2]))
				{
					$right = array();
					$this->fixOperatorToFunction($tree[$i+2],$right);
				}
				else
					$right    = $tree[$i+2];
				$result[] = $function;
				$result[] = array($left,",",$right);
				$i += 2;
			}
			else
			{
				if (is_array($tree[$i]))
				{
					$res = array();
					$this->fixOperatorToFunction($tree[$i],$res);
					$result[] = $res;
				}
				else
					$result[] = $tree[$i];
			}
		}

		for ($j = $i; $j < count($tree); ++$j)
		{
			if (is_array($tree[$j]))
			{
				$res = array();
				$this->fixOperatorToFunction($tree[$j],$res);
				$result[] = $res;			
			}
			else
				$result[] = $tree[$j];
		}
	}
	
	/*
	 * @brief process used to replace "," by ";" for function
	*/
	private function fixComaFunction($tree,$isFunctionGroup,&$result)
	{
		for ($i = 0; $i < count($tree); ++$i)
		{
			if (is_array($tree[$i]) && (count($tree[$i]) > 0))
			{
				$groupFunc = false;
				if (($i > 0) && (!is_array($tree[$i-1])))
				{
					$groupFunc = $this->isFunction($tree[$i-1]);
				}
				$res = array();
				$this->fixComaFunction($tree[$i],$groupFunc,$res);
				$result[] = $res;
			}
			else
			{
				if ($isFunctionGroup && ($tree[$i] == ','))
					$result[] = ';';
				else
					$result[] = $tree[$i];
			}
		}
	}

	/*
	 * @brief write the result expression from tree elements
	*/
	private function writeTranslate($tree,$params)
	{
		$translated = "";
		
		for ($i = 0; $i < count($tree); ++$i)
		{
			//echo "=> ".$tree[$i].PHP_EOL;
			if (is_array($tree[$i]))
			{
				//echo "ARRAY".PHP_EOL;
				if ((count($tree[$i]) > 1) || 
					(count($tree[$i]) == 1) && ($i>0) && (!is_array($tree[$i-1]) && $this->isFunction($tree[$i-1])))
					$translated .= ("(".$this->writeTranslate($tree[$i],$params).")");
				else
					$translated .= ($this->writeTranslate($tree[$i],$params));
			}
			else if ($this->isDecimal($tree[$i]))
			{
				//echo "DECIMAL ".$tree[$i].PHP_EOL;
				$translated .= $tree[$i];
			}
			else if ($this->isOperator($tree[$i]))
			{
				//echo "OPERATOR".PHP_EOL;
				$translated .= $tree[$i];
			}
			else if ($tree[$i] == ",")
			{
				//echo "COMA".PHP_EOL;
				$translated .= ",";
			}
			else if ($tree[$i] == ";")
			{
				//echo "DOT COMA".PHP_EOL;
				$translated .= ";";
			}
			else if ($this->isFunction($tree[$i]))
			{
				//echo "FUNCTION".PHP_EOL;
				$kernelFunction = $this->functionsArray[$tree[$i]]["kernel_name"];
				if ($kernelFunction == "")
					throw new Exception('Expression error - Function '.$tree[$i]." not implemented");
				$firstArgForFunc = ($this->functionsArray[$tree[$i]]["nb_args"] != 0);
				$translated .= $kernelFunction;
			}
			else
			{
				$founded = false;
				foreach ($params as $param)
				{
					//echo "TEST ".$param["id"].PHP_EOL;

					if ($param["id"] == $tree[$i])
					{
						$founded = true;
						$translated .= ("\$".$tree[$i]);
						break;
					}
					foreach ($param["indexes"] as $index)
					{
						$temp = "";
						$temp .= ($param["id"]."[".$index."]");
						//echo "TEST 2 ".$temp.PHP_EOL;
						if ($temp == $tree[$i])
						{
							$founded = true;
							$translated .= ("\$".$tree[$i]);
							break;
						}
					}
					if ($founded)
						break;
				}
				if (!$founded)
				{
					throw new Exception('Expression error - Unknown element '.$tree[$i]);
				}
			}
		}

		return $translated;
	}

	/*
	 * @brief sequence used to translate a tree elements
	*/
	private function translate($tree,&$params)
	{
		$res_1 = array();
		$this->regroupParameterAndComponent($tree,$params,$res_1);
		
		$res_2 = array();
		$this->fixComaFunction($res_1,false,$res_2);

		$res_3 = array();
		$this->fixOperatorToFunction($res_2,$res_3);
		
		return $this->writeTranslate($res_3,$params);
	}
}

/*$parser = new IHMExpressionParserClass();
 try {
$parser->test();
} catch (Exception $e) {
echo 'Exception detected : '.$e->getMessage().PHP_EOL;
}*/

?>