//5.N.10 Parser
//http://git.sugarlabs.org/projects/teacher-reporting
//
//Description:
/*

Select and use appropriate operations (addition, subtraction, multiplication, and division) to solve problems, including those involving money.

*/

<?php

$fp = fopen("./4.N.10.dat", "r");
if(!$fp) die ("Cannot open the file");

//Break Each line of the file into its own array element - will have to parse each array element to obtain fields
$lines = file($fp);


$numWords = str_word_count($fp); 
//Will always be a multiple of four so $NumRecords will be $numWords/4
$numRecords = $numWords / 5;
//Our Associative array Will also be in sequence 1,5,9,13.. + 4 etc 
//Need to tokenize each line and choose appropriate elements ($1)  
//This is just to fill the array with Variables. Next we will go through the same process for the remaining fields
// Perform the logic on them add them to additional associate arrays with various meanings
// For Example 

for (i=0;i<=$numRecords;i++)
{


	$tok = strtok($lines, " ");

			/*
			Because in the end statement we will have to loop through one of the arrays, which will be localized according
			#to specific aritmetic operations (- + / *). We need to account for the fact that some students may not answer a
			#question with one of these operations, and if we looped through that particular operation, we would not represent
			#that student in any of the logic containted within that loop in the END{} statment. Therefore an associative array
			#which absolutely, accounts for any student, contained in the .dat, the CLASS[] array.
			$Class[tok[0]];
			*/
	
	while ($tok !== false)
	 {
		$Class[tok[0]];
	 }
 
}

//in this loop we will cycle through each line of the .dat file and determine at each instance of 
for (i=0;i<=$numRecords;i++)
{
	$tok = strtok($lines, " ");
	//this if-statement allows us to determine if a student is on his/her second attempt	
		 		if ($attempts[$question_id] == 1) 
		 			{
		 				
		 			} 
	while ($tok !== false)
	 {		 
			$student_id	= $tok[0];
			$question_id = $tok[1];	
			$correct_sum = $tok[2];	
		 	$submitted_sum = $tok[3];
		 	$correct = $tok[4];
		 	
		 	//Need to associate question_id with student
		 	$whose_question[$question_id] = $student_id;
		 	
			//Need to determine which attempt this is for this particular question
		 	$attempts[$question_id]++;

			//determine total number of submissions of a student
			$num_submissions[$student_id]++; //$num_incorrect[] = (num_submissions[] - num_correct[])
		 			 	
		 	//*****************************Case: Correct Submission ******************************
		 	//How many correct submissions are there - important for determining percentages for yes/no 
		 	if ($submitted_sum == $correct_sum)
		 	{
		 		$num_correct[$student_id]++;
				//$question_num_correct[$question_id]++; will only ever be one

							 		
		 		
		 		//this if-statement allows us to determine if a student is on his/her second attempt	
		 		if ($attempts[$question_id] > 1) 
		 			{
		 				//the code is looking here if and only if the parser is analyzing a question which he/she
		 				//initially got wrong but has now gotten correct
		 				//We can assume it was initally wrong because gcompris money cents would not have a second record of a question_id
		 				// if it was correct initially.
		 				//TODO - determine whether wrong means previously overpaid or previously underpaid 

						//determine subtraction
						if ($previous_response[$question_id] == "o") // if you previously overpaid
						{
							$correct_subtraction[$student_id]++;	//The amount of times a student invoked subtractions correctly						
						}


		 				
		 			} 


		 	}
		 	
		 	//*****************************CASE: OVERPAID******************************
		 	//How many times does each student overpay - important for determining subraction understanding
		 	if ($submitted_sum > $correct_sum)
		 	{
		 		$student_num_overpaid[$student_id]++;
				$question_num_overpaid[$question_id]++;

		 		
		 		
		 		//this if-statement allows us to determine if a student is on his/her second attempt	
		 		if ($attempts[$question_id] == 1) 
		 			{
		 				if($previous_response[$question_id] == "u")
						{

						}
						elseif($previous_response[$question_id] == "o")
						{
							$strikes[$student_id]++;
							$incorrect_subtraction[$student_id]
						}	 				
		 			} 


			$previous_response[$question_id] = "o"

		 	}
		 	
		 	//******************************Case: Underpaid***********************************
		 			 	//how many times the student underpaid 
		 	if($submitted_sum < $correct_sum)
		 	{
		 		$student_num_underpaid[$student_id]++;
				$question_num_underpaid[$question_id]++;
		 		
		 		//this if-statement allows us to determine if a student is on his/her second attempt	
		 		if ($attempts[$question_id] == 1) 
		 			{
						if($previous_response[$question_id] == "u")
						{
							$strikes[$student_id]++;
						}
						elseif($previous_response[$question_id] == "o")
						{
							$incorrect_subtraction[$student_id]++;
						}
						
	
		 			} 

			$previous_response[$question_id] = "u"
		 	}
		}//end while()

//*******************************************************Output****************************************************
// addition can be determined if a student gets > 70% of the questions correct on their first attempt.
// subtraction can be determined if for > 70% of the questions the student initially over-paid, they immediately follow up with a correct payment. 

// If a student overpays and then increases their payment, or underpays, followed by an even lower payment it can be inferred the student does not
// understand the concepts of /ddition or subtraction with money.

//    * If for > 10% of the questions the student makes this mistake. He or she gets a "no" for addition and subtraction. 




//****************** Addition Yes / No ***************
foreach ($Class as $student)
{
	if( $num_correct[$student] >= ( .7 * ($num_submissions))
	{
		$understands_addition = true;
	}
	else
	{
		$understands_addition = false;
	}


//*************Subtraction Yes/No *************


	if($incorrect_subtraction[$student] / ($correct_subtraction[$student] + $incorrect_subtractions[$student]) <= .70)
	{
		$understands_subtraction = "y"; //we cannot use bool as there is a third case of "undetermined" with subtraction. 
	}
	elseif($incorrect_subtraction[$student] == NULL || $incorrect_subtraction[$student] == 0)
	{
		$understands_subtraction = "u" //undetermined
	}
	else
	{
		$understands_subtraction = "n"
	}

/*************** Strikes *******************
*
* If a student overpays and then increases their payment, or underpays, followed by an even lower payment 
* it can be inferred the student does not understand the concepts of addition or subtraction with money.
* If for > 10% of the total question_id's the student makes this mistake. He or she gets a "no" for addition and subtraction. 
*/

	if(!($strikes[$student] / $num_questions[$student] <= .10))
	{
		$understands_addition = false;
		$understands_subtraction = "n";
	}
	

	
} //end foreach
			
						
	
}	

fclose($fp); //close 4.n.10.dat

?>