(****
 *
 * This file defines operations related to Proctor Functionality.  
 *
 *)


module ProctorFunctionality;

    from Tests import all;
    from StudentFunctionality import all;
    export all;
 
    operation ChooseTest
        inputs: test:Test, tin:timeLimit;
        outputs: ptest:ProctorTest;
        precondition: ;
        postcondition: 
	    (*
	     * If the proctor doesn't define a time, the time limit defined on the
		 * test should be used.
	     *)
	    (if (tin = nil) then (ptest.time = test.time)
		else (ptest.time = tin))
		and
		(*
		 * Check that the list of questions on the test to be proctored is the
		 * same as the list of questions on the test chosen.
		 *)
		(ptest.questions = test.questions);
		
        description: (*
            The proctor chooses a test to distribute to the students, and has the 
			opportunity to change the time limit for the test.
        *);
    end ChooseTest;

    operation BeginTest
		inputs: test:Test, s:Server;
		outputs: s':Server;
		precondition: ;
		postcondition: 
			(*
			 * Make sure all the answers on the list of TakenTests for the students
			 * are blank, and that the InProgress flag is set to true.
			 *)
			(forall (test:TakenTest)
			  (test in s'.tests) iff ((test.answers = nil) and (test.flag)));
			(* (forall (test:s'.tests) ((test.answers = nil) and (test.flag))); *)

		description: (*
			Start the test for given students on a given server.
		*);
    end BeginTest;
 
    operation ExtendTime
        inputs: s:Server, new_time:timeLimit;
        outputs: s':Server;
        precondition:
	    (*
	     * Time limit input must be greater than zero
	     *)
	    (new_time > 0);
		
        postcondition: 
	    (*
	     * Check that each test being taken on the Server has the updated time.
	     *)
	        (forall (test:TakenTest)
	          (test in s'.tests) iff (test.time = new_time));
		(* (forall (test:s'.tests) (test.time = new_time)); *)
		
        description: (*
            Adds the amount of minutes specified to the current timeLimit.
        *);
    end ExtendTime;

    operation EndTest
		inputs: s:Server;
		outputs: submitted:SubmittedTests;
		precondition: ;
		postcondition: 
			(*
			 * The two test lists must be equal, and the InProgress flag must be false.
			 *)
			(forall (i:integer | (i >= 1) and (i < #s.tests) and (i < #submitted))
				(s.tests[i] = submitted[i])
				and
				(not submitted[i].flag));
	   
		description: (*
			Changes the time limit to zero.
		*);
    end EndTest;


end ProctorFunctionality;