(****
 *
 * Module Question defines the objects and operations related to the Management of the Questions.
 *
 *)

module Question;

   object QuestionDatabase
      components: questions;
      description: (* The complete DB of questions availible to be used. *);
   end;

   object questions = Question*;

   object Question
      components: ID and question and images* and key and difficulty and timeLimit and course and lastTaken and parentID;
      description: (*"A Question is the information stored about a complete question. The ID a unique identifier by which the question is identifiied. Images is a list of Images shown in a question. Key is the solution to the question. Difficulty is the level of difficulty of the question, either E = Easy , M = Medium, H = Hard. timeLimit is ammount of time allocated to complete the question. course is the course this question is designed for. lastTaken is the date the question was last used. *);
   end Question;

   object Date = string;
   object Images = string;
   object ID = integer;
   object question = string;
   object images = Images*;
   object key = string;
   object difficulty = integer;
   object timeLimit = integer;
   object course = string;
   object lastTaken = Date;
   object parentID = ID;

   object AnsweredQuestion
      components: answer;
      description: (* An AnsweredQuestion contains the students answer to a Question *);
   end AnsweredQuestion;

   object answer = string;

   object GradedQuestion
      components: score;
      description: (* A GradedQuestion contains the score for a completed and graded question *);
   end GradedQuestion;

   object score = integer;

   object MultipleChoice
      components: options and answeredIndeces and numAllowedChoices;
      description: (* A MultipleChoice questions contains the specific information for this type of question. *);
   end MultipleChoice;

   object options = string*;
   object answeredIndeces = integer*;
   object numAllowedChoices = integer;

   object Coding
      components: script and answer;
      description: (* A Coding question contains the file script for grading and the solution to the question *);
   end Coding;

   object File = string;
   object script = File;
   object Answer = string;

   object LongAnswer
      components: keywords and orderMatters and wordCountLimit;
      description: (* A LongAnswer question contains the information for creation this type of question *);
   end LongAnswer;

   object keywords = string*;
   object orderMatters = boolean;
   object wordCountLimit = integer;

   object Fillin
      components: answers;
      description: (* A Fillin question contains a list of answers to the question *);
   end Fillin;

   object answers = string*;


   operation addQestion
      inputs: q:Question, qd:QuestionDatabase;
      outputs: qd':QuestionDatabase;
      precondition: forall(q1 in qd)
                      q1 != q;
      postcondition: qd' = qd + q;
      description: (* Adds a question to the database *);
   end addQuestion;

   operation editQuestion
      inputs: q:Question, qd:QuestionDatabase;
      outputs:qd':QuestionDatabase;
      precondition: q in qd;
      postcondition: q in qd';
      description: (* Edits an existing question in the database *);
   end editQuestion;

   operation deleteQuestion
      inputs: q:Question, qd:QuestionDatabase;
      outputs: qd':QuestionDatabase;
      precondition: q in qd;
      postcondition: qd' = qd - q;
      description: (* Deletes a question from the database *);
   end deleteQuestion;


   operation setScore
      inputs: sc:score, AnsweredQuestion;
      outputs: GradedQuestion;
      precondition: sc >= 0;
      description: (* Sets the specific score of an Answered Question *);
   end setScore;

   operation getScore
      inputs: GradedQuestion;
      outputs: score;
      description: (* Gets the score for a GradedQuetion *);
   end getScore;

end Question;