(******
*
* Module Graphs is made to hold the graphing stuff.
*
*)


module Graphs

  from gradeditems import Gradebook;
  from NewClass import StatsBar;
  export all;

object Histogram is 
  components: HistoSegment*;
  description: (* The histogram object holds segments of the histogram,
		each representing a different grade.   
  *);
end Histogram;

object HistoSegment is
  components: HistoRow* and Grade and Color;  	
  description: (* The HistoSegment object contains a collection of rows
		which display a more detailed view of where students stand
		in the class.  It also contains the grade of the 
		segment and the color that represents that grade.
  *);
end HistoSegment;

object HistoRow is
  components: Score and NumOfStudents;
  description: (* The HistoRow keeps track of how many students have a 
		certain score, and the score that they all got.  This is 
		what is displayed as a row of datapoints on the histogram.
  *);
end HistoRow;

object PieChart is
  components: PieSegment* and Mean and Median and StdDev
	      and HighScore and LowScore;
  description: (* The pie chart is a collection of pie segments
		which represent different grades. It also has 
		a wide range of statistics.
  *);
end PieChart;
	
object PieSegment is
  components: Grade and Percentage and Color;
  description: (* Each segment represents a different grade, and
  		has its own corresponding color.  It also has
		a certain percentage of the whole pie chart which
		will decide how large a slice it is.
  *);
end PieSegment;

operation sumScores is
	inputs: g: GradeBook, s: Score;
	outputs: i: Integer;
	preconditions: #g.totalScore != 0;
        postconditions: i <= #g;
	description: (* Counts how many students are within a certain grade range.
	*);
end sumScores;

operation displayPie is
	inputs: g: GradeBook, a: Integer, b: Integer, c: Integer, d: Integer, f: Integer;
	outputs: pie: PieChart;
	preconditions: (#g.totalScore != 0); 
        (* If a,b,c,d or f is nil, then default to standard grading scale 
	*)
	postconditions: (sumScores(g,a) + sumScores(g,b) + sumScores(g,c) + 
	sumScores(g,d) + sumScores(g,f)) < #g.totalScore; 
	description: (* Displays a pie chart. 
	*);
end displayPie;

operation displayHisto is
	inputs: g: GradeBook, a: Integer, b: Integer, c: Integer, d: Integer, f: Integer;
	outputs: histo: Histogram;
	preconditions: (g#.totalScore != 0); 
	(* If a,b,c,d or f is nil, then default to standard grading scale;
	*)
	postconditions: (sumScores(g,a) + sumScores(g,b) + sumScores(g,c) +
	sumScores(g,d) + sumScores(g,f)) < #g.totalScore;
	description: (* Displays a histogram. *);
end displayHisto;

operation dragLinePie is
	inputs: gradebook: GradeBook, orig_low: Integer , orig_high: Integer,
 		origPie: PieChart;
	outputs: new_low: Integer, new_high: Integer, newPie: PieChart,
 		gradebook': GradeBook;
        precondition: orig_low < orig_high;
	postcondition: new_low <= new_high;
	description: This will simply call the displyPie operation with the new grade ranges.
end dragLinePie;

operation dragLineHisto is
	inputs: gradebook: GradeBook, orig_low: Integer, orig_high: Integer,
		origHisto: Histogram;
	outputs: newHisto: Histogram, new_low: Integer, new_high: Integer,
		gradebook':GradeBook;
	precondition: orig_low < orig_high;
	postcondition: new_low <= new_high;
	description: This will call the displayHisto operation with the new grade ranges.
end dragLineHisto;

object Color is 
	components: s: string;
	description: (* The name of the color to be displayed on the graphs.*);
end Color;
object Percentage is 
	components: r: real;
	description: (* The percentage of students with the same grade. *);
end Percentage;
object Grade is 
	components: s: string;
	description: (* A possible grade. *);
end Grade;
object NumOfStudents is 
	components: i: integer;
	description: (* Number of students *);
end NumOfStudents;
object Score is
	components: r: real;
	description: (* The raw score of a student. *);
end Score;

(* These need to be added to another file and imported to here.

object Mean is real;
object Median is real;
object StdDev is real;
object HighScore is real;
object LowScore is real; 

*)

end Graphs;