// Solution for Recursion Lab
// Author: Chris Wilcox
// Date:   Nov 3, 2016
// Class:  CS163
// Email:  wilcox@cs.colostate.edu

import java.util.ArrayList;

public class Recursion {

    // Array list of triangles
    public static ArrayList<Triangle> triangles = new ArrayList<Triangle>();
    
    // Main program
    public static void main(String[] args) {

        
        // Verify computeFactorial
        System.out.println("Factorials:");
        for (int number = 0; number <= 20; number++) {
            long factorial = computeFactorial(number);
            System.out.printf("Number: %2d, factorial = %d\n", number, factorial);
        }

        // Verify geometricSeries
        System.out.println("Geometric series: 1 + 1/2 + 1/4 + 1/8 + 1/16 + ...");
        for (int terms = 1; terms <= 50; terms++) {
            double sum = geometricSeries(1, 1, terms);
            System.out.printf("Number of terms: %4d, series = %.10f\n", terms, sum);
        }
    
        // Create triangles
        System.out.println("Sierpinski Triangle, number of levels: " + Integer.parseInt(args[0]));
        Triangle base = new Triangle(200.0, 300.0, 0.0, 0.0, 394.0, 0.0);
        sierpinski(base, Integer.parseInt(args[0]));
        System.out.print("Triangles generated: " + triangles.size());
        
        // Draw triangles
        UserInterface ui = new UserInterface();
        ui.draw(triangles);
    }

    // Factorial using recursion: for example 6! = 6 * 5 * 4 * 3 * 2 * 1 = 720
    public static long computeFactorial(long number) {

        // Base case
        
        // Recursive call
        
        // Return factorial
        return 0;
    }

    // Geometric series using recursion: 1 + 1/2 + 1/4 + 1/8 + 1/16 + ... 
    public static double geometricSeries(int numerator, long denominator, int numberTerms) {

        // Base case
        
        // Calculate term
        
        // Recursive call
        
        // Return accumulation
        return 0.0;
    }

    
    // Sierpinski triangle using recursion
    public static void sierpinski(Triangle triangle, int numberLevels) {

        // Base case, processed all levels
        if (numberLevels == 0) return;
        
        // Compute triangle midpoints
//      double x0x1 = 
//      double y0y1 = 
//      double x1x2 = 
//      double y1y2 = 
//      double x0x2 = 
//      double y0y2 = 
        
        // Create and add inside triangle
        triangles.add(triangle);

        // Create outside triangles

        // Add outside triangles

        // Recursively subdivide outside triangles
    }
}