/*
 * Copyright (c) 2015 Camil Staps
 */
package com.camilstaps.mandelbrot;

import fractals.Grid;

/**
 * Showing the Mandelbrot fractal on the screen
 * @author camilstaps
 */
public class MandelbrotView {
    
    private final MandelbrotProvider mandelbrotProvider;
    private final Grid grid;
    
    /**
     * Get info from a MandelbrotProvider; work with a Grid
     * @param mp
     * @param grid 
     */
    public MandelbrotView(MandelbrotProvider mp, Grid grid) {
        mandelbrotProvider = mp;
        this.grid = grid;
    }
    
    /**
     * Get the 'mathematical' x value for a certain x coordinate of the screen
     * @param x_on_screen
     * @return 
     */
    public double getX(int x_on_screen) {
        double centerX = mandelbrotProvider.getCenterX();
        double scale = mandelbrotProvider.getScale();
        int grid_w = grid.getWidth();
        double  min_x = centerX - grid_w / scale / 2,
                max_x = centerX + grid_w / scale / 2;
        
        return min_x + ((double) x_on_screen) * (max_x - min_x) / grid_w;
    }
    
    /**
     * Get the 'mathematical' y value for a certain y coordinate of the screen
     * @param y_on_screen
     * @return 
     */
    public double getY(int y_on_screen) {
        double centerY = mandelbrotProvider.getCenterY();
        double scale = mandelbrotProvider.getScale();
        int grid_h = grid.getHeight();
        double  min_y = centerY - grid_h / scale / 2,
                max_y = centerY + grid_h / scale / 2;
        
        return min_y + (((float) y_on_screen) * (max_y - min_y) / grid_h);
    }
    
    /**
     * (Re)draw the fractal
     */
    public void redraw() {
        int repetitions = mandelbrotProvider.getRepetitions();
        
        int grid_w = grid.getWidth(), grid_h = grid.getHeight();
        
        for (int i = 0; i < grid_w; i++) {
            for (int j = 0; j < grid_h; j++) {
                // Convert mandel number to some number in [0,pi] to let the colourise below work nicely
                double mandel = ((double) Mandelbrot.mandelNumber(getX(i), getY(j), repetitions) * Math.PI) / repetitions;
                // Different mandel numbers have different colours
                int[] colour = {
                    (int) (30 + 220 * Math.sin(mandel)), 
                    (int) (30 + 220 * Math.sin(mandel + 2 * Math.PI / 3)), 
                    (int) (30 + 220 * Math.sin(mandel + 4 * Math.PI / 3))};
                // This is a grayscale version:
                //int[] color = {(int) (255 * mandel), (int) (255 * mandel), (int) (255 * mandel)};
                grid.setPixel(i, j, colour);
            }               
        }
    }

    /**
     * Get user input
     */
    public interface MandelbrotProvider {
        /**
         * Get center X value
         * @return 
         */
        public double getCenterX();
        
        /**
         * Get center Y value
         * @return 
         */
        public double getCenterY();
        
        /**
         * Get scale factor
         * @return 
         */
        public double getScale();
        
        /**
         * Get max amount of iterations for the mandel function
         * @return 
         */
        public int getRepetitions();
    }
    
}