import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;

import javafx.scene.canvas.Canvas;
import javafx.scene.canvas.GraphicsContext;

public class MyCanvas extends Canvas {
    
    private double width, height;  // Canvas has them, as private
    private GraphicsContext gc;    // Canvas has it, as private
    
    private ArrayList<Stroke> strokes;
    
    public MyCanvas(double w, double h) {
        super(w, h);
        
        width  = w;
        height = h;
        
        gc = super.getGraphicsContext2D();
        
        strokes = new ArrayList<>();
    }
    
    public void addStroke(Stroke s) {
        strokes.add(s);
        
        // must repaint
        paint();
    }
    
    public void clearCanvas() {
        strokes.clear();
        
        paint();
    }
    
    public void paint() {
        // clear canvas
        gc.clearRect(0, 0, width, height);
        
        // draw all strokes in the arraylist
        for (Stroke s : strokes) {
            s.draw(gc);
        }
    }
    
    // allows user to save current drawing (canvas) into a text file
    // format:
    // #_of_strokes
    // C cx cy size filled r g b
    // S cx cy size filled r g b
    public void saveTextFile(File fh) {
        
        try {
            PrintWriter fileOut = new PrintWriter(fh);
        
            fileOut.println(strokes.size());
            
            for (Stroke s : strokes) {
                fileOut.println(s.toString());
            }
        
            fileOut.close();
        }
        catch(IOException e) {
            System.err.println("Error writing to " + fh.getName());
            e.printStackTrace();
        }
        
    }
    
}