package Chart;

import javax.swing.*;
import java.awt.*;
import java.awt.geom.Line2D;
import java.awt.geom.Rectangle2D;
import java.util.ArrayList;
import java.util.List;

class GraphComponent extends JComponent {
    private static final int DEFAULT_WIDTH = 1000;
    private static final int DEFAULT_HEIGHT = 750;
    private int width;
    private int height;
    private int screenWidth;
    private int screenHeight;
    private Point zeroPoint;
    private int gapPixels;
    private int gapValue;
    private Coordinates<Integer> displacement;

    private List<Function> functions;

    public GraphComponent() {
        functions = new ArrayList<>();
        displacement = new Coordinates<>(0, 0);
        Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
        screenWidth = (int) screenSize.getWidth();
        screenHeight = (int) screenSize.getHeight();
        width = 1000; //screenWidth*4/5;
        height = 1000; //screenHeight*3/5;
        zeroPoint = new Point(width/2, height/2);
        gapPixels = 20;
        gapValue = 1;
    }

    public void paintComponent(Graphics g) {
        Graphics2D g2 = (Graphics2D) g;
        drawBackground(g2);
        drawNet(g2, gapPixels);
        drawAxes(g2);
        drawAxesOverlay(g2, gapPixels);
    }

    private void drawBackground(Graphics2D g) {
        g.setPaint(Color.WHITE);
        Rectangle2D background = new Rectangle2D.Float(0, 0, width, height);
        g.fill(background);
        //g.draw(background);
    }

    private void drawAxes(Graphics2D g) {
        float size = 5;

        g.setPaint(Color.BLACK);

        //lines
        g.setStroke(new BasicStroke(1));

        g.draw(new Line2D.Float(0, height/2, width, height/2));
        g.draw(new Line2D.Float(width/2, 0, width/2, height));

        g.setStroke(new BasicStroke(1));

        drawArrow(Direction.UP, width/2, 0, size, g);
        drawArrow(Direction.RIGHT, width, height/2, size, g);

        //x and y
        g.drawString("y", width/2 + size*2,size*2);
        g.drawString("x", width - size*3, (int) (height/2 + size*2.5));
    }

    private void drawArrow(Direction direction, int tipX, int tipY, float size, Graphics2D g) {
        g.setPaint(Color.BLACK);
        g.setStroke(new BasicStroke(1));
        switch (direction) {
            case UP:
                g.draw(new Line2D.Float(tipX, tipY, tipX-size, tipY+size));
                g.draw(new Line2D.Float(tipX, tipY, tipX+size, tipY+size));
                break;
            case RIGHT:
                g.draw(new Line2D.Float(tipX, tipY, tipX-size, tipY-size));
                g.draw(new Line2D.Float(tipX, tipY, tipX-size, tipY+size));
                break;
            default:
                //Not supported
                throw new IllegalArgumentException();
        }
        g.setStroke(new BasicStroke(1));
    }

    private void drawAxesOverlay(Graphics2D g, int gap) {
        int val;

        /*
        //vertical
        val = 0 - gapValue * ((int) width/2/gap);
        for (int i = (int) zeroPoint.getX() - gap * ((int) width/2/gap); i < width; i += gap) {
            g.drawString(Integer.toString(val), width/2 + gap/2, i);
            val += gapValue;
        }

         */

        //horizontal
        val = 0 - gapValue * ((int) height/2/gap);
        for (int i = (int) zeroPoint.getY() - gap * ((int) height/2/gap); i < height; i += gap) {
            g.drawString(Integer.toString(val), i, height/2 + gap);
            val += gapValue;
        }



    }

    private void drawFunctions(Graphics2D g) {

    }

    private void drawFunction(Graphics2D g) {

    }

    private void drawNet(Graphics2D g, int gap) {
        //brighter lines
        int greyScale = 220;
        g.setPaint(new Color(greyScale, greyScale, greyScale));

        drawSimpleNet(g, gap);

        //darker lines
        greyScale = 190;
        g.setPaint(new Color(greyScale, greyScale, greyScale));

        drawSimpleNet(g, gap*5);
    }

    private void drawSimpleNet(Graphics2D g, int gap) {
        //vertical
        /*
        for (int i = (int) zeroPoint.getX(); i> 0; i -= gap) {
            g.draw(new Line2D.Float(i, 0, i, height));
        }

        for (int i = (int) zeroPoint.getX(); i < width; i += gap) {
            g.draw(new Line2D.Float(i, 0, i, height));
        }
         */

        for (int i = (int) zeroPoint.getX() - gap * ((int) width/2/gap); i < width; i += gap) {
            g.draw(new Line2D.Float(i, 0, i, height));
        }

        //horizontal
        /*
        for (int i = (int) zeroPoint.getY(); i > 0; i -= gap) {
            g.draw(new Line2D.Float(0, i, width, i));
        }

        for (int i = (int) zeroPoint.getY(); i < height; i += gap) {
            g.draw(new Line2D.Float(0, i, width, i));
        }
         */

        for (int i = (int) zeroPoint.getY() - gap * ((int) height/2/gap); i < height; i += gap) {
            g.draw(new Line2D.Float(0, i, width, i));
        }
    }


    public Dimension getPreferredSize() {
        return new Dimension(width, height);
    }
}