// CS10Display.java
// For displaying results of CS 10 assignments.
// cmc, updated 8/19/08

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GraphicsEnvironment;
import java.awt.GridLayout;
import java.awt.Rectangle;
import java.awt.geom.Line2D;
import java.awt.geom.Rectangle2D;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.border.LineBorder;

/**
   Provides static methods to display results of CS 10 assignments.
*/
public class CS10Display extends JPanel {

    // GraphicsEnvironment.isHeadless() returns true if no graphics available
    private final static boolean NOGRAPHICS = GraphicsEnvironment.isHeadless();

    // Maximum size of visible grid
    private final static int VIEW_SIZE = 400;

    // instance variables used by showGrid method
    private Color[][] grid;
    private Rectangle2D.Double[][] r;
    private int n, m;

    // only constructor is private - clients have no need to create an object
    // used by showGrid only
    private CS10Display(Color[][] grid) {
        this.grid = grid;
        n = grid.length; // okay: showGrid already tested null or 0 length
        m = 0;
        for (Color[] row : grid)
            if (row.length > m)
                m = row.length; // set to longest row
        r = new Rectangle2D.Double[n][m];

        double stepWidth = (double)VIEW_SIZE / m;
        double stepHeight = (double)VIEW_SIZE / n;

        for (int i = 0; i < n; i++)
            for (int j=0; j < m; j++)
                r[i][j] = new Rectangle2D.Double(j * stepWidth,
                    i * stepHeight, stepWidth, stepHeight);
    }

    /**
       Prints color values to standard output.
       @param color the color(s) to print. Can be a single Color, a comma-separated
              list of Colors, or an array of Colors.
    */
    public static void print(Color... color) {
        for (Color c : color)
            System.out.println(componentValuesString(c));
    }

    // utility creates string of color component values as percent
    private static String componentValuesString(Color c) {
        return String.format("red=%03d, green=%03d, blue=%03d",
            c.getRed(), c.getGreen(), c.getBlue());
    }

    /**
       Displays color(s). Uses graphics display if available. Otherwise just
       invokes print method.
       @param color the color(s) to display. Can be a single Color, a comma-separated
              list of Colors, or an array of Colors.
    */
    public static void show(Color... color) {

        // do nothing if no colors to show
        if (color == null || color.length == 0)
            return;

        // just print strings if no graphics environment available
        if (NOGRAPHICS) {
            System.err.println("No graphics display. " +
                "Just printing to standard output.");
            print(color);
            return;
        }

        // otherwise okay to display graphically
        JPanel panel = new JPanel();
        int n = color.length;
        panel.setLayout(new GridLayout(n, 2));
        JLabel label = null;
        for (Color c : color) {
            String text = "  " + componentValuesString(c) + ": ";
            label = new JLabel(text, JLabel.LEFT);
            label.setBorder(new LineBorder(Color.BLACK));
            panel.add(label);
            JPanel canvas = new JPanel();
            canvas.setBackground(c);
            canvas.setBorder(new LineBorder(Color.BLACK));
            panel.add(canvas);
        }
        JScrollPane scroller = new JScrollPane(panel);
        double height = label.getPreferredSize().getHeight() * n;
        if (height > VIEW_SIZE)
            height = VIEW_SIZE;
        scroller.setPreferredSize(new Dimension(VIEW_SIZE, (int)height + 10));
        JOptionPane.showMessageDialog(null, scroller, "Color Display",
            JOptionPane.PLAIN_MESSAGE);
    }

    /**
       Displays color grid. Only executes if graphics display is available.
       @param grid the array of colors to show - both dimensions must be <= 400.
    */
    public static void showGrid(Color[][] grid) {

        // do nothing if no colors to show
        if (grid == null || grid.length == 0)
            return;

        // just print error message if no graphics environment available
        if (NOGRAPHICS) {
            System.err.println("No graphics display. " +
                "Cannot show grid.");
            return;
        }

        // otherwise okay to display graphically if dimensions in range
        CS10Display panel = new CS10Display(grid);
        if (panel.n > VIEW_SIZE || panel.m > VIEW_SIZE) {
            System.err.println("Grid size exceeds maximum. " +
                "Cannot show.");
            return;
        }

        panel.setPreferredSize(new Dimension(VIEW_SIZE, VIEW_SIZE));
        panel.setBorder(new LineBorder(Color.BLACK));
        JOptionPane.showMessageDialog(null, panel, "Color Grid Display",
            JOptionPane.PLAIN_MESSAGE);
    }

    /**
       Called by the windowing system when showGrid is used.
       Do not attempt to call directly.
       @param g the graphics object passed by the windowing system.
    */
    public void paintComponent(Graphics g) {
        if (grid == null)
            return;

        Graphics2D g2 = (Graphics2D)g;

        // lay down the colors
        int i = 0;
        for (Color[] row : grid) {
            int j = 0;
            for (Color c : row) {
                g2.setColor(c);
                g2.fill(r[i][j]);
                ++j;
            }
            ++i;
        }

        // draw the grid lines, rows first, starting with second one
        g2.setColor(Color.BLACK);
        if (n < VIEW_SIZE/2) // otherwise only grid shows up
            for (i = 1; i < n; i++) {
                double y = r[i][0].getY();
                g2.draw(new Line2D.Double(0, y, VIEW_SIZE, y));
            }
        if (m < VIEW_SIZE/2)
            for (int j = 1; j < m; j++) {
                double x = r[0][j].getX();
                g2.draw(new Line2D.Double(x, 0, x, VIEW_SIZE));
            }
    }
}