/*
 * @(#)ColorPickerPanel.java
 *
 * $Date: 2014-06-06 11:04:49 -0700 (Fri, 06 Jun 2014) $
 *
 * Copyright (c) 2011 by Jeremy Wood.
 * All rights reserved.
 *
 * The copyright of this software is owned by Jeremy Wood. 
 * You may not use, copy or modify this software, except in  
 * accordance with the license agreement you entered into with  
 * Jeremy Wood. For details see accompanying license terms.
 * 
 * This software is probably, but not necessarily, discussed here:
 * https://javagraphics.java.net/
 * 
 * That site should also contain the most recent official version
 * of this software.  (See the SVN repository for more details.)
 */
package com.bric.swing;

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Cursor;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Insets;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.RenderingHints;
import java.awt.Shape;
import java.awt.event.ComponentAdapter;
import java.awt.event.ComponentEvent;
import java.awt.event.ComponentListener;
import java.awt.event.FocusEvent;
import java.awt.event.FocusListener;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.event.MouseEvent;
import java.awt.geom.Ellipse2D;
import java.awt.image.BufferedImage;
import java.util.Vector;

import javax.swing.JPanel;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
import javax.swing.event.MouseInputAdapter;
import javax.swing.event.MouseInputListener;

import com.bric.plaf.PlafPaintUtils;

/** This is the large graphic element in the <code>ColorPicker</code>
 * that depicts a wide range of colors.
 * <P>This panel can operate in 6 different modes.  In each mode a different
 * property is held constant: hue, saturation, brightness, red, green, or blue.
 * (Each property is identified with a constant in the <code>ColorPicker</code> class,
 * such as: <code>ColorPicker.HUE</code> or <code>ColorPicker.GREEN</code>.)
 * <P>In saturation and brightness mode, a wheel is used.  Although it doesn't
 * use as many pixels as a square does: it is a very aesthetic model since the hue can
 * wrap around in a complete circle.  (Also, on top of looks, this is how most
 * people learn to think the color spectrum, so it has that advantage, too).
 * In all other modes a square is used.
 * <P>The user can click in this panel to select a new color.  The selected color is
 * highlighted with a circle drawn around it.  Also once this
 * component has the keyboard focus, the user can use the arrow keys to
 * traverse the available colors.
 * <P>Note this component is public and exists independently of the
 * <code>ColorPicker</code> class.  The only way this class is dependent
 * on the <code>ColorPicker</code> class is when the constants for the modes
 * are used.
 * <P>The graphic in this panel will be based on either the width or
 * the height of this component: depending on which is smaller.
 *
 *
 * @see com.bric.swing.ColorPicker
 * @see com.bric.swing.ColorPickerDialog
 */
public class ColorPickerPanel extends JPanel {
	private static final long serialVersionUID = 1L;
	
	/** The maximum size the graphic will be.  No matter
	 *  how big the panel becomes, the graphic will not exceed
	 *  this length.
	 *  <P>(This is enforced because only 1 BufferedImage is used
	 *  to render the graphic.  This image is created once at a fixed
	 *  size and is never replaced.)
	 */
	public static final int MAX_SIZE = 325;
	
	/** This controls how the colors are displayed. */
	private int mode = ColorPicker.BRI;
	
	/** The point used to indicate the selected color. */
	private Point point = new Point(0,0);
	
	private Vector<ChangeListener> changeListeners = new Vector<ChangeListener>();
	
	/* Floats from [0,1].  They must be kept distinct, because
	 * when you convert them to RGB coordinates HSB(0,0,0) and HSB (.5,0,0)
	 * and then convert them back to HSB coordinates, the hue always shifts back to zero.
	 */
	float hue = -1, sat = -1, bri = -1;
	int red = -1, green = -1, blue = -1;
	
	MouseInputListener mouseListener = new MouseInputAdapter() {
		@Override
		public void mousePressed(MouseEvent e) {
			requestFocus();
			Point p = e.getPoint();
			if(mode==ColorPicker.BRI || mode==ColorPicker.SAT ||
					mode==ColorPicker.HUE) {
				float[] hsb = getHSB(p);
				setHSB(hsb[0], hsb[1], hsb[2]);
			} else {
				int[] rgb = getRGB(p);
				setRGB(rgb[0], rgb[1], rgb[2]);
			}
		}

		@Override
		public void mouseDragged(MouseEvent e) {
			mousePressed(e);
		}
	};
	
	KeyListener keyListener = new KeyAdapter() {
		@Override
		public void keyPressed(KeyEvent e) {
			int dx = 0;
			int dy = 0;
			if(e.getKeyCode()==KeyEvent.VK_LEFT) {
				dx = -1;
			} else if(e.getKeyCode()==KeyEvent.VK_RIGHT) {
				dx = 1;
			} else if(e.getKeyCode()==KeyEvent.VK_UP) {
				dy = -1;
			} else if(e.getKeyCode()==KeyEvent.VK_DOWN) {
				dy = 1;
			}
			int multiplier = 1;
			if(e.isShiftDown() && e.isAltDown()) {
				multiplier = 10;
			} else if(e.isShiftDown() || e.isAltDown()) {
				multiplier = 5;
			}
			if(dx!=0 || dy!=0) {
				int size = Math.min(MAX_SIZE, Math.min(getWidth()-imagePadding.left-imagePadding.right,getHeight()-imagePadding.top-imagePadding.bottom));
				
				int offsetX = getWidth()/2-size/2;
				int offsetY = getHeight()/2-size/2;
				mouseListener.mousePressed(new MouseEvent(ColorPickerPanel.this,
						MouseEvent.MOUSE_PRESSED,
						System.currentTimeMillis(), 0,
						point.x+multiplier*dx+offsetX,
						point.y+multiplier*dy+offsetY,
						1, false
						));
			}
		}
	};
	
	FocusListener focusListener = new FocusListener() {
		public void focusGained(FocusEvent e) {
			repaint();
		}
		public void focusLost(FocusEvent e) {
			repaint();
		}
	};
	
	ComponentListener componentListener = new ComponentAdapter() {

		@Override
		public void componentResized(ComponentEvent e) {
			regeneratePoint();
			regenerateImage();
		}
		
	};
	
	BufferedImage image = new BufferedImage(MAX_SIZE, MAX_SIZE, BufferedImage.TYPE_INT_ARGB);
	
	/** Creates a new <code>ColorPickerPanel</code> */
	public ColorPickerPanel() {
		setMaximumSize(new Dimension(MAX_SIZE+imagePadding.left+imagePadding.right, 
				MAX_SIZE+imagePadding.top+imagePadding.bottom));
		setPreferredSize(new Dimension( (int)(MAX_SIZE*.75), (int)(MAX_SIZE*.75)));
		
		setRGB(0,0,0);
		addMouseListener(mouseListener);
		addMouseMotionListener(mouseListener);
		
		setFocusable(true);
		addKeyListener(keyListener);
		addFocusListener(focusListener);

		setCursor(Cursor.getPredefinedCursor(Cursor.CROSSHAIR_CURSOR));
		addComponentListener(componentListener);
	}
	
	/** This listener will be notified when the current HSB or RGB values
	 * change.
	 */
	public void addChangeListener(ChangeListener l) {
		if(changeListeners.contains(l))
			return;
		changeListeners.add(l);
	}
	
	/** Remove a <code>ChangeListener</code> so it is no longer
	 * notified when the selected color changes.
	 */
	public void removeChangeListener(ChangeListener l) {
		changeListeners.remove(l);
	}
	
	protected void fireChangeListeners() {
		if(changeListeners==null)
			return;
		for(int a = 0; a<changeListeners.size(); a++) {
			ChangeListener l = changeListeners.get(a);
			try {
				l.stateChanged(new ChangeEvent(this));
			} catch(RuntimeException e) {
				e.printStackTrace();
			}
		}
	}
	
	Insets imagePadding = new Insets(6,6,6,6);
	
	@Override
	public void paint(Graphics g) {
		super.paint(g);

		Graphics2D g2 = (Graphics2D)g;
		int size = Math.min(MAX_SIZE, Math.min(getWidth()-imagePadding.left-imagePadding.right,getHeight()-imagePadding.top-imagePadding.bottom));
		
		g2.translate(getWidth()/2-size/2, getHeight()/2-size/2);
		g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);

		Shape shape;
			
		if(mode==ColorPicker.SAT || mode==ColorPicker.BRI) {
			shape = new Ellipse2D.Float(0,0,size,size);
		} else {
			Rectangle r = new Rectangle(0,0,size,size);
			shape = r;
		}
		
		if(hasFocus()) {
			PlafPaintUtils.paintFocus(g2,shape,3);
		}
		
		if(!(shape instanceof Rectangle)) {
			//paint a circular shadow
			g2.translate(2,2);
			g2.setColor(new Color(0,0,0,20));
			g2.fill(new Ellipse2D.Float(-2,-2,size+4,size+4));
			g2.setColor(new Color(0,0,0,40));
			g2.fill(new Ellipse2D.Float(-1,-1,size+2,size+2));
			g2.setColor(new Color(0,0,0,80));
			g2.fill(new Ellipse2D.Float(0,0,size,size));
			g2.translate(-2,-2);
		}
		
		g2.drawImage(image, 0, 0, size, size, 0, 0, size, size, null);
		
		g2.setStroke(new BasicStroke(1));
		if(shape instanceof Rectangle) {
			Rectangle r = (Rectangle)shape;
			PlafPaintUtils.drawBevel(g2,r);
		} else {
			g2.setColor(new Color(0,0,0,120));
			g2.draw(shape);
		}
		
		g2.setColor(Color.white);
		g2.setStroke(new BasicStroke(1));
		g2.draw(new Ellipse2D.Float(point.x-3,point.y-3,6,6));
		g2.setColor(Color.black);
		g2.draw(new Ellipse2D.Float(point.x-4,point.y-4,8,8));
		
		g.translate(-imagePadding.left, -imagePadding.top);
	}
	
	/** Set the mode of this panel.
	 * @param mode This must be one of the following constants from the <code>ColorPicker</code> class:
	 * <code>HUE</code>, <code>SAT</code>, <code>BRI</code>, <code>RED</code>, <code>GREEN</code>, or <code>BLUE</code>
	 */
	public void setMode(int mode) {
		if(!(mode==ColorPicker.HUE || mode==ColorPicker.SAT || mode==ColorPicker.BRI || 
				mode==ColorPicker.RED || mode==ColorPicker.GREEN || mode==ColorPicker.BLUE))
			throw new IllegalArgumentException("The mode must be HUE, SAT, BRI, RED, GREEN, or BLUE.");
			
		if(this.mode==mode)
			return;
		this.mode = mode;
		regenerateImage();
		regeneratePoint();
	}
	
	/** Sets the selected color of this panel.
	 * <P>If this panel is in HUE, SAT, or BRI mode, then
	 * this method converts these values to HSB coordinates
	 * and calls <code>setHSB</code>.
	 * <P>This method may regenerate the graphic if necessary.
	 * 
	 * @param r the red value of the selected color.
	 * @param g the green value of the selected color.
	 * @param b the blue value of the selected color.
	 */
	public void setRGB(int r,int g,int b) {
		if(r<0 || r>255)
			throw new IllegalArgumentException("The red value ("+r+") must be between [0,255].");
		if(g<0 || g>255)
			throw new IllegalArgumentException("The green value ("+g+") must be between [0,255].");
		if(b<0 || b>255)
			throw new IllegalArgumentException("The blue value ("+b+") must be between [0,255].");
		
		if(red!=r || green!=g || blue!=b) {
			if(mode==ColorPicker.RED || 
					mode==ColorPicker.GREEN ||
					mode==ColorPicker.BLUE) {
				int lastR = red;
				int lastG = green;
				int lastB = blue;
				red = r;
				green = g;
				blue = b;
				
				if(mode==ColorPicker.RED) {
					if(lastR!=r) {
						regenerateImage();
					}
				} else if(mode==ColorPicker.GREEN) {
					if(lastG!=g) {
						regenerateImage();
					}
				} else if(mode==ColorPicker.BLUE) {
					if(lastB!=b) {
						regenerateImage();
					}
				}
			} else {
				float[] hsb = new float[3];
				Color.RGBtoHSB(r, g, b, hsb);
				setHSB(hsb[0],hsb[1],hsb[2]);
				return;
			}
			regeneratePoint();
			repaint();
			fireChangeListeners();
		}
	}
	
	/** @return the HSB values of the selected color.
	 * Each value is between [0,1].
	 */
	public float[] getHSB() {
		return new float[] {hue, sat, bri};
	}
	
	/** @return the RGB values of the selected color.
	 * Each value is between [0,255].
	 */
	public int[] getRGB() {
		return new int[] {red, green, blue};
	}
	
	/** Returns the color at the indicated point in HSB values.
	 * 
	 * @param p a point relative to this panel.
	 * @return the HSB values at the point provided.
	 */
	public float[] getHSB(Point p) {
		if(mode==ColorPicker.RED || mode==ColorPicker.GREEN ||
				mode==ColorPicker.BLUE) {
			int[] rgb = getRGB(p);
			float[] hsb = Color.RGBtoHSB(rgb[0], rgb[1], rgb[2], null);
			return hsb;
		}
		
		int size = Math.min(MAX_SIZE, Math.min(getWidth()-imagePadding.left-imagePadding.right,getHeight()-imagePadding.top-imagePadding.bottom));
		p.translate(-(getWidth()/2-size/2), -(getHeight()/2-size/2));
		if(mode==ColorPicker.BRI || mode==ColorPicker.SAT) {
			//the two circular views:
			double radius = (size)/2.0;
			double x = p.getX()-size/2.0;
			double y = p.getY()-size/2.0;
			double r = Math.sqrt(x*x+y*y)/radius;
			double theta = Math.atan2(y,x)/(Math.PI*2.0);
			
			if(r>1) r = 1;
			
			if(mode==ColorPicker.BRI) {
				return new float[] { 
						(float)(theta+.25f),
						(float)(r),
						bri};
			} else {
				return new float[] {
						(float)(theta+.25f),
						sat,
						(float)(r)
				};
			}
		} else {
			float s = ((float)p.x)/((float)size);
			float b = ((float)p.y)/((float)size);
			if(s<0) s = 0;
			if(s>1) s = 1;
			if(b<0) b = 0;
			if(b>1) b = 1;
			return new float[] {hue, s, b};
		}
	}

	/** Returns the color at the indicated point in RGB values.
	 * 
	 * @param p a point relative to this panel.
	 * @return the RGB values at the point provided.
	 */
	public int[] getRGB(Point p) {
		if(mode==ColorPicker.BRI || mode==ColorPicker.SAT ||
				mode==ColorPicker.HUE) {
			float[] hsb = getHSB(p);
			int rgb = Color.HSBtoRGB(hsb[0], hsb[1], hsb[2]);
			int r = (rgb & 0xff0000) >> 16;
			int g = (rgb & 0xff00) >> 8;
			int b = (rgb & 0xff);
			return new int[] {r, g, b};
		}
		
		int size = Math.min(MAX_SIZE, Math.min(getWidth()-imagePadding.left-imagePadding.right,getHeight()-imagePadding.top-imagePadding.bottom));
		p.translate(-(getWidth()/2-size/2), -(getHeight()/2-size/2));
		
		int x2 = p.x*255/size;
		int y2 = p.y*255/size;
		if(x2<0) x2 = 0;
		if(x2>255) x2 = 255;
		if(y2<0) y2 = 0;
		if(y2>255) y2 = 255;
			
		if(mode==ColorPicker.RED) {
			return new int[] {red, x2, y2};
		} else if(mode==ColorPicker.GREEN) {
			return new int[] {x2, green, y2};
		} else {
			return new int[] {x2, y2, blue};
		}
	}

	/** Sets the selected color of this panel.
	 * <P>If this panel is in RED, GREEN, or BLUE mode, then
	 * this method converts these values to RGB coordinates
	 * and calls <code>setRGB</code>.
	 * <P>This method may regenerate the graphic if necessary.
	 * 
	 * @param h the hue value of the selected color.
	 * @param s the saturation value of the selected color.
	 * @param b the brightness value of the selected color.
	 */
	public void setHSB(float h,float s,float b) {
		//hue is cyclic: it can be any value
		h = (float)(h-Math.floor(h));
		
		if(s<0 || s>1)
			throw new IllegalArgumentException("The saturation value ("+s+") must be between [0,1]");
		if(b<0 || b>1)
			throw new IllegalArgumentException("The brightness value ("+b+") must be between [0,1]");
		
		if(hue!=h || sat!=s || bri!=b) {
			if(mode==ColorPicker.HUE || 
					mode==ColorPicker.BRI ||
					mode==ColorPicker.SAT) {
				float lastHue = hue;
				float lastBri = bri;
				float lastSat = sat;
				hue = h;
				sat = s;
				bri = b;
				if(mode==ColorPicker.HUE) {
					if(lastHue!=hue) {
						regenerateImage();
					}
				} else if(mode==ColorPicker.SAT) {
					if(lastSat!=sat) {
						regenerateImage();
					}
				} else if(mode==ColorPicker.BRI) {
					if(lastBri!=bri) {
						regenerateImage();
					}
				}
			} else {

				Color c = new Color(Color.HSBtoRGB(h, s, b));
				setRGB(c.getRed(), c.getGreen(), c.getBlue());
				return;
			}
			

			Color c = new Color(Color.HSBtoRGB(hue, sat, bri));
			red = c.getRed();
			green = c.getGreen();
			blue = c.getBlue();
			
			regeneratePoint();
			repaint();
			fireChangeListeners();
		}		
	}
	
	/** Recalculates the (x,y) point used to indicate the selected color. */
	private void regeneratePoint() {
		int size = Math.min(MAX_SIZE, Math.min(getWidth()-imagePadding.left-imagePadding.right,getHeight()-imagePadding.top-imagePadding.bottom));
		if(mode==ColorPicker.HUE || mode==ColorPicker.SAT || mode==ColorPicker.BRI) {
			if(mode==ColorPicker.HUE) {
				point = new Point((int)(sat*size+.5),(int)(bri*size+.5));
			} else if(mode==ColorPicker.SAT) {
				double theta = hue*2*Math.PI-Math.PI/2;
				if(theta<0) theta+=2*Math.PI;
				
				double r = bri*size/2;
				point = new Point((int)(r*Math.cos(theta)+.5+size/2.0),(int)(r*Math.sin(theta)+.5+size/2.0));
			} else if(mode==ColorPicker.BRI) {
				double theta = hue*2*Math.PI-Math.PI/2;
				if(theta<0) theta+=2*Math.PI;
				double r = sat*size/2;
				point = new Point((int)(r*Math.cos(theta)+.5+size/2.0),(int)(r*Math.sin(theta)+.5+size/2.0));
			}
		} else if(mode==ColorPicker.RED) {
			point = new Point((int)(green*size/255f+.49f),
					(int)(blue*size/255f+.49f) );
		} else if(mode==ColorPicker.GREEN) {
			point = new Point((int)(red*size/255f+.49f),
					(int)(blue*size/255f+.49f) );
		} else if(mode==ColorPicker.BLUE) {
			point = new Point((int)(red*size/255f+.49f),
					(int)(green*size/255f+.49f) );
		}
	}
	
	/** A row of pixel data we recycle every time we regenerate this image. */
	private int[] row = new int[MAX_SIZE];
	/** Regenerates the image. */
	private synchronized void regenerateImage() {
		int size = Math.min(MAX_SIZE, Math.min(getWidth()-imagePadding.left-imagePadding.right,getHeight()-imagePadding.top-imagePadding.bottom));
		
		if(mode==ColorPicker.BRI || mode==ColorPicker.SAT) {
			float bri2 = this.bri;
			float sat2 = this.sat;
			float radius = (size)/2f;
			float hue2;
			float k = 1.2f; //the number of pixels to antialias
			for(int y = 0; y<size; y++) {
				float y2 = (y-size/2f);
				for(int x = 0; x<size; x++) {
					float x2 = (x-size/2f);
					double theta = Math.atan2(y2,x2)-3*Math.PI/2.0;
					if(theta<0) theta+=2*Math.PI;
					
					double r = Math.sqrt(x2*x2+y2*y2);
					if(r<=radius) {
						if(mode==ColorPicker.BRI) {
							hue2 = (float)(theta/(2*Math.PI));
							sat2 = (float)(r/radius);
						} else { //SAT
							hue2 = (float)(theta/(2*Math.PI));
							bri2 = (float)(r/radius);
						}
						row[x] = Color.HSBtoRGB(hue2, sat2, bri2);
						if(r>radius-k) {
							int alpha = (int)(255-255*(r-radius+k)/k);
							if(alpha<0) alpha = 0;
							if(alpha>255) alpha = 255;
							row[x] = row[x] & 0xffffff+(alpha << 24);
						}
					} else {
						row[x] = 0x00000000;
					}
				}
				image.getRaster().setDataElements(0, y, size, 1, row);
			}
		} else if(mode==ColorPicker.HUE) {
			float hue2 = this.hue;
			for(int y = 0; y<size; y++) {
				float y2 = ((float)y)/((float)size);
				for(int x = 0; x<size; x++) {
					float x2 = ((float)x)/((float)size);
					row[x] = Color.HSBtoRGB(hue2, x2, y2);
				}
				image.getRaster().setDataElements(0, y, image.getWidth(), 1, row);
			}
		} else { //mode is RED, GREEN, or BLUE
			int red2 = red;
			int green2 = green;
			int blue2 = blue;
			for(int y = 0; y<size; y++) {
				float y2 = ((float)y)/((float)size);
				for(int x = 0; x<size; x++) {
					float x2 = ((float)x)/((float)size);
					if(mode==ColorPicker.RED) {
						green2 = (int)(x2*255+.49);
						blue2 = (int)(y2*255+.49);
					} else if(mode==ColorPicker.GREEN) {
						red2 = (int)(x2*255+.49);
						blue2 = (int)(y2*255+.49);
					} else {
						red2 = (int)(x2*255+.49);
						green2 = (int)(y2*255+.49);
					}
					row[x] = 0xFF000000 + (red2 << 16) + (green2 << 8) + blue2;
				}
				image.getRaster().setDataElements(0, y, size, 1, row);
			}
		}
		repaint();
	}
}
