/* Copyright (c) 2010, Carl Burch. License information is located in the
 * com.cburch.logisim.Main source code and at www.cburch.com/logisim/. */

package com.cburch.draw.tools;

import java.awt.Color;
import java.awt.Cursor;
import java.awt.Graphics;
import java.awt.event.KeyEvent;
import java.awt.event.MouseEvent;

import com.cburch.draw.actions.ModelAddAction;
import com.cburch.draw.canvas.Canvas;
import com.cburch.draw.model.CanvasModel;
import com.cburch.draw.model.CanvasObject;
import com.cburch.logisim.data.Bounds;
import com.cburch.logisim.data.Location;

abstract class RectangularTool extends AbstractTool {
	private boolean active;
	private Location dragStart;
	private int lastMouseX;
	private int lastMouseY;
	private Bounds currentBounds;
	
	public RectangularTool() {
		active = false;
		currentBounds = Bounds.EMPTY_BOUNDS;
	}
	
	public abstract CanvasObject createShape(int x, int y, int w, int h);
	public abstract void drawShape(Graphics g, int x, int y, int w, int h);
	public abstract void fillShape(Graphics g, int x, int y, int w, int h);
	
	@Override
	public Cursor getCursor(Canvas canvas) {
		return Cursor.getPredefinedCursor(Cursor.CROSSHAIR_CURSOR);
	}
	
	@Override
	public void toolDeselected(Canvas canvas) {
		Bounds bds = currentBounds;
		active = false;
		repaintArea(canvas, bds);
	}
	
	@Override
	public void mousePressed(Canvas canvas, MouseEvent e) {
		Location loc = Location.create(e.getX(), e.getY());
		Bounds bds = Bounds.create(loc);
		dragStart = loc;
		lastMouseX = loc.getX();
		lastMouseY = loc.getY();
		active = canvas.getModel() != null;
		repaintArea(canvas, bds);
	}
	
	@Override
	public void mouseDragged(Canvas canvas, MouseEvent e) {
		updateMouse(canvas, e.getX(), e.getY(), e.getModifiersEx());
	}
	
	@Override
	public void mouseReleased(Canvas canvas, MouseEvent e) {
		if (active) {
			Bounds oldBounds = currentBounds;
			Bounds bds = computeBounds(canvas, e.getX(), e.getY(), e.getModifiersEx());
			currentBounds = Bounds.EMPTY_BOUNDS;
			active = false;
			CanvasObject add = null;
			if (bds.getWidth() != 0 && bds.getHeight() != 0) {
				CanvasModel model = canvas.getModel();
				add = createShape(bds.getX(), bds.getY(),
						bds.getWidth(), bds.getHeight());
				canvas.doAction(new ModelAddAction(model, add));
				repaintArea(canvas, oldBounds.add(bds));
			}
			canvas.toolGestureComplete(this, add);
		}
	}
	
	@Override
	public void keyPressed(Canvas canvas, KeyEvent e) {
		int code = e.getKeyCode();
		if (active && (code == KeyEvent.VK_SHIFT || code == KeyEvent.VK_ALT
				|| code == KeyEvent.VK_CONTROL)) {
			updateMouse(canvas, lastMouseX, lastMouseY, e.getModifiersEx());
		}
	}
	
	@Override
	public void keyReleased(Canvas canvas, KeyEvent e) {
		keyPressed(canvas, e);
	}
	
	private void updateMouse(Canvas canvas, int mx, int my, int mods) {
		Bounds oldBounds = currentBounds;
		Bounds bds = computeBounds(canvas, mx, my, mods);
		if (!bds.equals(oldBounds)) {
			currentBounds = bds;
			repaintArea(canvas, oldBounds.add(bds));
		}
	}
	
	private Bounds computeBounds(Canvas canvas, int mx, int my, int mods) {
		lastMouseX = mx;
		lastMouseY = my;
		if (!active) {
			return Bounds.EMPTY_BOUNDS;
		} else {
			Location start = dragStart;
			int x0 = start.getX();
			int y0 = start.getY();
			int x1 = mx;
			int y1 = my;
			if (x0 == x1 && y0 == y1) {
				return Bounds.EMPTY_BOUNDS;
			}

			boolean ctrlDown = (mods & MouseEvent.CTRL_DOWN_MASK) != 0;
			if (ctrlDown) {
				x0 = canvas.snapX(x0);
				y0 = canvas.snapY(y0);
				x1 = canvas.snapX(x1);
				y1 = canvas.snapY(y1);
			}
			
			boolean altDown = (mods & MouseEvent.ALT_DOWN_MASK) != 0;
			boolean shiftDown = (mods & MouseEvent.SHIFT_DOWN_MASK) != 0;
			if (altDown) {
				if (shiftDown) {
					int r = Math.min(Math.abs(x0 - x1), Math.abs(y0 - y1));
					x1 = x0 + r;
					y1 = y0 + r;
					x0 -= r;
					y0 -= r;
				} else {
					x0 = x0 - (x1 - x0);
					y0 = y0 - (y1 - y0);
				}
			} else {
				if (shiftDown) {
					int r = Math.min(Math.abs(x0 - x1), Math.abs(y0 - y1));
					y1 = y1 < y0 ? y0 - r : y0 + r;
					x1 = x1 < x0 ? x0 - r : x0 + r;
				}
			}
			
			int x = x0;
			int y = y0;
			int w = x1 - x0;
			int h = y1 - y0;
			if (w < 0) {
				x = x1;
				w = -w;
			}
			if (h < 0) {
				y = y1;
				h = -h;
			}
			return Bounds.create(x, y, w, h);
		}
	}

	private void repaintArea(Canvas canvas, Bounds bds) {
		canvas.repaint();
		/* The below doesn't work because Java doesn't deal correctly with stroke
		 * widths that go outside the clip area
		canvas.repaintCanvasCoords(bds.getX() - 10, bds.getY() - 10,
				bds.getWidth() + 20, bds.getHeight() + 20);
		 */
	}
	
	@Override
	public void draw(Canvas canvas, Graphics g) {
		Bounds bds = currentBounds;
		if (active && bds != null && bds != Bounds.EMPTY_BOUNDS) {
			g.setColor(Color.GRAY);
			drawShape(g, bds.getX(), bds.getY(), bds.getWidth(), bds.getHeight());
		}
	}

}
