package com.rle.monitor;

/*
 * RLE Surface Crack Detector Graphing Software
 *
 * Copyright (C) 2002 RLE Technologies
 * For more information visit http://www.rletech.com/
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,
 * USA.
 */

/**
 * @author Andy Goth
 * @author Eric Peterson
 * @author Matt Lane
 * @version 0.1
 */

/** Data structure describing a selection in a roll chart. */
public class Selection {
	/** No selection. */
	public static final int NONE = 0;
	/** A selection is about to be made (maybe). */
	public static final int BEGIN = 1;
	/** A selection is being made or has been made. */
	public static final int SELECT = 2;
	/** The selection is zoomed in. */
	public static final int ZOOM = 3;

	private int left;
	private int right;
	private int state = NONE;

	private Buffer buffer;
	
	/** Constructor. */
	public Selection(Buffer buffer) {this.buffer = buffer;}

	/** Returns one endpoint of the selection. */
	public int getLeft()
	{
		if (state < SELECT) throw new UnsupportedOperationException(
				"No selection exists");
		return left;
	}
	/** Returns the left endpoint of the selection. */
	public int getLeftmost()
	{
		return left < right ? getLeft() : getRight();
	}
	/** Sets one endpoint of the selection. */
	public void setLeft(int left) {setRange(left, right);}

	/** Returns the other endpoint of the selection. */
	public int getRight()
	{
		if (state < SELECT) throw new UnsupportedOperationException(
				"No selection exists");
		return right;
	}
	/** Returns the right endpoint of the selection. */
	public int getRightmost()
	{
		return right > left ? getRight() : getLeft();
	}
	/** Sets the other endpoint of the selection. */
	public void setRight(int right) {setRange(left, right);}

	/** Returns the minimal endpoint. */
	public int getMin() {return buffer.getStart();}
	public int getMax() {return buffer.getSize() - 1;}
	/** Sets both endpoints of the selection. */
	public void setRange(int left, int right)
	{
		if (state < SELECT) throw new UnsupportedOperationException(
				"No selection exists");
		if (state == ZOOM) throw new UnsupportedOperationException(
				"Cannot resize a zoomed selection");
		int min = getMin();
		int max = getMax();
		if (left < min) left = min;
		if (left > max) left = max;
		if (right < min) right = min;
		if (right > max) right = max;
		this.left = left;
		this.right = right;
	}

	/** Grows the selection to include pos. */
	public void extend(int pos)
	{
		if (contains(pos)) return;

		int left = getLeftmost();
		int right = getRightmost();
		if (pos < getLeftmost()) left = pos;
		else /* if (pos > getRightmost()) */ right = pos;
		setRange(left, right);
	}

	/** Returns true if pos is within the selection. */
	public boolean contains(int pos)
	{
		if (state < SELECT) return false;
		if (pos >= left && pos <= right) return true;
		if (pos >= right && pos <= left) return true;
		return false;
	}

	/** Returns the current state of the selection. */
	public int getState() {return state;}
	/** Sets the state of the selection. */
	public void setState(int state)
	{
		switch (state) {
		case NONE: case BEGIN: case SELECT: case ZOOM:
			if (state == this.state) return;
			this.state = state;
			break;
		default: throw new IllegalArgumentException("Invalid state");
		}
	}
}