/*
 * Copyright (C) 1998  Ralf Wiebicke
 *
 * 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
 */

package de.rw7;

import java.applet.Applet;
import java.awt.Button;
import java.awt.Canvas;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Event;
import java.awt.Graphics;

class Display extends Canvas
{

	Applet app;
	Dimension mySize;

	Display(Applet app, Dimension mySize)
	{
		this.app = app;
		this.mySize = mySize;
	}

	private Function F = null;
	private int Fdim;
	private double[] args;
	private int fl;
	private double minX, maxX, DotsPerX;
	private int IdealDotsX = 40;
	private double minY, maxY, DotsPerY;
	private int IdealDotsY = 20;

	void setFunction(Function F)
	{
		this.F = F;
		if (F != null)
		{
			Fdim = F.getDim();
			args = new double[Fdim];
			for (int i = 0; i < Fdim; i++)
				args[i] = F.suggestVal(i);
			fl = F.suggestFloating();
			minX = F.suggestMin(fl);
			maxX = F.suggestMax(fl);
			DotsPerX = mySize.width / (maxX - minX);
			minY = F.suggestMin(-1);
			maxY = F.suggestMax(-1);
			DotsPerY = mySize.height / (maxY - minY);
		}
		repaint();
	}

	public void paintAxes(Graphics g)
	{
		Dimension d = mySize;
		g.drawRect(0, 0, d.width - 1, d.height - 1);
		if (F == null)
		{
			g.drawLine(0, 0, d.width, d.height);
			g.drawLine(0, d.height, d.width, 0);
			return;
		}

		int wx;
		int wy;
		double markStep, markEnd, curr;

		markStep = fit(IdealDotsX / DotsPerX);
		markEnd = Math.ceil(maxX / markStep) * markStep;
		for (int i = 0;; i++)
		{
			curr = markEnd - markStep * i;
			if (curr <= minX)
				break;
			wx = (int) ((curr - minX) * DotsPerX);
			switch (i)
			{
				case 0 :
					break;
				case 2 :
					g.drawString(F.getDesc(fl), wx, d.height - 8);
					break;
				default :
					g.drawString(String.valueOf(curr), wx, d.height - 8);
			}
			g.drawLine(wx, d.height - 4, wx, d.height);
		}

		markStep = fit(IdealDotsY / DotsPerY);
		markEnd = Math.ceil(maxY / markStep) * markStep;
		for (int i = 0;; i++)
		{
			curr = markEnd - markStep * i;
			if (curr <= minY)
				break;
			wy = d.height - (int) ((curr - minY) * DotsPerY);
			switch (i)
			{
				case 0 :
					break;
				case 2 :
					g.drawString(F.getDesc(-1), 8, wy - 3);
					break;
				default :
					g.drawString(String.valueOf(curr), 8, wy);
			}
			g.drawLine(0, wy, 4, wy);
		};
	}

	public void paintGraph(Graphics g)
	{
		if (F == null)
			return;
		double[] args = new double[Fdim];
		for (int i = 0; i < args.length; i++)
			args[i] = this.args[i];

		Dimension d = mySize;
		double DeltaX;
		double zX, zY;
		double[] fzY;
		int wx, wy;

		zX = minX;
		DeltaX = (1d) / DotsPerX;
		boolean notfirst = false;
		wy = 0;
		for (wx = 0; wx < d.width; wx++)
		{
			args[fl] = zX;
			fzY = F.value(args);
			for (int i = 0; i < fzY.length; i++)
			{
				zY = fzY[i];
				if ((minY <= zY) && (zY <= maxY))
				{
					wy = d.height - (int) ((zY - minY) * DotsPerY);
					if (notfirst)
						g.drawLine(wx, wy, wx, wy);
					else
						notfirst = true;
				}
				else
				{
					notfirst = false;
				};
			}
			zX += DeltaX;
			//if ((wx&15)==0) repaint();
		}
	}

	static double fit(double x)
	{
		double e10 = Math.pow(10d, Math.floor(Math.log(x) / Math.log(10d)));
		double z = x / e10;
		z = (z <= 1) ? 1 : (z <= 2) ? 2 : (z <= 2.5) ? 2.5 : (z <= 5) ? 5 : 10;
		return (z * e10);
	}

	// Umrechnung: double = ((double)(pix) / DotsPer) + min
	private int mouseDownX = 0, mouseDownY = 0;
	private int mouseUpX = 0, mouseUpY = 0;

	public boolean mouseMove(Event e, int x, int y)
	{
		app.showStatus(
			"("
				+ String.valueOf(minX + (double) (x) / DotsPerX)
				+ ","
				+ String.valueOf(maxY - (double) (y) / DotsPerY)
				+ ")");
		return (true);
	}

	public boolean mouseDrag(Event e, int x, int y)
	{
		app.showStatus(
			"Selected("
				+ String.valueOf(minX + (double) (x) / DotsPerX)
				+ ","
				+ String.valueOf(maxY - (double) (y) / DotsPerY)
				+ ")");
		return (true);
	}

	public boolean mouseDown(Event e, int x, int y)
	{
		mouseDownX = x;
		mouseDownY = y;
		return (true);
	}

	public boolean mouseUp(Event e, int x, int y)
	{
		mouseUpX = x;
		mouseUpY = y;
		return (true);
	}

	public boolean action(Event e, Object arg)
	{
		if (e.target instanceof Button)
		{
			if (arg.equals("Zoom In") || arg.equals("Zoom Out"))
			{
				DotsPerX = mySize.width / (maxX - minX);
				DotsPerY = mySize.height / (maxY - minY);

				if ((mouseDownX == mouseUpX) || (mouseDownY == mouseUpY))
					return (true);
				if (mouseDownX > mouseUpX)
				{
					int z = mouseDownX;
					mouseDownX = mouseUpX;
					mouseUpX = z;
				};
				if (mouseDownY > mouseUpY)
				{
					int z = mouseDownY;
					mouseDownY = mouseUpY;
					mouseUpY = z;
				};

				if (arg.equals("Zoom In"))
				{
					minX += (double) (mouseDownX) / DotsPerX;
					maxX -= (double) (mySize.width - mouseUpX) / DotsPerX;
					minY += (double) (mySize.height - mouseUpY) / DotsPerY;
					maxY -= (double) (mouseDownY) / DotsPerY;
				}
				else
				{
				}

				DotsPerX = mySize.width / (maxX - minX);
				DotsPerY = mySize.height / (maxY - minY);
				repaint();
				return (true);
			};
		};
		return (false);
	}

	public void paint(Graphics g)
	{
		DotsPerX = mySize.width / (maxX - minX);
		DotsPerY = mySize.height / (maxY - minY);
		g.setColor(Color.gray);
		paintAxes(g);
		g.setColor(Color.black);
		paintGraph(g);
		System.out.println("ready.");
	}

	public Dimension preferredSize()
	{
		return (mySize);
	}
	public Dimension minimumSize()
	{
		return (preferredSize());
	}

} // class Display