package awt;

import java.awt.*;
import java.awt.event.*;
import java.util.Vector;

public class TextPanel extends Panel {
	private String [][] text;
	
 Fresh text will overwrite text[fresh]
	  Line fresh-1 is shown at bottom of screen; at this line, characters are added 
	private int fresh;
	private ActionListener actionListener;
	
 Don't show the last scrollbackLines lines 
	private int scrollbackLines = 0;

	public TextPanel() {
		this(100);
	}

	public TextPanel(int capacity) {
		text = new String[capacity][];
		enableEvents(AWTEvent.MOUSE_EVENT_MASK);
	}

	public int getCapacity() {
		return text.length;
	}

	public void processMouseEvent(MouseEvent e) {
		int idx = (getSize().height-e.getY())/getGraphics().getFontMetrics().getHeight();
		switch (e.getID()) {
		case MouseEvent.MOUSE_PRESSED:
			if (e.getClickCount() == 2) {
				actionListener.actionPerformed(new ActionEvent(this,ActionEvent.ACTION_PERFORMED,""+idx));
			}
		}
		super.processMouseEvent(e);
	}

	public void addActionListener(ActionListener listener) {
		actionListener = AWTEventMulticaster.add(actionListener,listener);
	}

	
 Chop string into words 
	private String [] chop(String s) {
		Vector result = new Vector();
		int startidx = 0;
		int len = s.length();
		for (int i = 0; i < len; i++) {
			char c = s.charAt(i);
			if (c == ' ') {
				if (i > startidx)
					result.addElement(s.substring(startidx,i));
				startidx = i+1;
			} else if (c == 0) {
//System.out.println("chop: color at "+i);
				// nullbyte is color-indicator:
				// next 3 bytes indicate r,g,b values
				// first add previous word
				if (i > startidx)
					result.addElement(s.substring(startidx,i));
				result.addElement(s.substring(i,i+4));
				i += 3;
//System.out.println("next char is at "+(i+1)+" <"+s.charAt(i+1)+">");
				startidx = i+1;
			}
		}
		if (startidx < len)
			result.addElement(s.substring(startidx,len));
		String [] res = new String[result.size()];
		result.copyInto(res);
		result.setSize(0);
//println(res);
		return res;
	}

	
 Calculate height in pixels 
	private static int height(FontMetrics fm,String [] line,int width) {
		int x = 0;	// position of next word
		int y = 0;
		int fontheight = fm.getHeight();
		int spacewidth = fm.charWidth(' ');
		for (int i = 0; i < line.length; i++) {
			String word = line[i];
			if (word.equals("")) continue;
			if (word.charAt(0) == 0) continue;	// color
			int wordw = fm.stringWidth(word);
			if (x + wordw > width) {
				y += fontheight; x = wordw + spacewidth;
			} else x += wordw + spacewidth;
		}
		return y + fontheight;
	}

	public int linesUsed() {
		int result = 0;
		for (int i = 0; i < text.length; i++)
			if (text[i] != null) result++;
		return result;
	}

	
 paint line with top pixelheight ypos 
	private static void paintline(Graphics g,String [] line,int width,int y) {
		g.setColor(Color.black);
		FontMetrics fm = g.getFontMetrics();
		y += fm.getAscent();
		int x = 0;	// position of next word
		int fontheight = fm.getHeight();
		int spacewidth = fm.charWidth(' ');
		for (int i = 0; i < line.length; i++) {
			String word = line[i];
			if (word.equals("")) continue;
			if (word.charAt(0) == 0) {
				g.setColor(new Color(word.charAt(1),word.charAt(2),word.charAt(3)));
				continue;
			}
			int wordw = fm.stringWidth(word);
			if (x + wordw > width) {
				y += fontheight; x = 0;
			}
			g.drawString(word,x,y);
			x += wordw + spacewidth;
		}
		return;
	}

	public void invalidate() {
		super.invalidate();
		offscreen = null;
	}

	private Image offscreen;
	public void paint(Graphics g) {
		Dimension siz = getSize();
		if (offscreen == null) offscreen = createImage(siz.width,siz.height);
		Graphics oldg = g;
		g = offscreen.getGraphics();
		g.setClip(0,0,siz.width,siz.height);
		g.setColor(Color.lightGray);
		g.fillRect(0,0,siz.width,siz.height);
		int y = siz.height - 1;	// to paint: [0..siz.height]
		int lin = fresh;
		int scrollback = scrollbackLines;
		FontMetrics fm = g.getFontMetrics();
		while (true) {
			if (lin > 0) lin--;
			else lin = text.length - 1;
			if (text[lin] == null) break;
			if (scrollback > 0) scrollback--;
			else {
				int h = height(fm,text[lin],siz.width);
//System.out.println("height of line "+lin+" "+text[lin][0]+"... is "+h);
//System.out.println("\tpaint at y "+y+"..."+(y-h));
				y -= h;
				paintline(g,text[lin],siz.width,y);
			}
			if (y < 0) break;
		}
		oldg.drawImage(offscreen,0,0,null);
	}

	public void update(Graphics g) {
		paint(g);
	}

	
 Add color switch 
	public void add(Color c) {
		int lineno = fresh - 1;
		if (lineno < 0) lineno = text.length - 1;
		if (text[lineno] == null) {
			text[lineno] = new String[1];
			text[lineno][0] = "";
		}
		String [] newline = new String[text[lineno].length + 1];
		System.arraycopy(text[lineno],0,newline,0,text[lineno].length);
		newline[newline.length-1] = "\0"+(char)c.getRed()+(char)c.getGreen()+(char)c.getBlue();
		text[lineno] = newline;
	}

	public void add(char c) {
		int lineno = fresh - 1;
		if (lineno < 0) lineno = text.length - 1;
		if (text[lineno] == null) {
			text[lineno] = new String[1];
			text[lineno][0] = "";
		}
		if (c == ' ') {	// create new word
			String [] newline = new String[text[lineno].length + 1];
			System.arraycopy(text[lineno],0,newline,0,text[lineno].length);
			newline[newline.length-1] = "";
			text[lineno] = newline;
		} else if (c == '\n') {	// new line
			text[fresh] = new String[1];
			text[fresh][0] = "";
			if (fresh+1 < text.length) fresh++;
			else fresh = 0;
			repaint();
		} else {	// add char to word
			text[lineno][text[lineno].length-1] += c;
			repaint();
		}
	}

	
 Add CR, then full line 
	public void add(String line,Color c) {
		add("\0"+(char)c.getRed()+(char)c.getGreen()+(char)c.getBlue()+line);
	}

	
 Add CR, then full line 
	public void add(String line) {
		text[fresh] = chop(line);
		if (fresh+1 < text.length) fresh++;
		else fresh = 0;
		repaint();
	}

	
 if idx=0, return last line added
	  if idx=1, return line before last line added
	  if idx = 2, return line before that line, etc etc 
	  if idx = getCapacity()-1, return oldest line 
	public String getLine(int idx) {
		idx = fresh - 1 - idx;
		if (idx < 0) idx += text.length;
		String result = "";
		String [] texti = text[idx];
		if (texti == null) return null;
		for (int i = 0; i < texti.length-1; i++)
			result += texti[i] + " ";
		return result + texti[texti.length-1];
	}

	public void setScrollbackLines(int back) {
		scrollbackLines = back;
		repaint();
	}

	public int getScrollbackLines() { return scrollbackLines; }
}