// Game of Fanorona
// David Eppstein, UC Irvine, 11 Jun 1997
//
// Prompt user to move by putting messages in the status line

import java.util.*;
import java.awt.*;

class StatusLine implements Observer {
	// component used to find applet status line
	Component component;
	public Component getComponent() { return component; }
	public void setComponent(Component c) { component = c; }

	// initialize, tell game to update us when it changes
	StatusLine(Component c, Game g) { g.addObserver(this); setComponent(c); }
	
	// whenever game state changes, make sure status line is synchronized
	public void update(Observable g, Object o) {
		if (!(g instanceof Game)) throw new IllegalArgumentException("Status line: updated object is not game");
		Game game = (Game) g;
		Board board = game.getBoard();
		
		// test if game is over
		if (board.gameOver()) {
			if (board.whiteWins())
				Fanorona.showMessage(getComponent(), "White has won!", true);
			else Fanorona.showMessage(getComponent(), "Black has won!", true);
			return;
		}
		
		// not over, prompt human to move
		if (!game.humanToMove()) return;
		if (board.previousPosition == null || board.midCapture()) return;
		if (board.whiteToMove())
			Fanorona.showMessage(getComponent(), "White to move", true);
		else Fanorona.showMessage(getComponent(), "Black to move", true);
	}
}