@@ -1,62 +1,65 @@
 import dfl.all;
 import util;
 import game;
-import output;
 import driver;
-//import solver;
-pragma(lib, "dfl.lib");
 
-class GUI : Form, GameObserver
+class GUI(Solver) : Form, GameObserver
 {
-	bool on_game_changed(char c, const(Game) g, bool finished) {
-		draw(gr, g);
-		invalidate();
-		return false;
+	this(const(Game) g)
+	{
+		this.solver = new Solver(g);
+		setup_size(g.map.W, g.map.H);
+		setup_resources();
+		setup_keyhandling();
+		draw(g);
+	}
+
+	private void delegate(char c) fn;
+	void set_fn(F)(F f) { this.fn = f; }
+
+	void run()
+	{
+		Application.run(this);
 	}
 
-	private {
-		int cell;
-		int turn = 0;
-
-		Font font;
-		Color[char] colors;
-		string[char] render;
-		void delegate(char c) fn;
+	override void on_game_changed(char c, const(Game) g, bool finished)
+	{
+		draw(g);
 	}
 
-	this(const(Game) g)
-	{
-		noMessageFilter();
-		this.setStyle(ControlStyles.OPAQUE, true);
-		this.fn = fn;
+private:
+	int cell;
 
-		this.paint ~= &my_paint;
-		this.keyDown ~= &my_keydown;
-
+	void setup_size(int W, int H)
+	{
 		this.formBorderStyle = FormBorderStyle.FIXED_DIALOG;
 		this.maximizeBox = false;
 		this.minimizeBox = false;
-		this.cell = min(1024/g.map.W, 640/g.map.H);
-		this.clientSize = Size(g.map.W*cell, g.map.H*cell);
+		this.cell = min(1024/W, 640/H);
+		this.clientSize = Size(W*cell, H*cell);
+	}
 
-		const scrH = this.clientSize.height;
-		const scrW = this.clientSize.width;
-		this.gr = new MemoryGraphics(scrW, scrH);
+	Font         font;
+	Color[char]  colors;
+	string[char] render;
+	Graphics     graphicContext;
 
-		// Resources
+	void setup_resources()
+	{
+		this.graphicContext = new MemoryGraphics(this.clientSize.width, this.clientSize.height);
+		this.setStyle(ControlStyles.OPAQUE, true);
 		this.font = new Font("MS Gothic", cell-2, GraphicsUnit.PIXEL);
 		this.backColor = Color(255,255,255);
 		this.colors['#'] =
 		this.colors['.'] = Color(255,191,127);
 		this.colors['*'] = Color(255,127,127);
 		this.colors['R'] = Color(128,128,0);
-		this.colors['D'] = Color(255,0,0); // Dead
+		this.colors['D'] = Color(255,0,0);
 		this.colors['\\'] =
 		this.colors['L'] =
 		this.colors['O'] = Color(127,255,127);
-		this.colors['W'] = Color(204,229,255); // water
-
+		this.colors['W'] = Color(204,229,255);
 		this.render['#'] = "■";
 		this.render['*'] = "✹";
 		this.render['.'] = "♒";
 		this.render['\\'] = "λ";
@@ -63,35 +66,24 @@
 		this.render['R'] = "☃";
 		this.render['D'] = "☠";
 		this.render['L'] = "☒";
 		this.render['O'] = "☐";
-		draw(gr, g);
-	}
-
-	void set_fn(F)(F f) { this.fn = f; }
-
-	void run() {
-		Application.run(this);
+		this.paint ~= (Control c, PaintEventArgs ev) {
+			graphicContext.copyTo(ev.graphics, Rect(0,0,this.clientSize.width,this.clientSize.height));
+		};
 	}
 
-private:
-	Graphics gr;
-
-	void my_paint(Control, PaintEventArgs ev)
-	{
-		gr.copyTo(ev.graphics, Rect(0,0,this.clientSize.width,this.clientSize.height));
-	}
-
-	void draw(Graphics gr, const(Game) g)
+	void draw(const(Game) g)
 	{
 		int scrW = this.clientSize.width;
 		int scrH = this.clientSize.height;
+
 		// Fill bg.
-		gr.fillRectangle(this.backColor, Rect(0,0,scrW,scrH));
+		graphicContext.fillRectangle(this.backColor, Rect(0,0,scrW,scrH));
 
 		// Fill water.
 		int w = g.water_level();
-		gr.fillRectangle(this.colors['W'], Rect(0, scrH-cell*w-1, scrW, cell*w+1));
+		graphicContext.fillRectangle(this.colors['W'], Rect(0, scrH-cell*w-1, scrW, cell*w+1));
 
 		// Paint map.
 		for(int y=1; y<=g.map.H; ++y)
 		for(int x=1; x<=g.map.W; ++x) {
@@ -99,13 +91,22 @@
 			char c = g.map[y,x];
 			if( c != ' ' ) {
 				if( c == 'R' && g.dead )
 					c = 'D';
-				gr.drawText(this.render[c], font, this.colors[c], r);
+				graphicContext.drawText(this.render[c], font, this.colors[c], r);
 			}
 		}
 
-		set_text(g);
+		// Update textual info.
+		this.text = .text("Score: ", g.score, " Air: ", g.hp, " Tide: ", g.water_until_rise);
+		invalidate();
+	}
+
+private:
+	void setup_keyhandling()
+	{
+		noMessageFilter();
+		this.keyDown ~= &my_keydown;
 	}
 
 	void my_keydown(Control c, KeyEventArgs ev)
 	{
@@ -116,21 +117,11 @@
 		case Keys.LEFT:  fn('L'); break;
 		case Keys.RIGHT: fn('R'); break;
 		case Keys.W:     fn('W'); break;
 		case Keys.A:     fn('A'); break;
+		case Keys.G:     fn(solver.single_step()); break;
 		default:         break;
 		}
 	}
 
-	void set_text(const(Game) g) {
-		this.text = .text("Score: ", g.score, " Air: ", g.hp, " Tide: ", g.water_until_rise);
-	}
-}
-
-void main(string[] args)
-{
-	auto d = new Driver(File(args[1]));
-	d.addObserver!(GuardedOutput)();
-	GUI g = d.addObserver!(GUI)();
-	g.set_fn(&d.command);
-	g.run();
+	Solver solver;
 }