package kernel.ui;

import util.Signal.SignalListner;
import util.Vec.Vec2;
import util.Color;
import lib.TermWriteable;

class VirtualTermWriter implements TermWriteable extends TermBuffer {
    private static final defaultSize:Vec2<Int> = {x: 50,y: 50};

    private var target: TermWriteable;
    private var enabled:Bool = false;
    private var onResizeListner: SignalListner<Vec2<Int>>;

    public function new(?target: TermWriteable) {
        setTarget(target);

        if (enabled){
            enable();
        }

        super();
    }

    public function enable() {
        if (target != null){
            enabled = true;
            super.copyBufferToTarget(target);
        }
    }

    public function disable() {
        enabled = false;
    }

    public inline function isEnabled(): Bool {
        return enabled;
    }

    public function setTarget(newTarget: TermWriteable) {
        if (newTarget != null){
            super.setSize(newTarget.getSize());

            // Remove old target event listner
            if (onResizeListner != null && target != null){
                target.onResize.remove(onResizeListner);
            }

            // Add new target event listner
            onResizeListner = newTarget.onResize.on(newSize -> {
                setSuperSize(newSize);
            });

            target = newTarget;
        }
    }

    private function setSuperSize(size: Vec2<Int>) {
        super.setSize(target.getSize());
    }
    
    // 
    // TermWriteable functions.
    //
	public override function write(text:String) {
        if (isEnabled()){
            target.write(text);
        }
        
        super.write(text);
    }

	public override function scroll(y:Int) {
        if (isEnabled()){
            target.scroll(y);
        }
        super.scroll(y);
    }

	public override function getCursorPos():Vec2<Int> {
		if (isEnabled()){
            return target.getCursorPos();
        }else{
            return super.getCursorPos();
        }
	}

	public override function setCursorPos(x:Int, y:Int) {
        if (isEnabled()){
            target.setCursorPos(x,y);
        }

        super.setCursorPos(x,y);
    }

	public override function getCursorBlink():Bool {
		throw new haxe.exceptions.NotImplementedException();
	}

	public override function setCursorBlink(blink:Bool) {
        // TODO
    }

	public override function getSize():Vec2<Int> {
        // TODO: make sense ?
        if (target != null){
            return target.getSize();
        }

        return defaultSize;
	}

	public override function clear() {
        if (isEnabled()){
            target.clear();
        }
        
        super.clear();
    }

	public override function clearLine() {
        if (isEnabled()){
            target.clearLine();
        }

        super.clearLine();
    }

	public override function getTextColor():Color {
        if (isEnabled()){
            return target.getTextColor();
        }

        return super.getTextColor();
	}

	public override function setTextColor(colour:Color) {
        if (isEnabled()){
            target.setTextColor(colour);
        }

        super.setTextColor(colour);
    }

	public override function getBackgroundColor():Color {
        if (isEnabled()){
            return target.getBackgroundColor();
        }

        return super.getBackgroundColor();
	}

	public override function setBackgroundColor(color:Color) {
        if (isEnabled()){
            target.setBackgroundColor(color);
        }

        super.setBackgroundColor(color);
    }

	public override function isColor():Bool {
		throw new haxe.exceptions.NotImplementedException();
	}
}