import definition = require("fps-meter/fps-native");

class FrameHandlerImpl extends NSObject {

static new(): FrameHandlerImpl {

return <FrameHandlerImpl>super.new();

}

private _owner: FPSCallback;

public initWithOwner(owner: FPSCallback): FrameHandlerImpl {

this._owner = owner;

return this;

}

public handleFrame(sender: CADisplayLink): void {

this._owner._handleFrame(sender);

}

public static ObjCExposedMethods = {

"handleFrame": { returns: interop.types.void, params: [ CADisplayLink ] }

};

}

export class FPSCallback implements definition.FPSCallback {

public running: boolean;

private onFrame: Function;

private displayLink: CADisplayLink;

private impl: FrameHandlerImpl;

constructor(onFrame: (currentTimeMillis: number) => void) {

this.onFrame = onFrame;

this.impl = FrameHandlerImpl.new().initWithOwner(this);

this.displayLink = CADisplayLink.displayLinkWithTargetSelector(this.impl, "handleFrame");

this.displayLink.paused = true;

this.displayLink.addToRunLoopForMode(NSRunLoop.currentRunLoop(), NSDefaultRunLoopMode);

}

public start() {

if (this.running) {

return;

}

this.running = true;

this.displayLink.paused = false;

}

public stop() {

if (!this.running) {

return;

}

this.displayLink.paused = true;

this.running = false;

}

public _handleFrame(sender: CADisplayLink) {

if (!this.running) {

return;

}

// timestamp is CFTimeInterval, which is in seconds, the onFrame callback expects millis, so multiply by 1000

this.onFrame(sender.timestamp * 1000);

}

}