import MediaPlayer from "../MediaPlayer";

class AutoPause {
    private threshold: number;
    player: MediaPlayer;
    
    constructor(){
        this.threshold = 0.25;
        this.handlerIntersection = this.handlerIntersection.bind(this);
        this.handlerVisibilityChange = this.handlerVisibilityChange.bind(this);
    }

    run(player: MediaPlayer){
        this.player = player;

        const observer = new IntersectionObserver(this.handlerIntersection, {threshold : this.threshold})
        
        observer.observe(this.player.media)

        document.addEventListener("visibilitychange", this.handlerVisibilityChange)

    }

    private handlerVisibilityChange(){
        const isVisible = document.visibilityState === 'visible'

        if(isVisible){
            this.player.play();
        } else {
            this.player.pause();
        }
    }

    private handlerIntersection(entries: IntersectionObserverEntry[]) {
        
        const entry = entries[0]; 
        const isVisible = entry.intersectionRatio >= this.threshold;

        if( isVisible ){
            this.player.play();
        } else {
            this.player.pause();
        }

    }
}

export default AutoPause;