import { Vector2 } from 'touchcontroller';

export function getScroll(element: Element): Vector2 {
    //todo better
    const elementChild = element.children[0];
    if (!elementChild) {
        throw new Error(
            `There should be at least 1. child element if you want to measure scroll.`,
        );
    }
    const boundingRect = elementChild.getBoundingClientRect();
    return new Vector2(boundingRect.left, boundingRect.top).scaleInPlace(-1);
}
/*
//todo get working with fixed

let documentScroll  = TC.Vector2.Zero();
document.addEventListener('scroll',(event)=>{

    const event_:any = event;
    documentScroll = new TC.Vector2(event_.pageX,event_.pageY);

});



export function getScroll(element:Element):TC.Vector2{

    const scroll = TC.Vector2.Zero();
    let currentElement:Element|null = element;

    while(currentElement){

        if(currentElement instanceof HTMLElement){
            if(currentElement.style.position==='fixed'){
                break;
            }
        }
        if(currentElement === window.document.body){
            break;
        }


        const currentScroll = new TC.Vector2(element.scrollLeft,element.scrollTop)
        //console.log(currentElement,currentScroll);
        scroll.addInPlace(currentScroll);

        currentElement = currentElement.parentElement;

    }

    if(currentElement === window.document.body){
        scroll.addInPlace(documentScroll);
    }

    return scroll;

}



/*
setImmediate(()=>{
    window.addEventListener('scroll',(event)=>{
        console.log('window',event);
    });
    document.addEventListener('scroll',(event)=>{
        console.log('document',event);
    });
    document.body.addEventListener('scroll',(event)=>{
        console.log('document.body',event);
    });
});
*/