import ResizeObserver from 'resize-observer-polyfill';

const isServer = typeof window === 'undefined';

/* istanbul ignore next */
function resizeHandler(entries: any[]) {
  for (const entry of entries) {
    const listeners = entry.target.__resizeListeners__ || [];
    if (listeners.length) {
      listeners.forEach((fn: () => any) => {
        fn();
      });
    }
  }
}

/* istanbul ignore next */
export function addResizeListener(element: any, fn: () => any) {
  if (isServer) return;
  if (!element.__resizeListeners__) {
    element.__resizeListeners__ = [];
    element.__ro__ = new ResizeObserver(resizeHandler);
    element.__ro__.observe(element);
  }
  element.__resizeListeners__.push(fn);
}

/* istanbul ignore next */
export function removeResizeListener(element: any, fn: () => any) {
  if (!element || !element.__resizeListeners__) return;
  element.__resizeListeners__.splice(element.__resizeListeners__.indexOf(fn), 1);
  if (!element.__resizeListeners__.length) {
    element.__ro__.disconnect();
  }
}

export function triggerWindowResize() {
  const event = document.createEvent('HTMLEvents');
  event.initEvent('resize', true, true);
  (event as any).eventType = 'message';
  window.dispatchEvent(event);
}

export function setDivHeight(e: MouseEvent, minHeight, scroll) {
  e.preventDefault();
  e.stopPropagation();
  const divObject = e.currentTarget as HTMLElement;
  if (divObject) {
    const divHeight = divObject.offsetHeight;
    let height = divHeight;
    const startY = e.clientY;
    let isMove = false;
    document.onmousemove = function (res) {
      res.preventDefault();
      isMove = true;
      const distY = Math.abs(res.clientY - startY);
      if (res.clientY > startY) {
        if (divHeight - distY >= minHeight) {
          height = divHeight - distY;
        } else if (divHeight - distY < minHeight) {
          height = minHeight;
        }
      }
      if (res.clientY < startY) {
        height = divHeight + distY;
      }
      if (height > document.body.clientHeight - 175) height = document.body.clientHeight - 175;
      divObject.style.height = height + 'px';
    };
    document.onmouseup = function () {
      document.onmousemove = null;
      if (isMove && scroll.y != height - 100) {
        scroll.y = height - 100;
      }
    };
  }
}