import * as React from 'react';
import { useEventListener, useMountEffect } from 'primereact/hooks';
import { ObjectUtils } from 'primereact/utils';

function _extends() {
  _extends = Object.assign || function (target) {
    for (var i = 1; i < arguments.length; i++) {
      var source = arguments[i];

      for (var key in source) {
        if (Object.prototype.hasOwnProperty.call(source, key)) {
          target[key] = source[key];
        }
      }
    }

    return target;
  };

  return _extends.apply(this, arguments);
}

function _arrayWithHoles(arr) {
  if (Array.isArray(arr)) return arr;
}

function _iterableToArrayLimit(arr, i) {
  var _i = arr == null ? null : typeof Symbol !== "undefined" && arr[Symbol.iterator] || arr["@@iterator"];

  if (_i == null) return;
  var _arr = [];
  var _n = true;
  var _d = false;

  var _s, _e;

  try {
    for (_i = _i.call(arr); !(_n = (_s = _i.next()).done); _n = true) {
      _arr.push(_s.value);

      if (i && _arr.length === i) break;
    }
  } catch (err) {
    _d = true;
    _e = err;
  } finally {
    try {
      if (!_n && _i["return"] != null) _i["return"]();
    } finally {
      if (_d) throw _e;
    }
  }

  return _arr;
}

function _arrayLikeToArray(arr, len) {
  if (len == null || len > arr.length) len = arr.length;

  for (var i = 0, arr2 = new Array(len); i < len; i++) {
    arr2[i] = arr[i];
  }

  return arr2;
}

function _unsupportedIterableToArray(o, minLen) {
  if (!o) return;
  if (typeof o === "string") return _arrayLikeToArray(o, minLen);
  var n = Object.prototype.toString.call(o).slice(8, -1);
  if (n === "Object" && o.constructor) n = o.constructor.name;
  if (n === "Map" || n === "Set") return Array.from(o);
  if (n === "Arguments" || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)) return _arrayLikeToArray(o, minLen);
}

function _nonIterableRest() {
  throw new TypeError("Invalid attempt to destructure non-iterable instance.\nIn order to be iterable, non-array objects must have a [Symbol.iterator]() method.");
}

function _slicedToArray(arr, i) {
  return _arrayWithHoles(arr) || _iterableToArrayLimit(arr, i) || _unsupportedIterableToArray(arr, i) || _nonIterableRest();
}

var DeferredContent = /*#__PURE__*/React.forwardRef(function (props, ref) {
  var _React$useState = React.useState(false),
      _React$useState2 = _slicedToArray(_React$useState, 2),
      loadedState = _React$useState2[0],
      setLoadedState = _React$useState2[1];

  var elementRef = React.useRef(null);

  var _useEventListener = useEventListener({
    target: 'window',
    type: 'scroll',
    listener: function listener() {
      if (shouldLoad()) {
        load();
        unbindScrollListener();
      }
    }
  }),
      _useEventListener2 = _slicedToArray(_useEventListener, 2),
      bindScrollListener = _useEventListener2[0],
      unbindScrollListener = _useEventListener2[1];

  var shouldLoad = function shouldLoad() {
    if (loadedState) {
      return false;
    } else {
      var rect = elementRef.current.getBoundingClientRect();
      var winHeight = document.documentElement.clientHeight;
      return winHeight >= rect.top;
    }
  };

  var load = function load(event) {
    setLoadedState(true);
    props.onLoad && props.onLoad(event);
  };

  useMountEffect(function () {
    if (!loadedState) {
      shouldLoad() ? load() : bindScrollListener();
    }
  });
  var otherProps = ObjectUtils.findDiffKeys(props, DeferredContent.defaultProps);
  return /*#__PURE__*/React.createElement("div", _extends({
    ref: elementRef
  }, otherProps), loadedState && props.children);
});
DeferredContent.displayName = 'DeferredContent';
DeferredContent.defaultProps = {
  __TYPE: 'DeferredContent',
  onload: null
};

export { DeferredContent };
