/**
 * 转换尺寸 canvas缩放后 返回的尺寸不对 要做调整
 * @param  {[type]} width  canvas的CSS宽度
 * @param  {[type]} height canvas的CSS高度
 * @param  {[type]} canvasWidth  canvas的画布宽度
 * @param  {[type]} canvasHeight  canvas的画布高度
 * @param  {[type]} obj    需要转换的尺寸对象
 * @return {[type]}        转换后的尺寸对象
 */
const transSize = function (width, height, canvasWidth, canvasHeight, obj) {
  if (!obj) {
    return {
      width: 0,
      height: 0,
      left: 0,
      top: 0,
      right: 0,
      bottom: 0
    };
  }
  const res = {};
  let _ratio;
  const ratio = canvasWidth / canvasHeight;
  // 如果宽高比大于画布的宽高比 则比例以高度来计算 反之以宽度计算
  if (width / height > ratio) {
    _ratio = height / canvasHeight;
    const _width = (width - height * ratio) / 2;
    res.width = typeof obj.width === 'number' ? obj.width * _ratio : obj.width;
    res.height = typeof obj.height === 'number' ? obj.height * _ratio : obj.height;
    res.top = obj.top * _ratio;
    res.bottom = obj.bottom * _ratio;
    res.left = obj.left * _ratio + _width;
    res.right = obj.right * _ratio + _width;
  } else {
    _ratio = width / canvasWidth;
    const _height = (height - width / ratio) / 2;
    res.width = typeof obj.width === 'number' ? obj.width * _ratio : obj.width;
    res.height = typeof obj.height === 'number' ? obj.height * _ratio : obj.height;
    res.top = obj.top * _ratio + _height;
    res.bottom = obj.bottom * _ratio + _height;
    res.left = obj.left * _ratio;
    res.right = obj.right * _ratio;
  }
  // console.log('trans', res, 'obj', obj);
  // console.trace('transSize callStack');
  return res;
};

// 防抖
const debounce = function (fn, delay = 500) {
  var timer = null;
  return function () {
    // eslint-disable-next-line @typescript-eslint/no-this-alias
    var _this = this;
    var args = arguments;
    if (timer) clearTimeout(timer);
    timer = setTimeout(function () {
      fn.apply(_this, args);
    }, delay);
  };
};

// 节流
const throttle = function (fn, delay = 300) {
  var lastTime, timer;
  return function () {
    // eslint-disable-next-line @typescript-eslint/no-this-alias
    var _this = this;
    var args = arguments;
    var nowTime = Date.now();
    if (lastTime && nowTime - lastTime < delay) {
      if (timer) clearTimeout(timer);
      timer = setTimeout(function () {
        lastTime = nowTime;
        fn.apply(_this, args);
      }, delay);
    } else {
      lastTime = nowTime;
      fn.apply(_this, args);
    }
  };
};

/**
 * 执行指定次数的定时器
 * @param {回调} func
 * @param {等待时间} w
 * @param {重复次数} t
 */
const interval = function (func, w, t) {
  const interv = function () {
    if (typeof t === 'undefined' || t-- > 0) {
      setTimeout(interv, w);
      try {
        // eslint-disable-next-line no-useless-call
        func.call(null);
      } catch (e) {
        t = 0;
        throw e.toString();
      }
    }
  };

  setTimeout(interv, w);
};

export default {
  debounce,
  interval,
  throttle,
  transSize
};