const baseFindIndex = function(array, predicate, fromIndex, fromRight) {
  var length = array.length,
    index = fromIndex + (fromRight ? 1 : -1);

  while ((fromRight ? index-- : ++index < length)) {
    if (predicate(array[index], index, array)) {
      return index;
    }
  }
  return -1;
}

const filterByKey = function(objs,keys) {
  objs = objs || [];
  var newObjs = [];

  for (var i = 0, n = objs.length; i < n; i++) {
    var obj = objs[i];

    // 对象则在筛选时将键名替换
    var newObj = {};
    if(typeof keys === 'object'){
      for (var name in keys) {
        if(Array.isArray(keys[name])){
          // 数组第1个为字段名,第2个为函数,返回的值将覆盖新对象
          newObj[keys[name][0]] = keys[name][1](obj);
        }else{
          newObj[keys[name]] = obj[name];
        }
      }
    }else{
      for (let j = 0, n = keys.length; j < n; j++) {
        var key = keys[j];
        newObj[key] = obj[key];
      }
    }

    newObjs.push(newObj);
  }

  return newObjs;
}

const createRangeMethod = function(ranges,compareFun) {
  return function (curr) {
    var index = -1;

    for (var i = 0, n = ranges.length; i < n; i++) {
      if(compareFun(curr, ranges[i],i)) index = i;
    }

    return index;
  }
}


const debounce = function (func, wait) {
  var timer;
  return function () {
    var context = this,args = arguments;
    clearTimeout(timer);
    timer = setTimeout(function () {
      func.apply(context, args);
    }, wait);
  }
}



// 生成uuid
const uuid = function () {
  return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) {
    var r = Math.random()*16|0, v = c == 'x' ? r : (r&0x3|0x8);
    return v.toString(16);
  });
}

// debug函数，关联配置
const debug = function (message,config?) {

}

// base64图片大小
const base64ImageSize = function (base64Image) {
  var str = base64Image.substring(22).replace('=',''); // 去除头部
  var strLength = parseInt(str.length);
  var fileLength = strLength - (strLength/8) *2;
  return fileLength;
}

export const utils = {
  baseFindIndex,
  filterByKey,
  createRangeMethod,
  debounce,
  uuid,
  debug,
  base64ImageSize
}