// https://github.com/uxitten/polyfill/blob/master/string.polyfill.js
// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/padStart
if (!String.prototype.padStart) {
    String.prototype.padStart = function padStart(targetLength,padString) {
        targetLength = targetLength>>0; //floor if number or convert non-number to 0;
        padString = String((typeof padString !== 'undefined' ? padString : ' '));
        if (this.length > targetLength) {
            return String(this);
        }
        else {
            targetLength = targetLength-this.length;
            if (targetLength > padString.length) {
                padString += padString.repeat(targetLength/padString.length); //append to original to ensure we are longer than needed
            }
            return padString.slice(0,targetLength) + String(this);
        }
    };
}

export function copy(obj) {
    return JSON.parse(JSON.stringify(obj));
}

export function named(value) {
    return function (target) {
        target.definedName = value;
    }
}

export function formatCurrency(name) {
  if (name === 'USD' ) {
    return '$';
  } else if (name === 'RMB') {
    return '￥';
  } else if (name === 'EUR') {
    return '€'
  } else if (name === 'GBP') {
    return '£'
  } else {
    return name + ' ';
  }
}

export function formatPrice(price) {
  return Math.ceil(price).toLocaleString();
}

export function formatPercent(number) {
    return Math.round(number * 100) + '%'
}

export function formatDate(date) {
    if (isEmpty(date)) { return 'NaN'; }

    const year = date.getFullYear();
    const month = date.getMonth() + 1;
    const day = date.getDate();

    const monthStr = ('' + month).padStart(2, 0);
    const dayStr = ('' + day).padStart(2, 0);
    const formatted = year + '-' + monthStr + '-' + dayStr;

    return formatted; 
}

export function formatTime(date) {
    const hours = date.getHours();
    const minutes = date.getMinutes();

    const hoursStr = ('' + hours).padStart(2, 0);
    const minutesStr = ('' + minutes).padStart(2, 0);
    const formatted = hoursStr + ':' + minutesStr;

    return formatted;
}

export function formatDatetime(date) {

    const year = date.getFullYear();
    const month = date.getMonth() + 1;
    const day = date.getDate();

    const monthStr = ('' + month).padStart(2, 0);
    const dayStr = ('' + day).padStart(2, 0);

    const hours = date.getHours();
    const minutes = date.getMinutes();

    const hoursStr = ('' + hours).padStart(2, 0);
    const minutesStr = ('' + minutes).padStart(2, 0);

    const formatted = year + '-' + monthStr + '-' + dayStr + ' ' + hoursStr + ':' + minutesStr;

    return formatted;
}

export function mixins(...list) {
    return function (target) {
        list.forEach(val => {
            const mixinObj = Object.create(val.prototype, {})
            const name = Object.getPrototypeOf(mixinObj).constructor.name;
            const camelCase = name.substr(0, 1).toLowerCase() + name.substr(1);
            Object.assign(target.prototype, {[camelCase]: mixinObj})
        })
    }
}

export function camelCase(name) {
    return name.substr(0, 1).toLowerCase() + name.substr(1);
}

export class UrlBuilder {
    constructor(url) {
        this.url = url;
        this.paramList = [];
    }

    append(name, value) {
        if (isNotEmpty(value)) {
            this.paramList.push({'name': name, 'value': value});
        }
        return this;
    }

    build() {
        this.paramList.forEach((e, i, a) => {
            if (i === 0) {
                this.url += '?';
            } else {
                this.url += '&';
            }
            this.url += e.name + '=' + e.value;
        });
        return this.url;
    }
}

export function isNotEmpty(val) {
    return val !== undefined && val !== null && val !== '';
}

export function isEmpty(val) {
    return val === undefined || val === null || val === '';
}

export function empty(a) {
    if (a === "") return true; //检验空字符串
    if (a === "null") return true; //检验字符串类型的null
    if (a === "undefined") return true; //检验字符串类型的 undefined
    if (!a && a !== 0 && a !== "") return true; //检验 undefined 和 null
    if (Array.prototype.isPrototypeOf(a) && a.length === 0) return true; //检验空数组
    if (Object.prototype.isPrototypeOf(a) && Object.keys(a).length === 0) return true;  //检验空对象
    return false;
}

export function prepareUrl(url) {
    return new UrlBuilder(url);
}

export function debounce(fn, delay = 500) {
    let timer;
    return (e) => {
        e.persist();
        clearTimeout(timer);
        timer = setTimeout(() => {
            fn(e);
        }, delay);
    };
};

export function throttle(fn, delay, atleast) {
    let timeout = null,
    startTime = new Date();
    return function() {
        let curTime = new Date();
        clearTimeout(timeout);
        if (curTime - startTime >= atleast) {
            fn();
            startTime = curTime;
        } else {
            timeout = setTimeout(fn, delay);
        }
    }
}

export function clickUrl(url) {
    const httpLink = document.createElement('a');
    httpLink.href = url;
    httpLink.target = '_blank';
    httpLink.click();
}