import CryptoJS from 'crypto-js';

// 十六位十六進(jìn)制數(shù)作為密鑰
const SECRET_KEY = CryptoJS.enc.Utf8.parse("3333e6e143439161");
// 十六位十六進(jìn)制數(shù)作為密鑰偏移量
const SECRET_IV = CryptoJS.enc.Utf8.parse("e3bbe7e3ba84431a");

// 類型 window.localStorage,window.sessionStorage,
const config = {
    type: 'localStorage', // 本地存儲(chǔ)類型 sessionStorage
    prefix: 'SDF_0.0.1', // 名稱前綴 建議：項(xiàng)目名 + 項(xiàng)目版本
    expire: 1, //過期時(shí)間 單位：秒
    isEncrypt: true // 默認(rèn)加密 為了調(diào)試方便, 開發(fā)過程中可以不加密
}

// 判斷是否支持 Storage
export const isSupportStorage = () => {
    return (typeof (Storage) !== "undefined") ? true : false
}

// 設(shè)置 setStorage
export const setStorage = (key, value, expire = 0) => {
    if (value === '' || value === null || value === undefined) {
        value = null;
    }

    if (isNaN(expire) || expire < 0) throw new Error("Expire must be a number");

    expire = (expire ? expire : config.expire) * 1000;
    let data = {
        value: value, // 存儲(chǔ)值
        time: Date.now(), //存值時(shí)間戳
        expire: expire // 過期時(shí)間
    }
    
    const encryptString = config.isEncrypt 
    ? encrypt(JSON.stringify(data))
    : JSON.stringify(data);
    
    window[config.type].setItem(autoAddPrefix(key), encryptString);
}

// 獲取 getStorage
export const getStorage = (key) => {
    key = autoAddPrefix(key);
    // key 不存在判斷
    if (!window[config.type].getItem(key) || JSON.stringify(window[config.type].getItem(key)) === 'null') {
        return null;
    }

    // 優(yōu)化 持續(xù)使用中續(xù)期
    const storage = config.isEncrypt 
    ? JSON.parse(decrypt(window[config.type].getItem(key))) 
    : JSON.parse(window[config.type].getItem(key));
    
    let nowTime = Date.now();

    // 過期刪除
    if (storage.expire && config.expire * 6000 < (nowTime - storage.time)) {
        removeStorage(key);
        return null;
    } else {
        // 未過期期間被調(diào)用 則自動(dòng)續(xù)期 進(jìn)行?；?        setStorage(autoRemovePrefix(key), storage.value);
        return storage.value;
    }
}

// 是否存在 hasStorage
export const hasStorage = (key) => {
    key = autoAddPrefix(key);
    let arr = getStorageAll().filter((item)=>{
        return item.key === key;
    })
    return arr.length ? true : false;
}

// 獲取所有key
export const getStorageKeys = () => {
    let items = getStorageAll()
    let keys = []
    for (let index = 0; index < items.length; index++) {
        keys.push(items[index].key)
    }
    return keys
}

// 根據(jù)索引獲取key
export const getStorageForIndex = (index) => {
    return window[config.type].key(index)
}

// 獲取localStorage長(zhǎng)度
export const getStorageLength = () => {
    return window[config.type].length
}

// 獲取全部 getAllStorage
export const getStorageAll = () => {
    let len = window[config.type].length // 獲取長(zhǎng)度
    let arr = new Array() // 定義數(shù)據(jù)集
    for (let i = 0; i < len; i++) {
        // 獲取key 索引從0開始
        let getKey = window[config.type].key(i)
        // 獲取key對(duì)應(yīng)的值
        let getVal = window[config.type].getItem(getKey)
        // 放進(jìn)數(shù)組
        arr[i] = {'key': getKey, 'val': getVal,}
    }
    return arr
}

// 刪除 removeStorage
export const removeStorage = (key) => {
    window[config.type].removeItem(autoAddPrefix(key));
}

// 清空 clearStorage
export const clearStorage = () => {
    window[config.type].clear();
}

// 名稱前自動(dòng)添加前綴
const autoAddPrefix = (key) => {
    const prefix = config.prefix ? config.prefix + '_' : '';
    return  prefix + key;
}

// 移除已添加的前綴
const autoRemovePrefix = (key) => {
    const len = config.prefix ? config.prefix.length+1 : '';
    return key.substr(len)
    // const prefix = config.prefix ? config.prefix + '_' : '';
    // return  prefix + key;
}

/**
 * 加密方法
 * @param data
 * @returns {string}
 */
const encrypt = (data) => {
    if (typeof data === "object") {
        try {
            data = JSON.stringify(data);
        } catch (error) {
            console.log("encrypt error:", error);
        }
    }
    const dataHex = CryptoJS.enc.Utf8.parse(data);
    const encrypted = CryptoJS.AES.encrypt(dataHex, SECRET_KEY, {
        iv: SECRET_IV,
        mode: CryptoJS.mode.CBC,
        padding: CryptoJS.pad.Pkcs7
    });
    return encrypted.ciphertext.toString();
}

/**
 * 解密方法
 * @param data
 * @returns {string}
 */
const decrypt = (data) => {
    const encryptedHexStr = CryptoJS.enc.Hex.parse(data);
    const str = CryptoJS.enc.Base64.stringify(encryptedHexStr);
    const decrypt = CryptoJS.AES.decrypt(str, SECRET_KEY, {
        iv: SECRET_IV,
        mode: CryptoJS.mode.CBC,
        padding: CryptoJS.pad.Pkcs7
    });
    const decryptedStr = decrypt.toString(CryptoJS.enc.Utf8);
    return decryptedStr.toString();
}