import { CacheData, Theme } from './type'

/**
 * 全局缓存初始数据
 */
const initData: CacheData = {
    loginInfo: {
        expiresAt: 0,
        token: '',
        user: {
            userName: '访客'
        },
    },
    theme: Theme.default,
}

/**
 * 本地存储类
 */
function useStorage() {
    const getItem = <Key extends keyof CacheData>(key: Key): CacheData[Key] => {
        const str = wx.getStorageSync(key);
        if (str) {
            const value = JSON.parse(str);
            return value;
        } else {
            return initData[key];
        }
    }

    const setItem = <Key extends keyof CacheData>(key: Key, value: CacheData[Key]): void => {
        if (value !== undefined && value !== null) {
            const str = JSON.stringify(value);
            wx.setStorageSync(key, str);
        }
    }

    const removeItem = <Key extends keyof CacheData>(key: Key): void => {
        wx.removeStorageSync(key);
    }

    const clear = (): void => {
        wx.clearStorageSync();
    }

    return {
        get value() {
            const data = initData;
            type t = keyof CacheData;
            for (const key in data) {
                const k = key as t;
                (<CacheData[t]>data[k]) = getItem(k);
            }
            return data;
        },
        getItem,
        setItem,
        removeItem,
        clear
    }
}

export const globalCache = useStorage();