import { PluginObject } from 'vue'

type typeFn = 'sessionStorage' | 'localStorage'

interface IStorageData<T> {
    key: string,
    value: T,
    expire: number,
}

function setItem<T> (fn: typeFn, key: string, value: T, expire: number = -1) : T {
    window[fn].setItem(key, JSON.stringify({ key, value, expire }))
    return value
}

function getItem<T> (fn: typeFn, key: string, defValue: T | null = null) : T | null {
    let data = window[fn].getItem(key)
    if (data === null) {
        return defValue
    }
    const { expire, value } = JSON.parse(data) as IStorageData<T>
    if (expire === -1 || Date.now() < expire) {
        return value
    }
    removeItem(fn, key)
    return defValue
}

function removeItem(fn: typeFn, key: string): void {
    window[fn].removeItem(key)
}

function updateItem<T> (fn: typeFn, key: string, value: T, expire?: number) : T {
    const data = window[fn].getItem(key)
    if (data) {
        const { value: prevValue, expire: prevExpire } = JSON.parse(data) as IStorageData<T>
        if (prevExpire === -1 || Date.now() < prevExpire) {
            if (Array.isArray(value)) {
                value = [...prevValue as any as [], ...value] as any as T
            } else {
                value = Object.assign({}, prevValue, value)
            }
            if (!expire) {
                expire = prevExpire
            }
        }
    }
    return setItem<T>(fn, key, value, expire)
}

function clear(fn: typeFn) : void {
    window[fn].clear()
}

function generate (fn: typeFn) {
    return {
        setItem<T> (key: string, value: T, expire = -1) : T {
            return setItem<T>(fn, key, value, expire)
        },
        getItem<T> (key: string, defValue = null) : T | null{
            return getItem<T>(fn, key, defValue)
        },
        removeItem (key) {
            return removeItem(fn, key)
        },
        updateItem<T> (key: string, value: T, expire?) {
            return updateItem<T>(fn, key, value, expire)
        },
        clear () {
            return clear(fn)
        },
        generate (key: string) {
            return {
                setItem<T> (value: T, expire = -1) : T {
                    return setItem<T>(fn, key, value, expire)
                },
                getItem<T> (defValue = null) : T | null{
                    return getItem<T>(fn, key, defValue)
                },
                removeItem () {
                    return removeItem(fn, key)
                },
                updateItem<T> (value: T, expire?) {
                    return updateItem<T>(fn, key, value, expire)
                },
                clear () {
                    return clear(fn)
                },
            }
        }
    }
}

export const cache = generate('sessionStorage')

export const local = generate('localStorage')

const Storage: PluginObject<undefined> = {
    install(Vue) {
        Vue.prototype.$cache = cache
        Vue.prototype.$local = local
    }
}

export default Storage