import {Awaitable} from '../support/types'
import {Safe} from '../support/Safe'

/**
 * Abstract interface class for a cached object.
 */
export abstract class Cache {
    /**
     * Fetch a value from the cache by its key.
     * @param {string} key
     * @return Promise<any|undefined>
     */
    public abstract fetch(key: string): Awaitable<string|undefined>;

    /**
     * Fetch a value from the cache by its key as a Safe value.
     * @param key
     */
    public async safe(key: string): Promise<Safe> {
        return new Safe(await this.fetch(key))
    }

    /**
     * Store the given value in the cache by key.
     * @param {string} key
     * @param {string} value
     * @param expires
     */
    public abstract put(key: string, value: string, expires?: Date): Awaitable<void>;

    /**
     * Check if the cache has the given key.
     * @param {string} key
     * @return Promise<boolean>
     */
    public abstract has(key: string): Awaitable<boolean>;

    /**
     * Drop the given key from the cache.
     * @param {string} key
     */
    public abstract drop(key: string): Awaitable<void>;

    /**
     * Fetch an item from the cache by key, and then remove it.
     * @param key
     */
    public abstract pop(key: string): Awaitable<string|undefined>;

    /**
     * Increment a key in the cache by a given amount.
     * @param key
     * @param amount
     */
    public abstract increment(key: string, amount?: number): Awaitable<number|undefined>;

    /**
     * Decrement a key in the cache by a given amount.
     * @param key
     * @param amount
     */
    public abstract decrement(key: string, amount?: number): Awaitable<number|undefined>;

    /**
     * Push an item onto the end an array-like key.
     * @param key
     * @param value
     */
    public abstract arrayPush(key: string, value: string): Awaitable<void>;

    /**
     * Remove and return an item from the beginning of an array-like key.
     * @param key
     * @param value
     */
    public abstract arrayPop(key: string): Awaitable<string|undefined>;
}