const cookieStorage = {

	get COOKIE() { return window.document.cookie; },
	set COOKIE(v: string) { window.document.cookie = v; },

	get ITEMS(): { [key: string]: string } {
		return this.COOKIE
			.split(/;\s*/)
			.filter(Boolean)
			.map(s => s.match(/^([^=]+)=(.*)$/))
			.reduce((mem, [str, key, value]) => {
				mem[key] = decodeURIComponent(value);
				return mem;
			}, {});
	},

	get DEFAULT_OPTIONS() {
		const nextYear = new Date();
		nextYear.setFullYear(nextYear.getFullYear() + 1);

		return {
			path: '/',
			domain: window.location.hostname,
			expires: nextYear,
		};
	},

	get DEFAULT_CHUNK() {
		return {
			size: 4000,
			maxCount: 10,
		};
	},


	_getOptionsString(options: { path?: string, domain?: string, expires?: Date|number } = {}) {
		const opts = Object.assign(this.DEFAULT_OPTIONS, options) as {
			path: string,
			domain: string,
			expires?: Date|number|string,
		};

		if (typeof opts.expires === 'number')
			opts.expires = (opts.expires !== 0) ? new Date(opts.expires) : undefined;
		if (opts.expires instanceof Date)
			opts.expires = opts.expires.toUTCString();

		return Object.keys(opts)
			.filter(key => Boolean(opts[key]))
			.map(key => `${key}=${opts[key]}`)
			.join('; ');
	},


	getItem(key: string) {
		return this.ITEMS[key];
	},

	setItem(
		key: string,
		value: string,
		options: { path?: string, domain?: string, expires?: Date|number } = {}
	) {
		const optionsString = this._getOptionsString(options);

		const encoded = encodeURIComponent(value);
		if (encoded.length > this.DEFAULT_CHUNK.size) {
			console.warn('Cookie limit is 4 KB.');
		}

		this.COOKIE = `${key}=${encodeURIComponent(value)}; ${optionsString}`;
	},

	removeItem(key: string) {
		this.setItem(key, '', { expires: -1 });
	},


	setItemByChunks(
		key: string,
		value: string,
		options: { path?: string, domain?: string, expires?: Date|number } = {},
		chunkOptions: { size?: number, maxCount?: number } = {}
	) {
		const { size: chunkSize, maxCount: chunkMaxCount } = Object.assign(this.DEFAULT_CHUNK, chunkOptions) as {
			size: number,
			maxCount: number,
		};

		const optionsString = this._getOptionsString(options);

		encodeURIComponent(value)
			.match(/(%.{2}|.)/g)
			.reduce((chunks, symbol) => {
				let lastIndex = chunks.length - 1;
				let lastChunk = chunks[lastIndex];

				if ((lastChunk.length + symbol.length) > chunkSize) {
					lastIndex += 1;
					lastChunk = '';
				}

				chunks[lastIndex] = lastChunk + symbol;
				return chunks;
			}, [''])
			.forEach((chunk, index) => {
				this.COOKIE = `${key}-${index}=${chunk}; ${optionsString}`;
			});
	},

	getItemByChunks(key: string) {
		const items = this.ITEMS;
		return Object
			.keys(items)
			.map(k => k.match(/(^.*?)\-(\d+$)/))
			.filter(Boolean)
			.filter(([k, name, index]) => name === key)
			.map(([k, name, index]) => index)
			.map(Number)
			.sort()
			.reduce((result, index) => result + items[`${key}-${index}`], '');
	},

	removeItemByChunks(key: string) {
		Object
			.keys(this.ITEMS)
			.map(k => k.match(/(^.*?)\-(\d+$)/))
			.filter(Boolean)
			.filter(([k, name]) => name === key)
			.forEach(([k]) => this.removeItem(k));
	},


	clear() {
		Object
			.keys(this.ITEMS)
			.forEach(key => this.removeItem(key));
	},
}