/**
 * helper to deal with cookies
 */

export interface CookieAttributes {
    /**
     * A number will be interpreted as days from time of creation
     */
    expires?: Date | number;

    /**
     * Hosts to which the cookie will be sent
     */
    domain?: string;

    /**
     * The cookie will only be included in an HTTP request if the request
     * path matches (or is a subdirectory of) the cookie's path attribute.
     */
    path?: string;

    /**
     * If enabled, the cookie will only be included in an HTTP request
     * if it is transmitted over a secure channel (typically HTTP over TLS).
     */
    secure?: boolean;
}

function stringifyAttribute(name: string, value: string | boolean | undefined): string {
    if (!value) {
        return '';
    }

    const stringified = '; ' + name;

    if (value === true) {
        return stringified; // boolean attributes shouldn't have a value
    }

    return stringified + '=' + value;
}

function stringifyAttributes(attributes: CookieAttributes): string {
    if (typeof attributes.expires === 'number') {
        const expires = new Date();
        expires.setMilliseconds(expires.getMilliseconds() + attributes.expires * 864e+5);
        attributes.expires = expires;
    }

    return stringifyAttribute('Expires', attributes.expires ? attributes.expires.toUTCString() : '')
        + stringifyAttribute('Domain', attributes.domain)
        + stringifyAttribute('Path', attributes.path)
        + stringifyAttribute('Secure', attributes.secure);
}

export function encode(name: string, value: string, attributes: CookieAttributes): string {
    return encodeURIComponent(name)
            .replace(/%(23|24|26|2B|5E|60|7C)/g, decodeURIComponent) // allowed special characters
            .replace(/\(/g, '%28').replace(/\)/g, '%29') // replace opening and closing parens
        + '=' + encodeURIComponent(value)
            .replace(/%(23|24|26|2B|3A|3C|3E|3D|2F|3F|40|5B|5D|5E|60|7B|7D|7C)/g, decodeURIComponent) // allowed special characters
        + stringifyAttributes(attributes);
}

export function parse(cookieString: string): {[name: string]: string} {
    const result: {[name: string]: string} = {};
    const cookies = cookieString ? cookieString.split('; ') : [];
    const rdecode = /(%[0-9A-Z]{2})+/g;

    for (let i = 0; i < cookies.length; i++) {
        const parts = cookies[i].split('=');
        let cookie = parts.slice(1).join('=');

        if (cookie.charAt(0) === '"') {
            cookie = cookie.slice(1, -1);
        }

        try {
            const name = parts[0].replace(rdecode, decodeURIComponent);
            result[name] = cookie.replace(rdecode, decodeURIComponent);
        } catch (e) {
            // ignore cookies with invalid name/value encoding
        }
    }

    return result;
}

export function getAll(): {[name: string]: string} {
    return parse(document.cookie);
}

export function get(name: string): string | undefined {
    return getAll()[name];
}

export function set(name: string, value: string, attributes?: CookieAttributes): void {
    document.cookie = encode(name, value, {path: '/', ...attributes});
}

export function remove(name: string, attributes?: CookieAttributes): void {
    set(name, '', {...attributes, expires: -1});
}