import * as cookie from "cookie";
import setCookieParser from "set-cookie-parser";

const isBrowser = () => typeof window !== "undefined";

const createCookie = (name, value, options) => {
    let sameSite = options.sameSite;

    if (sameSite === true) {
        sameSite = "strict";
    }

    if (sameSite === undefined || sameSite === false) {
        sameSite = "lax";
    }

    const cookieToSet = { ...options, sameSite };
    delete cookieToSet.encode;

    return { name, value, ...cookieToSet };
};

const hasSameProperties = (firstCookie, secondCookie) => {
    const firstProperties = Object.getOwnPropertyNames(firstCookie);
    const secondProperties = Object.getOwnPropertyNames(secondCookie);

    if (firstProperties.length !== secondProperties.length) {
        return false;
    }

    return firstProperties.every(
        (propertyName) =>
            firstCookie[propertyName] === secondCookie[propertyName]
    );
};

const areCookiesEqual = (firstCookie, secondCookie) => {
    let sameSiteMatches = firstCookie.sameSite === secondCookie.sameSite;

    if (
        typeof firstCookie.sameSite === "string" &&
        typeof secondCookie.sameSite === "string"
    ) {
        sameSiteMatches =
            firstCookie.sameSite.toLowerCase() ===
            secondCookie.sameSite.toLowerCase();
    }

    return (
        hasSameProperties(
            { ...firstCookie, sameSite: undefined },
            { ...secondCookie, sameSite: undefined }
        ) && sameSiteMatches
    );
};

export const parseCookies = (ctx, options) => {
    if (ctx?.req?.headers?.cookie) {
        return cookie.parse(ctx.req.headers.cookie, options);
    }

    if (isBrowser()) {
        return cookie.parse(document.cookie, options);
    }

    return {};
};

export const setCookie = (ctx, name, value, options = {}) => {
    if (ctx?.res?.getHeader && ctx.res.setHeader) {
        if (ctx?.res?.finished) {
            console.warn(`Not setting "${name}" cookie. Response has finished.`);
            console.warn("You should set cookie before res.send()");
            return {};
        }

        let cookies = ctx.res.getHeader("Set-Cookie") || [];

        if (typeof cookies === "string") {
            cookies = [cookies];
        }

        if (typeof cookies === "number") {
            cookies = [];
        }

        const parsedCookies = setCookieParser.parse(cookies, {
            decodeValues: false
        });
        const newCookie = createCookie(name, value, options);
        const cookiesToSet = [];

        parsedCookies.forEach((parsedCookie) => {
            if (!areCookiesEqual(parsedCookie, newCookie)) {
                cookiesToSet.push(
                    cookie.serialize(parsedCookie.name, parsedCookie.value, {
                        encode: (cookieValue) => cookieValue,
                        ...parsedCookie
                    })
                );
            }
        });

        cookiesToSet.push(cookie.serialize(name, value, options));
        ctx.res.setHeader("Set-Cookie", cookiesToSet);
    }

    if (isBrowser()) {
        if (options?.httpOnly) {
            throw new Error("Can not set a httpOnly cookie in the browser.");
        }

        document.cookie = cookie.serialize(name, value, options);
    }

    return {};
};

export const destroyCookie = (ctx, name, options) =>
    setCookie(ctx, name, "", { ...(options || {}), maxAge: -1 });