import { api_base, CookieNames } from "$lib/configuration";
import { log_debug, log_error } from "$lib/logger";
import { error, redirect } from "@sveltejs/kit";
import { Temporal } from "temporal-polyfill";
import type { LayoutServerLoad } from "./$types";

export const load: LayoutServerLoad = async ({ route, cookies, locals }) => {
    const isBaseRoute = route.id === "/(main)";
    const isPublicRoute = (route.id?.startsWith("/(main)/(public)") || isBaseRoute) ?? true;
    const sessionIsValid = (await cached_result<Response>("sessionCheck", 120, () => fetch(api_base("_/valid-session"), {
        headers: {
            Cookie: CookieNames.session + "=" + cookies.get(CookieNames.session)
        }
    }).catch((e) => {
        log_error(e);
        throw error(503, {
            message: "We are experiencing a service disruption! Have patience while we resolve the issue."
        })
    }))).ok;

    log_debug("Base Layout loaded", {
        sessionIsValid,
        isPublicRoute,
        routeId: route.id
    });

    if (sessionIsValid && isPublicRoute) {
        throw redirect(302, "/home");
    } else if (isBaseRoute || !sessionIsValid && !isPublicRoute) {
        throw redirect(302, "/sign-in");
    }

    return {
        locale: locals.locale
    }
}

let resultCache = {};
async function cached_result<T>(key: string, staleAfterSeconds: number, code: any) {
    if (!resultCache[key]) {
        resultCache[key] = {
            l: 0,
            c: undefined as T
        }
    }
    const staleEpoch = ((resultCache[key]?.l ?? 0) + staleAfterSeconds);
    const isStale = staleEpoch < Temporal.Now.instant().epochSeconds;
    if (isStale || !resultCache[key]?.c) {
        resultCache[key].c = await code();
        resultCache[key].l = Temporal.Now.instant().epochSeconds;
    }

    log_debug("Ran cached_result", {
        cacheKey: key,
        isStale,
        cache: resultCache[key],
        staleEpoch
    });

    return resultCache[key].c as T;
}