(function () {
    const fallbackTimeoutMs = 10 * 60 * 1000;
    const syncIntervalMs = 15 * 1000;
    let authenticated = false;
    let timeoutMs = fallbackTimeoutMs;
    let idleTimer = null;
    let pendingSyncTimer = null;
    let lastSyncAt = 0;
    const nativeFetch = window.fetch ? window.fetch.bind(window) : null;

    function scheduleLogout(remainingMs = timeoutMs) {
        if (!authenticated) return;
        window.clearTimeout(idleTimer);
        idleTimer = window.setTimeout(() => {
            window.location.assign("/auth/logout?reason=idle");
        }, Math.max(remainingMs, 1000));
    }

    async function syncActivity() {
        if (!authenticated) return;
        window.clearTimeout(pendingSyncTimer);
        pendingSyncTimer = null;
        lastSyncAt = Date.now();
        try {
            const response = await nativeFetch("/api/auth/activity", {
                method: "POST",
                cache: "no-store",
                credentials: "include",
                headers: {"X-Requested-With": "idle-activity"},
            });
            if (response.status === 401) {
                authenticated = false;
                window.location.assign("/auth/logout?reason=idle");
            }
        } catch (error) {
            console.debug("Session activity sync deferred.", error);
        }
    }

    function onActualActivity() {
        if (!authenticated) return;
        scheduleLogout();
        const elapsed = Date.now() - lastSyncAt;
        if (elapsed >= syncIntervalMs) {
            void syncActivity();
            return;
        }
        if (!pendingSyncTimer) {
            pendingSyncTimer = window.setTimeout(syncActivity, syncIntervalMs - elapsed);
        }
    }

    async function initialize() {
        try {
            const response = await nativeFetch("/api/auth/me", {cache: "no-store", credentials: "include"});
            if (!response.ok) return;
            const data = await response.json();
            authenticated = Boolean(data.user);
            if (!authenticated) return;
            timeoutMs = Math.max(Number(data.idle_timeout_seconds || 600) * 1000, 1000);
            const remainingMs = Math.max(
                Number(data.idle_remaining_seconds || data.idle_timeout_seconds || 600) * 1000,
                1000,
            );
            lastSyncAt = Date.now();
            scheduleLogout(remainingMs);
        } catch (error) {
            console.debug("Session idle timer unavailable.", error);
        }
    }

    if (nativeFetch) {
        window.fetch = async (...args) => {
            const response = await nativeFetch(...args);
            const url = String(args[0]?.url || args[0] || "");
            if (authenticated && response.ok && !url.includes("/api/auth/activity")) {
                onActualActivity();
            }
            return response;
        };
    }

    ["mousemove", "pointerdown", "click", "keydown", "wheel", "touchstart"].forEach((eventName) => {
        window.addEventListener(eventName, onActualActivity, {passive: true});
    });
    document.addEventListener("visibilitychange", () => {
        if (!document.hidden) onActualActivity();
    });

    void initialize();
})();