/**
 * Fociz Session Guard (Release v1.6.1)
 * Realtime beveiligingsbeheer voor sessie-inactiviteit conform NIST SP 800-63B / ISO 27001
 * - Waarschuwt de gebruiker 2 minuten voor het verlopen met aftelklok
 * - Throttled keepalive pings tijdens actieve interactie
 * - Synchronisatie over meerdere open browsertabbladen via localStorage
 * - Beschermd tegen oneindige herlaad- en redirect-loops
 */

(function () {
    'use strict';

    // Script configuratie uitlezen
    var scriptTag = document.currentScript || document.querySelector('script[src*="session-guard.js"]');
    var rawTimeout = scriptTag ? parseInt(scriptTag.getAttribute('data-timeout'), 10) : 1800;
    var idleTimeout = (!isNaN(rawTimeout) && rawTimeout > 0) ? rawTimeout : 1800;

    // Waarschuwing 120 seconden voor afloop (of de helft indien timeout kort is)
    var warningSeconds = idleTimeout > 240 ? 120 : Math.max(10, Math.floor(idleTimeout / 2));

    var now = Date.now();
    var lastActivity = now;
    var lastPingTime = now;
    var isWarningShowing = false;
    var keepaliveInFlight = false;
    var hasRedirected = false;

    // Synchronisatie met andere tabbladen:
    // Alleen een timestamp overnemen als deze GELDIG is en NIET al verlopen is!
    // Aangezien DEZE pagina zojuist succesvol geladen is, is de sessie NU actief.
    var storedActivity = localStorage.getItem('fociz_session_last_activity');
    if (storedActivity) {
        var parsed = parseInt(storedActivity, 10);
        if (!isNaN(parsed) && parsed > 0 && parsed <= now && (now - parsed) < (idleTimeout * 1000)) {
            lastActivity = Math.max(now, parsed);
        }
    }

    // Direct opslaan zodat alle tabbladen weten dat er zojuist activiteit was
    try {
        localStorage.setItem('fociz_session_last_activity', lastActivity.toString());
        localStorage.removeItem('fociz_session_logged_out');
    } catch (e) {}

    // Veilige eenmalige redirect helper om redirect loops te voorkomen
    function redirectToExpired() {
        if (hasRedirected) return;
        hasRedirected = true;
        try {
            localStorage.setItem('fociz_session_logged_out', Date.now().toString());
        } catch (e) {}
        window.location.href = '/auth/login.php?expired=1';
    }

    // Modal DOM elementen
    var modalEl = null;
    var countdownEl = null;
    var keepaliveBtn = null;
    var logoutBtn = null;

    function initDom() {
        modalEl = document.getElementById('focizSessionModal');
        countdownEl = document.getElementById('focizSessionCountdown');
        keepaliveBtn = document.getElementById('focizSessionKeepaliveBtn');
        logoutBtn = document.getElementById('focizSessionLogoutBtn');

        if (keepaliveBtn) {
            keepaliveBtn.addEventListener('click', function (e) {
                e.preventDefault();
                sendKeepalive(true);
            });
        }

        if (logoutBtn) {
            logoutBtn.addEventListener('click', function (e) {
                e.preventDefault();
                performLogout();
            });
        }
    }

    // Luister naar tabblad synchronisatie
    window.addEventListener('storage', function (e) {
        if (e.key === 'fociz_session_last_activity') {
            var updated = parseInt(e.newValue, 10);
            if (!isNaN(updated) && updated > lastActivity) {
                lastActivity = updated;
                if (isWarningShowing) {
                    hideModal();
                }
            }
        } else if (e.key === 'fociz_session_logged_out') {
            if (!hasRedirected) {
                var loggedOutTime = parseInt(e.newValue, 10);
                if (!isNaN(loggedOutTime) && Math.abs(Date.now() - loggedOutTime) < 10000) {
                    hasRedirected = true;
                    window.location.href = '/auth/login.php?expired=1';
                }
            }
        }
    });

    // Formatteer seconden naar mm:ss
    function formatTime(seconds) {
        var m = Math.floor(seconds / 60);
        var s = seconds % 60;
        return (m < 10 ? '0' : '') + m + ':' + (s < 10 ? '0' : '') + s;
    }

    // Toon modal
    function showModal(remainingSeconds) {
        if (!modalEl) initDom();
        if (!modalEl) return;

        isWarningShowing = true;
        modalEl.classList.remove('hidden');
        modalEl.classList.add('flex');

        if (countdownEl) {
            countdownEl.textContent = formatTime(remainingSeconds);
        }
    }

    // Verberg modal
    function hideModal() {
        if (!modalEl) return;
        isWarningShowing = false;
        modalEl.classList.add('hidden');
        modalEl.classList.remove('flex');
    }

    // Verzend keepalive naar de backend
    function sendKeepalive(manualClick) {
        if (hasRedirected || keepaliveInFlight) return;
        keepaliveInFlight = true;

        if (manualClick && keepaliveBtn) {
            keepaliveBtn.disabled = true;
            keepaliveBtn.textContent = 'Verlengen...';
        }

        fetch('/api/session.php?action=keepalive', {
            method: 'POST',
            headers: {
                'X-Requested-With': 'XMLHttpRequest',
                'Accept': 'application/json'
            }
        })
        .then(function (res) {
            if (res.status === 401) {
                // Reeds verlopen op de server
                redirectToExpired();
                return null;
            }
            return res.json();
        })
        .then(function (data) {
            keepaliveInFlight = false;
            if (manualClick && keepaliveBtn) {
                keepaliveBtn.disabled = false;
                keepaliveBtn.textContent = 'Blijf Ingelogd';
            }

            if (data && data.success) {
                var currentNow = Date.now();
                lastActivity = currentNow;
                lastPingTime = currentNow;
                try {
                    localStorage.setItem('fociz_session_last_activity', currentNow.toString());
                } catch (e) {}
                hideModal();
            }
        })
        .catch(function (err) {
            keepaliveInFlight = false;
            if (manualClick && keepaliveBtn) {
                keepaliveBtn.disabled = false;
                keepaliveBtn.textContent = 'Blijf Ingelogd';
            }
            console.error('Session keepalive error:', err);
        });
    }

    // Direct uitloggen
    function performLogout() {
        if (hasRedirected) return;
        hasRedirected = true;
        try {
            localStorage.setItem('fociz_session_logged_out', Date.now().toString());
        } catch (e) {}
        fetch('/api/session.php?action=logout', {
            method: 'POST',
            headers: { 'X-Requested-With': 'XMLHttpRequest' }
        }).finally(function () {
            window.location.href = '/auth/logout.php';
        });
    }

    // Registreer gebruikersactiviteit (throttled)
    function registerUserActivity() {
        if (hasRedirected) return;
        var currentNow = Date.now();

        // Controleer of de sessie al verlopen is (bijv. laptop uit slaapstand)
        var elapsedSec = Math.floor((currentNow - lastActivity) / 1000);
        if (elapsedSec >= idleTimeout) {
            redirectToExpired();
            return;
        }

        // Als de waarschuwingsmodal actief is, vereisen we expliciete klik op 'Blijf Ingelogd'
        if (isWarningShowing) return;

        // Lokale activiteit bijwerken (maximaal eens per 3 seconden wegschrijven)
        if (currentNow - lastActivity > 3000) {
            lastActivity = currentNow;
            try {
                localStorage.setItem('fociz_session_last_activity', currentNow.toString());
            } catch (e) {}
        }

        // Server keepalive ping (maximaal eens per 60 seconden)
        var minPingInterval = Math.min(60000, Math.max(15000, (idleTimeout * 1000) / 4));
        if (currentNow - lastPingTime > minPingInterval) {
            lastPingTime = currentNow;
            sendKeepalive(false);
        }
    }

    // Direct controleren bij terugkeer naar tabblad of ontwaken uit slaapstand
    function checkIdleOnWakeup() {
        if (hasRedirected) return;
        var currentNow = Date.now();
        var stored = localStorage.getItem('fociz_session_last_activity');
        if (stored) {
            var parsed = parseInt(stored, 10);
            if (!isNaN(parsed) && parsed > 0 && parsed <= currentNow) {
                lastActivity = Math.max(lastActivity, parsed);
            }
        }
        var elapsedSec = Math.floor((currentNow - lastActivity) / 1000);
        if (elapsedSec >= idleTimeout) {
            redirectToExpired();
        }
    }

    window.addEventListener('focus', checkIdleOnWakeup);
    document.addEventListener('visibilitychange', function () {
        if (document.visibilityState === 'visible') {
            checkIdleOnWakeup();
        }
    });

    // Event listeners voor menselijke interactie
    var events = ['mousemove', 'keydown', 'click', 'scroll', 'touchstart'];
    events.forEach(function (evt) {
        window.addEventListener(evt, registerUserActivity, { passive: true });
    });

    // Hoofdtimer interval (elke seconde)
    function tick() {
        if (hasRedirected) return;
        var currentNow = Date.now();
        var elapsedSec = Math.floor((currentNow - lastActivity) / 1000);
        var remainingSec = idleTimeout - elapsedSec;

        if (remainingSec <= 0) {
            redirectToExpired();
            return;
        }

        if (remainingSec <= warningSeconds) {
            // Binnen waarschuwingsvenster
            showModal(remainingSec);
        } else if (isWarningShowing) {
            // Waarschuwing niet meer van toepassing (bijv. verlengd vanuit ander tabblad)
            hideModal();
        }
    }

    // Starten zodra DOM gereed is
    if (document.readyState === 'loading') {
        document.addEventListener('DOMContentLoaded', function () {
            initDom();
            setInterval(tick, 1000);
        });
    } else {
        initDom();
        setInterval(tick, 1000);
    }
})();