document.addEventListener('DOMContentLoaded', () => {
    const config = document.getElementById('game-waiting-config');
    if (!config) {
        return;
    }

    const publicUrl = config.dataset.mercurePublicUrl;
    const topic = config.dataset.topic;
    const readyAt = config.dataset.readyAt;

    let reloading = false;
    const reloadOnce = (eventSource) => {
        if (reloading) {
            return;
        }
        reloading = true;
        if (eventSource) {
            eventSource.close();
        }
        window.location.reload();
    };

    if (publicUrl && topic) {
        const url = new URL(publicUrl);
        url.searchParams.append('topic', topic);

        const eventSource = new EventSource(url);
        eventSource.onmessage = event => {
            const data = JSON.parse(event.data);
            if (data.type === 'all_ready' || data.type === 'player_ready') {
                reloadOnce(eventSource);
            }
        };
    }

    // Our own ready status expires 60s after we set it - proactively tell the
    // server as close to that deadline as possible, so the other players find
    // out live instead of only whenever someone else's request happens to
    // trigger the lazy check.
    if (readyAt) {
        const timeoutMs = 61000; // slightly more than the server-side 60s
        const readyAtMs = readyAt * 1000;
        const countdownEl = document.getElementById('ready-countdown');
        const expireForm = document.getElementById('expire-ready-form');

        const updateCountdown = () => {
            const remaining = Math.max(0, Math.ceil((readyAtMs + timeoutMs - Date.now()) / 1000));
            if (countdownEl) {
                const m = Math.floor(remaining / 60);
                const s = remaining % 60;
                countdownEl.textContent = m + ':' + s.toString().padStart(2, '0');
            }
            return remaining;
        };

        const remaining = updateCountdown();
        if (remaining <= 0) {
            expireForm?.submit();
        } else {
            const countdownInterval = setInterval(() => {
                if (updateCountdown() <= 0) {
                    clearInterval(countdownInterval);
                    expireForm?.submit();
                }
            }, 1000);
        }
    }
});