/**
 * Metered TURN Server Integration
 */

let globalIceServers = [
    { urls: 'stun:stun.l.google.com:19302' }
];
let meteredIceFetchPromise = null;

/**
 * Fetch ICE servers from /ice-servers endpoint and merge with default STUN server.
 * Handles network errors gracefully with fallback.
 * 
 * @returns {Promise<Array>} Resolves with the array of ICE server objects.
 */
export function getMeteredIceServers() {
    if (meteredIceFetchPromise) return meteredIceFetchPromise;

    meteredIceFetchPromise = fetch('/ice-servers', {
        headers: {
            'Accept': 'application/json',
            'X-Requested-With': 'XMLHttpRequest'
        }
    })
        .then(response => {
            if (!response.ok) {
                throw new Error(`Failed to fetch ICE servers: HTTP status ${response.status}`);
            }
            return response.json();
        })
        .then(meteredIce => {
            if (Array.isArray(meteredIce) && meteredIce.length > 0) {
                globalIceServers = [
                    { urls: 'stun:stun.l.google.com:19302' },
                    ...meteredIce.slice(0, 3)
                ];
            }
            window.globalIceServers = globalIceServers;
            return globalIceServers;
        })
        .catch(e => {
            console.warn('Metered TURN fetch warning:', e);
            window.globalIceServers = globalIceServers;
            return globalIceServers;
        });

    return meteredIceFetchPromise;
}

export function initMeteredIceServers() {
    return getMeteredIceServers();
}

export { globalIceServers };