(function () {
    const sessionKeyId = 'session_uid';
    const sessionKeyHash = 'device_hash';

    function generateUID() {
        return 'uid-' + Date.now().toString(36) + '-' + Math.random().toString(36).slice(2);
    }

    async function hashData(data) {
        const encoder = new TextEncoder();
        const buffer = encoder.encode(data);
        const digest = await crypto.subtle.digest('SHA-256', buffer);
        return Array.from(new Uint8Array(digest)).map(b => b.toString(16).padStart(2, '0')).join('');
    }

    const deviceInfo = {
        screenWidth: window.screen.width,
        screenHeight: window.screen.height,
        userAgent: navigator.userAgent
    };

    const rawData = `${deviceInfo.screenWidth}x${deviceInfo.screenHeight}|${deviceInfo.userAgent}`;

    if (!sessionStorage.getItem(sessionKeyId)) {
        sessionStorage.setItem(sessionKeyId, generateUID());
    }

    hashData(rawData).then(hash => {
        sessionStorage.setItem(sessionKeyHash, hash);
    });

})();