Initial commit - realms platform

frontend/src/lib/fingerprint.js

@@ -0,0 +1,63 @@
+// Guest-only fingerprinting module
+// Only guests are fingerprinted - registered users are NOT fingerprinted for privacy
+import { browser } from '$app/environment';
+
+let cachedFingerprint = null;
+let fingerprintPromise = null;
+
+export async function getGuestFingerprint() {
+    if (!browser) return null;
+
+    // Return cached fingerprint if available
+    if (cachedFingerprint) return cachedFingerprint;
+
+    // Return existing promise if fingerprint is being generated
+    if (fingerprintPromise) return fingerprintPromise;
+
+    fingerprintPromise = generateFingerprint();
+    cachedFingerprint = await fingerprintPromise;
+    fingerprintPromise = null;
+
+    return cachedFingerprint;
+}
+
+async function generateFingerprint() {
+    try {
+        const FingerprintJS = await import('@fingerprintjs/fingerprintjs');
+        const fp = await FingerprintJS.load();
+        const result = await fp.get();
+        return result.visitorId;
+    } catch (error) {
+        console.error('Failed to generate fingerprint:', error);
+        // Fallback: generate a simple fingerprint from available data
+        return generateFallbackFingerprint();
+    }
+}
+
+function generateFallbackFingerprint() {
+    // Fallback fingerprint using basic browser data
+    const data = [
+        navigator.userAgent,
+        navigator.language,
+        screen.width + 'x' + screen.height,
+        screen.colorDepth,
+        new Date().getTimezoneOffset(),
+        navigator.hardwareConcurrency || 0,
+        navigator.deviceMemory || 0
+    ].join('|');
+
+    // Simple hash function
+    let hash = 0;
+    for (let i = 0; i < data.length; i++) {
+        const char = data.charCodeAt(i);
+        hash = ((hash << 5) - hash) + char;
+        hash = hash & hash;
+    }
+    return 'fallback_' + Math.abs(hash).toString(36);
+}
+
+// Clear cached fingerprint (useful for testing)
+export function clearCachedFingerprint() {
+    cachedFingerprint = null;
+    fingerprintPromise = null;
+}