gamercomp/frontend/src/hooks/useFingerprint.js

import { useState, useEffect } from 'react';
import FingerprintJS from '@fingerprintjs/fingerprintjs';

const FINGERPRINT_KEY = 'gamercomp_device_fp';

// Cache fingerprint in memory and localStorage
let cachedFingerprint = null;

export function useFingerprint() {
  const [fingerprint, setFingerprint] = useState(() => {
    // Try to get from memory cache first
    if (cachedFingerprint) return cachedFingerprint;
    // Then from localStorage
    const stored = localStorage.getItem(FINGERPRINT_KEY);
    if (stored) {
      cachedFingerprint = stored;
      return stored;
    }
    return null;
  });
  const [loading, setLoading] = useState(!fingerprint);

  useEffect(() => {
    if (fingerprint) {
      setLoading(false);
      return;
    }

    let cancelled = false;

    async function generateFingerprint() {
      try {
        const fp = await FingerprintJS.load();
        const result = await fp.get();
        const visitorId = result.visitorId;

        if (!cancelled) {
          cachedFingerprint = visitorId;
          localStorage.setItem(FINGERPRINT_KEY, visitorId);
          setFingerprint(visitorId);
          setLoading(false);
        }
      } catch (err) {
        console.error('Failed to generate fingerprint:', err);
        if (!cancelled) {
          // Generate a fallback random ID
          const fallback = 'fb_' + Math.random().toString(36).substring(2) + Date.now().toString(36);
          cachedFingerprint = fallback;
          localStorage.setItem(FINGERPRINT_KEY, fallback);
          setFingerprint(fallback);
          setLoading(false);
        }
      }
    }

    generateFingerprint();

    return () => {
      cancelled = true;
    };
  }, [fingerprint]);

  return { fingerprint, loading };
}

// Sync getter for API client
export function getFingerprint() {
  if (cachedFingerprint) return cachedFingerprint;
  const stored = localStorage.getItem(FINGERPRINT_KEY);
  if (stored) {
    cachedFingerprint = stored;
    return stored;
  }
  return null;
}

export default useFingerprint;