dgb-wallet/packages/web-ui/src/usePrice.ts

import { useEffect, useState } from 'react';

// CoinGecko DGB→USD, opt-in via Settings > Display. Fetched once per
// mount + on manual refresh. NOT persisted per-second; caching for one
// session is enough — an approximate price stays useful for a while.
//
// Privacy trade-off: enabling this reveals to CoinGecko that a browser
// on the user's IP is checking the DGB price. Not seed-linked; not
// address-linked; but it IS a data point. The Settings toggle names
// the trade-off honestly.

const ENDPOINT = 'https://api.coingecko.com/api/v3/simple/price?ids=digibyte&vs_currencies=usd';

interface PriceState {
  usd: number | null;
  fetchedAt: number | null;
  error: string | null;
  loading: boolean;
}

export function usePrice(enabled: boolean): PriceState & { refresh: () => void } {
  const [state, setState] = useState<PriceState>({
    usd: null, fetchedAt: null, error: null, loading: false,
  });
  const [nonce, setNonce] = useState(0);

  useEffect(() => {
    if (!enabled) {
      setState({ usd: null, fetchedAt: null, error: null, loading: false });
      return;
    }
    let cancelled = false;
    setState((s) => ({ ...s, loading: true, error: null }));
    (async () => {
      try {
        const res = await fetch(ENDPOINT);
        if (!res.ok) throw new Error(`CoinGecko HTTP ${res.status}`);
        const body = (await res.json()) as { digibyte?: { usd?: number } };
        const usd = body.digibyte?.usd ?? null;
        if (cancelled) return;
        if (typeof usd !== 'number') throw new Error('price missing in response');
        setState({ usd, fetchedAt: Date.now(), error: null, loading: false });
      } catch (e) {
        if (cancelled) return;
        setState({ usd: null, fetchedAt: null, error: (e as Error).message, loading: false });
      }
    })();
    return () => { cancelled = true; };
  }, [enabled, nonce]);

  return { ...state, refresh: () => setNonce((n) => n + 1) };
}