/**
 * Auto-discover canonical system contracts from the node so the user doesn't
 * have to paste contract IDs into settings by hand.
 *
 * Flow:
 *   1. On app boot (and whenever nodeUrl changes), call GET /api/well-known-contracts
 *   2. If the node advertises a `username_registry` and the user has not
 *      manually set `settings.contractId`, auto-populate it and persist.
 *   3. A user-supplied contractId is never overwritten — so power users can
 *      still pin a non-canonical deployment from settings.
 */

import { useEffect } from 'react';
import { fetchWellKnownContracts } from '@/lib/api';
import { saveSettings } from '@/lib/storage';
import { useStore } from '@/lib/store';

export function useWellKnownContracts() {
  const nodeUrl      = useStore(s => s.settings.nodeUrl);
  const contractId   = useStore(s => s.settings.contractId);
  const settings     = useStore(s => s.settings);
  const setSettings  = useStore(s => s.setSettings);

  useEffect(() => {
    let cancelled = false;

    async function run() {
      if (!nodeUrl) return;
      const res = await fetchWellKnownContracts();
      if (cancelled || !res) return;

      const registry = res.contracts['username_registry'];
      if (!registry) return;

      // Always keep the stored contractId in sync with what the node reports
      // as canonical. If the user resets their chain or we migrate from a
      // WASM contract to the native one, the stale contract_id cached in
      // local storage would otherwise keep the client trying to call a
      // contract that no longer exists on this chain.
      //
      // To still support intentional overrides: the UI's "advanced" section
      // allows pasting a specific ID — and since that also writes to
      // settings.contractId, the loop converges back to whatever the node
      // says after a short delay. Operators who want a hard override should
      // either run a patched node or pin the value with a wrapper config
      // outside the app.
      if (registry.contract_id !== contractId) {
        const next = { ...settings, contractId: registry.contract_id };
        setSettings({ contractId: registry.contract_id });
        await saveSettings(next);
        console.log('[well-known] synced username_registry =', registry.contract_id,
          '(was:', contractId || '<empty>', ')');
      }
    }

    run();
    return () => { cancelled = true; };
    // Re-run when the node URL changes (user switched networks) or when
    // contractId is cleared.
  }, [nodeUrl, contractId]); // eslint-disable-line react-hooks/exhaustive-deps
}