function escapeRegex(input) {
  return String(input).replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
}

function globToRegex(glob) {
  const parts = String(glob).split('*').map(escapeRegex);
  const regex = `^${parts.join('.*')}$`;
  return new RegExp(regex);
}

export function createFakeRedis(initial = {}) {
  const kv = new Map(Object.entries(initial));

  return {
    isReady: true,

    async get(key) {
      return kv.has(key) ? kv.get(key) : null;
    },

    async set(key, value) {
      kv.set(key, String(value));
      return 'OK';
    },

    async del(key) {
      const existed = kv.delete(key);
      return existed ? 1 : 0;
    },

    async keys(pattern) {
      const re = globToRegex(pattern);
      return Array.from(kv.keys()).filter((k) => re.test(k));
    },

    // optional: used by logs route
    async lRange(key, start, stop) {
      const raw = kv.get(key);
      const list = Array.isArray(raw) ? raw : [];

      const normalizeIndex = (idx) => (idx < 0 ? list.length + idx : idx);
      const s = normalizeIndex(start);
      const e = normalizeIndex(stop);

      return list.slice(Math.max(0, s), Math.min(list.length, e + 1));
    },

    // helper for tests
    _dump() {
      return Object.fromEntries(kv.entries());
    },
  };
}