import AsyncStorage from "@react-native-async-storage/async-storage";

const STORAGE_KEY = "beenvoice:instance-url";

export function normalizeInstanceUrl(input: string): string | null {
  const trimmed = input.trim().replace(/\/$/, "");
  if (!trimmed) return null;

  let url = trimmed;
  if (!/^https?:\/\//i.test(url)) {
    const isLocal =
      /^(localhost|127\.|192\.168\.|10\.|172\.(1[6-9]|2\d|3[01])\.)/i.test(url);
    url = `${isLocal ? "http" : "https"}://${url}`;
  }

  try {
    const parsed = new URL(url);
    if (!parsed.hostname) return null;
    return `${parsed.protocol}//${parsed.host}`;
  } catch {
    return null;
  }
}

export async function loadStoredInstanceUrl(): Promise<string | null> {
  const stored = await AsyncStorage.getItem(STORAGE_KEY);
  if (!stored) return null;
  return normalizeInstanceUrl(stored) ?? stored.replace(/\/$/, "");
}

export async function saveStoredInstanceUrl(url: string): Promise<string> {
  const normalized = normalizeInstanceUrl(url);
  if (!normalized) {
    throw new Error("Enter a valid server URL (e.g. beenvoice.app or localhost:3000)");
  }
  await AsyncStorage.setItem(STORAGE_KEY, normalized);
  return normalized;
}

export async function clearStoredInstanceUrl(): Promise<void> {
  await AsyncStorage.removeItem(STORAGE_KEY);
}