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

const ACCOUNTS_KEY = "beenvoice:accounts";
const ACTIVE_ACCOUNT_KEY = "beenvoice:active-account-id";
const DRAFT_INSTANCE_URL_KEY = "beenvoice:draft-instance-url";

export type SavedAccount = {
  id: string;
  instanceUrl: string;
  userId: string;
  email: string;
  name: string;
  lastUsedAt: number;
};

function isSavedAccount(value: unknown): value is SavedAccount {
  if (!value || typeof value !== "object") return false;

  const account = value as Partial<SavedAccount>;
  return (
    typeof account.id === "string" &&
    account.id.length > 0 &&
    typeof account.instanceUrl === "string" &&
    account.instanceUrl.length > 0 &&
    typeof account.userId === "string" &&
    account.userId.length > 0 &&
    typeof account.email === "string" &&
    typeof account.name === "string" &&
    typeof account.lastUsedAt === "number"
  );
}

export function buildAccountId(instanceUrl: string, userId: string) {
  const host = instanceUrl.replace(/^https?:\/\//, "").replace(/\/$/, "");
  return `${host}::${userId}`;
}

export function authStoragePrefix(accountId: string) {
  return `beenvoice:auth:${accountId}`;
}

export async function loadAccounts(): Promise<SavedAccount[]> {
  const raw = await AsyncStorage.getItem(ACCOUNTS_KEY);
  if (!raw) return [];
  try {
    const parsed = JSON.parse(raw) as unknown;
    return Array.isArray(parsed) ? parsed.filter(isSavedAccount) : [];
  } catch {
    return [];
  }
}

export async function saveAccounts(accounts: SavedAccount[]) {
  await AsyncStorage.setItem(ACCOUNTS_KEY, JSON.stringify(accounts));
}

export async function loadActiveAccountId(): Promise<string | null> {
  return AsyncStorage.getItem(ACTIVE_ACCOUNT_KEY);
}

export async function saveActiveAccountId(accountId: string | null) {
  if (accountId) {
    await AsyncStorage.setItem(ACTIVE_ACCOUNT_KEY, accountId);
  } else {
    await AsyncStorage.removeItem(ACTIVE_ACCOUNT_KEY);
  }
}

export async function loadDraftInstanceUrl(): Promise<string | null> {
  return AsyncStorage.getItem(DRAFT_INSTANCE_URL_KEY);
}

export async function saveDraftInstanceUrl(url: string | null) {
  if (url) {
    await AsyncStorage.setItem(DRAFT_INSTANCE_URL_KEY, url);
  } else {
    await AsyncStorage.removeItem(DRAFT_INSTANCE_URL_KEY);
  }
}

export async function hasConfiguredInstanceUrl(): Promise<boolean> {
  const [accounts, draft] = await Promise.all([loadAccounts(), loadDraftInstanceUrl()]);
  return accounts.length > 0 || Boolean(draft);
}