import { getMockUser, type MockUser } from "@/mocks/users";

export const DEFAULT_MOCK_USER_ID = "user-1";
const SESSION_STORAGE_KEY = "seahaven-ap.mockUserId";

let currentUserId = DEFAULT_MOCK_USER_ID;

function readStoredUserId(): string | null {
  if (typeof sessionStorage === "undefined") {
    return null;
  }
  try {
    return sessionStorage.getItem(SESSION_STORAGE_KEY);
  } catch {
    return null;
  }
}

function writeStoredUserId(userId: string): void {
  if (typeof sessionStorage === "undefined") {
    return;
  }
  try {
    sessionStorage.setItem(SESSION_STORAGE_KEY, userId);
  } catch {
    // Ignore quota / private-mode failures in POC.
  }
}

export function getMockSessionUserId(): string {
  const stored = readStoredUserId();
  if (stored && getMockUser(stored)) {
    currentUserId = stored;
    return stored;
  }
  return currentUserId;
}

export function getMockSessionUser(): MockUser {
  const userId = getMockSessionUserId();
  const user = getMockUser(userId);
  if (user) {
    return user;
  }
  const fallback = getMockUser(DEFAULT_MOCK_USER_ID);
  if (!fallback) {
    throw new Error("Default mock user is missing from the seed store");
  }
  return fallback;
}

export function setMockSessionUserId(userId: string): MockUser {
  const user = getMockUser(userId);
  if (!user) {
    throw new Error(`Mock user not found: ${userId}`);
  }
  currentUserId = userId;
  writeStoredUserId(userId);
  return { ...user };
}

export function resetMockSession(): void {
  currentUserId = DEFAULT_MOCK_USER_ID;
  if (typeof sessionStorage === "undefined") {
    return;
  }
  try {
    sessionStorage.removeItem(SESSION_STORAGE_KEY);
  } catch {
    // Ignore storage failures in POC.
  }
}