import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
import { RudderClient, createClient } from '../src/client/RudderClient.js';
import {
  RudderError,
  RudderNetworkError,
  RudderHttpError,
  RudderAuthError,
  RudderModuleError,
  SDK_ERROR_INVALID_OPTIONS,
} from '../src/client/RudderError.js';
import { createFakeTokenStore } from './helpers/FakeTokenStore.js';

describe('RudderClient', () => {
  afterEach(() => {
    vi.unstubAllGlobals();
  });

  it('constructs with valid options', () => {
    const client = new RudderClient({
      baseUrl: 'https://api.example.com',
      projectKey: 'proj_123',
      tokenStore: createFakeTokenStore(),
    });
    expect(client.auth).toBeDefined();
  });

  it('defaults baseUrl and exposes createClient', () => {
    const client = createClient({ projectKey: 'proj_123', tokenStore: createFakeTokenStore() });
    expect(client).toBeInstanceOf(RudderClient);
    expect(client.options.baseUrl).toBe('https://api.rudder.build');
  });

  it('throws RudderError with sdk/invalid-options if projectKey is missing', () => {
    let caught: unknown;
    try {
      new RudderClient({ projectKey: '' });
    } catch (error) {
      caught = error;
    }
    expect(caught).toBeInstanceOf(RudderError);
    expect((caught as RudderError).code).toBe(SDK_ERROR_INVALID_OPTIONS);
    expect((caught as Error).message).toContain('projectKey');
  });

  it('creates a default localStorage-backed token store when tokenStore is omitted', () => {
    localStorage.clear();
    const client = new RudderClient({
      baseUrl: 'https://api.example.com',
      projectKey: 'proj_123',
    });
    client.options.tokenStore.saveTokens('at', 'rt');
    expect(localStorage.getItem('rudder_access_token')).toBe('at');
    expect(client.options.tokenStore.getAccessToken()).toBe('at');
    client.options.tokenStore.clear();
  });

  it('falls back to an in-memory token store when localStorage is unavailable', () => {
    vi.stubGlobal('localStorage', undefined);
    const client = new RudderClient({
      baseUrl: 'https://api.example.com',
      projectKey: 'proj_123',
    });
    client.options.tokenStore.saveTokens('at', 'rt');
    expect(client.options.tokenStore.getAccessToken()).toBe('at');
    expect(client.options.tokenStore.getRefreshToken()).toBe('rt');
    client.options.tokenStore.clear();
    expect(client.options.tokenStore.getAccessToken()).toBeNull();
  });
});

describe('transport error mapping', () => {
  let client: RudderClient;

  beforeEach(() => {
    client = new RudderClient({
      baseUrl: 'https://api.example.com',
      projectKey: 'proj_123',
      tokenStore: createFakeTokenStore(),
    });
  });

  it('throws RudderNetworkError with the underlying error as cause', async () => {
    const underlying = new Error('Network down');
    vi.stubGlobal('fetch', vi.fn().mockRejectedValue(underlying));
    let caught: unknown;
    await client.player.reload().catch((error) => {
      caught = error;
    });
    expect(caught).toBeInstanceOf(RudderNetworkError);
    expect((caught as RudderNetworkError).cause).toBe(underlying);
  });

  it('throws RudderAuthError on 401', async () => {
    vi.stubGlobal('fetch', vi.fn().mockResolvedValue(
      new Response('unauthorized', { status: 401, statusText: 'Unauthorized' }),
    ));
    await expect(client.player.reload())
      .rejects.toThrow(RudderAuthError);
  });

  it('throws RudderHttpError with the server error code on non-401 HTTP error', async () => {
    vi.stubGlobal('fetch', vi.fn().mockResolvedValue(
      new Response(JSON.stringify({ code: 'run_expired', error: 'gone' }), {
        status: 410,
        statusText: 'Gone',
      }),
    ));
    let caught: unknown;
    await client.player.reload().catch((error) => {
      caught = error;
    });
    expect(caught).toBeInstanceOf(RudderHttpError);
    expect((caught as RudderHttpError).code).toBe('run_expired');
  });

  it('returns undefined for 204 No Content', async () => {
    vi.stubGlobal('fetch', vi.fn().mockResolvedValue(
      new Response(null, { status: 204, statusText: 'No Content' }),
    ));
    const result = await client.auth.linkWithGoogle('id-token');
    expect(result).toBeUndefined();
  });

  it('returns parsed JSON for 200 responses', async () => {
    vi.stubGlobal('fetch', vi.fn().mockResolvedValue(
      new Response(JSON.stringify({ player: { id: 'player-1' }, wallets: [] }), { status: 200 }),
    ));
    const result = await client.player.reload();
    expect(result).toEqual({ player: { id: 'player-1' }, wallets: [] });
  });
});

describe('modules.call', () => {
  let client: RudderClient;

  beforeEach(() => {
    vi.useFakeTimers();
    client = createClient({
      baseUrl: 'https://api.example.com',
      projectKey: 'proj_123',
      tokenStore: createFakeTokenStore(),
    });
  });

  afterEach(() => {
    vi.useRealTimers();
    vi.unstubAllGlobals();
  });

  const respond = (status: number, body: unknown) =>
    new Response(JSON.stringify(body), { status });

  function headersOf(fetchMock: ReturnType<typeof vi.fn>, n: number): Headers {
    return new Headers(fetchMock.mock.calls[n][1].headers);
  }

  it('posts args, sends the version header, and returns result', async () => {
    const fetchMock = vi.fn().mockResolvedValue(respond(200, { result: { ok: true } }));
    vi.stubGlobal('fetch', fetchMock);

    const result = await client.modules.call<{ ok: boolean }>('quests', 'list', { limit: 10 }, {
      moduleVersion: '0.1.0',
    });

    expect(result).toEqual({ ok: true });
    const [url, init] = fetchMock.mock.calls[0];
    expect(new URL(String(url)).pathname).toBe('/sdk/v1/modules/quests/list');
    expect(JSON.parse(String(init.body))).toEqual({ args: { limit: 10 } });
    expect(headersOf(fetchMock, 0).get('X-Rudder-Module-Version')).toBe('quests@0.1.0');
    expect(headersOf(fetchMock, 0).get('Idempotency-Key')).toMatch(/^[0-9a-f-]{36}$/);
  });

  it('sends {} when args are omitted and no version header without moduleVersion', async () => {
    const fetchMock = vi.fn().mockResolvedValue(respond(200, { result: 1 }));
    vi.stubGlobal('fetch', fetchMock);
    await client.modules.call('m', 'f');
    expect(JSON.parse(String(fetchMock.mock.calls[0][1].body))).toEqual({ args: {} });
    expect(headersOf(fetchMock, 0).has('X-Rudder-Module-Version')).toBe(false);
  });

  it('retries network errors, 5xx and 409 conflict with the same Idempotency-Key', async () => {
    const fetchMock = vi
      .fn()
      .mockRejectedValueOnce(new Error('offline'))
      .mockResolvedValueOnce(respond(409, { code: 'conflict', error: 'busy' }))
      .mockResolvedValueOnce(respond(200, { result: 'done' }));
    vi.stubGlobal('fetch', fetchMock);

    const pending = client.modules.call('m', 'f', {});
    await vi.runAllTimersAsync();
    expect(await pending).toBe('done');

    expect(fetchMock).toHaveBeenCalledTimes(3);
    const key = headersOf(fetchMock, 0).get('Idempotency-Key');
    expect(headersOf(fetchMock, 1).get('Idempotency-Key')).toBe(key);
    expect(headersOf(fetchMock, 2).get('Idempotency-Key')).toBe(key);

    fetchMock.mockResolvedValueOnce(respond(200, { result: 'again' }));
    await client.modules.call('m', 'f', {});
    expect(headersOf(fetchMock, 3).get('Idempotency-Key')).not.toBe(key);
  });

  it('gives up after 2 retries on 5xx', async () => {
    const fetchMock = vi.fn().mockImplementation(async () => respond(503, { error: 'down' }));
    vi.stubGlobal('fetch', fetchMock);
    const pending = client.modules.call('m', 'f').catch((e) => e);
    await vi.runAllTimersAsync();
    const error = await pending;
    expect(error).toBeInstanceOf(RudderHttpError);
    expect((error as RudderHttpError).status).toBe(503);
    expect(fetchMock).toHaveBeenCalledTimes(3);
  });

  it('does not retry other 4xx, including 409 with another code', async () => {
    const fetchMock = vi.fn().mockResolvedValue(respond(409, { code: 'version_conflict' }));
    vi.stubGlobal('fetch', fetchMock);
    await expect(client.modules.call('m', 'f')).rejects.toBeInstanceOf(RudderHttpError);
    expect(fetchMock).toHaveBeenCalledTimes(1);
  });

  it('maps 422 to RudderModuleError', async () => {
    vi.stubGlobal('fetch', vi.fn().mockResolvedValue(
      respond(422, { error: 'not enough gold', code: 'insufficient_funds', requestId: 'req-1' }),
    ));
    const error = await client.modules.call('store', 'buy').catch((e) => e);
    expect(error).toBeInstanceOf(RudderModuleError);
    expect(error).toMatchObject({
      status: 422,
      code: 'insufficient_funds',
      message: 'not enough gold',
      requestId: 'req-1',
    });
  });
});