/**
 * RED test scaffold: broker/outboxWorker.ts — outbox state machine (D-04, D-07, D-08)
 *
 * Behaviors under test:
 *   1. runOutboxDrain transitions pending→done on mock 204 response
 *   2. runOutboxDrain transitions pending→failed on mock 412 (conflict, no retry), triggers re-sync
 *   3. runOutboxDrain transitions pending→backoff (nextAttemptAt advanced, attemptCount++)
 *      on mock 500 (transient error)
 *   4. runOutboxDrain transitions pending→dead when attemptCount reaches MAX_ATTEMPTS
 *   5. Edit-as-move (D-04): create row processed BEFORE the linked delete row (groupId)
 *
 * These tests FAIL (RED) because broker/outboxWorker.ts does not exist yet.
 * They will turn GREEN in Plan 03-03 when the implementation is added.
 */

import { describe, it, expect, vi, beforeEach } from 'vitest'

// This import fails (RED) — broker/outboxWorker.ts does not exist yet.
// eslint-disable-next-line @typescript-eslint/ban-ts-comment
// @ts-ignore intentional RED import
import { runOutboxDrain } from '../../src/broker/outboxWorker.js'

// ── Drizzle DB mock ────────────────────────────────────────────────────────
// Follows the pattern from PATTERNS.md §Drizzle DB mock in tests.

const mockUpdateSet = vi.fn().mockReturnValue({ where: vi.fn().mockResolvedValue(undefined) })
const mockUpdate = vi.fn().mockReturnValue({ set: mockUpdateSet })

let mockPendingRows: unknown[] = []
const mockWherePending = vi.fn().mockImplementation(() => Promise.resolve(mockPendingRows))
const mockLimitFn = vi.fn().mockReturnValue({ where: mockWherePending })
const mockFromFn = vi.fn().mockReturnValue({ where: mockLimitFn })
const mockSelectFn = vi.fn().mockReturnValue({ from: mockFromFn })

vi.mock('../../src/db/client.js', () => ({
  db: {
    select: mockSelectFn,
    update: mockUpdate,
  },
}))

// Mock write functions — these are called by outboxWorker for the actual CalDAV ops
vi.mock('../../src/broker/write.js', () => ({
  createCalendarEvent: vi.fn(),
  updateCalendarEvent: vi.fn(),
  deleteCalendarEvent: vi.fn(),
}))

// Mock sync — called after successful write (D-06)
vi.mock('../../src/broker/sync.js', () => ({
  syncCalendar: vi.fn().mockResolvedValue(undefined),
}))

// Mock client creation — the worker needs a DAVClient to call sync
vi.mock('../../src/broker/client.js', () => ({
  createFastmailClient: vi.fn().mockResolvedValue({
    fetchCalendars: vi.fn().mockResolvedValue([]),
  }),
}))

const makeRow = (overrides: Record<string, unknown> = {}) => ({
  id: 1,
  userId: 42,
  operation: 'create' as const,
  status: 'pending' as const,
  uid: 'test-uid@familysync',
  calendarUrl: 'https://caldav.fastmail.com/dav/calendars/user/test@fm.com/Default/',
  calendarObjectUrl: null,
  etag: null,
  payload: 'BEGIN:VCALENDAR\r\nEND:VCALENDAR',
  attemptCount: 0,
  nextAttemptAt: new Date(Date.now() - 5000), // already due
  lastError: null,
  groupId: null,
  createdAt: new Date(),
  updatedAt: new Date(),
  ...overrides,
})

const makeResponse = (status: number): Response =>
  ({ status, ok: status >= 200 && status < 300, headers: new Headers() }) as unknown as Response

describe('runOutboxDrain — state transitions', () => {
  beforeEach(() => {
    vi.clearAllMocks()
    mockPendingRows = []
    // Restore mock chain after clearAllMocks
    mockUpdateSet.mockReturnValue({ where: vi.fn().mockResolvedValue(undefined) })
    mockUpdate.mockReturnValue({ set: mockUpdateSet })
    mockWherePending.mockImplementation(() => Promise.resolve(mockPendingRows))
    mockLimitFn.mockReturnValue({ where: mockWherePending })
    mockFromFn.mockReturnValue({ where: mockLimitFn })
    mockSelectFn.mockReturnValue({ from: mockFromFn })
  })

  it('transitions pending→done on 204 response and triggers re-sync (D-06)', async () => {
    const { createCalendarEvent } = await import('../../src/broker/write.js')
    vi.mocked(createCalendarEvent).mockResolvedValue(makeResponse(204))
    mockPendingRows = [makeRow()]

    await runOutboxDrain()

    // Must update status to 'done'
    expect(mockUpdate).toHaveBeenCalled()
    const setArg = mockUpdateSet.mock.calls[0]?.[0] as { status?: string }
    expect(setArg?.status).toBe('done')
  })

  it('transitions pending→failed on 412 (conflict — no retry), marks failed (D-08)', async () => {
    const { createCalendarEvent } = await import('../../src/broker/write.js')
    vi.mocked(createCalendarEvent).mockResolvedValue(makeResponse(412))
    mockPendingRows = [makeRow()]

    await runOutboxDrain()

    // 412 = hard fail (conflict) — must NOT retry, must mark failed
    const setArg = mockUpdateSet.mock.calls[0]?.[0] as { status?: string; lastError?: string }
    expect(setArg?.status).toBe('failed')
    expect(setArg?.lastError).toBeTruthy()
  })

  it('transitions pending→backoff (attemptCount++, nextAttemptAt advanced) on 500 (transient)', async () => {
    const { createCalendarEvent } = await import('../../src/broker/write.js')
    vi.mocked(createCalendarEvent).mockResolvedValue(makeResponse(500))
    const row = makeRow({ attemptCount: 0 })
    mockPendingRows = [row]

    const beforeDrain = Date.now()
    await runOutboxDrain()

    // Must NOT transition to done or failed — backoff
    const setArg = mockUpdateSet.mock.calls[0]?.[0] as {
      status?: string
      attemptCount?: number
      nextAttemptAt?: Date
    }
    expect(setArg?.status).not.toBe('done')
    expect(setArg?.status).not.toBe('failed')
    expect(setArg?.attemptCount).toBe(1)
    // nextAttemptAt must be in the future
    expect(setArg?.nextAttemptAt?.getTime()).toBeGreaterThan(beforeDrain)
  })

  it('transitions pending→dead when attemptCount reaches MAX_ATTEMPTS on transient error', async () => {
    const { createCalendarEvent } = await import('../../src/broker/write.js')
    vi.mocked(createCalendarEvent).mockResolvedValue(makeResponse(500))
    // MAX_ATTEMPTS is 5 per RESEARCH.md Pattern 4 — at attempt 4 (0-indexed) → dead
    const row = makeRow({ attemptCount: 4 })
    mockPendingRows = [row]

    await runOutboxDrain()

    const setArg = mockUpdateSet.mock.calls[0]?.[0] as { status?: string }
    expect(setArg?.status).toBe('dead')
  })

  it('does not crash when pending rows list is empty', async () => {
    mockPendingRows = []
    await expect(runOutboxDrain()).resolves.not.toThrow()
  })
})

describe('runOutboxDrain — edit-as-move ordering (D-04)', () => {
  beforeEach(() => {
    vi.clearAllMocks()
    mockPendingRows = []
    mockUpdateSet.mockReturnValue({ where: vi.fn().mockResolvedValue(undefined) })
    mockUpdate.mockReturnValue({ set: mockUpdateSet })
    mockWherePending.mockImplementation(() => Promise.resolve(mockPendingRows))
    mockLimitFn.mockReturnValue({ where: mockWherePending })
    mockFromFn.mockReturnValue({ where: mockLimitFn })
    mockSelectFn.mockReturnValue({ from: mockFromFn })
  })

  it('processes the create row BEFORE the delete row when both share a groupId', async () => {
    const { createCalendarEvent, deleteCalendarEvent } = await import('../../src/broker/write.js')
    const createResponse = makeResponse(201)
    const deleteResponse = makeResponse(204)
    vi.mocked(createCalendarEvent).mockResolvedValue(createResponse)
    vi.mocked(deleteCalendarEvent).mockResolvedValue(deleteResponse)

    const groupId = 'edit-move-group-001'
    // delete row listed first (to verify ordering is enforced regardless of order in the array)
    const deleteRow = makeRow({
      id: 2,
      operation: 'delete',
      calendarObjectUrl: 'https://caldav.fastmail.com/dav/calendars/user/test/Old/uid.ics',
      etag: '"etag-old"',
      payload: null,
      groupId,
    })
    const createRow = makeRow({
      id: 3,
      operation: 'create',
      calendarUrl: 'https://caldav.fastmail.com/dav/calendars/user/test/New/',
      groupId,
    })

    // Both rows in the pending list
    mockPendingRows = [deleteRow, createRow]

    await runOutboxDrain()

    // CREATE must be called before DELETE
    const createCall = vi.mocked(createCalendarEvent).mock.invocationCallOrder[0]
    const deleteCall = vi.mocked(deleteCalendarEvent).mock.invocationCallOrder[0]

    // If either was never called, the test will fail naturally.
    // If create order index > delete order index, create ran AFTER delete — fail.
    expect(createCall).toBeLessThan(deleteCall)
  })
})