/**
 * Broker: ctag polling + change detection
 *
 * Tests runPoll in src/broker/poller.ts.
 * Key behavior (D-13): ctag unchanged → no DB write (skip sync entirely)
 * Credentials decrypted via decryptPassword before client creation (T-03-04).
 */

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

// --- module-level mocks (Vitest hoisting) ---

const mockSyncCalendar = vi.fn().mockResolvedValue(undefined)

vi.mock('../../src/broker/sync.js', () => ({
  syncCalendar: mockSyncCalendar,
}))

// decryptPassword returns a predictable plaintext for any input
vi.mock('../../src/broker/crypto.js', () => ({
  decryptPassword: vi.fn().mockReturnValue('decrypted-app-password'),
}))

// db mock: select() chain returns configurable results
const mockCalendarsSelectResult: Array<{ id: number; url: string; ctag: string | null }> = []
const mockCredentialsSelectResult: Array<{
  id: number
  userId: number
  fastmailEmail: string
  encryptedPassword: string
}> = []

// Each call to db.select() needs to return different chains
// We use a call counter to decide which data to return
let selectCallCount = 0

const mockSelectLimit = vi.fn()
const mockSelectWhere = vi.fn().mockReturnValue({ limit: mockSelectLimit })
const mockSelectFrom = vi.fn()
const mockSelect = vi.fn().mockImplementation(() => ({ from: mockSelectFrom }))

mockSelectFrom.mockImplementation(() => ({
  // For memberCredentials selects (no .where), resolve directly
  where: mockSelectWhere,
  // Support both: direct await (no where) and .where().limit()
  then: (resolve: (v: typeof mockCredentialsSelectResult) => void) => {
    selectCallCount++
    resolve(mockCredentialsSelectResult)
    return Promise.resolve(mockCredentialsSelectResult)
  },
}))

mockSelectLimit.mockImplementation(() =>
  Promise.resolve(mockCalendarsSelectResult),
)

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

// mockFetchCalendars: controlled per test
const mockFetchCalendars = vi.fn()
const mockCreateFastmailClient = vi.fn().mockResolvedValue({
  fetchCalendars: mockFetchCalendars,
})

vi.mock('../../src/broker/client.js', () => ({
  createFastmailClient: mockCreateFastmailClient,
}))

describe('broker poller — runPoll', () => {
  beforeEach(() => {
    vi.clearAllMocks()
    selectCallCount = 0

    // Reset implementations
    mockSyncCalendar.mockResolvedValue(undefined)
    mockCreateFastmailClient.mockResolvedValue({ fetchCalendars: mockFetchCalendars })
    mockSelect.mockImplementation(() => ({ from: mockSelectFrom }))
    mockSelectFrom.mockImplementation(() => ({
      where: mockSelectWhere,
      then: (resolve: (v: typeof mockCredentialsSelectResult) => void) => {
        resolve(mockCredentialsSelectResult)
        return Promise.resolve(mockCredentialsSelectResult)
      },
    }))
    mockSelectLimit.mockResolvedValue(mockCalendarsSelectResult)

    // Clear arrays
    mockCredentialsSelectResult.length = 0
    mockCalendarsSelectResult.length = 0
  })

  it('skips syncCalendar when ctag is unchanged', async () => {
    const { runPoll } = await import('../../src/broker/poller.js')

    // Set up one credential
    mockCredentialsSelectResult.push({
      id: 1,
      userId: 10,
      fastmailEmail: 'lucas@fastmail.com',
      encryptedPassword: 'encrypted-blob',
    })

    // Set up the stored calendar row with ctag 'ctag-v1'
    mockCalendarsSelectResult.push({ id: 100, url: 'https://caldav.fastmail.com/cal/', ctag: 'ctag-v1' })

    // fetchCalendars returns a calendar with the SAME ctag
    mockFetchCalendars.mockResolvedValue([
      {
        url: 'https://caldav.fastmail.com/cal/',
        displayName: 'Test Calendar',
        ctag: 'ctag-v1', // UNCHANGED
        syncToken: null,
      },
    ])

    await runPoll()

    expect(mockSyncCalendar).not.toHaveBeenCalled()
  })

  it('calls syncCalendar when ctag changes', async () => {
    const { runPoll } = await import('../../src/broker/poller.js')

    mockCredentialsSelectResult.push({
      id: 1,
      userId: 10,
      fastmailEmail: 'lucas@fastmail.com',
      encryptedPassword: 'encrypted-blob',
    })

    mockCalendarsSelectResult.push({ id: 100, url: 'https://caldav.fastmail.com/cal/', ctag: 'ctag-v1' })

    mockFetchCalendars.mockResolvedValue([
      {
        url: 'https://caldav.fastmail.com/cal/',
        displayName: 'Test Calendar',
        ctag: 'ctag-v2', // CHANGED
        syncToken: null,
      },
    ])

    await runPoll()

    expect(mockSyncCalendar).toHaveBeenCalledOnce()
  })

  it('calls syncCalendar when ctag was null (first sync)', async () => {
    const { runPoll } = await import('../../src/broker/poller.js')

    mockCredentialsSelectResult.push({
      id: 1,
      userId: 10,
      fastmailEmail: 'lucas@fastmail.com',
      encryptedPassword: 'encrypted-blob',
    })

    // No stored calendar row yet (empty array → first sync)
    // mockCalendarsSelectResult is empty

    mockFetchCalendars.mockResolvedValue([
      {
        url: 'https://caldav.fastmail.com/cal/',
        displayName: 'My Calendar',
        ctag: 'ctag-v1',
        syncToken: null,
      },
    ])

    await runPoll()

    expect(mockSyncCalendar).toHaveBeenCalledOnce()
  })

  it('handles decryptPassword failure gracefully without crashing the poller', async () => {
    const { runPoll } = await import('../../src/broker/poller.js')
    const { decryptPassword } = await import('../../src/broker/crypto.js')

    mockCredentialsSelectResult.push({
      id: 1,
      userId: 10,
      fastmailEmail: 'lucas@fastmail.com',
      encryptedPassword: 'corrupted',
    })

    // Make decryptPassword throw for this test
    ;(decryptPassword as Mock).mockImplementationOnce(() => {
      throw new Error('Decryption failed')
    })

    // runPoll should not throw — it should catch and skip the credential
    await expect(runPoll()).resolves.not.toThrow()
    expect(mockSyncCalendar).not.toHaveBeenCalled()
  })

  it('processes all member credentials in a poll cycle', async () => {
    const { runPoll } = await import('../../src/broker/poller.js')

    // Two credentials
    mockCredentialsSelectResult.push(
      { id: 1, userId: 10, fastmailEmail: 'lucas@fastmail.com', encryptedPassword: 'enc1' },
      { id: 2, userId: 20, fastmailEmail: 'wife@icloud.com', encryptedPassword: 'enc2' },
    )

    // Each member's calendar has a different (new) ctag → both trigger sync
    mockFetchCalendars.mockResolvedValue([
      {
        url: 'https://caldav.fastmail.com/cal/',
        displayName: 'Calendar',
        ctag: 'new-ctag',
        syncToken: null,
      },
    ])

    await runPoll()

    // createFastmailClient called once per credential
    expect(mockCreateFastmailClient).toHaveBeenCalledTimes(2)
    // syncCalendar called once per credential (one calendar each, ctag changed)
    expect(mockSyncCalendar).toHaveBeenCalledTimes(2)
  })
})