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

// Hoist mocks before any module resolution
const loggerMock = vi.hoisted(() => ({
  info: vi.fn(),
  warn: vi.fn(),
  error: vi.fn(),
  debug: vi.fn(),
}))

const insertOneMock = vi.hoisted(() => vi.fn())
const deleteOldestBeyondCapMock = vi.hoisted(() => vi.fn().mockResolvedValue(undefined))
const findOneAndUpdateMock = vi.hoisted(() => vi.fn().mockResolvedValue({ seq: 1 }))

vi.mock('@adonisjs/core/services/logger', () => ({
  default: loggerMock,
}))

vi.mock('#start/env', () => ({
  default: {
    get: (key: string, defaultValue?: any) => defaultValue,
  },
}))

vi.mock('#models/exchange', () => ({
  default: {
    getCollection: () => ({
      insertOne: insertOneMock,
    }),
    deleteOldestBeyondCap: deleteOldestBeyondCapMock,
  },
}))

vi.mock('#providers/mongodb_provider', () => ({
  getMongoDb: () => ({
    collection: () => ({
      findOneAndUpdate: findOneAndUpdateMock,
    }),
  }),
}))

vi.mock('#config/exchange_store', () => ({
  default: {
    maxMessagesPerDevice: 5000,
    retry: {
      maxAttempts: 3,
      baseDelayMs: 1000,
    },
    featureFlags: {
      persistence: true,
      sseEnabled: true,
      apiSource: 'mongodb',
    },
  },
}))

import { ExchangeStoreService } from '../../../app/services/exchange_store_service.js'
import type { CwmpExchange } from '../../../app/models/exchange.js'

describe('ExchangeStoreService — persistWithRetry', () => {
  let service: ExchangeStoreService

  beforeEach(() => {
    vi.clearAllMocks()
    vi.useFakeTimers()
    // Reset singleton for testing
    ;(ExchangeStoreService as any).instance = undefined
    service = ExchangeStoreService.getInstance()
  })

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

  const makeCriticalDoc = (method: string = 'Inform'): CwmpExchange => ({
    deviceId: 'device-001',
    direction: 'CPE→ACS',
    timestamp: new Date().toISOString(),
    sessionId: '10.0.0.1:54321->192.168.1.1:8080',
    cwmpMethod: method,
    rawXml: '<soap:Envelope><cwmp:Inform/></soap:Envelope>',
    sequenceNumber: 1,
    createdAt: new Date(),
  })

  const makeNonCriticalDoc = (method: string = 'Empty'): CwmpExchange => ({
    deviceId: 'device-001',
    direction: 'CPE→ACS',
    timestamp: new Date().toISOString(),
    sessionId: '10.0.0.1:54321->192.168.1.1:8080',
    cwmpMethod: method,
    rawXml: '',
    sequenceNumber: 1,
    createdAt: new Date(),
  })

  describe('isCriticalMethod', () => {
    it('classifies Inform as critical', () => {
      expect(service.isCriticalMethod('Inform')).toBe(true)
    })

    it('classifies GetParameterValues as critical', () => {
      expect(service.isCriticalMethod('GetParameterValues')).toBe(true)
    })

    it('classifies GetParameterValuesResponse as critical', () => {
      expect(service.isCriticalMethod('GetParameterValuesResponse')).toBe(true)
    })

    it('classifies SetParameterValues as critical', () => {
      expect(service.isCriticalMethod('SetParameterValues')).toBe(true)
    })

    it('classifies SetParameterValuesResponse as critical', () => {
      expect(service.isCriticalMethod('SetParameterValuesResponse')).toBe(true)
    })

    it('classifies AddObject as critical', () => {
      expect(service.isCriticalMethod('AddObject')).toBe(true)
    })

    it('classifies DeleteObject as critical', () => {
      expect(service.isCriticalMethod('DeleteObject')).toBe(true)
    })

    it('classifies Download as critical', () => {
      expect(service.isCriticalMethod('Download')).toBe(true)
    })

    it('classifies Upload as critical', () => {
      expect(service.isCriticalMethod('Upload')).toBe(true)
    })

    it('classifies Reboot as critical', () => {
      expect(service.isCriticalMethod('Reboot')).toBe(true)
    })

    it('classifies FactoryReset as critical', () => {
      expect(service.isCriticalMethod('FactoryReset')).toBe(true)
    })

    it('classifies Fault as critical', () => {
      expect(service.isCriticalMethod('Fault')).toBe(true)
    })

    it('classifies Empty as non-critical', () => {
      expect(service.isCriticalMethod('Empty')).toBe(false)
    })

    it('classifies Unknown as non-critical', () => {
      expect(service.isCriticalMethod('Unknown')).toBe(false)
    })
  })

  describe('critical messages — retry behavior', () => {
    it('succeeds on first attempt without retries', async () => {
      insertOneMock.mockResolvedValueOnce({ insertedId: 'abc' })

      await service.persistWithRetry(makeCriticalDoc(), true)

      expect(insertOneMock).toHaveBeenCalledTimes(1)
    })

    it('retries up to 3 times with exponential backoff on failure', async () => {
      const error = new Error('MongoDB write failed')
      insertOneMock.mockRejectedValue(error)

      const promise = service.persistWithRetry(makeCriticalDoc(), true)

      // Initial attempt fails immediately
      await vi.advanceTimersByTimeAsync(0)

      // Retry 1: after 1s delay (baseDelayMs * 2^0 = 1000ms)
      await vi.advanceTimersByTimeAsync(1000)

      // Retry 2: after 2s delay (baseDelayMs * 2^1 = 2000ms)
      await vi.advanceTimersByTimeAsync(2000)

      // Retry 3: after 4s delay (baseDelayMs * 2^2 = 4000ms)
      await vi.advanceTimersByTimeAsync(4000)

      await promise

      // 1 initial attempt + 3 retries = 4 total
      expect(insertOneMock).toHaveBeenCalledTimes(4)
    })

    it('succeeds on second retry attempt', async () => {
      const error = new Error('MongoDB write failed')
      // Initial attempt fails
      insertOneMock.mockRejectedValueOnce(error)
      // Retry 1 fails
      insertOneMock.mockRejectedValueOnce(error)
      // Retry 2 succeeds
      insertOneMock.mockResolvedValueOnce({ insertedId: 'abc' })

      const promise = service.persistWithRetry(makeCriticalDoc(), true)

      // Initial attempt fails
      await vi.advanceTimersByTimeAsync(0)
      // Retry 1 delay: 1000ms
      await vi.advanceTimersByTimeAsync(1000)
      // Retry 2 delay: 2000ms
      await vi.advanceTimersByTimeAsync(2000)

      await promise

      // 1 initial + 2 retries = 3 calls
      expect(insertOneMock).toHaveBeenCalledTimes(3)
    })

    it('never throws even when all retries are exhausted', async () => {
      insertOneMock.mockRejectedValue(new Error('persistent failure'))

      const promise = service.persistWithRetry(makeCriticalDoc(), true)

      await vi.advanceTimersByTimeAsync(10000)

      // Should not throw
      await expect(promise).resolves.toBeUndefined()
    })

    it('logs error when all retries exhausted', async () => {
      insertOneMock.mockRejectedValue(new Error('persistent failure'))

      const promise = service.persistWithRetry(makeCriticalDoc('Inform'), true)
      await vi.advanceTimersByTimeAsync(10000)
      await promise

      expect(loggerMock.error).toHaveBeenCalledWith(
        expect.objectContaining({
          deviceId: 'device-001',
          cwmpMethod: 'Inform',
          maxAttempts: 3,
        }),
        '[ExchangeStore] All retries exhausted for critical message — discarding'
      )
    })
  })

  describe('non-critical messages — discard immediately', () => {
    it('discards immediately on first failure (zero retries)', async () => {
      insertOneMock.mockRejectedValueOnce(new Error('write error'))

      await service.persistWithRetry(makeNonCriticalDoc('Empty'), false)

      // Only 1 attempt, no retries
      expect(insertOneMock).toHaveBeenCalledTimes(1)
    })

    it('never throws for non-critical messages', async () => {
      insertOneMock.mockRejectedValueOnce(new Error('write error'))

      await expect(
        service.persistWithRetry(makeNonCriticalDoc('Unknown'), false)
      ).resolves.toBeUndefined()
    })

    it('persists successfully on first attempt when no error', async () => {
      insertOneMock.mockResolvedValueOnce({ insertedId: 'abc' })

      await service.persistWithRetry(makeNonCriticalDoc(), false)

      expect(insertOneMock).toHaveBeenCalledTimes(1)
    })

    it('logs warning on failure for non-critical messages', async () => {
      insertOneMock.mockRejectedValueOnce(new Error('write error'))

      await service.persistWithRetry(makeNonCriticalDoc('Empty'), false)

      expect(loggerMock.warn).toHaveBeenCalledWith(
        expect.objectContaining({
          deviceId: 'device-001',
          cwmpMethod: 'Empty',
        }),
        '[ExchangeStore] Non-critical message persistence failed — discarding'
      )
    })
  })

  describe('CWMP session never interrupted', () => {
    it('critical message failure does not throw', async () => {
      insertOneMock.mockRejectedValue(new Error('catastrophic failure'))

      const promise = service.persistWithRetry(makeCriticalDoc('Inform'), true)
      await vi.advanceTimersByTimeAsync(10000)

      await expect(promise).resolves.toBeUndefined()
    })

    it('non-critical message failure does not throw', async () => {
      insertOneMock.mockRejectedValue(new Error('catastrophic failure'))

      await expect(
        service.persistWithRetry(makeNonCriticalDoc('Empty'), false)
      ).resolves.toBeUndefined()
    })
  })
})