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

/**
 * Integration test: Message cap enforcement
 * Validates: Requirements 1.4
 *
 * Verifies that when a device accumulates more than 5000 messages,
 * the oldest messages are deleted and only the 5000 most recent remain.
 *
 * This is a unit-level integration test using mocks (not a real MongoDB).
 * It mocks MongoDB operations but verifies the correct sequence of calls.
 */

// ─── Hoisted Mocks ────────────────────────────────────────────────────────────

const loggerMock = vi.hoisted(() => ({
  info: vi.fn(),
  warn: vi.fn(),
  error: vi.fn(),
  debug: vi.fn(),
}))

const insertOneMock = vi.hoisted(() => vi.fn().mockResolvedValue({ insertedId: 'mock-id' }))
const countDocumentsMock = vi.hoisted(() => vi.fn())
const findMock = vi.hoisted(() => vi.fn())
const deleteManyMock = vi.hoisted(() => vi.fn().mockResolvedValue({ deletedCount: 1 }))
const findOneAndUpdateMock = vi.hoisted(() => vi.fn())

// Track sequence numbers per device
let sequenceCounter: number

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

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

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',
    },
  },
}))

vi.mock('#models/exchange', () => ({
  default: {
    getCollection: () => ({
      insertOne: insertOneMock,
      countDocuments: countDocumentsMock,
      find: findMock,
      deleteMany: deleteManyMock,
    }),
    countByDevice: async (deviceId: string) => {
      return countDocumentsMock(deviceId)
    },
    deleteOldestBeyondCap: async (deviceId: string, maxCount: number) => {
      const count = await countDocumentsMock(deviceId)
      if (count <= maxCount) return

      const toDelete = count - maxCount
      // Simulate finding oldest documents
      const oldest = Array.from({ length: toDelete }, (_, i) => ({
        sequenceNumber: i + 1,
      }))

      if (oldest.length === 0) return

      const maxSeqToDelete = oldest[oldest.length - 1].sequenceNumber
      await deleteManyMock({
        deviceId,
        sequenceNumber: { $lte: maxSeqToDelete },
      })
    },
  },
}))

import { ExchangeStoreService } from '../../app/services/exchange_store_service.js'

// ─── Test Suite ───────────────────────────────────────────────────────────────

describe('Integration: Message Cap Enforcement', () => {
  let service: ExchangeStoreService

  beforeEach(() => {
    vi.clearAllMocks()
    ;(ExchangeStoreService as any).instance = undefined
    service = ExchangeStoreService.getInstance()
    sequenceCounter = 0

    // Each call to findOneAndUpdate increments and returns the next sequence number
    findOneAndUpdateMock.mockImplementation(() => {
      sequenceCounter++
      return Promise.resolve({ seq: sequenceCounter })
    })
  })

  it('enforces cap: inserting 5001 messages results in oldest being deleted and count = 5000', async () => {
    const deviceId = 'device-cap-test'
    const totalMessages = 5001
    const maxCap = 5000

    // Track the state: as messages are inserted, count grows
    // After each insert, enforceMessageCap is called
    // We simulate: for the first 5000 inserts, count <= 5000 so no delete
    // On the 5001st insert, count is 5001 so deleteOldestBeyondCap is called

    let currentCount = 0

    countDocumentsMock.mockImplementation((_filter?: any) => {
      // Return current count (updated after each insert)
      return Promise.resolve(currentCount)
    })

    // Track all deleteMany calls to verify which messages were deleted
    const deleteManyCalls: any[] = []
    deleteManyMock.mockImplementation((filter: any) => {
      deleteManyCalls.push(filter)
      // After delete, current count should decrease
      currentCount = maxCap
      return Promise.resolve({ deletedCount: 1 })
    })

    // Mock find for deleteOldestBeyondCap: returns the oldest documents to delete
    findMock.mockImplementation(() => ({
      sort: () => ({
        limit: (n: number) => ({
          project: () => ({
            toArray: () =>
              Promise.resolve(
                Array.from({ length: n }, (_, i) => ({
                  sequenceNumber: i + 1,
                }))
              ),
          }),
        }),
      }),
    }))

    // Simulate inserting 5001 messages
    for (let i = 0; i < totalMessages; i++) {
      currentCount = i + 1 // After this insert, count is i+1
      await service.persistExchange({
        deviceId,
        direction: 'CPE→ACS',
        sessionId: `session-${i}`,
        rawXml: `<soap-env:Envelope xmlns:cwmp="urn:dslforum-org:cwmp-1-0"><soap-env:Body><cwmp:Inform><DeviceId>${i}</DeviceId></cwmp:Inform></soap-env:Body></soap-env:Envelope>`,
      })
    }

    // Verify: insertOne was called 5001 times (all messages persisted first)
    expect(insertOneMock).toHaveBeenCalledTimes(totalMessages)

    // Verify: countByDevice (via countDocuments in the mock) was called
    // Each insert triggers enforceMessageCap which calls countByDevice
    expect(countDocumentsMock).toHaveBeenCalled()

    // Verify: deleteMany was called when count exceeded 5000
    // The 5001st message triggers a delete
    expect(deleteManyMock).toHaveBeenCalled()

    // Verify: after enforcement, the effective count is 5000 (capped)
    // The last countDocumentsMock returned 5001, which triggered the delete
    // After delete, count became 5000
    expect(currentCount).toBe(maxCap)

    // Verify: the deletion targeted the oldest message (sequenceNumber <= 1)
    const lastDeleteCall = deleteManyCalls[deleteManyCalls.length - 1]
    expect(lastDeleteCall).toHaveProperty('deviceId', deviceId)
    expect(lastDeleteCall).toHaveProperty('sequenceNumber')
    expect(lastDeleteCall.sequenceNumber.$lte).toBe(1)
  })

  it('verifies correct call sequence: countByDevice is called before deleteOldestBeyondCap', async () => {
    const deviceId = 'device-sequence-test'
    const callOrder: string[] = []

    // Track call order
    countDocumentsMock.mockImplementation((_filter?: any) => {
      callOrder.push('countByDevice')
      return Promise.resolve(5001) // Always over cap for this test
    })

    deleteManyMock.mockImplementation((filter: any) => {
      callOrder.push('deleteOldestBeyondCap')
      return Promise.resolve({ deletedCount: 1 })
    })

    findMock.mockImplementation(() => ({
      sort: () => ({
        limit: (n: number) => ({
          project: () => ({
            toArray: () =>
              Promise.resolve([{ sequenceNumber: 1 }]),
          }),
        }),
      }),
    }))

    await service.persistExchange({
      deviceId,
      direction: 'CPE→ACS',
      sessionId: 'session-test',
      rawXml: '<soap-env:Envelope xmlns:cwmp="urn:dslforum-org:cwmp-1-0"><soap-env:Body><cwmp:Inform/></soap-env:Body></soap-env:Envelope>',
    })

    // Verify call sequence: count is checked BEFORE delete
    const countIndex = callOrder.indexOf('countByDevice')
    const deleteIndex = callOrder.indexOf('deleteOldestBeyondCap')
    expect(countIndex).toBeGreaterThanOrEqual(0)
    expect(deleteIndex).toBeGreaterThan(countIndex)
  })

  it('retains the most recent messages by timestamp after cap enforcement', async () => {
    const deviceId = 'device-recent-test'
    const timestamps: string[] = []

    // Generate 5001 timestamps in ascending order
    const baseTime = new Date('2025-01-15T10:00:00.000Z')
    for (let i = 0; i < 5001; i++) {
      timestamps.push(new Date(baseTime.getTime() + i * 1000).toISOString())
    }

    let insertedDocs: any[] = []
    insertOneMock.mockImplementation((doc: any) => {
      insertedDocs.push({ ...doc })
      return Promise.resolve({ insertedId: `id-${doc.sequenceNumber}` })
    })

    // After 5001 inserts, count exceeds cap
    countDocumentsMock.mockImplementation((_filter?: any) => {
      return Promise.resolve(insertedDocs.length)
    })

    // Track what gets deleted
    let deletedMaxSeq = 0
    deleteManyMock.mockImplementation((filter: any) => {
      deletedMaxSeq = filter.sequenceNumber?.$lte || 0
      return Promise.resolve({ deletedCount: 1 })
    })

    findMock.mockImplementation(() => ({
      sort: () => ({
        limit: (n: number) => ({
          project: () => ({
            toArray: () => {
              // Return the oldest n documents (lowest sequence numbers)
              const oldest = insertedDocs
                .slice(0, n)
                .map((d) => ({ sequenceNumber: d.sequenceNumber }))
              return Promise.resolve(oldest)
            },
          }),
        }),
      }),
    }))

    // Override Date to control timestamps
    let dateIndex = 0
    const originalDateNow = Date.prototype.toISOString
    vi.spyOn(Date.prototype, 'toISOString').mockImplementation(function () {
      if (dateIndex < timestamps.length) {
        return timestamps[dateIndex++]
      }
      return originalDateNow.call(this)
    })

    // Insert 5001 messages
    for (let i = 0; i < 5001; i++) {
      await service.persistExchange({
        deviceId,
        direction: i % 2 === 0 ? 'CPE→ACS' : 'ACS→CPE',
        sessionId: `session-${i}`,
        rawXml: `<soap-env:Envelope xmlns:cwmp="urn:dslforum-org:cwmp-1-0"><soap-env:Body><cwmp:Inform><Seq>${i}</Seq></cwmp:Inform></soap-env:Body></soap-env:Envelope>`,
      })
    }

    // Verify: 5001 documents were inserted
    expect(insertedDocs).toHaveLength(5001)

    // Verify: the deletion targeted the oldest message (sequenceNumber = 1)
    // This means messages with seq 2..5001 remain (the 5000 most recent)
    expect(deletedMaxSeq).toBe(1)

    // Verify: retained messages are the most recent by checking the last inserted
    // has the highest sequence number (5001) and most recent timestamp
    const lastInserted = insertedDocs[insertedDocs.length - 1]
    expect(lastInserted.sequenceNumber).toBe(5001)

    // The retained set would be seq 2..5001 (most recent 5000)
    // The deleted set would be seq 1 (oldest)
    // Verify the oldest deleted doc has the earliest timestamp
    const oldestDoc = insertedDocs[0]
    const newestRetainedDoc = insertedDocs[1] // seq 2 is now the oldest retained
    expect(new Date(oldestDoc.timestamp).getTime()).toBeLessThan(
      new Date(newestRetainedDoc.timestamp).getTime()
    )

    vi.restoreAllMocks()
  })

  it('does not delete when count is exactly at cap (5000 messages)', async () => {
    const deviceId = 'device-exact-cap'

    countDocumentsMock.mockImplementation((_filter?: any) => {
      return Promise.resolve(5000) // Exactly at cap, no deletion needed
    })

    await service.persistExchange({
      deviceId,
      direction: 'CPE→ACS',
      sessionId: 'session-exact',
      rawXml: '<soap-env:Envelope xmlns:cwmp="urn:dslforum-org:cwmp-1-0"><soap-env:Body><cwmp:Inform/></soap-env:Body></soap-env:Envelope>',
    })

    // Verify: deleteMany was NOT called (count <= maxCap)
    expect(deleteManyMock).not.toHaveBeenCalled()
  })
})