import { test } from 'node:test'
import assert from 'node:assert/strict'
import { RealtimeClient } from '../realtime'

class FakeSocket {
  static readonly CONNECTING = 0
  static readonly OPEN = 1
  static readonly CLOSED = 3
  static instances: FakeSocket[] = []

  readyState = FakeSocket.CONNECTING
  onopen: (() => void) | null = null
  onmessage: ((event: { data: unknown }) => void) | null = null
  onerror: (() => void) | null = null
  onclose: ((event: { code: number }) => void) | null = null
  readonly url: string
  readonly sent: string[] = []

  constructor(url: string) {
    this.url = url
    FakeSocket.instances.push(this)
  }

  send(data: string): void {
    this.sent.push(data)
  }

  close(): void {
    this.readyState = FakeSocket.CLOSED
    this.onclose?.({ code: 1006 })
  }

  open(): void {
    this.readyState = FakeSocket.OPEN
    this.onopen?.()
  }

  emit(event: string, data: unknown): void {
    this.onmessage?.({ data: JSON.stringify({ event, data }) })
  }

  drop(code: number): void {
    this.readyState = FakeSocket.CLOSED
    this.onclose?.({ code })
  }
}

function installFakeWebSocket(): void {
  FakeSocket.instances = []
  ;(globalThis as { WebSocket?: unknown }).WebSocket = FakeSocket
}

function firstSocket(): FakeSocket {
  const socket = FakeSocket.instances[0]
  assert.ok(socket)
  return socket
}

// P0-1：服务端在客户端版本超前（换库 / 还原备份后 change_log 归零）时也会发快照，
// 若按版本号丢弃，大屏会永久冻结在旧数据上。
test('快照版本低于本地缓存也接受，并把版本重置到快照', () => {
  installFakeWebSocket()
  const seen: number[] = []
  const client = new RealtimeClient({
    role: 'display',
    url: 'ws://test/ws',
    initialVersion: 500,
    onSnapshot: (snapshot) => seen.push(snapshot.version),
  })
  client.connect()
  firstSocket().open()
  firstSocket().emit('snapshot', { version: 3 })

  assert.deepEqual(seen, [3])
  assert.equal(client.version, 3)
  client.close()
})

// P1-22：Console 的「已连接大屏实例」靠 hello 里的 page / instanceId 定位。
test('hello 上报 page 与 instanceId，翻页后补发', () => {
  installFakeWebSocket()
  const client = new RealtimeClient({
    role: 'display',
    url: 'ws://test/ws',
    instanceId: 'screen-1',
    page: 'standings',
  })
  client.connect()
  const socket = firstSocket()
  socket.open()

  assert.deepEqual(JSON.parse(socket.sent[0] ?? '{}'), {
    event: 'hello',
    data: { role: 'display', instanceId: 'screen-1', page: 'standings' },
  })

  socket.sent.length = 0
  client.setPage('team-medals')
  assert.equal(JSON.parse(socket.sent[0] ?? '{}').data.page, 'team-medals')
  client.close()
})

// P1-17：策略性拒绝（1008）重连也会被同样拒绝，必须停重连并提示登录。
test('close 1008 停止重连并回调 onAuthRequired', async () => {
  installFakeWebSocket()
  let authRequired = 0
  const client = new RealtimeClient({
    role: 'admin',
    url: 'ws://test/ws',
    reconnect: { baseDelayMs: 5, maxDelayMs: 5, jitterRatio: 0 },
    onAuthRequired: () => {
      authRequired += 1
    },
  })
  client.connect()
  const socket = firstSocket()
  socket.open()
  socket.drop(1008)

  assert.equal(authRequired, 1)
  assert.equal(client.status, 'offline')
  await new Promise((resolve) => setTimeout(resolve, 30))
  assert.equal(FakeSocket.instances.length, 1)
  client.close()
})

// P1-34：半开握手不触发 onopen/onclose，必须靠握手超时判死。
test('握手超时主动断开并重连', async () => {
  installFakeWebSocket()
  const errors: string[] = []
  const client = new RealtimeClient({
    role: 'display',
    url: 'ws://test/ws',
    handshakeMs: 10,
    reconnect: { baseDelayMs: 5, maxDelayMs: 5, jitterRatio: 0 },
    onError: (error) => errors.push(error.message),
  })
  client.connect()
  await new Promise((resolve) => setTimeout(resolve, 40))

  assert.ok(errors.some((message) => message.includes('握手超时')))
  assert.ok(FakeSocket.instances.length >= 2)
  client.close()
})

// P2-13：没有快照基准时不能直接合并 catchup。
test('没有快照基准时收到 catchup 先请求全量', () => {
  installFakeWebSocket()
  const catchups: unknown[] = []
  const client = new RealtimeClient({
    role: 'display',
    url: 'ws://test/ws',
    onCatchup: (message) => catchups.push(message),
  })
  client.connect()
  const socket = firstSocket()
  socket.open()
  socket.sent.length = 0
  socket.emit('catchup', { fromVersion: 0, version: 5, changes: [] })

  assert.equal(catchups.length, 0)
  assert.ok(socket.sent.some((raw) => raw.includes('"resync"')))
  client.close()
})