import Dependencies
import Logging
import Models
@_spi(Internal) import MQTTManager
import MQTTNIO
import NIO
import PsychrometricClientLive
@_spi(Internal) import SensorsService
import XCTest

final class SensorsClientTests: XCTestCase {

  static let hostname = ProcessInfo.processInfo.environment["MOSQUITTO_SERVER"] ?? "localhost"

  static let logger: Logger = {
    var logger = Logger(label: "SensorsClientTests")
    logger.logLevel = .trace
    return logger
  }()

  override func invokeTest() {
    let client = createClient(identifier: "\(Self.self)")

    withDependencies {
      $0.mqtt = .live(client: client, logger: Self.logger)
      $0.psychrometricClient = PsychrometricClient.liveValue
    } operation: {
      super.invokeTest()
    }
  }

  func testListeningResumesAfterDisconnectThenReconnect() async throws {
    struct TimeoutError: Error {}

    let sensor = TemperatureAndHumiditySensor(location: .return)
    let results = ResultContainer()

    try await withDependencies {
      $0.mqtt.publish = results.append
    } operation: {
      @Dependency(\.mqtt) var manager

      let sensorsService = SensorsService(sensors: [sensor], logger: Self.logger)
      let task = Task { try await sensorsService.run() }
      defer { task.cancel() }

      try await manager.connect()
      defer { manager.shutdown() }

      try await manager.withClient { client in
        try await client.disconnect()
        try await client.connect()

        while !client.isActive() {
          try await Task.sleep(for: .milliseconds(100))
        }

        // Give time to re-subscribe.
        try await Task.sleep(for: .milliseconds(200))

        try await client.publish(
          to: sensor.topics.temperature,
          payload: ByteBufferAllocator().buffer(string: "25"),
          qos: .atLeastOnce,
          retain: false
        )
        try await client.publish(
          to: sensor.topics.humidity,
          payload: ByteBufferAllocator().buffer(string: "50"),
          qos: .atLeastOnce,
          retain: false
        )
      }

      var timeoutCount = 0
      while !(await results.count == 2) {
        guard timeoutCount < 20 else {
          throw TimeoutError()
        }
        try await Task.sleep(for: .milliseconds(100))
        timeoutCount += 1
      }

      let results = await results.results()

      XCTAssertEqual(results.count, 2)
      XCTAssert(results.contains(where: { $0.topicName == sensor.topics.dewPoint }))
      XCTAssert(results.contains(where: { $0.topicName == sensor.topics.enthalpy }))
      try await sensorsService.shutdown()
    }
  }

  func createClient(identifier: String) -> MQTTClient {
    let envVars = EnvVars(
      appEnv: .testing,
      host: Self.hostname,
      port: "1883",
      identifier: identifier,
      userName: nil,
      password: nil
    )
    let config = MQTTClient.Configuration(
      version: .v3_1_1,
      userName: envVars.userName,
      password: envVars.password,
      useSSL: false,
      useWebSockets: false,
      tlsConfiguration: nil,
      webSocketURLPath: nil
    )
    return .init(
      host: Self.hostname,
      identifier: identifier,
      eventLoopGroupProvider: .shared(MultiThreadedEventLoopGroup(numberOfThreads: 1)),
      logger: Self.logger,
      configuration: config
    )
  }
}

// MARK: Helpers for tests.

struct TopicNotFoundError: Error {}

actor ResultContainer: Sendable {

  private var storage = [MQTTManager.PublishRequest]()

  init() {}

  @Sendable func append(_ result: MQTTManager.PublishRequest) async {
    storage.append(result)
  }

  var count: Int {
    get async { storage.count }
  }

  func results() async -> [MQTTManager.PublishRequest] {
    storage
  }
}