// Copyright 2024-present 650 Industries. All rights reserved.

import CoreLocation
import ExpoModulesCore

internal class LocationsStreamer: BaseStreamer {
  typealias LocationsStream = AsyncThrowingStream<[CLLocation], Error>

  private var locationsStream: LocationsStream?
  private var continuation: LocationsStream.Continuation?

  deinit {
    if continuation != nil {
      stopStreaming()
    }
  }

  func streamLocations() throws -> LocationsStream {
    if !CLLocationManager.locationServicesEnabled() {
      throw Exceptions.LocationServicesDisabled()
    }

    if let stream = locationsStream {
      return stream
    }
    let stream = LocationsStream { continuation in
      self.continuation = continuation
      manager.startUpdatingLocation()
    }
    locationsStream = stream
    return stream
  }

  override func stopStreaming() {
    manager.stopUpdatingLocation()
    continuation?.finish()

    locationsStream = nil
    continuation = nil
  }

  // MARK: - CLLocationManagerDelegate

  func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
    if !locations.isEmpty {
      continuation?.yield(locations)
    }
  }

  func locationManager(_ manager: CLLocationManager, didFailWithError error: any Error) {
    // Ignore `locationUnknown` (code 0) as it might be a temporary issue.
    // The location manager will keep trying to obtain the location.
    // It's a common error on simulator when there is no default location set in the scheme.
    guard let clError = error as? CLError, clError.code != .locationUnknown else {
      return
    }
    continuation?.finish(throwing: Exceptions.LocationUnavailable().causedBy(error))
    locationsStream = nil
    continuation = nil
  }
}