E2 on iOS

struct E2Client {
  // Configure the base URL for your deployment
  var baseURL = URL(string: "https://api.e2.example")!
  var session = URLSession.shared

  func get(_ path: String, query: [String: String]) async throws -> Data {
    var components = URLComponents(url: baseURL.appendingPathComponent(path),
                                    resolvingAgainstBaseURL: false)!
    components.queryItems = query.map { URLQueryItem(name: $0.key, value: $0.value) }
    let (data, _) = try await session.data(from: components.url!)
    return data
  }
}

struct FeatureCollection: Decodable {
  let features: [GeoFeature]
}
struct GeoFeature: Decodable {
  let geometry: Geometry
  let properties: [String: String?]?
}
struct Geometry: Decodable {
  let coordinates: [Double]
}

let data = try await client.get("search", query: [
  "feature": "restaurant", "area": "Manhattan", "limit": "500",
])
let places = try JSONDecoder().decode(FeatureCollection.self, from: data)

let annotations = places.features.map { feature -> MKPointAnnotation in
  let annotation = MKPointAnnotation()
  annotation.coordinate = CLLocationCoordinate2D(
    latitude: feature.geometry.coordinates[1],
    longitude: feature.geometry.coordinates[0],
  )
  annotation.title = feature.properties?["name"] ?? nil ?? "Restaurant"
  return annotation
}
mapView.addAnnotations(annotations)

struct RouteRequest: Encodable {
  let locations: [[String: Double]]
  let mode: String
}
struct RouteResponse: Decodable {
  let geometry: RouteGeometry
}
struct RouteGeometry: Decodable {
  let coordinates: [[Double]]
}

var request = URLRequest(url: baseURL.appendingPathComponent("route"))
request.httpMethod = "POST"
request.setValue("application/json", forHTTPHeaderField: "Content-Type")
request.httpBody = try JSONEncoder().encode(RouteRequest(
  locations: [["lat": 40.74, "lon": -73.99], ["lat": 40.71, "lon": -74.01]],
  mode: "walking",
))

let (data, _) = try await session.data(for: request)
let route = try JSONDecoder().decode(RouteResponse.self, from: data)

let coords = route.geometry.coordinates.map {
  CLLocationCoordinate2D(latitude: $0[1], longitude: $0[0])
}
mapView.addOverlay(MKPolyline(coordinates: coords, count: coords.count))

struct CountResponse: Decodable {
  let count: Int
}

let data = try await client.get("compute/count", query: [
  "feature": "restaurant", "region": "Manhattan",
  "near": "park", "distance": "500",
])
let nearParks = try JSONDecoder().decode(CountResponse.self, from: data)

statusText = "\(nearParks.count) restaurants within 500 m of a park"