iOS reference

.package(url: "https://github.com/faceping/faceping-ios", exact: "1.0.0-preview.1")

// Once, for example in your App's init. Returns at once and loads the models in the background.
try FacePing.configure(sandboxKey: "fp_test_…")       // sandbox: faces enrolled on the device
// try FacePing.configure(deviceToken: "fpd_…")       // production: faces synced from your list

// Anywhere later
let faceping = FacePing.shared                         // nil until it's set up

public final class FacePing {
    public static func configure(sandboxKey: String, region: FacePingRegion = .eu) throws -> FacePing
    public static func configure(deviceToken: String, region: FacePingRegion = .eu) throws -> FacePing
    public static func configure(_ options: FacePingOptions) throws -> FacePing
    public static var shared: FacePing? { get }
    public static let sdkVersion: String

    public var options: FacePingOptions { get }
    public var isSandbox: Bool { get }
    public var enrolledIds: Set<String> { get }
    public var synced: AsyncStream<SyncResult> { get }      // every sync, automatic or not

    public func enrol(id: String, photo: FaceImage) async throws -> EnrolResult    // also UIImage or Data
    @MainActor
    public func verifyLive(id: String, camera: FaceCameraView) async throws -> VerifyResult
    public func verify(id: String, photo: FaceImage) async throws -> VerifyResult  // also UIImage or Data

    public func forget(id: String) async throws -> Bool
    public func forgetAll() async throws

    public func sync() async throws -> SyncResult
    public func close()
}

@MainActor final class Model: ObservableObject {
    let camera = FaceCameraView()
}

FaceCamera(model.camera)
    .frame(height: 420)

public struct EnrolResult {
    public let outcome: EnrolOutcome
    public let id: String
    public var isEnrolled: Bool { get }     // outcome == .enrolled
}

public enum EnrolOutcome {
    case enrolled, noFace, multipleFaces, faceTooSmall, notLive, limitReached
}

public struct VerifyResult {
    public let outcome: VerifyOutcome
    public let similarity: Double
    public let livenessScore: Double?
    public let elapsed: TimeInterval
    public let isSandbox: Bool
    public var isMatch: Bool { get }        // outcome == .match
}

public enum VerifyOutcome {
    case match, noMatch, notEnrolled, noFace, livenessFailed, challengeFailed, expired, leaseExpired
}

public struct SyncResult {
    public let status: PackDownloadStatus  // .ok, .gone, .revoked or .unavailable
    public let enrolled: Int
    public let leaseUntil: Date?           // production: verifies offline until then
    public let deleteAfter: Date?
}

switch result.outcome {
case .match: openTheDoor()
case .noMatch, .livenessFailed: sendToStaff()
default: tryAgain()          // or list every case, plus @unknown default
}