Use remote authentication, add key display screen

Sesame/API/Data+Extensions.swift

@@ -0,0 +1,59 @@
+import Foundation
+
+extension Data {
+
+    public var hexEncoded: String {
+        return map { String(format: "%02hhx", $0) }.joined()
+    }
+
+    // Convert 0 ... 9, a ... f, A ...F to their decimal value,
+    // return nil for all other input characters
+    private func decodeNibble(_ u: UInt16) -> UInt8? {
+        switch(u) {
+        case 0x30 ... 0x39:
+            return UInt8(u - 0x30)
+        case 0x41 ... 0x46:
+            return UInt8(u - 0x41 + 10)
+        case 0x61 ... 0x66:
+            return UInt8(u - 0x61 + 10)
+        default:
+            return nil
+        }
+    }
+
+    public init?(fromHexEncodedString string: String) {
+        let utf16 = string.utf16
+        self.init(capacity: utf16.count/2)
+
+        var i = utf16.startIndex
+        guard utf16.count % 2 == 0 else {
+            return nil
+        }
+        while i != utf16.endIndex {
+            guard let hi = decodeNibble(utf16[i]),
+                let lo = decodeNibble(utf16[utf16.index(i, offsetBy: 1, limitedBy: utf16.endIndex)!]) else {
+                    return nil
+            }
+            var value = hi << 4 + lo
+            self.append(&value, count: 1)
+            i = utf16.index(i, offsetBy: 2, limitedBy: utf16.endIndex)!
+        }
+    }
+}
+
+extension Data {
+
+
+    func convert<T>(into value: T) -> T {
+        withUnsafeBytes {
+            $0.baseAddress!.load(as: T.self)
+        }
+    }
+
+    init<T>(from value: T) {
+        var target = value
+        self = Swift.withUnsafeBytes(of: &target) {
+            Data($0)
+        }
+    }
+}

Sesame/API/DeviceResponse.swift

@@ -16,6 +16,11 @@ struct DeviceResponse {
         .init(event: .deviceNotConnected)
     }
 
+    /// Shorthand property for a connected event.
+    static var deviceConnected: DeviceResponse {
+        .init(event: .deviceConnected)
+    }
+
     /// Shorthand property for an unexpected socket event.
     static var unexpectedSocketEvent: DeviceResponse {
         .init(event: .unexpectedSocketEvent)

Sesame/API/Message.swift

@@ -101,6 +101,10 @@ extension Message {
         mac + content.encoded
     }
 
+    var bytes: [UInt8] {
+        Array(encoded)
+    }
+
     /**
      Create a message from received bytes.
      - Parameter data: The sequence of bytes

Sesame/API/MessageResult.swift

@@ -38,6 +38,9 @@ enum MessageResult: UInt8 {
 
     /// Another message is being processed by the device
     case operationInProgress = 14
+
+    /// The device is connected
+    case deviceConnected = 15
 }
 
 extension MessageResult: CustomStringConvertible {
@@ -66,6 +69,8 @@ extension MessageResult: CustomStringConvertible {
             return "The device did not respond"
         case .operationInProgress:
             return "Another operation is in progress"
+        case .deviceConnected:
+            return "The device is connected"
         }
     }
 }

Sesame/API/ServerMessage.swift

@@ -0,0 +1,51 @@
+import Foundation
+import NIOCore
+
+#if canImport(CryptoKit)
+import CryptoKit
+#else
+import Crypto
+#endif
+
+struct ServerMessage {
+
+    static let authTokenSize = SHA256.byteCount
+
+    static let length = authTokenSize + Message.length
+
+    let authToken: Data
+
+    let message: Message
+
+    init(authToken: Data, message: Message) {
+        self.authToken = authToken
+        self.message = message
+    }
+    
+    /**
+     Decode a message from a byte buffer.
+     The buffer must contain at least `ServerMessage.length` bytes, or it will return `nil`.
+     - Parameter buffer: The buffer containing the bytes.
+     */
+    init?(decodeFrom buffer: ByteBuffer) {
+        guard let data = buffer.getBytes(at: 0, length: ServerMessage.length) else {
+            return nil
+        }
+        self.authToken = Data(data.prefix(ServerMessage.authTokenSize))
+        self.message = Message(decodeFrom: Data(data.dropFirst(ServerMessage.authTokenSize)))
+    }
+
+    var encoded: Data {
+        authToken + message.encoded
+    }
+
+    static func token(from buffer: ByteBuffer) -> Data? {
+        guard buffer.readableBytes == authTokenSize else {
+            return nil
+        }
+        guard let bytes = buffer.getBytes(at: 0, length: authTokenSize) else {
+            return nil
+        }
+        return Data(bytes)
+    }
+}