Add factory to initialise vehicles

SwiftyCar/Sources/SwiftyCar/VehicleFactory.swift

@@ -0,0 +1,27 @@
+//
+//  File.swift
+//  
+//
+//  Created by Michael Pivato on 20/5/20.
+//
+
+import Foundation
+import SwiftyGPIO
+
+
+
+func getVehicle2D() throws -> Vehicle2D {
+    if let value = ProcessInfo.processInfo.environment["CAR_VEHICLE"] {
+        switch value{
+        case "CAR_2D":
+            // Get car for rpi.
+            let pwms = SwiftyGPIO.hardwarePWMs(for:.RaspberryPi3)!
+            
+            // Read the feature database.
+            return try RPiVehicle2D(withThrottlePin: Servo(forPin: (pwms[0]?[.P18])!)!, withSteeringPin:Servo(forPin: (pwms[1]?[.P19])!)!)
+        default:
+            return MockVehicle()
+        }
+    }
+    return MockVehicle()
+}

SwiftyCar/Sources/SwiftyCar/main.swift

@@ -6,7 +6,6 @@
 //
 
 import NIO
-import SwiftyGPIO
 import GRPC
 
 func doServer() throws {
@@ -17,12 +16,9 @@ func doServer() throws {
       try! group.syncShutdownGracefully()
     }
     
-    let pwms = SwiftyGPIO.hardwarePWMs(for:.RaspberryPi3)!
     
-    // Read the feature database.
-    let vehicle = try RPiVehicle2D(withThrottlePin: Servo(forPin: (pwms[0]?[.P18])!)!, withSteeringPin:Servo(forPin: (pwms[1]?[.P19])!)!)
     // Create a provider using the features we read.
-    let provider = MotorProvider(vehicle: vehicle)
+    let provider = try MotorProvider(vehicle: getVehicle2D())
 
     // Start the server and print its address once it has started.
     let server = Server.insecure(group: group)