first cut of a view model

Signed-off-by: Matt Bruce <mbrucedogs@gmail.com>

EmployeeDirectory/ViewModels/EmployeesViewModel.swift

@@ -0,0 +1,52 @@
+//
+//  EmployeesViewModel.swift
+//  EmployeeDirectory
+//
+//  Created by Matt Bruce on 1/20/25.
+//
+
+import Foundation
+
+@MainActor
+public class EmployeesViewModel: ObservableObject {
+    private let service: EmployeeService
+    private var serviceMode: EmployeeServiceMode = .production
+
+    @Published public private(set) var employees: [Employee] = []
+    @Published public private(set) var errorMessage: String? = nil
+    @Published public private(set) var isLoading: Bool = false
+    
+    public init(service: EmployeeService = EmployeeService()) {
+        self.service = service
+    }
+    
+    public func fetchEmployees() {
+        // resetting values out the values before fetching new data
+        errorMessage = nil
+        isLoading = true
+
+        Task {
+            do {
+                // Fetch employees using the async method
+                let wrapper = try await service.getEmployees(serviceMode)
+                
+                // Update published properties
+                self.employees = wrapper.employees
+                self.isLoading = false
+
+            } catch {
+                // Handle errors
+                self.employees = []
+                self.isLoading = false
+                self.errorMessage = "An unexpected error occurred, please try to refresh"
+            }
+        }
+
+    }
+    
+    public func changeMode(to mode: EmployeeServiceMode) {
+        serviceMode = mode
+        fetchEmployees()
+    }
+}
+