Add lead workflows, PDF signing, AR projects and photo gallery integration

GasTankAR/Services/LoginUseCase.swift

@@ -0,0 +1,30 @@
+import Foundation
+
+protocol LoginUseCase: Sendable {
+    func execute(salesCode: String) async throws -> LoginSession
+}
+
+/// Shared by the use case and the form so that both enforce the same rule.
+enum SalesCodeValidator {
+    static func normalized(_ input: String) -> String {
+        input.trimmingCharacters(in: .whitespacesAndNewlines).uppercased()
+    }
+
+    static func isValid(_ input: String) -> Bool {
+        normalized(input).count >= 3
+    }
+}
+
+struct DefaultLoginUseCase: LoginUseCase {
+    let authenticationService: any AuthenticationService
+
+    func execute(salesCode: String) async throws -> LoginSession {
+        guard SalesCodeValidator.isValid(salesCode) else {
+            throw LoginError.invalidSalesCode
+        }
+        try Task.checkCancellation()
+        return try await authenticationService.signIn(
+            salesCode: SalesCodeValidator.normalized(salesCode)
+        )
+    }
+}