import "msal_bridge.dart";

enum AuthenticationMode { demo, azure }

class AuthService {
  AuthService._();

  static const String _configuredMode = String.fromEnvironment(
    "AUTH_MODE",
    defaultValue: "demo",
  );
  static const String azureTenantId = String.fromEnvironment("AZURE_TENANT_ID");
  static const String azureSpaClientId = String.fromEnvironment(
    "AZURE_SPA_CLIENT_ID",
  );
  static const String azureApiScope = String.fromEnvironment("AZURE_API_SCOPE");

  static const String demoStudentEmail = "lucas.martin@ensitech.eu";
  static const String demoResponsableEmail = "karim.benali@ensup.eu";

  static String? _demoEmail;
  static bool _azureInitialized = false;

  static AuthenticationMode get mode {
    return switch (_configuredMode) {
      "demo" => AuthenticationMode.demo,
      "azure" => AuthenticationMode.azure,
      _ => throw StateError("AUTH_MODE doit valoir demo ou azure."),
    };
  }

  static void selectDemoStudent() {
    _ensureDemoMode();
    _demoEmail = demoStudentEmail;
  }

  static void selectDemoResponsable() {
    _ensureDemoMode();
    _demoEmail = demoResponsableEmail;
  }

  static void clearSession() {
    _demoEmail = null;
  }

  static Future<void> signInWithMicrosoft() async {
    await _initializeAzure();
    await MsalBridge.signIn();
  }

  static Future<bool> hasMicrosoftAccount() async {
    await _initializeAzure();
    return MsalBridge.hasAccount();
  }

  static Future<void> signOut() async {
    if (mode == AuthenticationMode.azure) {
      await _initializeAzure();
      await MsalBridge.signOut();
      return;
    }

    clearSession();
  }

  static Future<Map<String, String>> requestHeaders() async {
    if (mode == AuthenticationMode.azure) {
      await _initializeAzure();
      final token = await MsalBridge.getAccessToken();
      return {"authorization": "Bearer $token"};
    }

    final email = _demoEmail;
    if (email == null) {
      throw StateError("Aucun utilisateur de demonstration selectionne.");
    }

    return {"x-user-email": email};
  }

  static Future<void> _initializeAzure() async {
    if (mode != AuthenticationMode.azure) {
      throw StateError("MSAL est disponible uniquement en mode Azure.");
    }
    if (_azureInitialized) {
      return;
    }
    if (azureTenantId.isEmpty ||
        azureSpaClientId.isEmpty ||
        azureApiScope.isEmpty) {
      throw StateError("La configuration Azure du frontend est incomplete.");
    }

    await MsalBridge.initialize(
      tenantId: azureTenantId,
      clientId: azureSpaClientId,
      scope: azureApiScope,
      redirectUri: Uri.base.origin,
    );
    _azureInitialized = true;
  }

  static void _ensureDemoMode() {
    if (mode != AuthenticationMode.demo) {
      throw StateError(
        "Une identite de demonstration est interdite en mode Azure.",
      );
    }
  }
}