import 'package:flutter/foundation.dart'
    show TargetPlatform, defaultTargetPlatform, kIsWeb;

import '../models/app_user.dart';
import 'auth_service_firebase.dart';
import 'auth_service_linux.dart';

/// Unified auth API for mobile, web, and Linux desktop development.
class AuthService {
  AuthService._();

  static final AuthService instance = AuthService._();

  /// True when running the Linux desktop app (not unit tests on a Linux host).
  static bool get isLinuxDesktop {
    if (kIsWeb) {
      return false;
    }
    if (const bool.fromEnvironment('FLUTTER_TEST')) {
      return false;
    }
    return defaultTargetPlatform == TargetPlatform.linux;
  }

  Stream<AppUser?> get authStateChanges => isLinuxDesktop
      ? AuthServiceLinux.instance.authStateChanges
      : AuthServiceFirebase.instance.authStateChanges;

  AppUser? get currentUser => isLinuxDesktop
      ? AuthServiceLinux.instance.currentUser
      : AuthServiceFirebase.instance.currentUser;

  Future<void> initialize() async {
    if (isLinuxDesktop) {
      await AuthServiceLinux.instance.initialize();
    } else {
      await AuthServiceFirebase.instance.initialize();
    }
  }

  Future<void> signInWithGoogle() async {
    if (isLinuxDesktop) {
      await AuthServiceLinux.instance.signInWithGoogle();
    } else {
      await AuthServiceFirebase.instance.signInWithGoogle();
    }
  }

  Future<void> signOut() async {
    if (isLinuxDesktop) {
      await AuthServiceLinux.instance.signOut();
    } else {
      await AuthServiceFirebase.instance.signOut();
    }
  }

  /// Firebase ID token for API requests. Returns null when signed out.
  Future<String?> getIdToken({bool forceRefresh = false}) async {
    if (isLinuxDesktop) {
      return AuthServiceLinux.instance.getIdToken(
        forceRefresh: forceRefresh,
      );
    }
    return AuthServiceFirebase.instance.getIdToken(
      forceRefresh: forceRefresh,
    );
  }
}