import 'package:auto_route/auto_route.dart';
import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:trainhub_flutter/core/constants/ui_constants.dart';
import 'package:trainhub_flutter/core/router/app_router.dart';
import 'package:trainhub_flutter/core/theme/app_colors.dart';
import 'package:trainhub_flutter/presentation/settings/ai_model_settings_controller.dart';
import 'package:trainhub_flutter/presentation/settings/ai_model_settings_state.dart';
import 'package:trainhub_flutter/presentation/welcome/widgets/download_progress.dart';
import 'package:trainhub_flutter/presentation/welcome/widgets/initial_prompt.dart';

@RoutePage()
class WelcomeScreen extends ConsumerStatefulWidget {
  const WelcomeScreen({super.key});

  @override
  ConsumerState<WelcomeScreen> createState() => _WelcomeScreenState();
}

class _WelcomeScreenState extends ConsumerState<WelcomeScreen> {
  bool _hasNavigated = false;

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addPostFrameCallback((_) {
      ref
          .read(aiModelSettingsControllerProvider.notifier)
          .validateModels()
          .then((_) {
        if (!mounted) return;
        final validated = ref
            .read(aiModelSettingsControllerProvider)
            .areModelsValidated;
        if (validated) _navigateToApp();
      });
    });
  }

  void _navigateToApp() {
    if (_hasNavigated) return;
    _hasNavigated = true;
    context.router.replace(const ShellRoute());
  }

  @override
  Widget build(BuildContext context) {
    final modelState = ref.watch(aiModelSettingsControllerProvider);

    ref.listen<AiModelSettingsState>(aiModelSettingsControllerProvider,
        (prev, next) {
      if (!_hasNavigated &&
          next.areModelsValidated &&
          !next.isDownloading) {
        _navigateToApp();
      }
    });

    return Scaffold(
      backgroundColor: AppColors.surface,
      body: Center(
        child: SizedBox(
          width: 560,
          child: AnimatedSwitcher(
            duration: UIConstants.animationDuration,
            child: modelState.isDownloading
                ? DownloadProgress(modelState: modelState)
                : InitialPrompt(
                    onDownload: () => ref
                        .read(aiModelSettingsControllerProvider.notifier)
                        .downloadAll(),
                    onSkip: _navigateToApp,
                  ),
          ),
        ),
      ),
    );
  }
}