/// Composes the FocusFlow Flutter application around Focus Flow App.
library;

import 'package:flutter/material.dart';

import '../controllers/today_screen_controller.dart';
import '../models/today_screen_models.dart';
import '../theme/focus_flow_theme.dart';
import '../theme/focus_flow_tokens.dart';
import '../widgets/app_shell.dart';
import '../widgets/required_banner.dart';
import '../widgets/sidebar.dart';
import '../widgets/task_selection_modal.dart';
import '../widgets/timeline/timeline_view.dart';
import '../widgets/top_bar.dart';
import 'demo_scheduler_composition.dart';

/// Root Material app for the FocusFlow desktop UI.
class FocusFlowApp extends StatelessWidget {
  /// Creates a FocusFlow app from an application composition.
  const FocusFlowApp({required this.composition, super.key});

  /// Factory and controller bundle used by the app tree.
  final DemoSchedulerComposition composition;

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'FocusFlow',
      debugShowCheckedModeBanner: false,
      theme: FocusFlowTheme.dark(),
      home: FocusFlowHome(composition: composition),
    );
  }
}

/// Stateful home screen that owns the Today controller lifecycle.
class FocusFlowHome extends StatefulWidget {
  /// Creates the FocusFlow home screen from an application composition.
  const FocusFlowHome({required this.composition, super.key});

  /// Factory and controller bundle used by the home screen.
  final DemoSchedulerComposition composition;

  @override
  State<FocusFlowHome> createState() => _FocusFlowHomeState();
}

class _FocusFlowHomeState extends State<FocusFlowHome> {
  late final TodayScreenController controller = widget.composition
      .createTodayScreenController();

  @override
  void initState() {
    super.initState();
    controller.load();
  }

  @override
  void dispose() {
    controller.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: FocusFlowTokens.appBackground,
      body: AppShell(
        sidebar: const Sidebar(),
        child: AnimatedBuilder(
          animation: controller,
          builder: (context, _) {
            return switch (controller.state) {
              TodayScreenLoading() => const Center(
                child: CircularProgressIndicator(),
              ),
              TodayScreenFailure(:final message) => _PlanIssue(
                message: message,
              ),
              TodayScreenEmpty() => _TodayScreenScaffold(
                data: TodayScreenData.empty(
                  dateLabel: widget.composition.dateLabel,
                ),
                selectedCard: controller.selectedCard,
                onSelectCard: controller.selectCard,
                onClearSelection: controller.clearSelection,
              ),
              TodayScreenReady(:final data) => _TodayScreenScaffold(
                data: data,
                selectedCard: controller.selectedCard,
                onSelectCard: controller.selectCard,
                onClearSelection: controller.clearSelection,
              ),
            };
          },
        ),
      ),
    );
  }
}

class _PlanIssue extends StatelessWidget {
  const _PlanIssue({required this.message});

  final String message;

  @override
  Widget build(BuildContext context) {
    return Center(
      child: Text(message, style: Theme.of(context).textTheme.titleMedium),
    );
  }
}

class _TodayScreenScaffold extends StatefulWidget {
  const _TodayScreenScaffold({
    required this.data,
    required this.selectedCard,
    required this.onSelectCard,
    required this.onClearSelection,
  });

  final TodayScreenData data;
  final TimelineCardModel? selectedCard;
  final ValueChanged<TimelineCardModel> onSelectCard;
  final VoidCallback onClearSelection;

  @override
  State<_TodayScreenScaffold> createState() => _TodayScreenScaffoldState();
}

class _TodayScreenScaffoldState extends State<_TodayScreenScaffold> {
  String? _timelineScrollTargetCardId;
  var _timelineScrollRequest = 0;

  void _showUpcomingRequiredTask() {
    final targetCardId = widget.data.requiredBanner?.timelineCardId;
    if (targetCardId == null) {
      return;
    }
    setState(() {
      _timelineScrollTargetCardId = targetCardId;
      _timelineScrollRequest += 1;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Stack(
      children: [
        Padding(
          padding: const EdgeInsets.fromLTRB(
            FocusFlowTokens.mainGutter,
            32,
            FocusFlowTokens.mainGutter,
            28,
          ),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.stretch,
            children: [
              TopBar(dateLabel: widget.data.dateLabel),
              const SizedBox(height: 24),
              RequiredBanner(
                model: widget.data.requiredBanner,
                onShowUpcoming: _showUpcomingRequiredTask,
              ),
              const SizedBox(height: 22),
              Expanded(
                child: TimelineView(
                  cards: widget.data.cards,
                  range: widget.data.timelineRange,
                  scrollTargetCardId: _timelineScrollTargetCardId,
                  scrollRequest: _timelineScrollRequest,
                  onCardSelected: widget.onSelectCard,
                ),
              ),
            ],
          ),
        ),
        if (widget.selectedCard != null) ...[
          Positioned.fill(
            child: GestureDetector(
              key: const ValueKey('modal-click-away'),
              behavior: HitTestBehavior.opaque,
              onTap: widget.onClearSelection,
              child: const ColoredBox(color: Colors.transparent),
            ),
          ),
          Center(
            child: TaskSelectionModal(
              card: widget.selectedCard!,
              onClose: widget.onClearSelection,
            ),
          ),
        ],
      ],
    );
  }
}