import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';

import '../features/command/presentation/tactical_command_page.dart';
import '../features/diagnostics/presentation/diagnostics_page.dart';
import '../features/observability/presentation/observability_controller.dart';

enum _ApplicationSurface { tactical, eventStream }

/// Owns the two first-class Ground Suite surfaces. Tactical planning never
/// hides decoded diagnostics or critical accessibility announcements.
class AppShell extends ConsumerStatefulWidget {
  const AppShell({super.key});

  @override
  ConsumerState<AppShell> createState() => _AppShellState();
}

class _AppShellState extends ConsumerState<AppShell> {
  _ApplicationSurface _surface = _ApplicationSurface.tactical;

  @override
  Widget build(BuildContext context) {
    final observation = ref.watch(observabilityControllerProvider);
    return Scaffold(
      body: Stack(
        children: [
          switch (_surface) {
            _ApplicationSurface.tactical => TacticalCommandPage(
              sourceLabel: observation.sourceLabel,
              sourceStatus: observation.status.label,
              onOpenEventStream: () =>
                  setState(() => _surface = _ApplicationSurface.eventStream),
            ),
            _ApplicationSurface.eventStream => _EventStreamWorkspace(
              onReturnToTactical: () =>
                  setState(() => _surface = _ApplicationSurface.tactical),
            ),
          },
          Semantics(
            liveRegion: true,
            label: observation.accessibilityAnnouncement ?? '',
            child: const SizedBox.shrink(),
          ),
        ],
      ),
    );
  }
}

class _EventStreamWorkspace extends StatelessWidget {
  const _EventStreamWorkspace({required this.onReturnToTactical});

  final VoidCallback onReturnToTactical;

  @override
  Widget build(BuildContext context) => Stack(
    children: [
      const Positioned.fill(child: DiagnosticsPage()),
      Positioned(
        top: 16,
        right: 20,
        child: FilledButton.icon(
          onPressed: onReturnToTactical,
          icon: const Icon(Icons.map_outlined),
          label: const Text('Tactical workspace'),
        ),
      ),
    ],
  );
}