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

import '../../data/sources/ble/ble_provisioner.dart';
import '../../providers.dart';

enum _Step { provision, done }

// Shared bottom sheet used by onboarding and the main sensor screens.
// Flow: scan → select device → enter WiFi credentials → provision → place on map.
class BleProvisionSheet extends ConsumerStatefulWidget {
  const BleProvisionSheet({super.key});

  @override
  ConsumerState<BleProvisionSheet> createState() => _BleProvisionSheetState();
}

class _BleProvisionSheetState extends ConsumerState<BleProvisionSheet> {
  final _provisioner = BleProvisioner();
  final _ssidController = TextEditingController();
  final _wifiPasswordController = TextEditingController();

  late final Stream<BleScanResult> _scanStream;

  _Step _step = _Step.provision;
  BleScanResult? _selected;
  bool _provisioning = false;
  String? _error;

  @override
  void initState() {
    super.initState();
    _scanStream = _provisioner.scan();
  }

  @override
  void dispose() {
    _provisioner.dispose();
    _ssidController.dispose();
    _wifiPasswordController.dispose();
    super.dispose();
  }

  Future<void> _provision() async {
    if (_selected == null) return;
    setState(() {
      _provisioning = true;
      _error = null;
    });
    try {
      final mqttBroker = await ref.read(mqttBrokerProvider.future);
      await _provisioner.provision(
        _selected!.deviceId,
        ssid: _ssidController.text.trim(),
        wifiPassword: _wifiPasswordController.text,
        mqttHost: mqttBroker?.host,
        mqttPort: mqttBroker?.port,
      );
      if (mounted) setState(() => _step = _Step.done);
    } catch (e) {
      if (mounted) setState(() => _error = e.toString());
    } finally {
      if (mounted) setState(() => _provisioning = false);
    }
  }

  void _reset() {
    setState(() {
      _step = _Step.provision;
      _selected = null;
      _error = null;
      _ssidController.clear();
      _wifiPasswordController.clear();
    });
  }

  @override
  Widget build(BuildContext context) {
    return DraggableScrollableSheet(
      expand: false,
      initialChildSize: 0.6,
      maxChildSize: 0.9,
      builder: (context, scrollController) => Padding(
        padding: EdgeInsets.fromLTRB(
          24,
          16,
          24,
          MediaQuery.of(context).viewInsets.bottom + 24,
        ),
        child: _step == _Step.done
            ? _DoneStep(
                onGoToFloorPlan: () {
                  final router = GoRouter.of(context);
                  Navigator.of(context).pop();
                  router.go('/floorplan');
                },
                onAddAnother: _reset,
                onDone: () => Navigator.of(context).pop(),
              )
            : _ProvisionStep(
                scrollController: scrollController,
                scanStream: _scanStream,
                selected: _selected,
                onSelected: (r) => setState(() => _selected = r),
                ssidController: _ssidController,
                wifiPasswordController: _wifiPasswordController,
                provisioning: _provisioning,
                error: _error,
                onProvision: _provision,
              ),
      ),
    );
  }
}

class _ProvisionStep extends StatefulWidget {
  const _ProvisionStep({
    required this.scrollController,
    required this.scanStream,
    required this.selected,
    required this.onSelected,
    required this.ssidController,
    required this.wifiPasswordController,
    required this.provisioning,
    required this.error,
    required this.onProvision,
  });

  final ScrollController scrollController;
  final Stream<BleScanResult> scanStream;
  final BleScanResult? selected;
  final ValueChanged<BleScanResult> onSelected;
  final TextEditingController ssidController;
  final TextEditingController wifiPasswordController;
  final bool provisioning;
  final String? error;
  final VoidCallback onProvision;

  @override
  State<_ProvisionStep> createState() => _ProvisionStepState();
}

class _ProvisionStepState extends State<_ProvisionStep> {
  final _discovered = <String, BleScanResult>{};

  @override
  Widget build(BuildContext context) {
    return ListView(
      controller: widget.scrollController,
      children: [
        Text('Add sensor', style: Theme.of(context).textTheme.titleLarge),
        const SizedBox(height: 16),

        Text('Nearby ESP32 devices',
            style: Theme.of(context).textTheme.labelLarge),
        const SizedBox(height: 8),

        StreamBuilder<BleScanResult>(
          stream: widget.scanStream,
          builder: (context, snapshot) {
            if (snapshot.hasData) {
              final r = snapshot.data!;
              _discovered[r.deviceId] = r;
            }
            if (_discovered.isEmpty) {
              return const Padding(
                padding: EdgeInsets.symmetric(vertical: 16),
                child: Row(
                  children: [
                    SizedBox.square(
                        dimension: 16,
                        child: CircularProgressIndicator(strokeWidth: 2)),
                    SizedBox(width: 12),
                    Text('Scanning…'),
                  ],
                ),
              );
            }
            return Column(
              children: _discovered.values.map((r) {
                final selected = widget.selected?.deviceId == r.deviceId;
                return ListTile(
                  contentPadding: EdgeInsets.zero,
                  leading: const Icon(Icons.sensors),
                  title: Text(r.name),
                  subtitle: Text('${r.rssi} dBm'),
                  trailing: selected
                      ? const Icon(Icons.check_circle,
                          color: Colors.green)
                      : null,
                  selected: selected,
                  onTap: () => widget.onSelected(r),
                );
              }).toList(),
            );
          },
        ),

        const SizedBox(height: 24),

        if (widget.selected != null) ...[
          Text('Selected: ${widget.selected!.name}'),
          const SizedBox(height: 16),
          TextField(
            controller: widget.ssidController,
            decoration: const InputDecoration(
              labelText: 'WiFi SSID',
              border: OutlineInputBorder(),
            ),
          ),
          const SizedBox(height: 12),
          TextField(
            controller: widget.wifiPasswordController,
            decoration: const InputDecoration(
              labelText: 'WiFi password',
              border: OutlineInputBorder(),
            ),
            obscureText: true,
          ),
          const SizedBox(height: 16),
        ],

        if (widget.error != null)
          Padding(
            padding: const EdgeInsets.only(bottom: 12),
            child: Text(widget.error!,
                style:
                    TextStyle(color: Theme.of(context).colorScheme.error)),
          ),

        FilledButton(
          onPressed:
              (widget.selected == null || widget.provisioning) ? null : widget.onProvision,
          child: widget.provisioning
              ? const SizedBox.square(
                  dimension: 20,
                  child: CircularProgressIndicator(strokeWidth: 2))
              : const Text('Provision & add'),
        ),
      ],
    );
  }
}

class _DoneStep extends StatelessWidget {
  const _DoneStep({
    required this.onGoToFloorPlan,
    required this.onAddAnother,
    required this.onDone,
  });

  final VoidCallback onGoToFloorPlan;
  final VoidCallback onAddAnother;
  final VoidCallback onDone;

  @override
  Widget build(BuildContext context) {
    return Column(
      mainAxisSize: MainAxisSize.min,
      crossAxisAlignment: CrossAxisAlignment.stretch,
      children: [
        const Icon(Icons.check_circle_outline, size: 56),
        const SizedBox(height: 16),
        Text(
          'Sensor provisioned!',
          style: Theme.of(context).textTheme.titleLarge,
          textAlign: TextAlign.center,
        ),
        const SizedBox(height: 8),
        Text(
          'The sensor will appear in the list once it connects to the network. '
          'Open the floor plan to place it.',
          style: Theme.of(context).textTheme.bodyMedium,
          textAlign: TextAlign.center,
        ),
        const SizedBox(height: 32),
        FilledButton.icon(
          icon: const Icon(Icons.map_outlined),
          label: const Text('Place on floor plan'),
          onPressed: onGoToFloorPlan,
        ),
        const SizedBox(height: 12),
        OutlinedButton.icon(
          icon: const Icon(Icons.add),
          label: const Text('Add another sensor'),
          onPressed: onAddAnother,
        ),
        const SizedBox(height: 8),
        TextButton(
          onPressed: onDone,
          child: const Text('Done'),
        ),
      ],
    );
  }
}