import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import '../database/siab_database.dart';
import '../models/registered_device.dart';
import '../services/ble_service.dart';
import '../siab_config.dart';

class DevicesScreen extends StatefulWidget {
  const DevicesScreen({super.key});

  @override
  State<DevicesScreen> createState() => _DevicesScreenState();
}

class _DevicesScreenState extends State<DevicesScreen> {
  final _db = SiabDatabase();
  List<RegisteredDevice> _saved = [];
  List<SiabScanResult> _scanResults = [];
  bool _loading = false;

  Future<void> _loadSaved() async {
    setState(() => _loading = true);
    _saved = await _db.getAll();
    setState(() => _loading = false);
  }

  Future<void> _scan() async {
    final ble = context.read<BLEService>();
    setState(() => _scanResults = []);
    final list = await ble.scanForAllSiabDevices();
    setState(() => _scanResults = list);
  }

  Future<void> _register( SiabScanResult result, String label) async {
    await _db.insert(RegisteredDevice(
      uuid: result.address,
      label: label.isEmpty ? result.address : label,
    ));
    await _loadSaved();
  }

  Future<void> _connectToScanResult(SiabScanResult result) async {
    final ble = context.read<BLEService>();
    final ok = await ble.connectToDevice(result.device);
    if (mounted && !ok) {
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(content: Text('Connection failed'), backgroundColor: Colors.red),
      );
    } else if (mounted && ok) {
      await Future.delayed(const Duration(seconds: 2));
      if (mounted && ble.packetCount == 0) ble.tryStartCommands();
      await _loadSaved();
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(content: Text('Connected'), backgroundColor: Colors.green),
        );
      }
    }
  }

  Future<void> _connectToSaved(RegisteredDevice device) async {
    final ble = context.read<BLEService>();
    final ok = await ble.connectToAddress(device.uuid);
    if (mounted && !ok) {
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(content: Text('Device not found or connection failed'), backgroundColor: Colors.red),
      );
    } else if (mounted && ok) {
      await Future.delayed(const Duration(seconds: 2));
      if (mounted && ble.packetCount == 0) ble.tryStartCommands();
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(content: Text('Connected'), backgroundColor: Colors.green),
        );
      }
    }
  }

  Future<void> _unregisterDevice(RegisteredDevice device) async {
    final confirmed = await showDialog<bool>(
      context: context,
      builder: (ctx) => AlertDialog(
        title: const Text('Unregister device'),
        content: Text(
          'Remove \"${device.label}\" (${device.uuid}) from registered devices?',
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(ctx, false),
            child: const Text('Cancel'),
          ),
          FilledButton(
            onPressed: () => Navigator.pop(ctx, true),
            child: const Text('Unregister'),
          ),
        ],
      ),
    );

    if (confirmed != true) return;

    if (device.id != null) {
      await _db.delete(device.id!);
    } else {
      await _db.deleteByUuid(device.uuid);
    }
    await _loadSaved();
  }

  @override
  void initState() {
    super.initState();
    _loadSaved();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Timbangan'),
        actions: [
          IconButton(
            onPressed: _loading ? null : _loadSaved,
            icon: const Icon(Icons.refresh),
          ),
        ],
      ),
      body: Consumer<BLEService>(
        builder: (context, ble, _) {
          return ListView(
            padding: const EdgeInsets.all(16),
            children: [
              // Scan section at top
              const Text('Daftar Timbangan (scan)', style: TextStyle(fontSize: 16, fontWeight: FontWeight.bold)),
              const SizedBox(height: 8),
              OutlinedButton.icon(
                onPressed: ble.isScanning ? null : () async { await _scan(); },
                icon: ble.isScanning
                    ? const SizedBox(
                        width: 18,
                        height: 18,
                        child: CircularProgressIndicator(strokeWidth: 2),
                      )
                    : const Icon(Icons.bluetooth_searching, size: 20),
                label: Text(ble.isScanning ? 'Scanning...' : 'Scan Timbangan'),
              ),
              const SizedBox(height: 12),
              if (_scanResults.isEmpty && !ble.isScanning)
                const Card(child: Padding(
                  padding: EdgeInsets.all(16),
                  child: Text('Tap \"Scan Timbangan\" lihat melihat timbangan di sekitar.'),
                ))
              else
                ..._scanResults.map((r) {
                  RegisteredDevice? registered;
                  for (final d in _saved) {
                    if (d.uuid == r.address) { registered = d; break; }
                  }
                  final labelId = registered?.label;
                  final hasLabel = labelId != null && labelId.isNotEmpty;
                  return Card(
                    margin: const EdgeInsets.only(bottom: 8),
                    child: Padding(
                      padding: const EdgeInsets.all(12),
                      child: Column(
                        crossAxisAlignment: CrossAxisAlignment.start,
                        children: [
                          _ListRow(label: 'NAMA', value: labelId ?? '—'),
                          _ListRow(label: 'ID', value: r.device.remoteId.toString()),
                          const SizedBox(height: 8),
                          Row(
                            mainAxisAlignment: MainAxisAlignment.end,
                            children: [
                              if (!hasLabel)
                                Padding(
                                  padding: const EdgeInsets.only(right: 8),
                                  child: TextButton.icon(
                                    onPressed: () => _showRegisterDialog(r),
                                    icon: const Icon(Icons.app_registration, size: 18),
                                    label: const Text('Register'),
                                  ),
                                ),
                              TextButton.icon(
                                onPressed: ble.isConnecting ? null : () => _connectToScanResult(r),
                                icon: const Icon(Icons.link, size: 18),
                                label: const Text('Connect'),
                              ),
                            ],
                          ),
                        ],
                      ),
                    ),
                  );
                }),

              const SizedBox(height: 24),

              // Registered devices below scan
              const Text('Registered devices (saved)', style: TextStyle(fontSize: 16, fontWeight: FontWeight.bold)),
              const SizedBox(height: 8),
              if (_loading)
                const Center(child: CircularProgressIndicator())
              else if (_saved.isEmpty)
                const Card(child: Padding(
                  padding: EdgeInsets.all(16),
                  child: Text('No registered devices. Scan and register above.'),
                ))
              else
                ..._saved.map((d) => Card(
                  margin: const EdgeInsets.only(bottom: 8),
                  child: Padding(
                    padding: const EdgeInsets.all(12),
                    child: Column(
                      crossAxisAlignment: CrossAxisAlignment.start,
                      children: [
                        _ListRow(label: 'NAMA', value: d.label),
                        _ListRow(label: 'ID', value: d.uuid),
                        const SizedBox(height: 8),
                        Row(
                          mainAxisAlignment: MainAxisAlignment.end,
                          children: [
                            TextButton.icon(
                              onPressed: () => _unregisterDevice(d),
                              icon: const Icon(Icons.delete_outline, size: 18),
                              label: const Text('Unregister'),
                            ),
                            const SizedBox(width: 8),
                            if (ble.isConnected && ble.deviceAddress == d.uuid)
                              const Icon(Icons.bluetooth_connected, color: Colors.green, size: 28)
                            else
                              TextButton.icon(
                                onPressed: ble.isConnecting ? null : () => _connectToSaved(d),
                                icon: const Icon(Icons.link, size: 18),
                                label: const Text('Connect'),
                              ),
                          ],
                        ),
                      ],
                    ),
                  ),
                )),
            ],
          );
        },
      ),
    );
  }

  void _showRegisterDialog(SiabScanResult result) {
    final controller = TextEditingController(
      text: result.name.isNotEmpty ? result.name : SiabConfig.deviceName,
    );
    showDialog<void>(
      context: context,
      builder: (ctx) => AlertDialog(
        title: const Text('Register device'),
        content: TextField(
          controller: controller,
          decoration: const InputDecoration(
            labelText: 'Nama',
            hintText: 'contoh : Scale 1, TIMBANGAN 1',
          ),
          autofocus: true,
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(ctx),
            child: const Text('Cancel'),
          ),
          FilledButton(
            onPressed: () async {
              final label = controller.text.trim();
              await _register(result, label.isEmpty ? result.address : label);
              if (mounted) Navigator.pop(ctx);
            },
            child: const Text('Save'),
          ),
        ],
      ),
    );
  }
}

class _ListRow extends StatelessWidget {
  final String label;
  final String value;

  const _ListRow({required this.label, required this.value});

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.symmetric(vertical: 2),
      child: Row(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          SizedBox(
            width: 110,
            child: Text(
              '$label:',
              style: TextStyle(
                fontWeight: FontWeight.w600,
                color: Theme.of(context).colorScheme.onSurface.withOpacity(0.8),
                fontSize: 13,
              ),
            ),
          ),
          Expanded(
            child: SelectableText(
              value,
              style: const TextStyle(fontSize: 13),
            ),
          ),
        ],
      ),
    );
  }
}