import 'dart:async';
import 'dart:typed_data';

import 'package:buffer/buffer.dart';
import 'package:flutter/material.dart';
import 'package:flutter_reactive_ble/flutter_reactive_ble.dart';

class Find extends StatefulWidget {
  final DiscoveredDevice device;

  const Find({Key? key, required this.device}) : super(key: key);

  @override
  State<StatefulWidget> createState() {
    return _State();
  }
}

class _State extends State<Find> {
  final flutterReactiveBle = FlutterReactiveBle();

  final ValueNotifier<String> _infoNotifier = ValueNotifier("正在连接...");

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

    _connect(widget.device).then((value) => Navigator.of(context).pop());
  }

  Future _write(QualifiedCharacteristic characteristicWrite, Uint8List data) async {
    int length = data.length + 4;
    ByteDataWriter writer = ByteDataWriter();
    writer.writeUint8(0xAA);
    writer.writeUint8(length);
    writer.writeUint8(0xFF - length);
    if (data.isNotEmpty) writer.write(data);
    int ver = writer.toBytes().reduce((value, element) => value + element);
    writer.writeUint8(ver);
    Uint8List out = writer.toBytes();
    await flutterReactiveBle.writeCharacteristicWithoutResponse(characteristicWrite, value: out);
  }

  Future _connect(DiscoveredDevice device) async {
    bool _connecting = true;

    try {
      final stream = flutterReactiveBle.connectToDevice(id: device.id, connectionTimeout: const Duration(seconds: 10));
      await for (var state in stream) {
        print("device state: $state");
        if (state.connectionState == DeviceConnectionState.connected) {
          _infoNotifier.value = "连接成功";
          var services = await flutterReactiveBle.discoverServices(device.id);
          _infoNotifier.value = "连接成功，已发现服务${services.length}";
          for (DiscoveredService service in services) {
            for (var characteristic in service.characteristics) {
              if (characteristic.isWritableWithoutResponse) {
                QualifiedCharacteristic characteristicWrite = QualifiedCharacteristic(serviceId: service.serviceId, characteristicId: characteristic.characteristicId, deviceId: device.id);
                _infoNotifier.value = "连接成功，正在发送闪灯和震动";
                Stream.periodic(const Duration(seconds: 1)).take(5).forEach((element) {
                  _write(characteristicWrite, Uint8List.fromList([0xB0, 0x01]));
                });
                for(var i = 0; i < 5; i++){
                  ByteDataWriter writer = ByteDataWriter();
                  writer.writeUint8(0xAC);
                  writer.writeUint16(1000);
                  _write(characteristicWrite, writer.toBytes());

                  writer = ByteDataWriter();
                  writer.writeUint8(0xA4);
                  writer.writeUint16(1000);
                  writer.writeUint8(0);
                  _write(characteristicWrite, writer.toBytes());
                  await Future.delayed(const Duration(milliseconds: 2000));
                }

                _connecting = false;
              }
            }
          }

          break;
        } else if (state.connectionState == DeviceConnectionState.disconnected) {
          if (state.failure?.code == ConnectionError.failedToConnect) {
            _infoNotifier.value = "${state.failure?.message}";
            await Future.delayed(const Duration(seconds: 3));
          }
          break;
        }

        if (!_connecting) {
          break;
        }
      }
    } catch (e) {
      print("bluetooth -- connect error: $e");
    }
  }

  @override
  Widget build(BuildContext context) {
    return Material(
      type: MaterialType.transparency,
      child: Scaffold(
        backgroundColor: Colors.transparent,
        body: Center(
          child: Container(
            width: 140,
            height: 140,
            decoration: const BoxDecoration(
              borderRadius: BorderRadius.all(Radius.circular(10.0)),
              color: Colors.white,
            ),
            child: Center(
              child: Column(
                mainAxisSize: MainAxisSize.min,
                children: [
                  const CircularProgressIndicator(),
                  Padding(
                    padding: const EdgeInsets.only(top: 16.0),
                    child: ValueListenableBuilder<String>(
                      valueListenable: _infoNotifier,
                      builder: (_, value, __) => Padding(
                        padding: const EdgeInsets.all(8.0),
                        child: Text(
                          value,
                          style: Theme.of(context).textTheme.bodyText1,
                        ),
                      ),
                    ),
                  )
                ],
              ),
            ),
          ),
        ),
      ),
    );
  }
}