//---------------------------------------------------------------------------

// This software is Copyright (c) 2015 Embarcadero Technologies, Inc.
// You may only use this software if you are an authorized licensee
// of an Embarcadero developer tools product.
// This software is considered a Redistributable as defined under
// the software license agreement that comes with the Embarcadero Products
// and is subject to that software license agreement.

//---------------------------------------------------------------------------

unit Unit6;

interface

uses
  System.SysUtils, System.Types, System.UITypes, System.Classes, System.Variants,
  FMX.Types, FMX.Controls, FMX.Forms, FMX.Graphics, FMX.Dialogs,
  System.Bluetooth, FMX.StdCtrls, System.Bluetooth.Components, FMX.Layouts,
  FMX.ListBox, FMX.Controls.Presentation, FMX.Edit, FMX.ScrollBox, FMX.Memo;

type
  TFormMaim = class(TForm)
    Panel1: TPanel;
    LBoxDevice: TListBox;
    BLE: TBluetoothLE;
    BtnScan: TButton;
    BtnStopScan: TButton;
    Timer1: TTimer;
    ProgressBar1: TProgressBar;
    LBoxCharacteristics: TListBox;
    MemoLog: TMemo;
    EdSend: TEdit;
    BtnSend: TButton;
    procedure BtnScanClick(Sender: TObject);
    procedure BtnStopScanClick(Sender: TObject);
    procedure BLEDiscoverLEDevice(const Sender: TObject;
      const ADevice: TBluetoothLEDevice; Rssi: Integer;
      const ScanResponse: TScanResponse);
    procedure Timer1Timer(Sender: TObject);
    procedure BLEEndDiscoverDevices(const Sender: TObject;
      const ADeviceList: TBluetoothLEDeviceList);
    procedure FormShow(Sender: TObject);
    procedure BLEServicesDiscovered(const Sender: TObject;
      const AServiceList: TBluetoothGattServiceList);
    procedure LBoxDeviceItemClick(const Sender: TCustomListBox;
      const Item: TListBoxItem);
    procedure Log(const aMsg:String);
    procedure GChrLog(const aMsg:String);
    procedure FormCloseQuery(Sender: TObject; var CanClose: Boolean);
    procedure BLECharacteristicRead(const Sender: TObject;
      const ACharacteristic: TBluetoothGattCharacteristic;
      AGattStatus: TBluetoothGattStatus);
    procedure BLECharacteristicReadRequest(const Sender: TObject;
      const ACharacteristic: TBluetoothGattCharacteristic;
      var AGattStatus: TBluetoothGattStatus);
    procedure BLECharacteristicSubscribed(const Sender: TObject;
      const AClientId: string;
      const ACharacteristic: TBluetoothGattCharacteristic);
    procedure BtnSendClick(Sender: TObject);
  private
    Scanning: Boolean;
    ScanningStart: DWORD;
    { Private declarations }
  public
    { Public declarations }
  end;

const
  ScanningTime = 1500; // in msecs
  UsrUartSvcUUID:TBluetoothUUID=      '{0003cdd0-0000-1000-8000-00805f9b0131}';
  UsrUartNotifyChrUUID:TBluetoothUUID='{0003cdd1-0000-1000-8000-00805f9b0131}';
  UsrUartWriteChrUUID:TBluetoothUUID= '{0003cdd2-0000-1000-8000-00805f9b0131}';
var
  FormMaim: TFormMaim;
  ApplicationClose:Boolean=false;

implementation

{$R *.fmx}

var
 SelectedDev:TBluetoothLEDevice;
 UsrUartGatSvc:TBluetoothGattService;
 UsrUartGatNotifyChar:TBluetoothGattCharacteristic;
 UsrUartGatWriteChar:TBluetoothGattCharacteristic;

procedure TFormMaim.BLECharacteristicRead(const Sender: TObject;
  const ACharacteristic: TBluetoothGattCharacteristic;
  AGattStatus: TBluetoothGattStatus);
begin
 Log('R>'+ACharacteristic.ToString);
end;

procedure TFormMaim.BLECharacteristicReadRequest(const Sender: TObject;
  const ACharacteristic: TBluetoothGattCharacteristic;
  var AGattStatus: TBluetoothGattStatus);
begin
 Log('RR>'+ACharacteristic.ToString);
end;

procedure TFormMaim.BLECharacteristicSubscribed(const Sender: TObject;
  const AClientId: string; const ACharacteristic: TBluetoothGattCharacteristic);
begin
 Log('CS>'+ACharacteristic.UUIDName);
end;

procedure TFormMaim.BLEDiscoverLEDevice(const Sender: TObject;
  const ADevice: TBluetoothLEDevice; Rssi: Integer;
  const ScanResponse: TScanResponse);
var
 DevName: string;
 i:Integer;
begin
  if ApplicationClose then
   Exit;

  for i:=0 to BLE.DiscoveredDevices.Count - 1 do
  begin
    DevName:=BLE.DiscoveredDevices[i].DeviceName;
    if DevName = '' then
     DevName:='Unknown';
    if i >= LBoxDevice.Items.Count then
     LBoxDevice.Items.Add('');
    LBoxDevice.Items[i]:=Format('%d: %s - %s [%d]', [i+1, DevName, BLE.DiscoveredDevices[i].Identifier, Rssi]);
  end;
end;

procedure TFormMaim.BLEEndDiscoverDevices(const Sender: TObject;
  const ADeviceList: TBluetoothLEDeviceList);
begin
 if ApplicationClose then
  Exit;

  if Scanning then
    ProgressBar1.Value := ProgressBar1.Max;
  Timer1.Enabled := False;
  Scanning := False;
end;

procedure TFormMaim.BLEServicesDiscovered(const Sender: TObject;
  const AServiceList: TBluetoothGattServiceList);
var
  ServInd, CharInd, DescInd: Integer;
  GatChar:TBluetoothGattCharacteristic;
begin
  if AServiceList.Count > 0 then
  begin
    for ServInd:=0 to AServiceList.Count - 1 do
    begin
      GChrLog(Format('s%.2d - %s:%s',[(ServInd + 1), AServiceList[ServInd].UUIDName,AServiceList[ServInd].UUID.ToString]));
      for CharInd:=0 to AServiceList[ServInd].Characteristics.Count - 1 do
      begin
       GatChar:=AServiceList[ServInd].Characteristics[CharInd];
       GChrLog(Format('--c%.2d> - %s:%s',[CharInd+1, GatChar.UUIDName, GatChar.UUID.ToString]));
       for DescInd:=0 to GatChar.Descriptors.Count - 1 do
        GChrLog(Format('----d%.2d> - %s:%s',[DescInd+1, GatChar.Descriptors[DescInd].UUIDName, GatChar.Descriptors[DescInd].UUID.ToString]));
      end

    end;
  end
  else
   GChrLog('- Not allow access or no services');

  UsrUartGatSvc:=BLE.GetService(SelectedDev, UsrUartSvcUUID);
  if Assigned(UsrUartGatSvc) then
  begin
   UsrUartGatWriteChar:=BLE.GetCharacteristic(UsrUartGatSvc, UsrUartWriteChrUUID);
   UsrUartGatNotifyChar:=BLE.GetCharacteristic(UsrUartGatSvc, UsrUartNotifyChrUUID);

   //*************************************************************************************
   //*************************************************************************************
   // Проблема здесь !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 
   SelectedDev.SetCharacteristicNotification(UsrUartGatNotifyChar, true);
   BLE.SubscribeToCharacteristic(SelectedDev, UsrUartGatNotifyChar);
   //*************************************************************************************
   //*************************************************************************************

  end;

  LBoxDevice.Enabled := True;
end;

procedure TFormMaim.BtnScanClick(Sender: TObject);
begin
  if not Scanning then
  begin
    LBoxDevice.Clear;
    ScanningStart := TThread.GetTickCount;
    ProgressBar1.Value := 0;
    if not BLE.DiscoverDevices(ScanningTime{, [UsrServiceUUID]}) then
    begin
     Log('Error start scan!');
     Exit;
    end;
    Timer1.Enabled := True;
    Scanning := True;
  end;
end;

procedure TFormMaim.BtnSendClick(Sender: TObject);
begin
 UsrUartGatWriteChar.SetValueAsString(EdSend.Text);
 BLE.WriteCharacteristic(SelectedDev, UsrUartGatWriteChar);
end;

procedure TFormMaim.BtnStopScanClick(Sender: TObject);
begin
  Timer1.Enabled := False;
  Scanning := False;
  BLE.CancelDiscovery;
end;

procedure TFormMaim.FormCloseQuery(Sender: TObject; var CanClose: Boolean);
begin
 ApplicationClose:=true;
end;

procedure TFormMaim.FormShow(Sender: TObject);
begin
  Scanning := False;
end;

procedure TFormMaim.GChrLog(const aMsg: String);
begin
 LBoxCharacteristics.Items.Add(aMsg);
end;

procedure TFormMaim.LBoxDeviceItemClick(const Sender: TCustomListBox;
  const Item: TListBoxItem);
begin
  LBoxDevice.Enabled := False;

  BtnStopScanClick(Sender);
  LBoxCharacteristics.Clear;
  GChrLog('- Discovering services -->');

  SelectedDev:=BLE.DiscoveredDevices[LBoxDevice.ItemIndex];

  TThread.CreateAnonymousThread(procedure begin
    if not SelectedDev.DiscoverServices then
      TThread.Synchronize(nil, procedure begin
        GChrLog('- Discover services not allow');
        LBoxDevice.Enabled := True;
      end);
  end).Start;
end;

procedure TFormMaim.Log(const aMsg: String);
begin
 MemoLog.Lines.Add(aMsg);
end;

procedure TFormMaim.Timer1Timer(Sender: TObject);
var
  LElapsed: DWORD;
begin
  LElapsed := TThread.GetTickCount - ScanningStart;
  ProgressBar1.Value := ProgressBar1.Max * LElapsed.ToSingle/ScanningTime;
end;

end.

 SelectedDev.SetCharacteristicNotification(UsrUartGatNotifyChar, true); 

 BLE.SubscribeToCharacteristic(SelectedDev, UsrUartGatNotifyChar);

// Комбинация предыдущих двух
     SelectedDev.SetCharacteristicNotification(UsrUartGatNotifyChar, true);
     BLE.SubscribeToCharacteristic(SelectedDev, UsrUartGatNotifyChar);

// Перед вызовом второго и третьего варианта добавлял 
UsrUartGatNotifyChar.Descriptors[0].Indication:=true; //<-- здесь возникала проблема т.к. дескриптор с таким UUID '{20003D9C-0000-0000-0000-000020002902}' считается как Unknown, а если DescriptorKind = Unknown, то запись запрещена. Вот если бы 
дескриптор начинался с  $00002902 вот тогда бы было счастье)  
SelectedDev.WriteDescriptor(UsrUartGatNotifyChar.Descriptors[0]);

function TBluetoothLEDevice.SetCharacteristicNotification(const ACharacteristic: TBluetoothGattCharacteristic; Enable: Boolean):Boolean;
begin
  Result := False;
  if [TBluetoothProperty.Notify, TBluetoothProperty.Indicate] * ACharacteristic.GetProperties <> [] then
  begin
    // This is to ensure that we have read the descriptors before querying.
    ACharacteristic.Descriptors;
    // We check that we have the Configurarion descriptor, and then we set the notification accordingly.
    if ACharacteristic.Descriptors.Count > 0 then
      Result := DoSetCharacteristicNotification(ACharacteristic, Enable);
  end;
end;