unit WebServer;

{
  WebServer.pas — HTTP + WebSocket сервер для удалённого управления трансивером.

  Архитектура (по образцу OpenWebRX):
  ─────────────────────────────────
  HTTP GET /          → index.html (см. WebPageHtml)
  HTTP GET /ws        → Upgrade: WebSocket
  WebSocket сессия:
    • Сервер → клиент:
        - каждые ~50 ms: бинарный фрейм типа 'S' + 1024×Float32 спектр
        - каждые ~50 ms: бинарный фрейм типа 'W' + N×Float32 waterfall строка
        - каждые ~100ms: бинарный фрейм типа 'A' + Opus-пакет (48kHz mono)
        - каждые ~200ms: JSON-текст со state (freq, mode, smeter, …)
    • Клиент → сервер: JSON-команды
        "cmd":"freq","hz":14200000
        "cmd":"mode","mode":1
        "cmd":"filter","bw":2700
        "cmd":"agc","mode":1
        "cmd":"agctop","db":90
        "cmd":"band","idx":5
        "cmd":"span","hz":192000
        "cmd":"volume","v":70
        "cmd":"wfagc","on":true
        "cmd":"wfnf","on":true

  Аудио: 48kHz mono Float32 → Opus (20ms frames, 32 kbps)
  Спектр: 1024 Float32 dBm значений
  Авторизация: Basic Auth через HTTP заголовок при первом запросе

  Зависимости: WebUtils, WsClient, WebPageHtml + RTL + libopus (динамическая загрузка)
  Платформы: Windows + Linux (Winsock2 / BSD sockets)

  ИСПРАВЛЕНИЯ:
    - (Windows build fix) SyncObjs перенесён в конец блока uses — устраняет
      конфликт идентификатора Create с символами из WinSock2 в {$MODE Delphi}.
    - (Windows runtime fix) Добавлены WSAStartup/WSACleanup в конструктор и
      деструктор — без этого socket/bind/listen возвращают WSANOTINITIALISED.
    - (Linux shutdown fix) В Stop: перед SockClose вызывается SockShutdown для
      listen-сокета и для каждого клиентского сокета. На Linux закрытие
      дескриптора не прерывает блокирующий fpAccept/fpRecv в чужом потоке —
      только shutdown(SHUT_RDWR) гарантированно разблокирует их, позволяя
      потокам выйти и WaitFor завершиться без зависания.
}

{$IFDEF FPC}
  {$MODE Delphi}
  {$LONGSTRINGS ON}
{$ENDIF}

interface

uses
  Classes, SysUtils, Math,
  WebUtils, WsClient, WebPageHtml
  {$IFDEF WINDOWS}, Windows, WinSock2{$ELSE}, BaseUnix, Sockets{$ENDIF},
  SyncObjs;   // ← после платформенных юнитов: исключает конфликт идентификатора Create

const
  WEB_PORT         = 8080;
  OPUS_SAMPLE_RATE = 48000;
  OPUS_FRAME_MS    = 20;
  OPUS_FRAME_SAMP  = OPUS_SAMPLE_RATE * OPUS_FRAME_MS div 1000;  // 960 samples
  OPUS_BITRATE     = 32000;
  OPUS_CHANNELS    = 1;
  MAX_WS_CLIENTS   = 4;
  WS_GUID          = '258EAFA5-E914-47DA-95CA-C5AB0DC85B11';

  // Типы бинарных фреймов (первый байт = тип)
  WS_MSG_SPECTRUM  = Byte(Ord('S'));  // S + 1024×Float32
  WS_MSG_WATERFALL = Byte(Ord('W'));  // W + N×Float32
  WS_MSG_AUDIO     = Byte(Ord('A'));  // A + Opus bytes
  WS_MSG_AUDIO_PCM = Byte(Ord('P'));  // P + N×Float32 (mono 48k)
  WS_MSG_STATE     = Byte(Ord('J'));  // J + JSON text

type
  // ── Opus dynamic binding ──────────────────────────────────────────────────
  POpusEncoder = Pointer;

  TOpus_encoder_create  = function(Fs, channels, application: Integer;
                                   error: PInteger): POpusEncoder; cdecl;
  TOpus_encoder_destroy = procedure(st: POpusEncoder); cdecl;
  TOpus_encode_float    = function(st: POpusEncoder;
                                   pcm: PSingle; frame_size: Integer;
                                   data: PByte; max_data_bytes: Integer): Integer; cdecl;
  TOpus_encoder_ctl_set = function(st: POpusEncoder;
                                   request: Integer; value: Integer): Integer; cdecl;

  // ── Callbacks в MainForm ──────────────────────────────────────────────────
  TWebCmdFreq    = procedure(Hz: Double) of object;
  TWebCmdMode    = procedure(Mode: Integer) of object;
  TWebCmdFilter  = procedure(BW: Integer) of object;
  TWebCmdAGC     = procedure(Mode: Integer) of object;
  TWebCmdAGCTop  = procedure(DB: Integer) of object;
  TWebCmdBand    = procedure(Idx: Integer) of object;
  TWebCmdSpan    = procedure(Hz: Integer) of object;
  TWebCmdVolume  = procedure(V: Integer) of object;
  TWebCmdWfAGC   = procedure(On_: Boolean) of object;
  TWebCmdWfNF    = procedure(On_: Boolean) of object;
  TWebCmdRun     = procedure(On_: Boolean) of object;
  TWebCmdMute    = procedure(On_: Boolean) of object;
  TWebCmdCtun    = procedure(On_: Boolean) of object;
  TWebCmdNR      = procedure(On_: Boolean) of object;
  TWebCmdNB      = procedure(On_: Boolean) of object;
  TWebCmdANF     = procedure(On_: Boolean) of object;

  // ── Главный класс сервера ─────────────────────────────────────────────────
  TWebServer = class
  private
    // ── Opus ──
    FOpusLib:     THandle;
    FOpusEnc:     POpusEncoder;
    FOpusCreate:  TOpus_encoder_create;
    FOpusDestroy: TOpus_encoder_destroy;
    FOpusEncode:  TOpus_encode_float;
    FOpusCtl:     TOpus_encoder_ctl_set;
    FOpusBuf:     array[0..OPUS_FRAME_SAMP-1] of Single;
    FOpusBufPos:  Integer;
    FOpusOut:     array[0..3999] of Byte;
    FOpusReady:   Boolean;

    // ── TCP ──
    FListenSock:  TSocket;
    FClients:     array[0..MAX_WS_CLIENTS-1] of TWsClient;
    FClientCount: Integer;
    FClientLock:  TCriticalSection;

    // ── Потоки ──
    FAcceptThread: TThread;
    FPushThread:   TThread;
    FRunning:      Boolean;

    // ── Авторизация ──
    FAuthToken: string;  // Base64(user:pass)

    // ── Состояние (обновляется из MainForm) ──
    FSpectrumBuf: array[0..1023] of Single;
    FWfBuf:       array[0..1023] of Single;
    FWfCount:     Integer;
    FSMeter:      Double;
    FFreq:        Double;
    FMode:        Integer;
    FFilterBW:    Integer;
    FAGCMode:     Integer;
    FAGCTop:      Integer;
    FSpanHz:      Double;
    FVolume:      Integer;
    FWfAGC:       Boolean;
    FWfNF:        Boolean;
    FBandIdx:     Integer;
    FConnected:   Boolean;
    FTrxRunning:  Boolean;
    FMuted:       Boolean;
    FCtun:        Boolean;
    FNR:          Boolean;
    FNB:          Boolean;
    FANF:         Boolean;
    FCenterHz:    Double;
    FFilterIdx:   Integer;
    FStateLock:   TCriticalSection;

    // ── Callbacks ──
    FOnFreq:   TWebCmdFreq;
    FOnMode:   TWebCmdMode;
    FOnFilter: TWebCmdFilter;
    FOnAGC:    TWebCmdAGC;
    FOnAGCTop: TWebCmdAGCTop;
    FOnBand:   TWebCmdBand;
    FOnSpan:   TWebCmdSpan;
    FOnVolume: TWebCmdVolume;
    FOnWfAGC:  TWebCmdWfAGC;
    FOnWfNF:   TWebCmdWfNF;
    FOnRun:    TWebCmdRun;
    FOnMute:   TWebCmdMute;
    FOnCtun:   TWebCmdCtun;
    FOnNR:     TWebCmdNR;
    FOnNB:     TWebCmdNB;
    FOnANF:    TWebCmdANF;

    FWebClientActive: Boolean;

    // ── Внутренние методы ──
    function  LoadOpus: Boolean;
    procedure UnloadOpus;
    function  InitListen: Boolean;
    procedure AcceptLoop;
    procedure PushLoop;
    procedure HandleClient(Client: TWsClient);
    procedure ProcessCommand(Client: TWsClient; const Json: string);
    procedure BroadcastBinary(const Data; Len: Integer);
    procedure BroadcastText(const S: string);
    procedure RemoveClient(Client: TWsClient);
    function  BuildStateJson: string;
    function  CheckAuth(const Header: string): Boolean;
    procedure SendHttp(Client: TWsClient; Code: Integer; const ContentType, Body: string);
    // Stub-методы (реализация встроена в HandleClient)
    procedure DoHandshake(Client: TWsClient);
    procedure ProcessWsFrame(Client: TWsClient; const Data: array of Byte; Len: Integer; Opcode: Byte);

  public
    constructor Create(const Username, Password: string);
    destructor  Destroy; override;

    function  Start: Boolean;
    procedure Stop;

    // Вызывается из DSP-потока (аудио, 48kHz mono)
    procedure PushAudio(const Samples: PSingle; Count: Integer);
    // Вызывается из таймера спектра (UI thread)
    procedure PushSpectrum(
      const Buf: array of Single; Count: Integer;
      const WfBuf_: array of Single;
      SMeter: Double;
      Freq: Double; Mode, FilterBW, AGCMode, AGCTop: Integer;
      SpanHz: Double; Volume: Integer;
      WfAGC, WfNF: Boolean; BandIdx: Integer;
      TrxConnected: Boolean;
      TrxRunning, Muted, Ctun, NR, NB, ANF: Boolean;
      CenterHz: Double; FilterIdx: Integer);

    property WebClientActive: Boolean read FWebClientActive;

    property OnFreq:   TWebCmdFreq   read FOnFreq   write FOnFreq;
    property OnMode:   TWebCmdMode   read FOnMode   write FOnMode;
    property OnFilter: TWebCmdFilter read FOnFilter write FOnFilter;
    property OnAGC:    TWebCmdAGC    read FOnAGC    write FOnAGC;
    property OnAGCTop: TWebCmdAGCTop read FOnAGCTop write FOnAGCTop;
    property OnBand:   TWebCmdBand   read FOnBand   write FOnBand;
    property OnSpan:   TWebCmdSpan   read FOnSpan   write FOnSpan;
    property OnVolume: TWebCmdVolume read FOnVolume write FOnVolume;
    property OnWfAGC:  TWebCmdWfAGC  read FOnWfAGC  write FOnWfAGC;
    property OnWfNF:   TWebCmdWfNF   read FOnWfNF   write FOnWfNF;
    property OnRun:    TWebCmdRun    read FOnRun    write FOnRun;
    property OnMute:   TWebCmdMute   read FOnMute   write FOnMute;
    property OnCtun:   TWebCmdCtun   read FOnCtun   write FOnCtun;
    property OnNR:     TWebCmdNR     read FOnNR     write FOnNR;
    property OnNB:     TWebCmdNB     read FOnNB     write FOnNB;
    property OnANF:    TWebCmdANF    read FOnANF    write FOnANF;
  end;

implementation

{ ═══════════════════════════════════════════════════════════════════════════
  Внутренние классы потоков
  ═══════════════════════════════════════════════════════════════════════════ }

type
  TAcceptThread = class(TThread)
  private FServer: TWebServer;
  protected procedure Execute; override;
  public constructor Create(AServer: TWebServer);
  end;

  TPushThread = class(TThread)
  private FServer: TWebServer;
  protected procedure Execute; override;
  public constructor Create(AServer: TWebServer);
  end;

  TClientThread = class(TThread)
  private FServer: TWebServer; FClient: TWsClient;
  protected procedure Execute; override;
  public constructor Create(AServer: TWebServer; AClient: TWsClient);
  end;

constructor TAcceptThread.Create(AServer: TWebServer);
begin
  inherited Create(True);
  FServer := AServer;
  FreeOnTerminate := False;
end;

procedure TAcceptThread.Execute;
begin
  FServer.AcceptLoop;
end;

constructor TPushThread.Create(AServer: TWebServer);
begin
  inherited Create(True);
  FServer := AServer;
  FreeOnTerminate := False;
end;

procedure TPushThread.Execute;
begin
  FServer.PushLoop;
end;

constructor TClientThread.Create(AServer: TWebServer; AClient: TWsClient);
begin
  inherited Create(True);
  FServer := AServer;
  FClient := AClient;
  FreeOnTerminate := True;
end;

procedure TClientThread.Execute;
begin
  FServer.HandleClient(FClient);
end;

{ ═══════════════════════════════════════════════════════════════════════════
  TWebServer — конструктор / деструктор
  ═══════════════════════════════════════════════════════════════════════════ }

constructor TWebServer.Create(const Username, Password: string);
{$IFDEF WINDOWS}
var
  WSAData: TWSAData;
{$ENDIF}
begin
  {$IFDEF WINDOWS}
  // Инициализация Winsock2 — обязательна перед любыми вызовами socket API
  WSAStartup($0202, WSAData);
  {$ENDIF}
  inherited Create;
  FAuthToken   := Base64EncodeStr(Username + ':' + Password);
  FListenSock  := SOCK_INVALID;
  FRunning     := False;
  FClientCount := 0;
  FOpusReady   := False;
  FOpusBufPos  := 0;
  FWebClientActive := False;
  FClientLock  := TCriticalSection.Create;
  FStateLock   := TCriticalSection.Create;
  // Начальные значения состояния
  FFreq    := 14200000;
  FMode    := 1;
  FFilterBW:= 2700;
  FAGCMode := 1;
  FAGCTop  := 90;
  FSpanHz  := 192000;
  FVolume  := 70;
  FSMeter  := -120;
  FBandIdx := 5;
end;

destructor TWebServer.Destroy;
begin
  Stop;
  FClientLock.Free;
  FStateLock.Free;
  inherited;
  {$IFDEF WINDOWS}
  // Освобождение ресурсов Winsock2
  WSACleanup;
  {$ENDIF}
end;

{ ═══════════════════════════════════════════════════════════════════════════
  Загрузка / выгрузка Opus
  ═══════════════════════════════════════════════════════════════════════════ }

function TWebServer.LoadOpus: Boolean;
const
  {$IFDEF WINDOWS} LIBNAME = 'libopus-0.dll';
  {$ELSE}          LIBNAME = 'libopus.so.0';
  {$ENDIF}
var Err: Integer;
begin
  Result := False;
  FOpusLib := LoadLibrary(LIBNAME);
  if FOpusLib = 0 then Exit;

  FOpusCreate  := TOpus_encoder_create( GetProcAddress(FOpusLib, 'opus_encoder_create'));
  FOpusDestroy := TOpus_encoder_destroy(GetProcAddress(FOpusLib, 'opus_encoder_destroy'));
  FOpusEncode  := TOpus_encode_float(   GetProcAddress(FOpusLib, 'opus_encode_float'));
  FOpusCtl     := TOpus_encoder_ctl_set(GetProcAddress(FOpusLib, 'opus_encoder_ctl'));

  if not Assigned(FOpusCreate) or not Assigned(FOpusEncode) then
  begin
    FreeLibrary(FOpusLib); FOpusLib := 0; Exit;
  end;

  FOpusEnc := FOpusCreate(OPUS_SAMPLE_RATE, OPUS_CHANNELS,
                           2101 {OPUS_APPLICATION_AUDIO}, @Err);
  if (FOpusEnc = nil) or (Err <> 0) then
  begin
    FreeLibrary(FOpusLib); FOpusLib := 0; Exit;
  end;
  // OPUS_SET_BITRATE_REQUEST = 4002
  if Assigned(FOpusCtl) then
    FOpusCtl(FOpusEnc, 4002, OPUS_BITRATE);

  FOpusBufPos := 0;
  FOpusReady  := True;
  Result      := True;
end;

procedure TWebServer.UnloadOpus;
begin
  if FOpusReady and Assigned(FOpusDestroy) and (FOpusEnc <> nil) then
    FOpusDestroy(FOpusEnc);
  FOpusEnc   := nil;
  FOpusReady := False;
  if FOpusLib <> 0 then
  begin
    FreeLibrary(FOpusLib);
    FOpusLib := 0;
  end;
end;

{ ═══════════════════════════════════════════════════════════════════════════
  Start / Stop
  ═══════════════════════════════════════════════════════════════════════════ }

function TWebServer.InitListen: Boolean;
var
  Addr: {$IFDEF WINDOWS}TSockAddrIn{$ELSE}TInetSockAddr{$ENDIF};
  One: Integer;
begin
  Result := False;
  {$IFDEF WINDOWS}
  FListenSock := socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
  {$ELSE}
  FListenSock := fpSocket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
  {$ENDIF}
  if FListenSock = SOCK_INVALID then Exit;

  One := 1;
  {$IFDEF WINDOWS}
  setsockopt(FListenSock, SOL_SOCKET, SO_REUSEADDR, @One, SizeOf(One));
  FillChar(Addr, SizeOf(Addr), 0);
  Addr.sin_family      := AF_INET;
  Addr.sin_port        := htons(WEB_PORT);
  Addr.sin_addr.S_addr := INADDR_ANY;
  if bind(FListenSock, @Addr, SizeOf(Addr)) = SOCKET_ERROR then Exit;
  if listen(FListenSock, 5) = SOCKET_ERROR then Exit;
  {$ELSE}
  fpSetSockOpt(FListenSock, SOL_SOCKET, SO_REUSEADDR, @One, SizeOf(One));
  FillChar(Addr, SizeOf(Addr), 0);
  Addr.sin_family      := AF_INET;
  Addr.sin_port        := htons(WEB_PORT);
  Addr.sin_addr.s_addr := htonl(INADDR_ANY);
  if fpBind(FListenSock, @Addr, SizeOf(Addr)) <> 0 then Exit;
  if fpListen(FListenSock, 5) <> 0 then Exit;
  {$ENDIF}
  Result := True;
end;

function TWebServer.Start: Boolean;
begin
  Result := False;
  if FRunning then Exit;
  if not LoadOpus then ; // Opus опционален — продолжаем без него
  if not InitListen then Exit;
  FRunning := True;
  FAcceptThread := TAcceptThread.Create(Self);
  TAcceptThread(FAcceptThread).Start;
  FPushThread := TPushThread.Create(Self);
  TPushThread(FPushThread).Start;
  Result := True;
end;

procedure TWebServer.Stop;
var i: Integer;
begin
  if not FRunning then Exit;
  FRunning := False;

  // ── Шаг 1: shutdown + close listen-сокета ────────────────────────────────
  // SockShutdown ОБЯЗАТЕЛЕН перед SockClose на Linux: закрытие дескриптора
  // не прерывает fpAccept в AcceptThread — только shutdown разблокирует его.
  // На Windows это тоже корректно (SD_BOTH).
  if FListenSock <> SOCK_INVALID then
  begin
    SockShutdown(FListenSock);
    SockClose(FListenSock);
    FListenSock := SOCK_INVALID;
  end;

  // ── Шаг 2: shutdown всех клиентских сокетов ──────────────────────────────
  // Разблокирует все HandleClient, заблокированные в Client.Recv (fpRecv).
  // FreeOnTerminate=True у TClientThread — они освободятся сами после выхода.
  FClientLock.Enter;
  try
    for i := 0 to FClientCount - 1 do
      if FClients[i] <> nil then
      begin
        FClients[i].State := wsClosed;
        SockShutdown(FClients[i].Socket);  // ← разблокирует fpRecv в клиентском потоке
      end;
  finally
    FClientLock.Leave;
  end;

  // ── Шаг 3: ждём завершения фоновых потоков ───────────────────────────────
  // После shutdown потоки получат ошибку из recv/accept и выйдут сами.
  if FAcceptThread <> nil then begin FAcceptThread.WaitFor; FreeAndNil(FAcceptThread); end;
  if FPushThread   <> nil then begin FPushThread.WaitFor;   FreeAndNil(FPushThread);   end;

  // ── Шаг 4: освобождаем клиентов ──────────────────────────────────────────
  FClientLock.Enter;
  try
    for i := 0 to FClientCount - 1 do FreeAndNil(FClients[i]);
    FClientCount := 0;
  finally
    FClientLock.Leave;
  end;

  UnloadOpus;
end;

{ ═══════════════════════════════════════════════════════════════════════════
  Accept loop
  ═══════════════════════════════════════════════════════════════════════════ }

procedure TWebServer.AcceptLoop;
var
  CSock:  TSocket;
  Addr:   {$IFDEF WINDOWS}TSockAddrIn{$ELSE}TInetSockAddr{$ENDIF};
  ALen:   {$IFDEF WINDOWS}Integer{$ELSE}TSockLen{$ENDIF};
  Client: TWsClient;
  T:      TClientThread;
begin
  while FRunning do
  begin
    ALen := SizeOf(Addr);
    {$IFDEF WINDOWS}
    CSock := accept(FListenSock, @Addr, @ALen);
    {$ELSE}
    CSock := fpAccept(FListenSock, @Addr, @ALen);
    {$ENDIF}
    if CSock = SOCK_INVALID then
    begin
      if FRunning then Sleep(10);
      Continue;
    end;
    if FClientCount >= MAX_WS_CLIENTS then
    begin
      SockClose(CSock);
      Continue;
    end;
    Client := TWsClient.Create(CSock);
    FClientLock.Enter;
    try
      FClients[FClientCount] := Client;
      Inc(FClientCount);
    finally
      FClientLock.Leave;
    end;
    T := TClientThread.Create(Self, Client);
    T.Start;
  end;
end;

{ ═══════════════════════════════════════════════════════════════════════════
  HTTP / WebSocket обработчик клиента
  ═══════════════════════════════════════════════════════════════════════════ }

function TWebServer.CheckAuth(const Header: string): Boolean;
var
  Pos_: Integer;
  Token, HeaderLC: string;
begin
  Result := False;
  HeaderLC := LowerCase(Header);
  Pos_ := System.Pos('authorization: basic ', HeaderLC);
  if Pos_ = 0 then Exit;
  Token := Copy(Header, Pos_ + 21, 200);
  Pos_ := System.Pos(#13, Token); if Pos_ > 0 then Token := Copy(Token, 1, Pos_ - 1);
  Pos_ := System.Pos(#10, Token); if Pos_ > 0 then Token := Copy(Token, 1, Pos_ - 1);
  Token := Trim(Token);
  Result := (Token = FAuthToken);
end;

procedure TWebServer.SendHttp(Client: TWsClient; Code: Integer;
  const ContentType, Body: string);
var
  StatusText, Response: string;
begin
  case Code of
    200: StatusText := 'OK';
    401: StatusText := 'Unauthorized';
    404: StatusText := 'Not Found';
    else StatusText := 'Error';
  end;
  Response := Format('HTTP/1.1 %d %s'#13#10 +
    'Content-Type: %s'#13#10 +
    'Content-Length: %d'#13#10 +
    'Connection: close'#13#10 +
    #13#10 + '%s', [Code, StatusText, ContentType, Length(Body), Body]);
  Client.SendRaw(Response[1], Length(Response));
end;

procedure TWebServer.HandleClient(Client: TWsClient);
var
  R, HeaderEnd:  Integer;
  Header, HeaderLC, Key, Path, AcceptKey: string;
  Response:      string;
  WsHandled:     Boolean;
  IsWsRequest:   Boolean;
  // WS frame parsing
  B0, B1:        Byte;
  Masked:        Boolean;
  PayLen:        Integer;
  Mask:          array[0..3] of Byte;
  Payload:       array of Byte;
  Opcode:        Byte;
  i, Need:       Integer;
  j:             Integer;
  P1, P2:        Integer;
  KPos, KEnd:    Integer;
  Consumed:      Integer;
  Raw:           array[0..8191] of Byte;
  RawLen:        Integer;
begin
  WsHandled := False;
  RawLen    := 0;

  // ── Фаза 1: чтение HTTP-запроса ──────────────────────────────────────────
  Header := '';
  repeat
    R := SockRecv(Client.Socket, @Raw[RawLen], SizeOf(Raw) - RawLen, 0);
    if R <= 0 then begin Client.State := wsClosed; Break; end;
    Inc(RawLen, R);
    SetLength(Header, RawLen);
    Move(Raw[0], Header[1], RawLen);
    HeaderEnd := System.Pos(#13#10#13#10, Header);
  until (HeaderEnd > 0) or (RawLen >= SizeOf(Raw));

  if (Client.State = wsClosed) or (HeaderEnd = 0) then
  begin
    RemoveClient(Client); Exit;
  end;

  Header   := Copy(Header, 1, HeaderEnd + 3);
  HeaderLC := LowerCase(Header);

  // Извлечь путь
  Path := '';
  if System.Pos('GET /', Header) > 0 then
  begin
    P1 := System.Pos('GET ', Header) + 4;
    P2 := System.Pos(' HTTP', Header);
    if P2 > P1 then Path := Copy(Header, P1, P2 - P1);
  end;

  IsWsRequest := (Path = '/ws') and (System.Pos('upgrade: websocket', HeaderLC) > 0);

  // Basic Auth (только для HTTP-страниц; WS handshake без авторизации)
  if (not IsWsRequest) and (not CheckAuth(Header)) then
  begin
    Response := 'HTTP/1.1 401 Unauthorized'#13#10 +
      'WWW-Authenticate: Basic realm="HPSDR"'#13#10 +
      'Content-Length: 0'#13#10 +
      'Connection: close'#13#10#13#10;
    Client.SendRaw(Response[1], Length(Response));
    RemoveClient(Client); Exit;
  end;

  // WebSocket upgrade
  if System.Pos('upgrade: websocket', HeaderLC) > 0 then
  begin
    KPos := System.Pos('sec-websocket-key: ', HeaderLC);
    if KPos > 0 then
    begin
      Key  := Copy(Header, KPos + 19, 100);
      KEnd := System.Pos(#13, Key);
      if KEnd > 0 then Key := Copy(Key, 1, KEnd - 1);
      Key := Trim(Key);
    end;
    AcceptKey := Base64EncodeBytes(SHA1(Key + WS_GUID), 20);
    Response := 'HTTP/1.1 101 Switching Protocols'#13#10 +
      'Upgrade: websocket'#13#10 +
      'Connection: Upgrade'#13#10 +
      'Sec-WebSocket-Accept: ' + AcceptKey + #13#10#13#10;
    Client.SendRaw(Response[1], Length(Response));
    Client.State := wsOpen;

    FStateLock.Enter;
    FWebClientActive := True;
    FStateLock.Leave;

    Client.SendText(BuildStateJson);
    WsHandled := True;
  end
  else if Path = '/' then
  begin
    SendHttp(Client, 200, 'text/html; charset=utf-8', GetIndexHtml);
    RemoveClient(Client); Exit;
  end
  else
  begin
    SendHttp(Client, 404, 'text/plain', 'Not Found');
    RemoveClient(Client); Exit;
  end;

  if not WsHandled then begin RemoveClient(Client); Exit; end;

  // ── Фаза 2: цикл WebSocket-сообщений ─────────────────────────────────────
  Client.BufLen := 0;
  while FRunning and (Client.State = wsOpen) do
  begin
    R := Client.Recv;
    if R <= 0 then Break;

    while Client.BufLen >= 2 do
    begin
      B0     := Client.BufData[0];
      B1     := Client.BufData[1];
      Opcode := B0 and $0F;
      Masked := (B1 and $80) <> 0;
      PayLen := B1 and $7F;

      Need := 2;
      if PayLen = 126 then Inc(Need, 2)
      else if PayLen = 127 then Inc(Need, 8);
      if Masked then Inc(Need, 4);

      if Client.BufLen < Need then Break;

      i := 2;
      if PayLen = 126 then
      begin
        PayLen := (Client.BufData[2] shl 8) or Client.BufData[3];
        Inc(i, 2);
      end
      else if PayLen = 127 then
      begin
        PayLen := (Client.BufData[6] shl 24) or (Client.BufData[7] shl 16) or
                  (Client.BufData[8] shl 8)  or  Client.BufData[9];
        Inc(i, 8);
      end;

      if Client.BufLen < Need + PayLen then Break;

      if Masked then
      begin
        Mask[0] := Client.BufData[i];   Mask[1] := Client.BufData[i+1];
        Mask[2] := Client.BufData[i+2]; Mask[3] := Client.BufData[i+3];
        Inc(i, 4);
      end;

      SetLength(Payload, PayLen);
      if PayLen > 0 then
      begin
        Move(Client.BufData[i], Payload[0], PayLen);
        if Masked then
          for j := 0 to PayLen - 1 do
            Payload[j] := Payload[j] xor Mask[j and 3];
      end;

      Consumed := i + PayLen;
      if Client.BufLen > Consumed then
        Move(Client.BufData[Consumed], Client.BufData[0], Client.BufLen - Consumed);
      Client.BufLen := Client.BufLen - Consumed;

      case Opcode of
        $01: // Text → команда
          begin
            SetLength(Header, PayLen);
            if PayLen > 0 then Move(Payload[0], Header[1], PayLen);
            ProcessCommand(Client, Header);
          end;
        $08: // Close
          begin
            Client.State := wsClosed;
            Break;
          end;
        $09: // Ping → Pong
          Client.SendWsFrame($0A, Payload[0], PayLen);
      end;
    end;
  end;

  FStateLock.Enter;
  FWebClientActive := (FClientCount > 1);
  FStateLock.Leave;

  RemoveClient(Client);
end;

procedure TWebServer.RemoveClient(Client: TWsClient);
var i, j: Integer;
begin
  FClientLock.Enter;
  try
    for i := 0 to FClientCount - 1 do
      if FClients[i] = Client then
      begin
        FClients[i].Free;
        for j := i to FClientCount - 2 do FClients[j] := FClients[j+1];
        FClients[FClientCount-1] := nil;
        Dec(FClientCount);
        Break;
      end;
    FWebClientActive := False;
    for i := 0 to FClientCount - 1 do
      if (FClients[i] <> nil) and (FClients[i].State = wsOpen) then
      begin FWebClientActive := True; Break; end;
  finally
    FClientLock.Leave;
  end;
end;

{ ═══════════════════════════════════════════════════════════════════════════
  Обработка JSON-команд от браузера
  ═══════════════════════════════════════════════════════════════════════════ }

procedure TWebServer.ProcessCommand(Client: TWsClient; const Json: string);
var
  Cmd:  string;
  HzF:  Double;
  HzI, ModeValue, BW, DB, Idx, V: Integer;
  On_:  Boolean;
begin
  Cmd := JsonGetStr(Json, 'cmd');

  if Cmd = 'freq' then
  begin
    HzF := JsonGetFloat(Json, 'hz', FFreq);
    FStateLock.Enter; FFreq := HzF; FStateLock.Leave;
    if Assigned(FOnFreq) then FOnFreq(HzF);
  end
  else if Cmd = 'mode' then
  begin
    ModeValue := JsonGetInt(Json, 'mode', FMode);
    FStateLock.Enter; FMode := ModeValue; FStateLock.Leave;
    if Assigned(FOnMode) then FOnMode(ModeValue);
  end
  else if Cmd = 'filter' then
  begin
    BW := JsonGetInt(Json, 'bw', FFilterBW);
    FStateLock.Enter; FFilterBW := BW; FStateLock.Leave;
    if Assigned(FOnFilter) then FOnFilter(BW);
  end
  else if Cmd = 'agc' then
  begin
    ModeValue := JsonGetInt(Json, 'mode', FAGCMode);
    FStateLock.Enter; FAGCMode := ModeValue; FStateLock.Leave;
    if Assigned(FOnAGC) then FOnAGC(ModeValue);
  end
  else if Cmd = 'agctop' then
  begin
    DB := JsonGetInt(Json, 'db', FAGCTop);
    FStateLock.Enter; FAGCTop := DB; FStateLock.Leave;
    if Assigned(FOnAGCTop) then FOnAGCTop(DB);
  end
  else if Cmd = 'band' then
  begin
    Idx := JsonGetInt(Json, 'idx', FBandIdx);
    FStateLock.Enter; FBandIdx := Idx; FStateLock.Leave;
    if Assigned(FOnBand) then FOnBand(Idx);
  end
  else if Cmd = 'span' then
  begin
    HzI := JsonGetInt(Json, 'hz', Round(FSpanHz));
    FStateLock.Enter; FSpanHz := HzI; FStateLock.Leave;
    if Assigned(FOnSpan) then FOnSpan(HzI);
  end
  else if Cmd = 'volume' then
  begin
    V := JsonGetInt(Json, 'v', FVolume);
    FStateLock.Enter; FVolume := V; FStateLock.Leave;
    if Assigned(FOnVolume) then FOnVolume(V);
  end
  else if Cmd = 'wfagc' then
  begin
    On_ := JsonGetBool(Json, 'on', FWfAGC);
    FStateLock.Enter; FWfAGC := On_; FStateLock.Leave;
    if Assigned(FOnWfAGC) then FOnWfAGC(On_);
  end
  else if Cmd = 'wfnf' then
  begin
    On_ := JsonGetBool(Json, 'on', FWfNF);
    FStateLock.Enter; FWfNF := On_; FStateLock.Leave;
    if Assigned(FOnWfNF) then FOnWfNF(On_);
  end
  else if Cmd = 'set_run' then
  begin
    On_ := JsonGetBool(Json, 'on', FTrxRunning);
    FStateLock.Enter; FTrxRunning := On_; FStateLock.Leave;
    if Assigned(FOnRun) then FOnRun(On_);
  end
  else if Cmd = 'set_mute' then
  begin
    On_ := JsonGetBool(Json, 'on', FMuted);
    FStateLock.Enter; FMuted := On_; FStateLock.Leave;
    if Assigned(FOnMute) then FOnMute(On_);
  end
  else if Cmd = 'set_ctun' then
  begin
    On_ := JsonGetBool(Json, 'on', FCtun);
    FStateLock.Enter; FCtun := On_; FStateLock.Leave;
    if Assigned(FOnCtun) then FOnCtun(On_);
  end
  else if Cmd = 'set_nr' then
  begin
    On_ := JsonGetBool(Json, 'on', FNR);
    FStateLock.Enter; FNR := On_; FStateLock.Leave;
    if Assigned(FOnNR) then FOnNR(On_);
  end
  else if Cmd = 'set_nb' then
  begin
    On_ := JsonGetBool(Json, 'on', FNB);
    FStateLock.Enter; FNB := On_; FStateLock.Leave;
    if Assigned(FOnNB) then FOnNB(On_);
  end
  else if Cmd = 'set_anf' then
  begin
    On_ := JsonGetBool(Json, 'on', FANF);
    FStateLock.Enter; FANF := On_; FStateLock.Leave;
    if Assigned(FOnANF) then FOnANF(On_);
  end;
end;

{ ═══════════════════════════════════════════════════════════════════════════
  Push-цикл — рассылает спектр / водопад / состояние всем клиентам
  ═══════════════════════════════════════════════════════════════════════════ }

procedure TWebServer.PushLoop;
var
  Tick, StateLastTick: QWord;
  SpecBuf: array[0..4096] of Byte;
  WfBuf:   array[0..4096] of Byte;
  i:       Integer;
  HasClients: Boolean;
begin
  StateLastTick := GetTickCount64;
  while FRunning do
  begin
    Sleep(50);  // 20 fps
    Tick := GetTickCount64;

    FClientLock.Enter;
    HasClients := FClientCount > 0;
    FClientLock.Leave;

    if not HasClients then Continue;

    FStateLock.Enter;
    try
      SpecBuf[0] := WS_MSG_SPECTRUM;
      for i := 0 to 1023 do
        PSingle(Pointer(PByte(@SpecBuf[1]) + i*4))^ := FSpectrumBuf[i];

      WfBuf[0] := WS_MSG_WATERFALL;
      for i := 0 to 1023 do
        PSingle(Pointer(PByte(@WfBuf[1]) + i*4))^ := FWfBuf[i];
    finally
      FStateLock.Leave;
    end;

    BroadcastBinary(SpecBuf[0], 1 + 1024*4);
    BroadcastBinary(WfBuf[0],   1 + 1024*4);

    if Tick - StateLastTick >= 200 then
    begin
      StateLastTick := Tick;
      BroadcastText(BuildStateJson);
    end;
  end;
end;

procedure TWebServer.BroadcastBinary(const Data; Len: Integer);
var i: Integer;
begin
  FClientLock.Enter;
  try
    for i := 0 to FClientCount - 1 do
      if (FClients[i] <> nil) and (FClients[i].State = wsOpen) then
        FClients[i].SendBinary(Data, Len);
  finally
    FClientLock.Leave;
  end;
end;

procedure TWebServer.BroadcastText(const S: string);
var i: Integer;
begin
  FClientLock.Enter;
  try
    for i := 0 to FClientCount - 1 do
      if (FClients[i] <> nil) and (FClients[i].State = wsOpen) then
        FClients[i].SendText(S);
  finally
    FClientLock.Leave;
  end;
end;

{ ═══════════════════════════════════════════════════════════════════════════
  Формирование JSON-состояния
  ═══════════════════════════════════════════════════════════════════════════ }

function TWebServer.BuildStateJson: string;
const
  MODE_N: array[0..7] of string =
    ('LSB','USB','DSB','CWL','CWU','FM','AM','SAM');
begin
  FStateLock.Enter;
  try
    Result := Format(
      '{"vfo_a_hz":%.0f,"mode":%d,"mode_name":"%s",' +
      '"filter":%d,"filter_bw":%d,' +
      '"agc_mode":%d,"agc_top":%d,' +
      '"span_hz":%.0f,"center_hz":%.0f,"volume":%d,' +
      '"wf_agc":%s,"wf_nf":%s,"band_idx":%d,"smeter_dbm":%.1f,' +
      '"running":%s,"mute":%s,"ctun":%s,' +
      '"nr":%s,"nb":%s,"anf":%s,"connected":%s}',
      [FFreq, FMode, MODE_N[FMode mod 8],
       FFilterIdx, FFilterBW,
       FAGCMode, FAGCTop,
       FSpanHz, FCenterHz, FVolume,
       BoolToStr(FWfAGC,      'true', 'false'),
       BoolToStr(FWfNF,       'true', 'false'),
       FBandIdx, FSMeter,
       BoolToStr(FTrxRunning, 'true', 'false'),
       BoolToStr(FMuted,      'true', 'false'),
       BoolToStr(FCtun,       'true', 'false'),
       BoolToStr(FNR,         'true', 'false'),
       BoolToStr(FNB,         'true', 'false'),
       BoolToStr(FANF,        'true', 'false'),
       BoolToStr(FConnected,  'true', 'false')
      ]);
  finally
    FStateLock.Leave;
  end;
end;

{ ═══════════════════════════════════════════════════════════════════════════
  Аудио push (вызывается из DSP-потока)
  ═══════════════════════════════════════════════════════════════════════════ }

procedure TWebServer.PushAudio(const Samples: PSingle; Count: Integer);
var
  HasWs: Boolean;
  i, n, Enc: Integer;
  Pkt: array of Byte;
begin
  if not FRunning then begin AudioLog('EXIT: FRunning=false'); Exit; end;
  FClientLock.Enter;
  HasWs := FClientCount > 0;
  FClientLock.Leave;
  if not HasWs then begin AudioLog('EXIT: FClientCount=0'); Exit; end;
  if (Samples = nil) or (Count <= 0) then begin AudioLog('EXIT: Samples nil/Count=0'); Exit; end;
  if not FOpusReady then begin AudioLog('EXIT: FOpusReady=false'); Exit; end;

  i := 0;
  while i < Count do
  begin
    n := Count - i;
    if n > OPUS_FRAME_SAMP - FOpusBufPos then
      n := OPUS_FRAME_SAMP - FOpusBufPos;
    Move(Samples[i], FOpusBuf[FOpusBufPos], n * SizeOf(Single));
    Inc(FOpusBufPos, n);
    Inc(i, n);
    if FOpusBufPos >= OPUS_FRAME_SAMP then
    begin
      Enc := FOpusEncode(FOpusEnc, @FOpusBuf[0], OPUS_FRAME_SAMP,
                         @FOpusOut[0], SizeOf(FOpusOut));
      if Enc > 0 then
      begin
        SetLength(Pkt, 1 + Enc);
        Pkt[0] := WS_MSG_AUDIO;
        Move(FOpusOut[0], Pkt[1], Enc);
        BroadcastBinary(Pkt[0], Length(Pkt));
        AudioLog('SENT opus bytes=' + IntToStr(Enc) + ' clients=' + IntToStr(FClientCount));
      end
      else
        AudioLog('ENCODE FAILED Enc=' + IntToStr(Enc));
      FOpusBufPos := 0;
    end;
  end;
end;

{ ═══════════════════════════════════════════════════════════════════════════
  Обновление состояния из MainForm (UI thread, из таймера спектра)
  ═══════════════════════════════════════════════════════════════════════════ }

procedure TWebServer.PushSpectrum(
  const Buf: array of Single; Count: Integer;
  const WfBuf_: array of Single;
  SMeter: Double;
  Freq: Double; Mode, FilterBW, AGCMode, AGCTop: Integer;
  SpanHz: Double; Volume: Integer;
  WfAGC, WfNF: Boolean; BandIdx: Integer;
  TrxConnected: Boolean;
  TrxRunning, Muted, Ctun, NR, NB, ANF: Boolean;
  CenterHz: Double; FilterIdx: Integer);
var N, i: Integer;
begin
  if not FRunning then Exit;
  N := Min(Count, 1024);
  FStateLock.Enter;
  try
    for i := 0 to N-1 do FSpectrumBuf[i] := Buf[i];
    for i := 0 to Min(High(WfBuf_), 1023) do FWfBuf[i] := WfBuf_[i];
    FSMeter     := SMeter;
    FFreq       := Freq;
    FMode       := Mode;
    FFilterBW   := FilterBW;
    FAGCMode    := AGCMode;
    FAGCTop     := AGCTop;
    FSpanHz     := SpanHz;
    FVolume     := Volume;
    FWfAGC      := WfAGC;
    FWfNF       := WfNF;
    FBandIdx    := BandIdx;
    FConnected  := TrxConnected;
    FTrxRunning := TrxRunning;
    FMuted      := Muted;
    FCtun       := Ctun;
    FNR         := NR;
    FNB         := NB;
    FANF        := ANF;
    FCenterHz   := CenterHz;
    FFilterIdx  := FilterIdx;
  finally
    FStateLock.Leave;
  end;
end;

{ ═══════════════════════════════════════════════════════════════════════════
  Stub-методы (реализация встроена в HandleClient)
  ═══════════════════════════════════════════════════════════════════════════ }

procedure TWebServer.DoHandshake(Client: TWsClient);
begin
  // Not used separately — handshake is in HandleClient
end;

procedure TWebServer.ProcessWsFrame(Client: TWsClient;
  const Data: array of Byte; Len: Integer; Opcode: Byte);
begin
  // Not used separately — frame processing is inlined in HandleClient
end;

end.