unit KPAnsi;

{ KPAnsi - ANSI BBS terminal emulation component for Delphi 1.0.           }
{                                                                           }
{ TKPAnsi is a TCustomControl descendant providing a visual ANSI terminal   }
{ display with scrollback buffer, cursor blinking, and ANSI music support.  }
{ Renders incoming data using standard ANSI/VT100 escape sequences for      }
{ cursor positioning, color attributes, and screen manipulation.            }
{                                                                           }
{ Installs to the "KP" palette tab alongside TKPComm.                      }

interface

uses
  SysUtils, Classes, WinTypes, WinProcs, Messages, Graphics, Controls, Forms;

type
  TKeyDataEvent = procedure(Sender: TObject; const Data: string) of object;

  TParseState = (psNormal, psEscape, psCSI, psCSIQuestion, psMusic);

  TTermCell = record
    Ch:    Char;
    FG:    TColor;
    BG:    TColor;
    Bold:  Boolean;
    Blink: Boolean;
  end;

  PTermLine = ^TTermLineRec;
  TTermLineRec = record
    Cells: array[0..255] of TTermCell;
  end;

  TKPAnsi = class(TCustomControl)
  private
    FScreen:         TList;
    FScrollback:     TList;
    FCursorRow:      Integer;
    FCursorCol:      Integer;
    FSaveCurRow:     Integer;
    FSaveCurCol:     Integer;
    FAttrFG:         Integer;
    FAttrBG:         Integer;
    FAttrBold:       Boolean;
    FAttrBlink:      Boolean;
    FAttrReverse:    Boolean;
    FParseState:     TParseState;
    FParamStr:       string;
    FMusicStr:       string;
    FCellWidth:      Integer;
    FCellHeight:     Integer;
    FBlinkOn:        Boolean;
    FTimerActive:    Boolean;
    FScrollPos:      Integer;
    FWrapMode:       Boolean;
    FCols:           Integer;
    FRows:           Integer;
    FScrollbackSize: Integer;
    FCursorVisible:  Boolean;
    FOnKeyData:      TKeyDataEvent;
    FPaintFont:      HFont;
    FStockFont:      Boolean;
    FMemDC:          HDC;
    FMemBmp:         HBitmap;
    FMemOldBmp:      HBitmap;
    FBufW:           Integer;
    FBufH:           Integer;
    FTextBlinkOn:    Boolean;
    FBlinkCount:     Integer;
    procedure AllocLine(Line: PTermLine);
    procedure ClearLine(Line: PTermLine);
    procedure CMFontChanged(var Msg: TMessage); message cm_FontChanged;
    procedure CreateBackBuffer;
    procedure CreatePaintFont;
    procedure DeleteChars(N: Integer);
    procedure DeleteLines(N: Integer);
    procedure DestroyBackBuffer;
    procedure DoScrollDown;
    procedure DoScrollUp;
    procedure EraseDisplay(Mode: Integer);
    procedure EraseLine(Mode: Integer);
    procedure ExecuteCSI(FinalCh: Char);
    procedure ExecuteMusic;
    procedure FreeLineList(List: TList);
    function  GetCursorCol: Integer;
    function  GetCursorRow: Integer;
    procedure InsertChars(N: Integer);
    procedure InsertLines(N: Integer);
    procedure ParseData(const S: string);
    procedure ParseSGR;
    procedure ProcessChar(Ch: Char);
    procedure RecalcCellSize;
    procedure ResizeScreen;
    procedure SetCols(Value: Integer);
    procedure SetCursorVisible(Value: Boolean);
    procedure SetRows(Value: Integer);
    procedure SetScrollbackSize(Value: Integer);
    procedure TrimScrollback;
    procedure UpdateScrollbar;
    procedure WMEraseBkgnd(var Msg: TWMEraseBkgnd); message wm_EraseBkgnd;
    procedure WMGetDlgCode(var Msg: TMessage); message wm_GetDlgCode;
    procedure WMTimer(var Msg: TWMTimer); message wm_Timer;
    procedure WMVScroll(var Msg: TWMScroll); message wm_VScroll;
  protected
    procedure CreateParams(var Params: TCreateParams); override;
    procedure KeyDown(var Key: Word; Shift: TShiftState); override;
    procedure KeyPress(var Key: Char); override;
    procedure Paint; override;
  public
    constructor Create(AOwner: TComponent); override;
    destructor Destroy; override;
    procedure Clear;
    procedure Reset;
    procedure Write(const S: string);
    property CursorCol: Integer read GetCursorCol;
    property CursorRow: Integer read GetCursorRow;
  published
    property Cols: Integer read FCols write SetCols default 80;
    property Rows: Integer read FRows write SetRows default 25;
    property ScrollbackSize: Integer read FScrollbackSize
      write SetScrollbackSize default 500;
    property CursorVisible: Boolean read FCursorVisible
      write SetCursorVisible default True;
    property Font;
    property Color default clBlack;
    property OnKeyData: TKeyDataEvent read FOnKeyData write FOnKeyData;
    property TabStop default True;
  end;

procedure Register;

implementation

const
  AnsiColors: array[0..15] of TColor = (
    $00000000,  { 0  Black }
    $00000080,  { 1  Red (low) -- BGR order }
    $00008000,  { 2  Green }
    $00008080,  { 3  Yellow/Brown }
    $00800000,  { 4  Blue }
    $00800080,  { 5  Magenta }
    $00808000,  { 6  Cyan }
    $00C0C0C0,  { 7  White (low) }
    $00808080,  { 8  Dark Gray }
    $000000FF,  { 9  Red (bright) }
    $0000FF00,  { 10 Green (bright) }
    $0000FFFF,  { 11 Yellow (bright) }
    $00FF0000,  { 12 Blue (bright) }
    $00FF00FF,  { 13 Magenta (bright) }
    $00FFFF00,  { 14 Cyan (bright) }
    $00FFFFFF   { 15 White (bright) }
  );

  CursorBlinkMs = 500;

  { OUT_RASTER_PRECIS may not be defined in Delphi 1.0 WinTypes }
  OutRasterPrecis = 6;

  { ANSI music note frequencies (octave 0, multiply by 2^octave) }
  { C, C#, D, D#, E, F, F#, G, G#, A, A#, B }
  BaseNoteFreq: array[0..11] of Word = (
    262, 277, 294, 311, 330, 349, 370, 392, 415, 440, 466, 494
  );


{ ----------------------------------------------------------------------- }
{ Helper: parse semicolon-delimited parameter string into integer array    }
{ ----------------------------------------------------------------------- }

procedure ParseParams(const S: string; var Params: array of Integer;
  var Count: Integer);
var
  I:     Integer;
  Start: Integer;
  Token: string;
begin
  Count := 0;
  if Length(S) = 0 then
    Exit;
  Start := 1;
  for I := 1 to Length(S) do
  begin
    if S[I] = ';' then
    begin
      if Count <= High(Params) then
      begin
        Token := Copy(S, Start, I - Start);
        if Length(Token) > 0 then
          Params[Count] := StrToIntDef(Token, 0)
        else
          Params[Count] := 0;
        Inc(Count);
      end;
      Start := I + 1;
    end;
  end;
  { Last token after final semicolon (or entire string if no semicolons) }
  if Count <= High(Params) then
  begin
    Token := Copy(S, Start, Length(S) - Start + 1);
    if Length(Token) > 0 then
      Params[Count] := StrToIntDef(Token, 0)
    else
      Params[Count] := 0;
    Inc(Count);
  end;
end;


{ ----------------------------------------------------------------------- }
{ TKPAnsi                                                                   }
{ ----------------------------------------------------------------------- }

procedure TKPAnsi.AllocLine(Line: PTermLine);
var
  I: Integer;
begin
  for I := 0 to FCols - 1 do
  begin
    Line^.Cells[I].Ch    := ' ';
    Line^.Cells[I].FG    := AnsiColors[7];
    Line^.Cells[I].BG    := AnsiColors[0];
    Line^.Cells[I].Bold  := False;
    Line^.Cells[I].Blink := False;
  end;
end;


procedure TKPAnsi.Clear;
var
  I:    Integer;
  Line: PTermLine;
begin
  { Move current screen lines to scrollback }
  for I := 0 to FScreen.Count - 1 do
  begin
    FScrollback.Add(FScreen[I]);
  end;
  FScreen.Clear;

  TrimScrollback;

  { Allocate fresh screen lines }
  for I := 0 to FRows - 1 do
  begin
    GetMem(Line, SizeOf(TTermLineRec));
    AllocLine(Line);
    FScreen.Add(Line);
  end;

  FCursorRow := 0;
  FCursorCol := 0;
  FScrollPos := 0;
  UpdateScrollbar;
  Invalidate;
end;


procedure TKPAnsi.ClearLine(Line: PTermLine);
var
  I: Integer;
begin
  for I := 0 to FCols - 1 do
  begin
    Line^.Cells[I].Ch    := ' ';
    Line^.Cells[I].FG    := AnsiColors[7];
    Line^.Cells[I].BG    := AnsiColors[0];
    Line^.Cells[I].Bold  := False;
    Line^.Cells[I].Blink := False;
  end;
end;


procedure TKPAnsi.CMFontChanged(var Msg: TMessage);
begin
  inherited;
  RecalcCellSize;
end;


constructor TKPAnsi.Create(AOwner: TComponent);
var
  I:    Integer;
  Line: PTermLine;
begin
  inherited Create(AOwner);
  Width            := 640;
  Height           := 400;
  Color            := clBlack;
  TabStop          := True;
  FCols            := 80;
  FRows            := 25;
  FScrollbackSize  := 500;
  FCursorVisible   := True;
  FScreen          := TList.Create;
  FScrollback      := TList.Create;
  FCursorRow       := 0;
  FCursorCol       := 0;
  FSaveCurRow      := 0;
  FSaveCurCol      := 0;
  FAttrFG          := 7;
  FAttrBG          := 0;
  FAttrBold        := False;
  FAttrBlink       := False;
  FAttrReverse     := False;
  FParseState      := psNormal;
  FParamStr        := '';
  FMusicStr        := '';
  FCellWidth       := 8;
  FCellHeight      := 16;
  FBlinkOn         := True;
  FTimerActive     := False;
  FScrollPos       := 0;
  FWrapMode        := True;
  FPaintFont       := 0;
  FStockFont       := False;
  FMemDC           := 0;
  FMemBmp          := 0;
  FMemOldBmp       := 0;
  FBufW            := 0;
  FBufH            := 0;
  FTextBlinkOn     := True;
  FBlinkCount      := 0;

  { Set a monospace font -- OEM charset selected in CreatePaintFont }
  Font.Name  := 'Terminal';
  Font.Size  := 9;
  Font.Pitch := fpFixed;

  { Allocate initial screen lines }
  for I := 0 to FRows - 1 do
  begin
    GetMem(Line, SizeOf(TTermLineRec));
    AllocLine(Line);
    FScreen.Add(Line);
  end;
end;


procedure TKPAnsi.CreateBackBuffer;
var
  ScreenDC: HDC;
begin
  DestroyBackBuffer;
  FBufW := FCols * FCellWidth;
  FBufH := FRows * FCellHeight;
  if (FBufW < 1) or (FBufH < 1) then
    Exit;

  { Create a memory DC with compatible bitmap for double buffering. }
  { We manage this DC directly with GDI calls -- no TCanvas/TBitmap }
  { involvement -- so our OEM_CHARSET font stays selected and       }
  { cannot be overridden by VCL font realization.                   }
  ScreenDC := GetDC(0);
  FMemDC     := CreateCompatibleDC(ScreenDC);
  FMemBmp    := CreateCompatibleBitmap(ScreenDC, FBufW, FBufH);
  ReleaseDC(0, ScreenDC);
  FMemOldBmp := SelectObject(FMemDC, FMemBmp);
  if FPaintFont <> 0 then
    SelectObject(FMemDC, FPaintFont);
  SetBkMode(FMemDC, OPAQUE);
end;


procedure TKPAnsi.CreatePaintFont;
var
  LF:       TLogFont;
  ActualLF: TLogFont;
  NewFont:  HFont;
begin
  { Free previous font (stock fonts must not be deleted) }
  if (FPaintFont <> 0) and not FStockFont then
    DeleteObject(FPaintFont);
  FPaintFont := 0;
  FStockFont := False;

  { Build LOGFONT requesting OEM_CHARSET with raster precision for CP437 }
  { box-drawing, block elements, and other BBS ANSI art glyphs.          }
  FillChar(LF, SizeOf(LF), 0);
  LF.lfHeight         := Font.Height;
  LF.lfPitchAndFamily := FIXED_PITCH or FF_MODERN;
  LF.lfCharSet        := OEM_CHARSET;
  LF.lfOutPrecision   := OutRasterPrecis;
  if fsBold in Font.Style then
    LF.lfWeight := FW_BOLD
  else
    LF.lfWeight := FW_NORMAL;
  StrPCopy(LF.lfFaceName, Font.Name);

  NewFont := CreateFontIndirect(LF);
  if NewFont <> 0 then
  begin
    { Verify Windows actually gave us an OEM charset font }
    GetObject(NewFont, SizeOf(ActualLF), @ActualLF);
    if ActualLF.lfCharSet = OEM_CHARSET then
    begin
      FPaintFont := NewFont;
      if FMemDC <> 0 then
        SelectObject(FMemDC, FPaintFont);
      Exit;
    end;
    { Windows substituted a non-OEM font; discard it }
    DeleteObject(NewFont);
  end;

  { Fall back to the stock OEM fixed font -- guaranteed CP437 }
  FPaintFont := GetStockObject(OEM_FIXED_FONT);
  FStockFont := True;
  if FMemDC <> 0 then
    SelectObject(FMemDC, FPaintFont);
end;


procedure TKPAnsi.CreateParams(var Params: TCreateParams);
begin
  inherited CreateParams(Params);
  Params.Style := Params.Style or ws_VScroll;
end;


procedure TKPAnsi.DeleteChars(N: Integer);
var
  Line: PTermLine;
  I:    Integer;
begin
  if N < 1 then
    N := 1;
  Line := FScreen[FCursorRow];
  { Shift cells left }
  for I := FCursorCol to FCols - 1 - N do
  begin
    Line^.Cells[I] := Line^.Cells[I + N];
  end;
  { Clear vacated cells at end }
  for I := FCols - N to FCols - 1 do
  begin
    if I >= 0 then
    begin
      Line^.Cells[I].Ch    := ' ';
      Line^.Cells[I].FG    := AnsiColors[7];
      Line^.Cells[I].BG    := AnsiColors[0];
      Line^.Cells[I].Bold  := False;
      Line^.Cells[I].Blink := False;
    end;
  end;
end;


procedure TKPAnsi.DeleteLines(N: Integer);
var
  I:    Integer;
  Line: PTermLine;
begin
  if N < 1 then
    N := 1;
  for I := 1 to N do
  begin
    if FCursorRow < FScreen.Count then
    begin
      Line := FScreen[FCursorRow];
      FreeMem(Line, SizeOf(TTermLineRec));
      FScreen.Delete(FCursorRow);
      { Add a blank line at the bottom }
      GetMem(Line, SizeOf(TTermLineRec));
      AllocLine(Line);
      FScreen.Add(Line);
    end;
  end;
end;


procedure TKPAnsi.DestroyBackBuffer;
begin
  if FMemDC <> 0 then
  begin
    SelectObject(FMemDC, FMemOldBmp);
    DeleteObject(FMemBmp);
    DeleteDC(FMemDC);
    FMemDC     := 0;
    FMemBmp    := 0;
    FMemOldBmp := 0;
  end;
end;


destructor TKPAnsi.Destroy;
begin
  if FTimerActive then
  begin
    KillTimer(Handle, 1);
    FTimerActive := False;
  end;
  DestroyBackBuffer;
  if (FPaintFont <> 0) and not FStockFont then
  begin
    DeleteObject(FPaintFont);
    FPaintFont := 0;
  end;
  FreeLineList(FScreen);
  FScreen.Free;
  FreeLineList(FScrollback);
  FScrollback.Free;
  inherited Destroy;
end;


procedure TKPAnsi.DoScrollDown;
var
  Line: PTermLine;
begin
  if FScreen.Count < FRows then
    Exit;
  { Remove bottom line }
  Line := FScreen[FScreen.Count - 1];
  FreeMem(Line, SizeOf(TTermLineRec));
  FScreen.Delete(FScreen.Count - 1);
  { Insert blank line at top }
  GetMem(Line, SizeOf(TTermLineRec));
  AllocLine(Line);
  FScreen.Insert(0, Line);
end;


procedure TKPAnsi.DoScrollUp;
var
  Line: PTermLine;
begin
  if FScreen.Count < FRows then
    Exit;
  { Move top line to scrollback }
  Line := FScreen[0];
  FScrollback.Add(Line);
  FScreen.Delete(0);
  TrimScrollback;
  { Add blank line at bottom }
  GetMem(Line, SizeOf(TTermLineRec));
  AllocLine(Line);
  FScreen.Add(Line);
  UpdateScrollbar;
end;


procedure TKPAnsi.EraseDisplay(Mode: Integer);
var
  I:    Integer;
  J:    Integer;
  Line: PTermLine;
begin
  case Mode of
    0: { Erase below: current position to end of screen }
      begin
        { Erase rest of current line }
        Line := FScreen[FCursorRow];
        for J := FCursorCol to FCols - 1 do
        begin
          Line^.Cells[J].Ch    := ' ';
          Line^.Cells[J].FG    := AnsiColors[7];
          Line^.Cells[J].BG    := AnsiColors[0];
          Line^.Cells[J].Bold  := False;
          Line^.Cells[J].Blink := False;
        end;
        { Erase all lines below }
        for I := FCursorRow + 1 to FScreen.Count - 1 do
        begin
          ClearLine(FScreen[I]);
        end;
      end;
    1: { Erase above: start of screen to current position }
      begin
        { Erase all lines above }
        for I := 0 to FCursorRow - 1 do
        begin
          ClearLine(FScreen[I]);
        end;
        { Erase current line up to and including cursor }
        Line := FScreen[FCursorRow];
        for J := 0 to FCursorCol do
        begin
          Line^.Cells[J].Ch    := ' ';
          Line^.Cells[J].FG    := AnsiColors[7];
          Line^.Cells[J].BG    := AnsiColors[0];
          Line^.Cells[J].Bold  := False;
          Line^.Cells[J].Blink := False;
        end;
      end;
    2: { Erase all: move screen to scrollback, allocate fresh }
      begin
        for I := 0 to FScreen.Count - 1 do
        begin
          FScrollback.Add(FScreen[I]);
        end;
        FScreen.Clear;
        TrimScrollback;
        for I := 0 to FRows - 1 do
        begin
          GetMem(Line, SizeOf(TTermLineRec));
          AllocLine(Line);
          FScreen.Add(Line);
        end;
        UpdateScrollbar;
      end;
  end;
end;


procedure TKPAnsi.EraseLine(Mode: Integer);
var
  J:    Integer;
  Line: PTermLine;
begin
  Line := FScreen[FCursorRow];
  case Mode of
    0: { Erase from cursor to end of line }
      begin
        for J := FCursorCol to FCols - 1 do
        begin
          Line^.Cells[J].Ch    := ' ';
          Line^.Cells[J].FG    := AnsiColors[7];
          Line^.Cells[J].BG    := AnsiColors[0];
          Line^.Cells[J].Bold  := False;
          Line^.Cells[J].Blink := False;
        end;
      end;
    1: { Erase from start of line to cursor }
      begin
        for J := 0 to FCursorCol do
        begin
          Line^.Cells[J].Ch    := ' ';
          Line^.Cells[J].FG    := AnsiColors[7];
          Line^.Cells[J].BG    := AnsiColors[0];
          Line^.Cells[J].Bold  := False;
          Line^.Cells[J].Blink := False;
        end;
      end;
    2: { Erase entire line }
      begin
        ClearLine(Line);
      end;
  end;
end;


procedure TKPAnsi.ExecuteCSI(FinalCh: Char);
var
  Params: array[0..15] of Integer;
  Count:  Integer;
  P1:     Integer;
  P2:     Integer;
begin
  ParseParams(FParamStr, Params, Count);

  if Count > 0 then
    P1 := Params[0]
  else
    P1 := 0;
  if Count > 1 then
    P2 := Params[1]
  else
    P2 := 0;

  case FinalCh of
    'A': { CUU - Cursor Up }
      begin
        if P1 < 1 then
          P1 := 1;
        FCursorRow := FCursorRow - P1;
        if FCursorRow < 0 then
          FCursorRow := 0;
      end;
    'B': { CUD - Cursor Down }
      begin
        if P1 < 1 then
          P1 := 1;
        FCursorRow := FCursorRow + P1;
        if FCursorRow >= FRows then
          FCursorRow := FRows - 1;
      end;
    'C': { CUF - Cursor Forward }
      begin
        if P1 < 1 then
          P1 := 1;
        FCursorCol := FCursorCol + P1;
        if FCursorCol >= FCols then
          FCursorCol := FCols - 1;
      end;
    'D': { CUB - Cursor Back }
      begin
        if P1 < 1 then
          P1 := 1;
        FCursorCol := FCursorCol - P1;
        if FCursorCol < 0 then
          FCursorCol := 0;
      end;
    'H', 'f': { CUP/HVP - Cursor Position (1-based params) }
      begin
        if P1 < 1 then
          P1 := 1;
        if P2 < 1 then
          P2 := 1;
        FCursorRow := P1 - 1;
        FCursorCol := P2 - 1;
        if FCursorRow >= FRows then
          FCursorRow := FRows - 1;
        if FCursorCol >= FCols then
          FCursorCol := FCols - 1;
      end;
    'J': { ED - Erase Display }
      begin
        EraseDisplay(P1);
      end;
    'K': { EL - Erase Line }
      begin
        EraseLine(P1);
      end;
    'L': { IL - Insert Lines }
      begin
        InsertLines(P1);
      end;
    'M': { DL - Delete Lines }
      begin
        DeleteLines(P1);
      end;
    'P': { DCH - Delete Characters }
      begin
        DeleteChars(P1);
      end;
    'S': { SU - Scroll Up }
      begin
        if P1 < 1 then
          P1 := 1;
        while P1 > 0 do
        begin
          DoScrollUp;
          Dec(P1);
        end;
      end;
    'T': { SD - Scroll Down }
      begin
        if P1 < 1 then
          P1 := 1;
        while P1 > 0 do
        begin
          DoScrollDown;
          Dec(P1);
        end;
      end;
    '@': { ICH - Insert Characters }
      begin
        InsertChars(P1);
      end;
    'm': { SGR - Set Graphic Rendition }
      begin
        ParseSGR;
      end;
    's': { SCP - Save Cursor Position }
      begin
        FSaveCurRow := FCursorRow;
        FSaveCurCol := FCursorCol;
      end;
    'c': { DA - Device Attributes }
      begin
        { Respond as VT100 with no options }
        if Assigned(FOnKeyData) then
          FOnKeyData(Self, #27'[?1;0c');
      end;
    'n': { DSR - Device Status Report }
      begin
        if P1 = 5 then
        begin
          { Terminal status: report OK }
          if Assigned(FOnKeyData) then
            FOnKeyData(Self, #27'[0n');
        end
        else if P1 = 6 then
        begin
          { Cursor Position Report: respond with ESC[row;colR (1-based) }
          if Assigned(FOnKeyData) then
            FOnKeyData(Self, #27'[' + IntToStr(FCursorRow + 1) + ';' +
              IntToStr(FCursorCol + 1) + 'R');
        end;
      end;
    'u': { RCP - Restore Cursor Position }
      begin
        FCursorRow := FSaveCurRow;
        FCursorCol := FSaveCurCol;
        if FCursorRow >= FRows then
          FCursorRow := FRows - 1;
        if FCursorCol >= FCols then
          FCursorCol := FCols - 1;
      end;
  end;
end;


procedure TKPAnsi.ExecuteMusic;
var
  Tempo:      Integer;
  DefLen:     Integer;
  Octave:     Integer;
  I:          Integer;
  Ch:         Char;
  NoteIdx:    Integer;
  Duration:   Integer;
  Dotted:     Boolean;
  NoteDurMs:  Integer;
  Freq:       Integer;
  OctMul:     Integer;
  J:          Integer;
  NumStr:     string;
begin
  if Length(FMusicStr) = 0 then
    Exit;

  Tempo  := 120;
  DefLen := 4;
  Octave := 4;

  { Open sound device }
  OpenSound;

  I := 1;
  while I <= Length(FMusicStr) do
  begin
    Ch := UpCase(FMusicStr[I]);
    Inc(I);

    case Ch of
      'T': { Tempo }
        begin
          NumStr := '';
          while (I <= Length(FMusicStr)) and
                (FMusicStr[I] >= '0') and (FMusicStr[I] <= '9') do
          begin
            NumStr := NumStr + FMusicStr[I];
            Inc(I);
          end;
          if Length(NumStr) > 0 then
            Tempo := StrToIntDef(NumStr, 120);
          if Tempo < 32 then
            Tempo := 32;
          if Tempo > 255 then
            Tempo := 255;
        end;
      'L': { Default length }
        begin
          NumStr := '';
          while (I <= Length(FMusicStr)) and
                (FMusicStr[I] >= '0') and (FMusicStr[I] <= '9') do
          begin
            NumStr := NumStr + FMusicStr[I];
            Inc(I);
          end;
          if Length(NumStr) > 0 then
            DefLen := StrToIntDef(NumStr, 4);
          if DefLen < 1 then
            DefLen := 1;
        end;
      'O': { Octave }
        begin
          NumStr := '';
          while (I <= Length(FMusicStr)) and
                (FMusicStr[I] >= '0') and (FMusicStr[I] <= '9') do
          begin
            NumStr := NumStr + FMusicStr[I];
            Inc(I);
          end;
          if Length(NumStr) > 0 then
            Octave := StrToIntDef(NumStr, 4);
          if Octave < 0 then
            Octave := 0;
          if Octave > 7 then
            Octave := 7;
        end;
      '>': { Octave up }
        begin
          if Octave < 7 then
            Inc(Octave);
        end;
      '<': { Octave down }
        begin
          if Octave > 0 then
            Dec(Octave);
        end;
      'A'..'G': { Note }
        begin
          { Map note letter to semitone index: C=0 D=2 E=4 F=5 G=7 A=9 B=11 }
          case Ch of
            'C': NoteIdx := 0;
            'D': NoteIdx := 2;
            'E': NoteIdx := 4;
            'F': NoteIdx := 5;
            'G': NoteIdx := 7;
            'A': NoteIdx := 9;
            'B': NoteIdx := 11;
            else NoteIdx := 0;
          end;
          { Check for sharp/flat }
          if I <= Length(FMusicStr) then
          begin
            if (FMusicStr[I] = '#') or (FMusicStr[I] = '+') then
            begin
              Inc(NoteIdx);
              if NoteIdx > 11 then
                NoteIdx := 11;
              Inc(I);
            end
            else if FMusicStr[I] = '-' then
            begin
              Dec(NoteIdx);
              if NoteIdx < 0 then
                NoteIdx := 0;
              Inc(I);
            end;
          end;
          { Parse optional duration }
          Duration := 0;
          NumStr := '';
          while (I <= Length(FMusicStr)) and
                (FMusicStr[I] >= '0') and (FMusicStr[I] <= '9') do
          begin
            NumStr := NumStr + FMusicStr[I];
            Inc(I);
          end;
          if Length(NumStr) > 0 then
            Duration := StrToIntDef(NumStr, 0);
          if Duration < 1 then
            Duration := DefLen;
          { Check for dot }
          Dotted := False;
          if (I <= Length(FMusicStr)) and (FMusicStr[I] = '.') then
          begin
            Dotted := True;
            Inc(I);
          end;
          { Calculate duration in ms: whole note = 4 beats, beat = 60000/tempo ms }
          NoteDurMs := (4 * 60000) div (Tempo * Duration);
          if Dotted then
            NoteDurMs := (NoteDurMs * 3) div 2;
          { Calculate frequency }
          Freq := BaseNoteFreq[NoteIdx];
          OctMul := 1;
          for J := 1 to Octave do
          begin
            OctMul := OctMul * 2;
          end;
          Freq := (Freq * OctMul) div 16;  { BaseNoteFreq is at octave 4 }
          { Queue the note }
          SetVoiceAccent(1, Tempo, 128, 0, 0);
          SetVoiceNote(1, Freq, Duration, 0);
        end;
      'P': { Pause/Rest }
        begin
          Duration := 0;
          NumStr := '';
          while (I <= Length(FMusicStr)) and
                (FMusicStr[I] >= '0') and (FMusicStr[I] <= '9') do
          begin
            NumStr := NumStr + FMusicStr[I];
            Inc(I);
          end;
          if Length(NumStr) > 0 then
            Duration := StrToIntDef(NumStr, 0);
          if Duration < 1 then
            Duration := DefLen;
          { Dotted rest }
          if (I <= Length(FMusicStr)) and (FMusicStr[I] = '.') then
            Inc(I);
          SetVoiceNote(1, 0, Duration, 0);
        end;
    end;
  end;

  StartSound;
  CloseSound;
end;


procedure TKPAnsi.FreeLineList(List: TList);
var
  I: Integer;
begin
  for I := 0 to List.Count - 1 do
  begin
    FreeMem(PTermLine(List[I]), SizeOf(TTermLineRec));
  end;
  List.Clear;
end;


function TKPAnsi.GetCursorCol: Integer;
begin
  Result := FCursorCol;
end;


function TKPAnsi.GetCursorRow: Integer;
begin
  Result := FCursorRow;
end;


procedure TKPAnsi.InsertChars(N: Integer);
var
  Line: PTermLine;
  I:    Integer;
begin
  if N < 1 then
    N := 1;
  Line := FScreen[FCursorRow];
  { Shift cells right }
  for I := FCols - 1 downto FCursorCol + N do
  begin
    Line^.Cells[I] := Line^.Cells[I - N];
  end;
  { Clear inserted cells }
  for I := FCursorCol to FCursorCol + N - 1 do
  begin
    if I < FCols then
    begin
      Line^.Cells[I].Ch    := ' ';
      Line^.Cells[I].FG    := AnsiColors[7];
      Line^.Cells[I].BG    := AnsiColors[0];
      Line^.Cells[I].Bold  := False;
      Line^.Cells[I].Blink := False;
    end;
  end;
end;


procedure TKPAnsi.InsertLines(N: Integer);
var
  I:    Integer;
  Line: PTermLine;
begin
  if N < 1 then
    N := 1;
  for I := 1 to N do
  begin
    { Remove bottom line }
    if FScreen.Count > 0 then
    begin
      Line := FScreen[FScreen.Count - 1];
      FreeMem(Line, SizeOf(TTermLineRec));
      FScreen.Delete(FScreen.Count - 1);
    end;
    { Insert blank line at cursor row }
    GetMem(Line, SizeOf(TTermLineRec));
    AllocLine(Line);
    FScreen.Insert(FCursorRow, Line);
  end;
end;


procedure TKPAnsi.KeyDown(var Key: Word; Shift: TShiftState);
var
  S: string;
begin
  S := '';
  case Key of
    vk_Up:
      S := #27'[A';
    vk_Down:
      S := #27'[B';
    vk_Right:
      S := #27'[C';
    vk_Left:
      S := #27'[D';
    vk_Home:
      S := #27'[H';
    vk_End:
      S := #27'[K';
    vk_Prior: { Page Up }
      S := #27'[V';
    vk_Next: { Page Down }
      S := #27'[U';
    vk_Insert:
      S := #27'[@';
    vk_Delete:
      S := #27#127;
    vk_F1:
      S := #27'OP';
    vk_F2:
      S := #27'OQ';
    vk_F3:
      S := #27'OR';
    vk_F4:
      S := #27'OS';
    vk_F5:
      S := #27'Ot';
    vk_F6:
      S := #27'Ou';
    vk_F7:
      S := #27'Ov';
    vk_F8:
      S := #27'Ow';
    vk_F9:
      S := #27'Ox';
    vk_F10:
      S := #27'Oy';
  end;
  if (Length(S) > 0) and Assigned(FOnKeyData) then
  begin
    FOnKeyData(Self, S);
    Key := 0;
  end;
  inherited KeyDown(Key, Shift);
end;


procedure TKPAnsi.KeyPress(var Key: Char);
var
  S: string;
begin
  if Key = #13 then
    S := #13
  else if Key >= ' ' then
    S := Key
  else if Key = #8 then
    S := #8
  else if Key = #9 then
    S := #9
  else if Key = #27 then
    S := #27
  else
    S := '';
  if (Length(S) > 0) and Assigned(FOnKeyData) then
  begin
    FOnKeyData(Self, S);
  end;
  inherited KeyPress(Key);
end;


procedure TKPAnsi.Paint;
var
  Row:       Integer;
  Col:       Integer;
  X:         Integer;
  Y:         Integer;
  Line:      PTermLine;
  StartCol:  Integer;
  BatchBuf:  array[0..255] of Char;
  BatchLen:  Integer;
  BatchFG:   TColor;
  BatchBG:   TColor;
  CellFG:    TColor;
  VisRow:    Integer;
  SbkOffset: Integer;
  SbkCount:  Integer;
  R:         TRect;
  HBr:       HBrush;
begin
  { Ensure back buffer exists (created by RecalcCellSize) }
  if FMemDC = 0 then
    RecalcCellSize;
  if FMemDC = 0 then
    Exit;

  { Pre-fill entire back buffer with black so no white pixels can }
  { leak through gaps between rows or at the edges.               }
  R.Left   := 0;
  R.Top    := 0;
  R.Right  := FBufW;
  R.Bottom := FBufH;
  HBr := CreateSolidBrush(ColorToRGB(AnsiColors[0]));
  FillRect(FMemDC, R, HBr);
  DeleteObject(HBr);

  SbkCount := FScrollback.Count;

  for Row := 0 to FRows - 1 do
  begin
    Y := Row * FCellHeight;

    { Determine which line to display based on scroll position }
    VisRow := Row - FScrollPos;
    if VisRow < 0 then
    begin
      { Drawing from scrollback }
      SbkOffset := SbkCount + VisRow;
      if (SbkOffset >= 0) and (SbkOffset < SbkCount) then
        Line := FScrollback[SbkOffset]
      else
        Line := nil;
    end
    else
    begin
      { Drawing from active screen }
      if VisRow < FScreen.Count then
        Line := FScreen[VisRow]
      else
        Line := nil;
    end;

    if Line = nil then
      Continue;

    { Batch consecutive cells with same effective colors into a single }
    { TextOut call for performance.  Uses a fixed char array instead   }
    { of string concatenation to avoid heap allocation per cell.       }
    { When text blink is in the off phase, blinking cells render with  }
    { FG = BG so the text becomes invisible.                           }
    Col := 0;
    while Col < FCols do
    begin
      StartCol := Col;
      BatchBG  := Line^.Cells[Col].BG;
      if Line^.Cells[Col].Blink and not FTextBlinkOn then
        BatchFG := BatchBG
      else
        BatchFG := Line^.Cells[Col].FG;
      BatchBuf[0] := Line^.Cells[Col].Ch;
      BatchLen    := 1;
      Inc(Col);

      { Extend batch while effective colors match }
      while Col < FCols do
      begin
        if Line^.Cells[Col].BG <> BatchBG then
          Break;
        if Line^.Cells[Col].Blink and not FTextBlinkOn then
          CellFG := BatchBG
        else
          CellFG := Line^.Cells[Col].FG;
        if CellFG <> BatchFG then
          Break;
        BatchBuf[BatchLen] := Line^.Cells[Col].Ch;
        Inc(BatchLen);
        Inc(Col);
      end;

      X := StartCol * FCellWidth;
      SetTextColor(FMemDC, ColorToRGB(BatchFG));
      SetBkColor(FMemDC, ColorToRGB(BatchBG));
      WinProcs.TextOut(FMemDC, X, Y, @BatchBuf[0], BatchLen);
    end;

    { Draw cursor if on this row and visible }
    if FCursorVisible and FBlinkOn and (FScrollPos = 0) and
       (Row = FCursorRow) and (FCursorCol < FCols) then
    begin
      X := FCursorCol * FCellWidth;
      { Invert the cursor cell }
      SetTextColor(FMemDC, ColorToRGB(Line^.Cells[FCursorCol].BG));
      SetBkColor(FMemDC, ColorToRGB(Line^.Cells[FCursorCol].FG));
      WinProcs.TextOut(FMemDC, X, Y,
        @Line^.Cells[FCursorCol].Ch, 1);
    end;
  end;

  { Blit the completed frame to screen in one operation }
  BitBlt(Canvas.Handle, 0, 0, FBufW, FBufH,
    FMemDC, 0, 0, SRCCOPY);
end;


procedure TKPAnsi.ParseData(const S: string);
var
  I: Integer;
begin
  for I := 1 to Length(S) do
  begin
    ProcessChar(S[I]);
  end;

  { Snap to bottom on new data }
  if FScrollPos <> 0 then
  begin
    FScrollPos := 0;
    UpdateScrollbar;
  end;

  { Reset cursor blink to visible on new data }
  FBlinkOn := True;

  { Invalidate + Update forces an immediate synchronous repaint.     }
  { Without Update, WM_PAINT is low-priority and gets starved by     }
  { incoming WM_COMMNOTIFY messages, causing visible input lag.      }
  { The paint loop uses a fixed char array (no heap allocs) and our  }
  { own GDI memory DC, so repainting is fast enough for this.        }
  Invalidate;
  Update;
end;


procedure TKPAnsi.ParseSGR;
var
  Params: array[0..15] of Integer;
  Count:  Integer;
  I:      Integer;
  Code:   Integer;
begin
  ParseParams(FParamStr, Params, Count);

  { SGR with no parameters means reset }
  if Count = 0 then
  begin
    FAttrFG      := 7;
    FAttrBG      := 0;
    FAttrBold    := False;
    FAttrBlink   := False;
    FAttrReverse := False;
    Exit;
  end;

  for I := 0 to Count - 1 do
  begin
    Code := Params[I];
    case Code of
      0: { Reset }
        begin
          FAttrFG      := 7;
          FAttrBG      := 0;
          FAttrBold    := False;
          FAttrBlink   := False;
          FAttrReverse := False;
        end;
      1: { Bold }
        FAttrBold := True;
      5: { Blink }
        FAttrBlink := True;
      7: { Reverse }
        FAttrReverse := True;
      22: { Normal intensity (cancel bold) }
        FAttrBold := False;
      25: { Blink off }
        FAttrBlink := False;
      27: { Reverse off }
        FAttrReverse := False;
      30..37: { Foreground color }
        FAttrFG := Code - 30;
      40..47: { Background color }
        FAttrBG := Code - 40;
    end;
  end;
end;


procedure TKPAnsi.ProcessChar(Ch: Char);
var
  FGIdx:  Integer;
  BGIdx:  Integer;
  TabCol: Integer;
  Line:   PTermLine;
begin
  case FParseState of
    psNormal:
      begin
        case Ch of
          #27: { ESC }
            FParseState := psEscape;
          #13: { CR }
            FCursorCol := 0;
          #10: { LF }
            begin
              Inc(FCursorRow);
              if FCursorRow >= FRows then
              begin
                FCursorRow := FRows - 1;
                DoScrollUp;
              end;
            end;
          #8: { BS }
            begin
              if FCursorCol > 0 then
                Dec(FCursorCol);
            end;
          #9: { TAB }
            begin
              TabCol := ((FCursorCol div 8) + 1) * 8;
              if TabCol >= FCols then
                TabCol := FCols - 1;
              FCursorCol := TabCol;
            end;
          #5: { ENQ - Answerback }
            begin
              if Assigned(FOnKeyData) then
                FOnKeyData(Self, #27'[?1;0c');
            end;
          #7: { BEL }
            MessageBeep(0);
          else
            begin
              { Printable character }
              if (FCursorCol >= FCols) then
              begin
                if FWrapMode then
                begin
                  FCursorCol := 0;
                  Inc(FCursorRow);
                  if FCursorRow >= FRows then
                  begin
                    FCursorRow := FRows - 1;
                    DoScrollUp;
                  end;
                end
                else
                begin
                  FCursorCol := FCols - 1;
                end;
              end;

              { Calculate effective colors.  Bold maps FG to bright }
              { (index + 8).  Blink is stored as a cell attribute    }
              { and rendered in Paint -- NOT mapped to bright BG, so }
              { colored backgrounds (SGR 40-47) display correctly.   }
              if FAttrBold then
                FGIdx := FAttrFG + 8
              else
                FGIdx := FAttrFG;
              BGIdx := FAttrBG;

              Line := FScreen[FCursorRow];
              if FAttrReverse then
              begin
                Line^.Cells[FCursorCol].FG := AnsiColors[BGIdx];
                Line^.Cells[FCursorCol].BG := AnsiColors[FGIdx];
              end
              else
              begin
                Line^.Cells[FCursorCol].FG := AnsiColors[FGIdx];
                Line^.Cells[FCursorCol].BG := AnsiColors[BGIdx];
              end;
              Line^.Cells[FCursorCol].Ch    := Ch;
              Line^.Cells[FCursorCol].Bold  := FAttrBold;
              Line^.Cells[FCursorCol].Blink := FAttrBlink;

              Inc(FCursorCol);
            end;
        end;
      end;

    psEscape:
      begin
        case Ch of
          '[':
            begin
              FParamStr   := '';
              FParseState := psCSI;
            end;
          else
            begin
              { Unrecognized escape sequence, return to normal }
              FParseState := psNormal;
            end;
        end;
      end;

    psCSI:
      begin
        case Ch of
          '0'..'9', ';':
            begin
              FParamStr := FParamStr + Ch;
            end;
          '?':
            begin
              FParseState := psCSIQuestion;
            end;
          'M':
            begin
              { Check if this is ANSI music: ESC[M starts music mode }
              if Length(FParamStr) = 0 then
              begin
                FMusicStr   := '';
                FParseState := psMusic;
              end
              else
              begin
                { DL - Delete Lines with params }
                ExecuteCSI('M');
                FParseState := psNormal;
              end;
            end;
          else
            begin
              { Final byte: execute the command }
              ExecuteCSI(Ch);
              FParseState := psNormal;
            end;
        end;
      end;

    psCSIQuestion:
      begin
        case Ch of
          '0'..'9', ';':
            FParamStr := FParamStr + Ch;
          'h': { Set Mode }
            begin
              if FParamStr = '7' then
                FWrapMode := True
              else if FParamStr = '25' then
                FCursorVisible := True;
              FParseState := psNormal;
            end;
          'l': { Reset Mode }
            begin
              if FParamStr = '7' then
                FWrapMode := False
              else if FParamStr = '25' then
                FCursorVisible := False;
              FParseState := psNormal;
            end;
          else
            begin
              { Unrecognized DEC private mode, return to normal }
              FParseState := psNormal;
            end;
        end;
      end;

    psMusic:
      begin
        if Ch = #14 then { Ctrl-N terminates music }
        begin
          ExecuteMusic;
          FParseState := psNormal;
        end
        else
        begin
          FMusicStr := FMusicStr + Ch;
        end;
      end;
  end;
end;


procedure TKPAnsi.RecalcCellSize;
var
  DC:      HDC;
  OldFont: HFont;
  Extent:  Longint;
begin
  if not HandleAllocated then
    Exit;

  { Destroy back buffer first so the old font is not selected in any }
  { DC when CreatePaintFont deletes it.                               }
  DestroyBackBuffer;

  { Recreate the OEM charset paint font from current Font properties }
  CreatePaintFont;

  { Measure actual rendered character size with GetTextExtent.        }
  { TEXTMETRIC fields can disagree with actual rendering for OEM      }
  { raster fonts; GetTextExtent returns the real pixel dimensions.    }
  DC := GetDC(Handle);
  try
    OldFont := SelectObject(DC, FPaintFont);
    Extent  := GetTextExtent(DC, 'W', 1);
    SelectObject(DC, OldFont);
    FCellWidth  := LoWord(Extent);
    FCellHeight := HiWord(Extent);
  finally
    ReleaseDC(Handle, DC);
  end;
  if FCellWidth < 1 then
    FCellWidth := 8;
  if FCellHeight < 1 then
    FCellHeight := 16;

  { Resize control to fit terminal dimensions }
  Width  := FCols * FCellWidth + GetSystemMetrics(sm_CxVScroll);
  Height := FRows * FCellHeight;

  { (Re)create the GDI back buffer at the new size }
  CreateBackBuffer;

  { Start cursor blink timer }
  if not FTimerActive then
  begin
    SetTimer(Handle, 1, CursorBlinkMs, nil);
    FTimerActive := True;
  end;

  Invalidate;
end;


procedure TKPAnsi.Reset;
begin
  FAttrFG      := 7;
  FAttrBG      := 0;
  FAttrBold    := False;
  FAttrBlink   := False;
  FAttrReverse := False;
  FParseState  := psNormal;
  FParamStr    := '';
  FMusicStr    := '';
  FWrapMode    := True;
  FSaveCurRow  := 0;
  FSaveCurCol  := 0;
  Clear;
end;


procedure TKPAnsi.ResizeScreen;
var
  I:    Integer;
  Line: PTermLine;
begin
  { Free existing screen lines }
  FreeLineList(FScreen);

  { Allocate new screen lines }
  for I := 0 to FRows - 1 do
  begin
    GetMem(Line, SizeOf(TTermLineRec));
    AllocLine(Line);
    FScreen.Add(Line);
  end;

  FCursorRow := 0;
  FCursorCol := 0;
  FScrollPos := 0;
  UpdateScrollbar;
  RecalcCellSize;
end;


procedure TKPAnsi.SetCols(Value: Integer);
begin
  if Value < 1 then
    Value := 1;
  if Value > 256 then
    Value := 256;
  if Value <> FCols then
  begin
    FCols := Value;
    ResizeScreen;
  end;
end;


procedure TKPAnsi.SetCursorVisible(Value: Boolean);
begin
  if Value <> FCursorVisible then
  begin
    FCursorVisible := Value;
    Invalidate;
  end;
end;


procedure TKPAnsi.SetRows(Value: Integer);
begin
  if Value < 1 then
    Value := 1;
  if Value > 255 then
    Value := 255;
  if Value <> FRows then
  begin
    FRows := Value;
    ResizeScreen;
  end;
end;


procedure TKPAnsi.SetScrollbackSize(Value: Integer);
begin
  if Value < 0 then
    Value := 0;
  FScrollbackSize := Value;
  TrimScrollback;
end;


procedure TKPAnsi.TrimScrollback;
var
  Line: PTermLine;
begin
  while FScrollback.Count > FScrollbackSize do
  begin
    Line := FScrollback[0];
    FreeMem(Line, SizeOf(TTermLineRec));
    FScrollback.Delete(0);
  end;
end;


procedure TKPAnsi.UpdateScrollbar;
var
  SbkCount: Integer;
begin
  if not HandleAllocated then
    Exit;
  SbkCount := FScrollback.Count;
  if SbkCount > 0 then
  begin
    SetScrollRange(Handle, sb_Vert, 0, SbkCount, False);
    SetScrollPos(Handle, sb_Vert, SbkCount - FScrollPos, True);
  end
  else
  begin
    SetScrollRange(Handle, sb_Vert, 0, 0, False);
    SetScrollPos(Handle, sb_Vert, 0, True);
  end;
end;


procedure TKPAnsi.WMEraseBkgnd(var Msg: TWMEraseBkgnd);
begin
  { Suppress background erase -- double-buffered Paint covers everything }
  Msg.Result := 1;
end;


procedure TKPAnsi.WMGetDlgCode(var Msg: TMessage);
begin
  Msg.Result := dlgc_WantArrows or dlgc_WantTab or dlgc_WantChars;
end;


procedure TKPAnsi.WMTimer(var Msg: TWMTimer);
begin
  FBlinkOn := not FBlinkOn;

  { Text blink runs at half the cursor rate (every other tick) so }
  { blinking text toggles roughly once per second.                 }
  Inc(FBlinkCount);
  if FBlinkCount >= 2 then
  begin
    FBlinkCount  := 0;
    FTextBlinkOn := not FTextBlinkOn;
  end;

  { Always repaint: cursor blink and text blink both need it }
  Invalidate;
end;


procedure TKPAnsi.WMVScroll(var Msg: TWMScroll);
var
  SbkCount: Integer;
  NewPos:   Integer;
begin
  SbkCount := FScrollback.Count;
  if SbkCount = 0 then
    Exit;

  NewPos := FScrollPos;
  case Msg.ScrollCode of
    sb_LineUp:
      Inc(NewPos);
    sb_LineDown:
      Dec(NewPos);
    sb_PageUp:
      Inc(NewPos, FRows);
    sb_PageDown:
      Dec(NewPos, FRows);
    sb_ThumbPosition, sb_ThumbTrack:
      NewPos := SbkCount - Msg.Pos;
    sb_Top:
      NewPos := SbkCount;
    sb_Bottom:
      NewPos := 0;
  end;

  if NewPos < 0 then
    NewPos := 0;
  if NewPos > SbkCount then
    NewPos := SbkCount;

  if NewPos <> FScrollPos then
  begin
    FScrollPos := NewPos;
    SetScrollPos(Handle, sb_Vert, SbkCount - FScrollPos, True);
    Invalidate;
  end;
end;


procedure TKPAnsi.Write(const S: string);
begin
  if Length(S) > 0 then
    ParseData(S);
end;


{ ----------------------------------------------------------------------- }
{ Component registration                                                   }
{ ----------------------------------------------------------------------- }

procedure Register;
begin
  RegisterComponents('KP', [TKPAnsi]);
end;

end.