// ====================================================================
// Mystic BBS Software               Copyright 1997-2013 By James Coyle
// ====================================================================
//
// This file is part of Mystic BBS.
//
// Mystic BBS is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Mystic BBS is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Mystic BBS.  If not, see <http://www.gnu.org/licenses/>.
//
// ====================================================================
Unit m_MenuHelp;

{$I M_OPS.PAS}

Interface

Uses
  m_Input,
  m_Output;

Const
  mMaxHelpTest      = 200;
  mMaxHelpKeyLen    = 20;
  mMaxHelpLineLinks = 10;

Type
  TLinkInfoRec = Record
    Key     : String[mMaxHelpKeyLen];
    LinkPos : Byte;
    LinkLen : Byte;
  End;

  TLineInfoRec = Record
    Text  : String;
    Links : Byte;
    Link  : Array[1..mMaxHelpLineLinks] of TLinkInfoRec
  End;

  TMenuHelp = Class
    HelpFile : Text;
    CurKey   : String[mMaxHelpKeyLen];
    Text     : Array[1..mMaxHelpTest] of TLineInfoRec;
    Lines    : Word;
    Console  : TOutput;
    Input    : TInput;
    WinX1    : Byte;
    WinY1    : Byte;
    WinX2    : Byte;
    WinY2    : Byte;

    Constructor Create (Var C: TOutput; Var I: TInput);
    Destructor  Destroy; Override;

    Function    ReadKeywordData : Boolean;
    Procedure   OpenHelp   (Str: String);
    Function    StripLinks (Str: String) : String;
  End;

Implementation

Uses
  m_Strings;

Constructor TMenuHelp.Create (Var C: TOutput; Var I: TInput);
Begin
  Inherited Create;

  Console := C;
  Input   := I;
  WinX1   := 1;
  WinY1   := 11;
  WinX2   := 79;
  WinY2   := 23;
End;

Destructor TMenuHelp.Destroy;
Begin
  Inherited Destroy;
End;

Function TMenuHelp.StripLinks (Str: String) : String;
Var
  A : Byte;
  B : Byte;
Begin
  A := 255;

  While A > 0 Do Begin
    A := Pos('<link=', Str);

    If A > 0 Then Begin
      B := 1;
      While Str[A + 6 + B] <> '>' Do Inc(B);
      Delete (Str, A, 7 + B);

      A := Pos('</link>', Str);
      If A = 0 Then A := Length(Str);
      Delete (Str, A, 7);
    End;
  End;

  Result := Str;
End;

Function TMenuHelp.ReadKeywordData : Boolean;
Var
  Str    : String;
  Key    : String;
  Temp1  : Byte;
  Temp2  : Byte;
  Done   : Boolean;
  Buffer : Array[1..4 * 1024] of Char;
Begin
  SetTextBuf (HelpFile, Buffer);
  Reset      (HelpFile);

  Done := False;

  While Not Eof(HelpFile) And Not Done Do Begin
    ReadLn (HelpFile, Str);

    Temp1 := Pos('<keyword> ', Str);

    If Temp1 = 0 Then Continue;

    Key := Copy(Str, Temp1 + 10, Length(Str));

    If Key <> CurKey Then Continue;

    Lines := 0;

    While Not Eof(HelpFile) Do Begin
      ReadLn (HelpFile, Str);

      If Pos('<end>', Str) > 0 Then Begin
        Done := True;
        Break;
      End;

      Inc (Lines);

      Text[Lines].Text  := StripLinks(Str);
      Text[Lines].Links := 0;
      Str               := strStripPipe(Str);

      Repeat
        Temp1 := Pos('<link=', Str);

        If Temp1 = 0 Then Break;

        Inc (Text[Lines].Links);

        Text[Lines].Link[Text[Lines].Links].LinkPos := Temp1;

        Temp2 := 0;
        Key   := '';

        While Str[Temp1 + 6 + Temp2] <> '>' Do Begin
          Key := Key + Str[Temp1 + 6 + Temp2];
          Inc (Temp2);
        End;

        Delete (Str, Temp1, 7 + Temp2);
        Temp2 := Pos('</link>', Str);
        Delete (Str, Temp2, 7);

        Text[Lines].Link[Text[Lines].Links].LinkLen := Temp2 - Temp1;
        Text[Lines].Link[Text[Lines].Links].Key     := Key;
      Until False;
    End;
  End;

  Close (HelpFile);

  Result := Done And (Lines > 0);
End;

Procedure TMenuHelp.OpenHelp (Str: String);
Var
  FN       : String;
  Keyword  : String;
  TopPage  : Integer;
  CurLine  : Integer;
  CurLPos  : Byte = 1;
  WinSize  : Integer;
  LastPos  : Byte;
  LastKey  : Array[1..10] of String[mMaxHelpKeyLen];

  Procedure LinkOFF (LineNum: Word; YPos, LPos: Byte);
  Var
    S : String;
  Begin
    If Text[LineNum].Links = 0 Then Exit;

    With Text[LineNum] Do
      S := Copy(strStripPipe(Text), Link[LPos].LinkPos, Link[LPos].LinkLen);

    Console.WriteXY (WinX1 + Text[LineNum].Link[LPos].LinkPos - 1, YPos, 9, S);
  End;

  Procedure DrawPage;
  Var
    Count1 : Byte;
    Count2 : Byte;
  Begin
    For Count1 := 1 to WinSize Do Begin
      If TopPage + Count1 - 1 <= Lines Then Begin
        Console.WriteXYPipe (WinX1, Count1 + WinY1 - 1, 7, WinX2 - WinX1 + 1, Text[TopPage + Count1 - 1].Text);

        For Count2 := 1 to Text[TopPage + Count1 - 1].Links Do
          LinkOFF (TopPage + Count1 - 1, Count1 + WinY1 - 1, Count2);
      End Else
        Console.WriteXYPipe (WinX1, Count1 + WinY1 - 1, 7, WinX2 - WinX1 + 1, '');
    End;
  End;

  Procedure LinkON;
  Var
    S : String;
  Begin
    With Text[TopPage + CurLine - 1] Do
      S := Copy(strStripPipe(Text), Link[CurLPos].LinkPos, Link[CurLPos].LinkLen);

    Console.WriteXY  (WinX1 + Text[TopPage + CurLine - 1].Link[CurLPos].LinkPos - 1, WinY1 + CurLine - 1, 30, S);
    Console.CursorXY (WinX1 + Text[TopPage + CurLine - 1].Link[CurLPos].LinkPos - 1, WinY1 + CurLine - 1);
  End;

  Procedure UpdateCursor;
  Begin
    If Text[TopPage + CurLine - 1].Links > 0 Then Begin
      If CurLPos > Text[TopPage + CurLine - 1].Links Then CurLPos := Text[TopPage + CurLine - 1].Links;
      If CurLPos < 1 Then CurLPos := 1;

      LinkON;
    End Else Begin
      CurLPos := 1;

      Console.CursorXY (WinX1, WinY1 + CurLine - 1);
    End;
  End;

  Procedure PageDown;
  Begin
    If Lines > WinSize Then Begin
      If TopPage + WinSize <= Lines - WinSize Then Begin
        Inc (TopPage, WinSize);
      End Else Begin
        TopPage := Lines - WinSize + 1;
        CurLine := WinSize;
      End;
    End Else
      CurLine := Lines;
  End;

Var
  OK    : Boolean;
  Count : Byte;
  Ch    : Char;
Begin
  FillChar(LastKey, SizeOf(LastKey), 0);

  FN       := strWordGet(1, Str, ';');
  Keyword  := strWordGet(2, Str, ';');

  Assign (HelpFile, FN + '.hlp');
  {$I-} Reset (HelpFile); {$I+}

  If IoResult <> 0 Then Exit;

  Close (HelpFile);

  TopPage := 1;
  CurLine := 1;
  LastPos := 0;
  WinSize := WinY2 - WinY1 + 1;
  CurKey  := Keyword;
  OK      := ReadKeywordData;

  If Not OK and (CurKey <> 'INDEX') Then Begin
    CurKey := 'INDEX';
    OK     := ReadKeywordData;
  End;

  If Not OK Then Exit;

  While OK Do Begin
    TopPage := 1;
    CurLine := 1;

    DrawPage;

    For Count := 1 to WinSize Do
      If Text[Count].Links > 0 Then Begin
        CurLine := Count;
        Break;
      End;

    UpdateCursor;

    Repeat
      Ch := Input.ReadKey;

      Case Ch of
        #00 : Case Input.ReadKey of
                #71 : If (TopPage > 1) or (CurLine > 1) Then Begin
                        TopPage := 1;
                        CurLine := 1;

                        DrawPage;
                        UpdateCursor;
                      End;
                #72 : Begin
                        If (CurLine = 1) and (TopPage > 1) Then Begin
                          Dec (TopPage);

                          DrawPage;

                          UpdateCursor;
                        End Else If CurLine > 1 Then Begin
                          LinkOFF(TopPage + CurLine - 1, WinY1 + CurLine - 1, CurLPos);

                          Dec (CurLine);

                          UpdateCursor;
                        End;
                      End;
                #73 : Begin
                        If TopPage - WinSize > 0 Then Begin
                          Dec (TopPage, WinSize);

                          DrawPage;
                          UpdateCursor;
                        End Else If CurLine > 1 Then Begin
                          TopPage := 1;
                          CurLine := 1;

                          DrawPage;
                          UpdateCursor;
                        End;
                      End;
                #75 : If (CurLPos > 1) and (Text[TopPage + CurLine - 1].Links > 0) Then Begin
                        LinkOFF(TopPage + CurLine - 1, WinY1 + CurLine - 1, CurLPos);

                        Dec(CurLPos);

                        LinkON;
                      End;
                #77 : If CurLPos < Text[TopPage + CurLine - 1].Links Then Begin
                        LinkOFF(TopPage + CurLine - 1, WinY1 + CurLine - 1, CurLPos);

                        Inc(CurLPos);

                        LinkON;
                      End;
                #79 : If TopPage + WinSize <= Lines Then Begin
                        Repeat
                          PageDown;
                        Until TopPage >= Lines - WinSize - 1;

                        DrawPage;
                        UpdateCursor;
                      End Else
                      If TopPage + CurLine <= Lines Then Begin
                        LinkOFF (TopPage + CurLine - 1, WinY1 + CurLine - 1, CurLPos);

                        CurLine := Lines - TopPage + 1;

                        UpdateCursor;
                      End;
                #80 : Begin
                        If (CurLine = WinSize) and (TopPage + WinSize <= Lines) Then Begin
                          Inc(TopPage);

                          DrawPage;

                          UpdateCursor;
                        End Else
                        If (CurLine < WinSize) And (TopPage + CurLine <= Lines) Then Begin
                          LinkOFF(TopPage + CurLine - 1, WinY1 + CurLine - 1, CurLPos);

                          Inc(CurLine);

                          UpdateCursor;
                        End;
                      End;
                #81 : If TopPage + WinSize <= Lines Then Begin
                        PageDown;

                        DrawPage;

                        UpdateCursor;
                      End Else
                      If TopPage + CurLine <= Lines Then Begin
                        LinkOFF (TopPage + CurLine - 1, WinY1 + CurLine - 1, CurLPos);

                        CurLine := Lines - TopPage + 1;

                        UpdateCursor;
                      End;
              End;
        #08 : Begin
                If LastPos = 0 Then
                  CurKey := Keyword
                Else Begin
                  CurKey := LastKey[LastPos];

                  Dec (LastPos);
                End;

                OK := ReadKeywordData;

                If Not OK Then Begin
                  CurKey := 'INDEX';
                  OK     := ReadKeywordData;
                End;

                Break;
              End;
        #13 : If Text[TopPage + CurLine - 1].Links > 0 Then Begin
                If Text[TopPage + CurLine - 1].Link[CurLPos].Key = '@PREV' Then Begin
                  If LastPos = 0 Then
                    CurKey := Keyword
                  Else Begin
                    CurKey := LastKey[LastPos];

                    Dec (LastPos);
                  End;
                End Else Begin
                  If LastPos < 10 Then
                    Inc (LastPos)
                  Else
                    For Count := 1 to 9 Do LastKey[Count] := LastKey[Count + 1];

                  LastKey[LastPos] := CurKey;

                  CurKey := Text[TopPage + CurLine - 1].Link[CurLPos].Key;
                End;

                OK := ReadKeywordData;

                If Not OK Then Begin
                  CurKey := 'INDEX';
                  OK     := ReadKeywordData;
                End;

                Break;
              End;
        #27 : Begin
                OK := False;

                Break;
              End;
      End;
    Until False;
  End;
End;

End.