{
    This file is part of the Free Pascal Integrated Development Environment
    Copyright (c) 2000 by Berczi Gabor

    Help support for Norton Guide (.NG) files

    See the file COPYING.FPC, included in this distribution,
    for details about the copyright.

    This program 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.

 **********************************************************************}
{$R-}
unit WNGHelp;

interface

uses Objects,
     WUtils,WHelp;

const
      NGFileSignature = 'NG';
      NGXORByte       = $1a;

      NGMinRecordSize = $1a;

      ng_rtContainer    = Byte ($0);
      ng_rtTopic        = Byte ($1);

type
      TNGFileHeader = packed record
        Signature     : array[1..2] of char;
        Unknown       : word;
        Version       : word;
        MenuCount     : word;
        GuideName     : array[8..47] of char;
        Credits       : array[48..377] of char;
      end;

      TNGRecordHeader = packed record
        RecType      : word;
        RecLength    : word;
      end;

      TNGContainerItem = packed record
        EntryNameOfs  : word; { relative in record }
        SubItemsOfs   : longint; { file offset to a new record header }
      end;

      PNGContainerRecord = ^TNGContainerRecord;
      TNGContainerRecord = packed record
        ItemCount     : word;
        Unknown       : word;
        IndexInParent : integer;
        ParentOfs     : longint;
        MenuNo        : integer;{ belongs to menu # }
        MenuItemNo    : integer;{ belongs to menu item # }
        Unknown2      : array[18..25] of byte;
        Items         : array[0..0] of TNGContainerItem;
      end;

      TNGTopicRecord = packed record
        NumberOfLines : word;
        SeeAlsoOfs    : word;
        IndexInParent : integer;
        ParentOfs     : longint;
        MenuNo        : integer;{ belongs to menu # }
        MenuItemNo    : integer;{ belongs to menu item # }
        PrevTopicOfs  : longint;
        NextTopicOfs  : longint;
        TopicLines    : record end;
        { array of TNGSeeAlsoRec }
      end;

      PNGSeeAlsoRec = ^TNGSeeAlsoRec;
      TNGSeeAlsoRec = packed record
        EntryCount    : word;
        Entries       : record end;
        { array of LinkedRecOfs  : longint; }
        { array of LinkNames : ASCIIZ; }
      end;

      PContainerItemRec = ^TContainerItemRec;
      TContainerItemRec = record
        Name     : string;
        FilePos  : longint;
        Container: PNGContainerRecord;
      end;

      PLinkRec = ^TLinkRec;
      TLinkRec = record
        Name     : string;
        FilePos  : longint;
      end;

      PNGHelpFile = ^TNGHelpFile;
      TNGHelpFile = object(THelpFile)
        constructor Init(AFileName: string; AID: word);
        destructor  Done; virtual;
      public
        function    LoadIndex: boolean; virtual;
        function    ReadTopic(T: PTopic): boolean; virtual;
      private
        F: PStream;
        Header: TNGFileHeader;
        FirstRecordPos: longint;
        IndexLoaded: boolean;
{        NextHelpCtx: longint;}
        function ReadHeader: boolean;
        function ReadContainer(EnumProc: pointer): boolean;
        function ReadTopicRec(LineEnumProc: pointer; LinkEnumProc: pointer): boolean;
        function ReadRecord(var R: TRecord; ReadData: boolean): boolean;
      end;

    TNGGetAttrColorProc = function(Attr: char; var Color: byte): boolean;

function DefNGGetAttrColor(Attr: char; var Color: byte): boolean;

const NGGetAttrColor : TNGGetAttrColorProc = {$ifdef fpc}@{$endif}DefNGGetAttrColor;

procedure RegisterHelpType;

implementation


function DefNGGetAttrColor(Attr: char; var Color: byte): boolean;
begin
  DefNGGetAttrColor:=false;
end;

function NGDecompressStr(const S: string): string;
var NS: string;
    I: sw_integer;
begin
  NS:='';
  I:=1;
  while (I<=length(S)) do
  begin
    if S[I]=#255 then
      begin
        NS:=NS+CharStr(' ',ord(S[I+1]));
        Inc(I);
      end
    else
      NS:=NS+S[I];
    Inc(I);
  end;
  NGDecompressStr:=NS;
end;

function TranslateStr(const S: string): string;
var NS: string;
    I: sw_integer;
    InHiLite: boolean;
    Color: byte;
begin
  NS:=''; InHiLite:=false;
  I:=1;
  while (I<=length(S)) do
  begin
    case S[I] of
      '^'  : begin
               Inc(I);
               case S[I] of
                 '^' : NS:=NS+'^';
                 'A'..'Z',
                 'a'..'z' :
                       begin
                         if InHiLite then
                           NS:=NS+hscNormText
                         else
                           if NGGetAttrColor(S[I],Color) then
                             NS:=NS+hscTextColor+chr(Color);
                         InHiLite:=not InHiLite;
                       end;
               else
                 NS:=NS;
               end;
             end;
    else NS:=NS+S[I];
    end;
    Inc(I);
  end;
  if InHiLite then NS:=NS+hscNormText;
  TranslateStr:=NS;
end;

procedure TranslateLines(P: PUnsortedStringCollection);
var S: string;
    I: sw_integer;
begin
  for I:=0 to P^.Count-1 do
  begin
    S:=GetStr(P^.At(I));
    P^.AtFree(I);
    P^.AtInsert(I,NewStr(TranslateStr(S)));
  end;
end;

constructor TNGHelpFile.Init(AFileName: string; AID: word);
var OK: boolean;
begin
  if inherited Init(AID)=false then Fail;
  F:=New(PFastBufStream, Init(AFileName, stOpenRead, HelpStreamBufSize));
  OK:=F<>nil;
  if OK then OK:=(F^.Status=stOK);
  if OK then
    begin
      OK:=ReadHeader;
      if OK then
        FirstRecordPos:=F^.GetPos;
    end;
  if OK=false then
  begin
    Done;
    Fail;
  end;
end;

function TNGHelpFile.ReadHeader: boolean;
var OK: boolean;
begin
  F^.Read(Header,sizeof(Header));
  OK:=(F^.Status=stOK);
  OK:=OK and (Header.Signature=NGFileSignature);
  ReadHeader:=OK;
end;

function TNGHelpFile.ReadContainer(EnumProc: pointer): boolean;
var OK: boolean;
    R: TRecord;
    I: longint;
    P: pointer;
    CIR: TContainerItemRec;
begin
  OK:=ReadRecord(R, true);
  if OK then
  with TNGContainerRecord(R.Data^) do
  begin
    I:=0;
    while (I<ItemCount) do
    with Items[I] do
    begin
      P:=@(PByteArray(R.Data)^[NGMinRecordSize-sizeof(TNGRecordHeader)+EntryNameOfs]);
      FillChar(CIR,sizeof(CIR),0);
      with CIR do
      begin
        Container:=R.Data;
        Name:=NGDecompressStr(StrPas(P));
        FilePos:=SubItemsOfs;
      end;
      CallPointerLocal(EnumProc,get_caller_frame(get_frame,get_pc_addr),@CIR);
      Inc(I);
    end;
  end;
  DisposeRecord(R);
  ReadContainer:=OK;
end;

function TNGHelpFile.ReadTopicRec(LineEnumProc, LinkEnumProc: pointer): boolean;
var OK: boolean;
    R: TRecord;
    I: sw_integer;
    LineP: pointer;
    S: string;
    ParamS: string;
    NextLinkOfsPtr,NextLinkNamePtr: pointer;
    SeeAlso: PNGSeeAlsoRec;
    LR: TLinkRec;
begin
  OK:=ReadRecord(R, true);
  if OK then
  with TNGTopicRecord(R.Data^) do
  begin
    LineP:=@TopicLines;
    if Assigned(LineEnumProc) then
    for I:=1 to NumberOfLines do
    begin
      S:=StrPas(LineP);
      ParamS:=NGDecompressStr(S);
      CallPointerLocal(LineEnumProc,get_caller_frame(get_frame,get_pc_addr),@ParamS);
      Inc(Ptrint(LineP),length(S)+1);
    end;
    if Assigned(LinkEnumProc) and (SeeAlsoOfs>0) then
    begin
      SeeAlso:=@PByteArray(R.Data)^[NGMinRecordSize-sizeof(TNGRecordHeader)+SeeAlsoOfs];
      NextLinkOfsPtr:=@SeeAlso^.Entries;
      NextLinkNamePtr:=@PByteArray(NextLinkOfsPtr)^[SeeAlso^.EntryCount*4];
      for I:=1 to SeeAlso^.EntryCount do
      begin
        FillChar(LR,sizeof(LR),0);
        S:=StrPas(NextLinkNamePtr);
        LR.Name:=S;
        Move(NextLinkOfsPtr^,LR.FilePos,4);
        CallPointerLocal(LinkEnumProc,get_caller_frame(get_frame,get_pc_addr),@LR);
        Inc(Ptrint(NextLinkNamePtr),length(S)+1);
        Inc(Ptrint(NextLinkOfsPtr),4);
      end;
    end;
  end;
  DisposeRecord(R);
  ReadTopicRec:=OK;
end;

function TNGHelpFile.ReadRecord(var R: TRecord; ReadData: boolean): boolean;
var OK: boolean;
    H: TNGRecordHeader;
    I: sw_integer;
begin
  FillChar(R, SizeOf(R), 0);
  F^.Read(H,SizeOf(H));
  OK:=F^.Status=stOK;
  if OK then
    for I:=0 to SizeOf(H)-1 do
      PByteArray(@H)^[I]:=PByteArray(@H)^[I] xor NGXORByte;
  if OK then
  begin
    R.SClass:=H.RecType; R.Size:=H.RecLength+(NGMinRecordSize-sizeof(TNGRecordHeader));
    if (R.Size>0) and ReadData then
    begin
      GetMem(R.Data,R.Size);
      F^.Read(R.Data^,R.Size);
      if R.Size>0 then
      for I:=0 to R.Size-1 do
        PByteArray(R.Data)^[I]:=PByteArray(R.Data)^[I] xor NGXORByte;
      OK:=F^.Status=stOK;
    end;
    if OK=false then DisposeRecord(R);
  end;
  ReadRecord:=OK;
end;

function TNGHelpFile.LoadIndex: boolean;
{function FormatAlias(Alias: string): string;
var StartP,EndP: sw_integer;
begin
  repeat
    StartP:=Pos('  ',Alias);
    if StartP>0 then
    begin
      EndP:=StartP;
      while (EndP+1<=length(Alias)) and (Alias[EndP+1]=' ') do Inc(EndP);
      Alias:=copy(Alias,1,StartP-1)+' | '+copy(Alias,EndP+1,High(Alias));
    end;
  until StartP=0;
  if Assigned(HelpFacility) then
    if length(Alias)>HelpFacility^.IndexTabSize-4 then
      Alias:=Trim(copy(Alias,1,HelpFacility^.IndexTabSize-4-2))+'..';
  FormatAlias:=Alias;
end;}
procedure AddToIndex(P: PContainerItemRec);
var S: string;
begin
  S:=Trim(P^.Name);
  S:=TranslateStr(S);
  S:=Trim({FormatAlias}(S));
  if (S<>'') and (P^.FilePos<>-1) then
    begin
{      Inc(NextHelpCtx);}
      AddIndexEntry(S,P^.FilePos);
      AddTopic(P^.FilePos,P^.FilePos,'',nil,0);
    end;
end;
var OK: boolean;
    FS: longint;
    R: TRecord;
    L: longint;
begin
  if IndexLoaded then OK:=true else
  begin
    FS:=F^.GetSize;
    OK:=FirstRecordPos<>0;

    while OK do
    begin
      L:=F^.GetPos;
      if (L>=FS) then Break;
      OK:=ReadRecord(R,false);
      if (OK=false) then Break;
      case R.SClass of
        ng_rtContainer : begin F^.Seek(L); OK:=ReadContainer(@AddToIndex); end;
        ng_rtTopic     : ;
      else
       begin
       {$ifdef DEBUGMSG}
         ClearFormatParams;
         AddFormatParamInt(R.SClass);
         AddFormatParamInt(L);
         AddFormatParamInt(R.Size);
         ErrorBox('Uknown help record tag %x encountered, '+
                  'offset %x, size %d',@FormatParams);
       {$else}
         {Skip};
       {$endif}
       end;
      end;
      if OK then
         begin
           Inc(L, sizeof(TNGRecordHeader)+R.Size); F^.Seek(L);
           OK:=(F^.Status=stOK);
         end;
    end;
    IndexLoaded:=OK;
  end;
  LoadIndex:=OK;
end;

function TNGHelpFile.ReadTopic(T: PTopic): boolean;
function ExtractStr(var Buf; BufSize: word): string;
var S: string;
    I,Size: integer;
    StartP,EndP: sw_integer;
begin
  S:='';
  Size:=BufSize;
  while (PByteArray(@Buf)^[Size-1]=0) and (Size>0) do
    Dec(Size);
  S:=MemToStr(Buf,Size);

  S:=NGDecompressStr(S);

  for I:=1 to length(S) do
    if S[I]=#0 then S[I]:=#32;

  { kill long spaces }
  repeat
    StartP:=Pos('  ',S);
    if StartP>0 then
    begin
      EndP:=StartP;
      while (EndP+1<=length(S)) and (S[EndP+1]=' ') do Inc(EndP);
      S:=copy(S,1,StartP-1)+hscLineBreak+copy(S,EndP+1,High(S));
    end;
  until StartP=0;

  S:=Trim(S);

  ExtractStr:=S;
end;
var Lines: PUnsortedStringCollection;
procedure AddLine(const S: string);
begin
  Lines^.InsertStr(S);
end;
procedure AddToTopic(P: PContainerItemRec);
begin
  AddLine(hscLink+Trim(P^.Name)+hscLink);
  AddLinkToTopic(T,ID,P^.FilePos);
end;
procedure AddTopicLine(P: PString);
begin
  AddLine(' '+GetStr(P));
end;
var LinkCount: sw_integer;
procedure AddLink(P: PLinkRec);
begin
  Inc(LinkCount);
  if LinkCount=1 then
  begin
    AddLine('');
    AddLine(' See also :');
  end;
  AddLine('  '+hscLink+Trim(P^.Name)+hscLink);
  AddLinkToTopic(T,ID,P^.FilePos);
end;
var OK: boolean;
    R: TRecord;
begin
  LinkCount:=0;
  New(Lines, Init(100,100));
  F^.Seek(T^.FileOfs); OK:=F^.Status=stOK;
  if OK then OK:=ReadRecord(R,false);
  case R.SClass of
      ng_rtContainer :
        begin
          F^.Seek(T^.FileOfs);
          AddLine('');
          OK:=ReadContainer(@AddToTopic);
          RenderTopic(Lines,T);
        end;
      ng_rtTopic     :
        begin
          F^.Seek(T^.FileOfs);
          AddLine('');
          OK:=ReadTopicRec(@AddTopicLine,@AddLink);
          TranslateLines(Lines);
          AddLine('');
          { include copyright info }
{          AddLine(CharStr('Ä',80));
          AddLine(ExtractStr(Header.GuideName,sizeof(Header.GuideName)));
          AddLine(ExtractStr(Header.Credits,sizeof(Header.Credits)));}
          RenderTopic(Lines,T);
        end;
  else OK:=false;
  end;
  Dispose(Lines, Done);
  ReadTopic:=OK;
end;

destructor TNGHelpFile.Done;
begin
  if Assigned(F) then Dispose(F, Done); F:=nil;
  inherited Done;
end;

function CreateProc(const FileName,Param: string;Index : longint): PHelpFile;
begin
  CreateProc:=New(PNGHelpFile, Init(FileName,Index));
end;

procedure RegisterHelpType;
begin
  RegisterHelpFileType({$ifdef FPC}@{$endif}CreateProc);
end;

END.
