// functions imported from C:

function isspace(ch: integer): integer; cdecl;
 external 'msvcrt.dll' name 'isspace';

function strchr(s: PChar; ch: integer): PChar; cdecl;
 external 'msvcrt.dll' name 'strchr';

function isdigit(ch: integer): integer; cdecl;
 external 'msvcrt.dll' name 'isdigit';

function strlwr(s1: PChar): PChar; cdecl;
 external 'msvcrt.dll' name '_strlwr';

function isctrl(ch: integer): integer; cdecl;
 external 'msvcrt.dll' name 'iscntrl';

function c_strlen(s: PChar): integer; cdecl;
 external 'msvcrt.dll' name 'strlen';


// remove trailing spaces from null-terminated string
function TrimRightSz(psz: PChar): PChar;
var
  pch: PChar;
begin
  if psz^<>#0 then begin
    pch:=psz+strlen(psz)-1;
    while ((isspace(integer(pch^))<>0)or(isctrl(integer(pch^))<>0))
    and(pch>psz) do begin
      pch^:=#0;
      Dec(pch);
    end;
  end;
  Result:=psz;
end;

function NextToken_(var psz: PChar; ch: string): PChar;
begin
  Result:= TrimRightSz(NextParsel(psz, PChar(ch)));
end;

// returns the next "parsel" of characters up to the specified delimiter(s),
// and removes that parsel from input string.
// skips leading spaces even if a space is one of the delimiters;
// ignores delimiters within quotes;
// if delimiter string is empty, returns entire input string (minus leading spaces)
function NextParsel(var psz: PChar; pszDelimiters: PChar): PChar; stdcall;
var
  bQuoted: boolean;
begin
  bQuoted:=false;

  // skip leading spaces
  while isspace(Integer(psz^))<>0 do Inc(psz);
  Result := psz;

  while psz^<>#0 do begin
    if psz^='"' then bQuoted := not bQuoted;
    if (strchr(pszDelimiters,Integer(psz^))<>nil) and not bQuoted then break;
    Inc(psz);
  end;

  if psz^<>#0 then begin
    psz^:=#0;
    Inc(psz);
  end;

end;

// translate AW coords (s) -> SDK coords (sWorld,Z,X,Y,W);
// (Z=NS, X=WE, Y=Alt W=yaw);
// returns true if successful, false if fails (invalid input)
function GetSDKCoords(s: string; var sWorld: string;
                                 var Z: integer; var X: integer;
                                 var Y: integer; var W: integer): boolean;
var
  sz: array [0..200] of char;
  psz1,psz: PChar;
  b: boolean;
  i: integer;
  dZ,dX,dY,dW: double;
begin
  StrLCopy(@sz,PChar(Trim(s)),200);
  psz1:=strlwr(sz);

  psz:=NextToken_(psz1,' '); // get world name or Z
  if isdigit(integer(psz^))=0 then begin
    // must be a world name
    sWorld:=Copy(psz,1,strlen(psz));
    psz:=NextToken_(psz1,' '); // get next parsel, hopefully Z coord
  end else
    sWorld:=''; // first thing was Z

  Z:=0;
  X:=0;
  Y:=0;
  W:=0;
  Result:=false;

  i:=c_strlen(psz)-1;
  if i<0 then exit;
  if psz[i]='s' then begin // it's south
    b:=true;
    psz[i]:=#0;
  end else begin
    if psz[i]<>'n' then exit; // neither south nor north, error
    b:=false;
    psz[i]:=#0;
  end;
  try
    dZ:=StrToFloat(string(psz)); // read the number
  except
    exit;
  end;
  if b then dZ:=-dZ; // invert it if it was south

  if psz1^=#0 then exit; // only Z given, error

  psz:=NextToken_(psz1,' '); // get X

  i:=c_strlen(psz)-1;
  if i<0 then exit;
  if psz[i]='e' then begin // it's east
    b:=true;
    psz[i]:=#0;
  end else begin
    if psz[i]<>'w' then exit; // neither east nor west, error
    b:=false;
    psz[i]:=#0;
  end;
  try
    dX:=StrToFloat(string(psz)); // read it
  except
    exit;
  end;
  if b then dX:=-dX; // invert it if it was east

  // default if none found
  dY:=0.0;
  dW:=0.0;

  if psz1^<>#0 then begin // there is an alt and/or yaw

    psz:=NextToken_(psz1,' '); // alt or maybe yaw

    i:=strlen(psz)-1;
    if psz[i]='a' then begin // it was alt
      b:=false;
      psz[i]:=#0;
    end else begin // it was yaw
      b:=true;
    end;

    try
      dY:=StrToFloat(string(psz));
    except
      exit;
    end;
    if b then begin
      dW:=dY; // it's yaw not alt
      dY:=0;
    end else

      // it was alt, so now look for yaw
      if psz1^<>#0 then begin
        psz:=NextToken_(psz1,' ');
        try
          dW:=StrToFloat(string(psz));
        except
          exit;
        end;
      end; // was no yaw, so use default

  end;

  Z:=INT_(dZ * 1000.0);
  X:=INT_(dX * 1000.0);
  Y:=INT_(dY * 100.0);
  W:=INT_(dW * 10.0);
  Result:=true;
end;


// the AW coords button:
procedure TfrmMain.btnAWCoordsClick(Sender: TObject);
var
  X,Y,Z,W: integer;
  s,sWorld: string;
begin
  GetAWCoords(edWorld.Text,spinNS.value,spinWE.Value,spinAlt.value,spinYaw.value,s);

  if not InputQuery('Coordinates','Enter AW-style coordinates',s) then
    exit;

  if GetSDKCoords(s,sWorld,Z,X,Y,W) then begin
    if sWorld<>'' then edWorld.Text:=sWorld;
    spinNS.value:=Z;
    spinWE.value:=X;
    spinAlt.value:=Y;
    spinYaw.value:=W;
  end else
    MessageDlg('Invalid AW coordinates',mtError,[mbOk],0);
end;