{
    fpGUI  -  Free Pascal GUI Toolkit

    Unit to handle command line processing

    Copyright (C) 2007 - 2010 See the file AUTHORS.txt, included in this
    distribution, for details of the copyright.

    See the file COPYING.modifiedLGPL, included in this distribution,
    for details about redistributing fpGUI.

    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.
}

{ TODO : Make sure Unicode parameter handling is supported. }

unit fpg_cmdlineparams;

{$mode objfpc}{$H+}

interface

uses
  Classes;

const
  ctiCommandLineParamPrefix = '-';

type

  TGfxCommandLineParams = class(TObject)
  private
    FsParams: string;
    FslParams: TStringList;
    procedure   ReadParams;
    function    WordExtract(const AInput: string; const APos: integer; const ADelims: string): string;
    function    WordCount(const AStrToProcess: string; ADelims: string): integer;
    function    WordPosition(const AN: integer; const AStr: string; ADelims: string): integer;
    function    ExtractChar(const AValue: string; const APos: integer): char;
    function    CharInStr(const AChr: char; const AStr: string): boolean;
    function    StripLeadingDelims(const AStrToProcess: string; ADelims: string): string;
    function    StripTrailingDelims(const AStrToProcess: string; ADelims: string): string;
    function    NumToken(const AValue, AToken: string): integer;
    function    Token(const AValue, AToken: string; const APos: integer): string;
    function    StrTran(AValue, ADel, AIns: string): string;
  public
    constructor Create;
    destructor  Destroy; override;
    function    IsParam(const AParam: string): boolean; overload;
    function    IsParam(const AParams: array of string): boolean; overload;
    function    GetParam(const AParam: string): string;
    property    Params: TStringList read FslParams;
    property    AsString: string read FsParams;
  end;


// Singleton
function gCommandLineParams: TGfxCommandLineParams;


implementation

uses
  SysUtils;

var
  uCommandLineParams: TGfxCommandLineParams;

// Singleton
function gCommandLineParams: TGfxCommandLineParams;
begin
  if uCommandLineParams = nil then
    uCommandLineParams := TGfxCommandLineParams.Create;
  result := uCommandLineParams;
end;

{ TGfxCommandLineParams }

constructor TGfxCommandLineParams.Create;
begin
  inherited;
  FslParams := TStringList.Create;
  ReadParams;
end;

destructor TGfxCommandLineParams.destroy;
begin
  FslParams.Free;
  inherited;
end;

function TGfxCommandLineParams.GetParam(const AParam: string): string;
begin
  result := FslParams.Values[ upperCase(AParam)];
end;

function TGfxCommandLineParams.IsParam(const AParam: string): boolean;
var
  i: integer;
begin
  result := false;
  for i := 0 to FslParams.Count - 1 do begin
    if FslParams.Names[i] = upperCase(AParam) then begin
      result := true;
      break; //==>
    end;
  end;
end;

function TGfxCommandLineParams.IsParam(const AParams: array of string): boolean;
var
  i: integer;
begin
  result := false;
  for i := Low(AParams) to High(AParams) do
    if IsParam(AParams[i]) then
    begin
      result := true;
      Exit; //==>
    end;
end;

procedure TGfxCommandLineParams.ReadParams;
var
  i: integer;
  j: integer;
  lsNameValue: string;
  lsValue: string;
  lsName: string;
const
  cDelim = ' ';
begin
  lsValue := '';
  FsParams := '';
  j := ParamCount;
  for i := 1 to j do begin
    if FsParams <> '' then FsParams := FsParams + cDelim;
    FsParams := FsParams + ParamStr(i);
  end ;

  j := WordCount(FsParams, ctiCommandLineParamPrefix);
  for i := 1 to j do begin
    lsNameValue := WordExtract(FsParams, i, ctiCommandLineParamPrefix);
    lsName := Token(lsNameValue, cDelim, 1);
    lsValue := copy(lsNameValue, length(lsName) + 1,
                     length(FsParams) - length(lsValue));

    lsValue := Trim(lsValue);
    lsName := StrTran(lsName, ctiCommandLineParamPrefix, '');
    lsName := upperCase(lsName);

    FslParams.Add(lsName + '=' + lsValue);
  end;
end;

function TGfxCommandLineParams.StrTran(AValue, ADel, AIns: string): string;
var
  i: integer;
  sToChange: string;
begin
  result := '';
  sToChange := AValue;
  i := pos(ADel, sToChange);
  while i <> 0 do
  begin
    result := result + copy(sToChange, 1, i-1) + AIns;
    delete(sToChange, 1, i+length(ADel)-1);
    i := pos(ADel, sToChange);
  end;
  result := result + sToChange;
end;

function TGfxCommandLineParams.NumToken(const AValue, AToken: string): integer;
var
  i, iCount: integer;
  lsValue: string;
begin
  result := 0;
  if AValue = '' then
    Exit; //==>

  iCount := 0;
  lsValue := AValue;
  i := pos(AToken, lsValue);
  while i <> 0 do
  begin
    delete(lsValue, i, length(AToken));
    inc(iCount);
    i := pos(AToken, lsValue);
  end;
  result := iCount + 1;
end;

function TGfxCommandLineParams.Token(const AValue, AToken: string;
    const APos: integer): string;
var
  i, iCount, iNumToken: integer;
  lsValue: string;
begin
  result := '';

  iNumToken := NumToken(AValue, AToken);
  if APos = 1 then
  begin
    if pos(AToken, AValue) = 0 then
      result := AValue
    else
      result := copy(AValue, 1, pos(AToken, AValue)-1);
  end
  else if (iNumToken < APos-1) or (APos<1) then
  begin
    result := '';
  end
  else
  begin
    { Remove leading blocks }
    iCount := 1;
    lsValue := AValue;
    i := pos(AToken, lsValue);
    while (i<>0) and (iCount<APos) do
    begin
      delete(lsValue, 1, i + length(AToken) - 1);
      inc(iCount);
      i := pos(AToken, lsValue);
    end;

    if (i=0) and (iCount=APos) then
      result := lsValue
    else if (i=0) and (iCount<>APos) then
      result := ''
    else
      result := copy(lsValue, 1, i-1);
  end;
end;

function TGfxCommandLineParams.WordExtract(const AInput: string;
    const APos: integer; const ADelims: string): string;
var
  iStart: integer;
  i: integer;
	iLen: integer;
begin
  result := '';

  // Find the starting pos of the Nth word
  iStart := WordPosition(APos, AInput, ADelims);

  if iStart <> 0 then
  begin
    i := iStart;
    iLen := length(AInput);
    // Build up result until we come to our next wordDelim
    // while (i <= iLen) and not(S[i] in ADelims) do begin
    while (i <= iLen) and not(CharInStr(ExtractChar(AInput, i), ADelims)) do
    begin
      result := result + ExtractChar(AInput, i);
      inc(i);
    end;
  end;
end;

function TGfxCommandLineParams.WordPosition(const AN: integer;
    const AStr: string; ADelims: string): integer;
var
  lCount: integer;
  lI: Word;
  lSLen: integer;
begin
  lCount  := 0;
  lI      := 1;
  Result  := 0;
  lSLen   := length(AStr);

  while (lI <= lSLen) and (lCount <> AN) do
  begin
    while (lI <= lSLen) and (CharInStr(ExtractChar(AStr, lI), ADelims)) do
    begin
      Inc(lI);
    end;

    // if we're not beyond end of S, we're at the start of a word
    if lI <= lSLen then
    begin
      Inc(lCount);
    end;

    // if not finished, find the end of the current word
    if lCount <> AN then
    begin
      while (lI <= lSLen) and not(CharInStr(ExtractChar(AStr, lI), ADelims)) do
      begin
        Inc(lI);
      end;
    end
    else
    begin
      Result := lI;
    end;
  end;
end;

function TGfxCommandLineParams.ExtractChar(const AValue: string;
    const APos: integer): char;
var
  lResult: string;
begin
  if APos > length(AValue) then
  begin
    result := ' ';
    exit;
   end;
  lResult := copy(AValue, APos, 1);
  result := lResult[1];
end;

function TGfxCommandLineParams.StripLeadingDelims(const AStrToProcess: string;
    ADelims: string): string;
var
  i: integer;
  lCharCurrent: char;
begin
  result := AStrToProcess;
  // Loop through each char in the string
  for i := 1 to length(AStrToProcess) do
  begin
    // Extract the current character
    lCharCurrent := ExtractChar(AStrToProcess, i);

    // Is this character a NON word delim?, then we have found the body of the string.
    if not CharInStr(lCharCurrent, ADelims) then
    begin
      result := copy(AStrToProcess, i,
                      length(AStrToProcess) - i + 1);
      exit; //==>
    // The current char is a word delim, but we are at the end of the string -
    // so no words
    end
    else
    begin
      if i = length(AStrToProcess) then
      begin
        result := '';
      end;
    end;
  end;
end;

// Strip any trailing ADelims
function TGfxCommandLineParams.StripTrailingDelims(const AStrToProcess: string;
    ADelims: string): string;
var
  i: integer;
  lCharCurrent: char;
begin
  result := AStrToProcess;
  // Loop through each char in the string
  for i := length(AStrToProcess) downto 1 do
  begin
    // Extract the current character
    lCharCurrent := ExtractChar(AStrToProcess, i);

    // Is this character a NON word delim?, then we have found the body of the string.
    if not CharInStr(lCharCurrent, ADelims) then
    begin
      result := copy(AStrToProcess, 1, i);
      exit; //==>
    // The current char is a word delim, but we are at the beginning of the string -
    // so no words
    end
    else
    begin
      if i = length(AStrToProcess) then
      begin
        result := '';
      end;
    end;
  end;
end;

// Given a set of word delimiters, return number of words in S
function TGfxCommandLineParams.WordCount(const AStrToProcess: string;
    ADelims: string): integer;
var
  i: integer;
  lCharLast: char;
  lCharCurrent: char;
  lStrToProcess: string;
begin
  // Strip any leading ADelims
  lStrToProcess := StripLeadingDelims(AStrToProcess, ADelims);
  lStrToProcess := StripTrailingDelims(lStrToProcess, ADelims);

  // If lStrToProcess is empty, then there are no words
  if lStrToProcess = '' then
  begin
    result := 0;
    Exit; //==>
  end;

  // lStrToProcess is not empty, therefore there must be at least one word
  // Every wordDelim we find equals another word:
  // 0 word delim := 1 word
  // 1 word delim := 2 words...
  result := 1;

  // lCharLast is used to check for more than 1 wordDelim together
  lCharLast := #0;

  for i := 1 to length(lStrToProcess) do
  begin
    lCharCurrent := ExtractChar(lStrToProcess, i);
    if CharInStr(lCharCurrent, ADelims) and not(CharInStr(lCharLast, ADelims)) then
    begin
      inc(result);
    end;
    lCharLast := lCharCurrent;
  end;
end;

// Is AChr in the string AStr ?
function TGfxCommandLineParams.CharInStr(const AChr: char; const AStr: string): boolean;
begin
  result := pos(AChr, AStr) <> 0;
end;


initialization

finalization
  uCommandLineParams.Free;

end.