unit Main;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Vcl.ExtCtrls, Vcl.Menus;

type
  TArr = array of Byte;
  TArrOfTheSets = array[0..1000] of Int64;

  TLab_5_2 = class(TForm)
    edAmountCells: TEdit;
    lbInf: TLabel;
    edAmountWays: TEdit;
    shLine: TShape;
    btnCountMoves: TButton;
    lbAmountMoves: TLabel;
    MainMenu1: TMainMenu;
    File1: TMenuItem;
    Open1: TMenuItem;
    Save1: TMenuItem;
    Help1: TMenuItem;
    Aboutauthor1: TMenuItem;
    Help2: TMenuItem;
    OpenFile: TOpenDialog;
    SaveFile: TSaveDialog;
    procedure edAmountCellsKeyPress(Sender: TObject; var Key: Char);
    procedure edAmountCellsKeyDown(Sender: TObject; var Key: Word;
      Shift: TShiftState);
    procedure edAmountCellsKeyUp(Sender: TObject; var Key: Word;
      Shift: TShiftState);
    procedure btnCountMovesClick(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure edAmountCellsChange(Sender: TObject);
    procedure Open1Click(Sender: TObject);
    procedure Save1Click(Sender: TObject);
    procedure FormClose(Sender: TObject; var Action: TCloseAction);
    procedure Aboutauthor1Click(Sender: TObject);
    procedure Help2Click(Sender: TObject);
    function  IsCorrectNumber(strNumber: string): Boolean;
  private
    { Private declarations }
  public
    { Public declarations }
  end;

  TCount = class
  private
    Arr: TArr;
    ArrOfTheSets: TArrOfTheSets;
    procedure SetArrWithZeros(var ArrOfTheSets: TArrOfTheSets);
    function CountAmountMoves(Arr: TArr): Int64;
  public
    function FindAmountMoves(N: Integer): Int64;
  end;

var
  Lab_5_2: TLab_5_2;
  CountObj: TCount;


implementation

{$R *.dfm}

procedure TCount.SetArrWithZeros(var ArrOfTheSets: TArrOfTheSets);
var
   index: Word;
begin
   for index := 0 to Length(ArrOfTheSets) do
      ArrOfTheSets[index] := 0;
end;

function TCount.CountAmountMoves(Arr: TArr): Int64;
begin
   if (Length(Arr) = 1) or (Length(Arr) = 0) then
      Result := 1
   else
   begin
      if ArrOfTheSets[Length(Arr)] = 0 then
         ArrOfTheSets[Length(Arr)] := CountAmountMoves(copy(Arr, 1, Length(Arr))) + CountAmountMoves(copy(Arr, 2, Length(Arr)));
      Result := ArrOfTheSets[Length(Arr)];
   end;
end;

function TCount.FindAmountMoves(N: Integer): Int64;
begin
   SetLength(Arr, N);
   SetArrWithZeros(ArrOfTheSets);
   ArrOfTheSets[0] := 1;
   ArrOfTheSets[1] := 1;
   Result := CountAmountMoves(Arr);
end;

procedure TLab_5_2.Aboutauthor1Click(Sender: TObject);
begin
    MessageBox(Handle, PChar('The author of this program id Vladislav Mironuk (851001)'),
               PChar('Error.'), MB_ICONINFORMATION);
end;

procedure TLab_5_2.btnCountMovesClick(Sender: TObject);
var
   Arr: TArr;
begin
   edAmountWays.Text := IntToStr(CountObj.FindAmountMoves(StrToInt(edAmountCells.Text)));
end;

procedure TLab_5_2.edAmountCellsChange(Sender: TObject);
begin
   edAmountWays.Text := '';
   if Length(edAmountCells.Text) = 0 then
      btnCountMoves.Enabled := False
   else
      btnCountMoves.Enabled := True
end;

procedure TLab_5_2.edAmountCellsKeyDown(Sender: TObject; var Key: Word;
  Shift: TShiftState);
begin
   edAmountCells.SelStart := (Length(edAmountCells.Text))
end;

procedure TLab_5_2.edAmountCellsKeyPress(Sender: TObject; var Key: Char);
begin
   if (Key = '0') and (Length(edAmountCells.Text) = 0) then
      Key := #0
end;

procedure TLab_5_2.edAmountCellsKeyUp(Sender: TObject; var Key: Word;
  Shift: TShiftState);
begin
   edAmountCells.SelStart := (Length(edAmountCells.Text) + 1)
end;

procedure TLab_5_2.FormClose(Sender: TObject; var Action: TCloseAction);
begin
   if MessageBox(Handle, PChar('Are you sure?'), PChar('Are you sure?'), MB_ICONINFORMATION + MB_YESNO) = mrNo then
      Action := caNone;
end;

procedure TLab_5_2.FormCreate(Sender: TObject);
begin
   CountObj := TCount.Create;
end;

procedure TLab_5_2.Help2Click(Sender: TObject);
const
   Msg1 = 'There is a strip of checkered paper with a width of one cell and a ';
   Msg2 = 'length of n cells. The first cage is a checker. With one move the ';
   Msg3 = 'piece can be moved one or two cells. This program recursively ';
   Msg4 = 'determines the number of ways to move checkers to the n-th cell.';
begin
   MessageBox(Handle, PChar(Msg1 + Msg2 + Msg3 + Msg4), PChar('Error.'), MB_ICONINFORMATION);
end;


function TLab_5_2.IsCorrectNumber(strNumber: string): Boolean;
var
   Number: Integer;
begin
    try
       Number := StrToInt(strNumber);
       if (Number > 9999) then
       begin
          MessageBox(Handle, PChar('File contain incorrect value'), PChar('Error.'), MB_ICONSTOP);
          Result := False;
       end;
    except
       MessageBox(Handle, PChar('File containg incorrect valur'), PChar('Error.'), MB_ICONSTOP);
       Result := False;
    end;
end;

procedure TLab_5_2.Open1Click(Sender: TObject);
var
   txtFile: TextFile;
   Number: Integer;
   strNumber: string;
begin
   if OpenFile.Execute then
   begin
      try
         AssignFile(txtFile, OpenFile.FileName);
         Reset(txtFile);
      except
         MessageBox(Handle, PChar('Eror opening to file.'), PChar('Error.'), MB_ICONSTOP);
         CloseFile(txtFile);
         Exit
      end;

      if Eof(txtFile) then
      begin
         MessageBox(Handle, PChar('File is empty'), PChar('Error.'), MB_ICONSTOP);
         CloseFile(txtFile);
         Exit
      end;

      Read(txtFile, strNumber);
      if not  IsCorrectNumber(strNumber) then
      begin
         MessageBox(Handle, PChar('File is empty'), PChar('Error.'), MB_ICONSTOP);
         CloseFile(txtFile);
         Exit
      end;
      edAmountCells.Text := IntToStr(Number);
      btnCountMoves.Enabled := True;
      CloseFile(txtFile);
   end;
end;

procedure TLab_5_2.Save1Click(Sender: TObject);
var
   txtFile: TextFile;
begin
   if SaveFile.Execute then
   begin
      try
         AssignFile(txtFile, SaveFile.FileName);
         Rewrite(txtFile);
      except
         MessageBox(Handle, PChar('Eror writing to file.'), PChar('Error.'), MB_ICONSTOP);
         CloseFile(txtFile);
         Exit
      end;
      Writeln(txtFile, 'Count cells: ', edAmountCells.Text);
      Writeln(txtFile, 'Amount ways: ', edAmountWays.Text);
      CloseFile(txtFile);
   end;
end;

end.