unit UnitIntro;

interface

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

type
   TMyString = string[11];
   TData = record
      Name: TMyString;
   end;
   TNamesPt = ^TNames;
   TNames = record
      Data: TData;
      Next: TNamesPt;
   end;
  TPlMenu = class(TForm)
    Empty: TPopupMenu;
    iBackground: TImage;
    laQuestion: TLabel;
    sbYes: TSpeedButton;
    sbNo: TSpeedButton;
    laYesCase: TLabel;
    eName: TEdit;
    sbAcceptName: TSpeedButton;
    laWelcome: TLabel;
    EndTimer: TTimer;
    cbNames: TComboBox;
    procedure sbYesClick(Sender: TObject);
    procedure sbAcceptNameClick(Sender: TObject);
    procedure EndTimerTimer(Sender: TObject);
    procedure eNameKeyPress(Sender: TObject; var Key: Char);
    procedure eNameChange(Sender: TObject);
    function CheckAndSaveName(Name: TMyString): Boolean;
    procedure AddElem(Data: TData; var Prev: TNamesPt);
    procedure sbNoClick(Sender: TObject);
    procedure NameAcception(Name: string);
    procedure InputFromFile(Sender: TObject);
    procedure cbNamesChange(Sender: TObject);
    procedure cbNamesKeyPress(Sender: TObject; var Key: Char);
    procedure FormCreate(Sender: TObject);
    procedure FormCloseQuery(Sender: TObject; var CanClose: Boolean);
    procedure eNameKeyDown(Sender: TObject; var Key: Word; Shift: TShiftState);
    procedure DeleteList(var Head: TNamesPt);
    function IsNameFounded(var IsFound: Boolean; Head: TNamesPt;
      var Prev: TNamesPt; Name: TMyString): Boolean;
    procedure WriteList(Head: TNamesPt; FileName: string);
    function IsFileCorrect(FileName: string): Boolean;
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  PlMenu: TPlMenu;

implementation

{$R *.dfm}

uses UnitMain;

const
   PreStartDelay = 2000;

var
   TimeLeft: Integer;
   State: Byte; //1 for Yes; 2 for No

procedure TPlMenu.eNameChange(Sender: TObject);
begin
   if Length(eName.Text) > 0 then
      sbAcceptName.Enabled := True
   else
      sbAcceptName.Enabled := False;
end;

procedure TPlMenu.eNameKeyDown(Sender: TObject; var Key: Word;
  Shift: TShiftState);
begin
   if ssShift in Shift then
      Key := 0;
end;

procedure TPlMenu.eNameKeyPress(Sender: TObject; var Key: Char);
const
   Latin: set of Char = ['A'..'Z', 'a'..'z', #8];
begin
   if (Key = #13) and sbAcceptName.Enabled then
      sbAcceptNameClick(Sender);
   if not (Key in Latin) then
      Key := #0;
end;

procedure TPlMenu.EndTimerTimer(Sender: TObject);
begin
   TimeLeft := TimeLeft - 1000;
   if (TimeLeft = 0) then
      Self.Close;
end;

procedure TPlMenu.FormCloseQuery(Sender: TObject; var CanClose: Boolean);
begin
   CanClose := False;
   if TimeLeft = 0 then
      CanClose := True;
end;

function TPlMenu.IsFileCorrect(FileName: string): Boolean;
const
   Letters: set of Char = ['A'..'Z', 'a'..'z'];
var
   OutputFile: file of TData;
   i: Integer;
   FileData: TData;
   IsCorrect: Boolean;
begin
   IsCorrect := True;
   AssignFile(OutputFile, FileName);
   Reset(OutputFile);
   if EOF(OutputFile) then
   begin
      CloseFile(OutputFile);
      Erase(OutputFile);
      IsCorrect := False;
      ShowMessage(msgFileIsInvalid);
   end
   else
   begin
      Reset(OutputFile);
      Read(OutputFile, FileData);
      CloseFile(OutputFile);
      i := 1;
      while (i <= Length(FileData.Name)) and IsCorrect do
      begin
         if not(FileData.Name[i] in Letters) then
         begin
            IsCorrect := False;
            ShowMessage(msgFileIsInvalid);
            DeleteFile(FileName);
         end;
         Inc(i);
      end;
   end;
   Result := IsCorrect;
end;

procedure TPlMenu.FormCreate(Sender: TObject);
const
   FileName = 'Names';
begin
   iBackground.Picture.Bitmap.LoadFromResourceName(HInstance, 'IMAGE6');
   TimeLeft := PreStartDelay;
   if FileExists(FileName) and IsFileCorrect(FileName) then
      sbNo.Enabled := True
   else
      sbNo.Enabled := False;
end;

procedure TPlMenu.AddElem(Data: TData; var Prev: TNamesPt);
var
   Curr: TNamesPt;
begin
   New(Curr);
   Curr.Data := Data;
   Prev.Next := Curr;
   Curr.Next := nil;
end;

procedure TPlMenu.cbNamesChange(Sender: TObject);
begin
   if Length(cbNames.Text) > 0  then
      sbAcceptName.Enabled := True
   else
      sbAcceptName.Enabled := False;
end;

procedure TPlMenu.cbNamesKeyPress(Sender: TObject; var Key: Char);
begin
   if (Key = #13) and sbAcceptName.Enabled then
      sbAcceptNameClick(Sender);
end;

procedure TPlMenu.DeleteList(var Head: TNamesPt);
var
   Curr: TNamesPt;
begin
   while (Head <> nil) do
   begin
      Curr := Head.Next;
      Dispose(Head);
      Head := Curr;
   end;
end;

function TPlMenu.IsNameFounded(var IsFound: Boolean; Head: TNamesPt;
  var Prev: TNamesPt; Name: TMyString): Boolean;
var
   Curr: TNamesPt;
begin
   Curr := Head;
   Result := True;
   IsFound := False;
   while (Curr <> nil) and not IsFound do
   begin
      if Curr.Data.Name = Name then
      begin
         Result := False;
         IsFound := True;
      end;
      Prev := Curr;
      Curr := Curr.Next;
   end;
end;

procedure TPlMenu.WriteList(Head: TNamesPt; FileName: string);
var
   Curr: TNamesPt;
   i: Integer;
   OutputFile: file of TData;
begin
   AssignFile(OutputFile, FileName);
   Reset(OutputFile);
   Curr := Head;
   i := 0;
   while (Curr <> nil) do
   begin
      Seek(OutputFile, i);
      Write(OutputFile, Curr.Data);
      Curr := Curr.Next;
      Inc(i);
   end;
   CloseFile(OutputFile);
end;

function TPlMenu.CheckAndSaveName(Name: TMyString): Boolean;
const
   FileName = 'Names';
var
   Head, Curr, Prev: TNamesPt;
   FileData, Data: TData;
   OutputFile: file of TData;
   IsFound: Boolean;
   i: Integer;
begin
   Result := True;
   if FileExists(FileName) then
   begin
      AssignFile(OutputFile, FileName);
      Reset(OutputFile);
      Read(OutputFile, FileData);
      New(Head);
      Head.Data := FileData;
      Head.Next := nil;
      Curr := Head;
      Seek(OutputFile, 1);
      while not EOF(OutputFile) do
      begin
         Read(OutputFile, FileData);
         AddElem(FileData, Curr);
         Curr := Curr.Next;
      end;
      CloseFile(OutputFile);
      Result := IsNameFounded(IsFound, Head, Curr, Name);
      if not IsFound then
      begin
         Data.Name := Name;
         AddElem(Data, Curr);
         WriteList(Head, FileName);
      end;
      DeleteList(Head);
   end
   else
   begin
      Data.Name := Name;
      AssignFile(OutputFile, FileName);
      Rewrite(OutputFile);
      Write(OutputFile, Data);
      CloseFile(OutputFile);
   end;
end;

procedure TPlMenu.NameAcception(Name: string);
begin
   if FileAvailable then
      Main.mpSound.Play;
   laYesCase.Visible := False;
   eName.Visible := False;
   cbNames.Visible := False;
   sbAcceptName.Visible := False;
   laQuestion.Visible := False;
   laWelcome.Visible := True;
   laWelcome.Caption := msgWelcomeStart + Name + msgWelcomeEnd;
   Main.laPlayerName.Caption := Name ;
   EndTimer.Enabled := True;
end;

procedure TPlMenu.sbAcceptNameClick(Sender: TObject);
var
   IsCorrect: Boolean;
begin
   if State = 1 then
   begin
     IsCorrect := CheckAndSaveName(eName.Text);
     if IsCorrect then
        NameAcception(eName.Text)
     else
     begin
        MessageDlg(msgNameIsTaken, mtWarning, [mbOk], 0);
        eName.Clear;
     end;
   end
   else
   begin
      NameAcception(cbNames.Text);
   end;
end;

procedure TPlMenu.InputFromFile(Sender: TObject);
const
   FileName = 'Names';
var
   InputFile: File of TData;
   FileData: TData;
begin
   AssignFile(InputFile, FileName);
   Reset(InputFile);
   while not EOF(InputFile) do
   begin
      Read(InputFile, FileData);
      cbNames.AddItem(FileData.Name, Sender);
   end;
   CloseFile(InputFile);
end;

procedure TPlMenu.sbNoClick(Sender: TObject);
begin
   if FileAvailable then
      Main.mpSound.Play;
   State := 2;
   laQuestion.Caption := msgChooseName;
   sbYes.Visible := False;
   sbNo.Visible := False;
   cbNames.Visible := True;
   InputFromFile(Sender);
   sbAcceptName.Visible := True;
end;

procedure TPlMenu.sbYesClick(Sender: TObject);
begin
   if FileAvailable then
      Main.mpSound.Play;
   State := 1;
   laQuestion.Visible := False;
   sbYes.Visible := False;
   sbNo.Visible := False;
   sbAcceptName.Visible := True;
   laYesCase.Visible := True;
   eName.Visible := True;
   eName.SetFocus;
end;

end.