unit UnitMain;

interface

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

type
   TFormMain = class(TForm)
      BtnAdd: TButton;
      BtnEdit: TButton;
      BtnDel: TButton;
      BtnView: TButton;
      MainMenu: TMainMenu;
      Help: TMenuItem;
      ButtonLoad: TButton;
      ButtonSave: TButton;
      OpenDialogMain: TOpenDialog;
      SaveDialogMain: TSaveDialog;
      procedure BtnAddClick(Sender: TObject);
      procedure FormCreate(Sender: TObject);
      procedure BtnDelClick(Sender: TObject);
      procedure BtnViewClick(Sender: TObject);
      procedure ButtonLoadClick(Sender: TObject);
      procedure ButtonSaveClick(Sender: TObject);
      procedure HelpClick(Sender: TObject);
    procedure FormCloseQuery(Sender: TObject; var CanClose: Boolean);
   private
      { Private declarations }
   public
      { Public declarations }
   end;
   TStats = record
      GroupNum: Integer;
      Surname: string[15];
      Math: Integer;
      Physics: Integer;
      Programming: Integer;
      EGraphics: Integer;
   end;
   TStatsArr = array of TStats;
   TGroupInfo = record
      GroupNum: Integer;
      FirstIndex: Integer;
      LastIndex: Integer;
      HiMark: Integer;
      LowMark: Integer;
   end;
   TGroupArr = array of TGroupInfo;
   TCompareFunc = function(x1, x2: TStats): Boolean;

var
   FormMain: TFormMain;
   isSaved: Boolean;
   isChanged: Boolean;
   GroupArr: TGroupArr;

implementation

{$R *.dfm}

uses
   UnitAdd, UnitEdit, UnitDelete, UnitView;

procedure TFormMain.BtnAddClick(Sender: TObject);
var
   i: Integer;
begin
   if not Assigned(FormAdd) then
      FormAdd := TFormAdd.Create(FormMain)
   else
   begin
      for i := 1 to FormAdd.StringGridAdd.RowCount - 1 do
         FormAdd.StringGridAdd.Rows[i].Clear;
      FormAdd.StringGridAdd.RowCount := 1;
      FormAdd.StringGridAdd.Width := 455*2;
      FormAdd.Visible := True;
      FormAdd.EditGrp.SetFocus;
   end;
   FormMain.Visible := False;
end;

function Merge(Left, Right: TStatsArr; CompareFunc: TCompareFunc): TStatsArr;
var
   TempArr: TStatsArr;
   i, k: Integer;
begin
   SetLength(TempArr, Length(Left) + Length(Right));
   k := 0;
   while (Length(Left) > 0) and (Length(Right) > 0) do
      if CompareFunc(Left[0], Right[0]) then
      begin
         TempArr[k] := Left[0];
         Inc(k);
         Left := Copy(Left, 1, Length(Left) - 1);
      end
      else
      begin
         TempArr[k] := Right[0];
         Inc(k);
         Right := Copy(Right, 1, Length(Right) - 1);
      end;
   if Length(Left) > 0 then
      for i := 0 to High(Left) do
      begin
         TempArr[k] := Left[i];
         Inc(k);
      end;
   if Length(Right) > 0 then
      for i := 0 to High(Right) do
      begin
         TempArr[k] := Right[i];
         Inc(k);
      end;
   Result := TempArr;
end;

function MergeSort(DataArr: TStatsArr; CompareFunc: TCompareFunc): TStatsArr;
var
   i: Integer;
   Middle: Integer;
   Left, Right: TStatsArr;
begin
   if Length(DataArr) <= 1 then
      Result := DataArr
   else
   begin
      Middle := (Length(DataArr) div 2) - 1;
      for i := 0 to Middle do
      begin
         SetLength(Left, Length(Left) + 1);
         Left[High(Left)] := DataArr[i];
      end;
      for i := Middle + 1 to High(DataArr) do
      begin
         SetLength(Right, Length(Right) + 1);
         Right[High(Right)] := DataArr[i];
      end;
      left := MergeSort(Left, CompareFunc);
      Right := MergeSort(Right, CompareFunc);
      Result := Merge(left, right, CompareFunc);
   end;
end;

function ReadGrdArr: TStatsArr;
var
   Arr: TStatsArr;
   TempRec: TStats;
   i: Integer;
begin
   SetLength(Arr, FormDelete.StringGridDelete.RowCount - 1);
   for i := 1 to FormDelete.StringGridDelete.RowCount - 1 do
   begin
      TempRec.GroupNum := StrToInt(FormDelete.StringGridDelete.Cells[1, i]);
      TempRec.Surname := (FormDelete.StringGridDelete.Cells[2, i]);
      TempRec.Math := StrToInt(FormDelete.StringGridDelete.Cells[3, i]);
      TempRec.Physics := StrToInt(FormDelete.StringGridDelete.Cells[4, i]);
      TempRec.Programming := StrToInt(FormDelete.StringGridDelete.Cells[5, i]);
      TempRec.EGraphics := StrToInt(FormDelete.StringGridDelete.Cells[6, i]);
      Arr[i - 1] := TempRec;
   end;
   ReadGrdArr := (Arr);
end;

procedure PrepareGroupArray(Arr: TStatsArr);
var
   i: Integer;
begin
   SetLength(GroupArr, 1);
   GroupArr[0].GroupNum := Arr[0].GroupNum;
   GroupArr[0].FirstIndex := 0;
   if Length(Arr) = 1 then
   begin
      GroupArr[0].LastIndex := 0;
   end
   else
   begin
      i := 1;
      while i <> Length(Arr) do
      begin
         if Arr[i].GroupNum <> GroupArr[High(GroupArr)].GroupNum then
         begin
            SetLength(GroupArr, Length(GroupArr) + 1);
            GroupArr[High(GroupArr)].GroupNum := Arr[i].GroupNum;
            GroupArr[High(GroupArr)].FirstIndex := i;
            GroupArr[High(GroupArr) - 1].LastIndex := i - 1;
         end;
         Inc(i);
      end;
      GroupArr[High(GroupArr)].LastIndex := High(Arr);
   end;
end;

function CompareMarks(x1, x2: TStats): Boolean;
begin
   if ((x1.Physics + x1.Math + x1.Programming + x1.EGraphics)) > ((x2.Physics + x2.Math + x2.Programming + x2.EGraphics)) then
      CompareMarks := True
   else
      CompareMarks := False;
end;

function CompareGroups(x1, x2: TStats): Boolean;
begin
   if x1.GroupNum < x2.GroupNum then
      CompareGroups := True
   else
      CompareGroups := False;
end;

function CompareNames(x1, x2: TStats): Boolean;
begin
   if x1.Surname < x2.Surname then
      CompareNames := True
   else
      CompareNames := False;
end;

procedure ReloadMainGrid(Arr: TStatsArr);
var
   i: Integer;
begin
   FormDelete.StringGridDelete.RowCount := 1;
   for i := 0 to High(Arr) do
   begin
      FormDelete.StringGridDelete.RowCount := FormDelete.StringGridDelete.RowCount + 1;
      FormDelete.StringGridDelete.Cells[0, FormDelete.StringGridDelete.RowCount - 1] := IntToStr(FormDelete.StringGridDelete.RowCount - 1);
      FormDelete.StringGridDelete.Cells[1, FormDelete.StringGridDelete.RowCount - 1] := IntToStr(Arr[i].GroupNum);
      FormDelete.StringGridDelete.Cells[2, FormDelete.StringGridDelete.RowCount - 1] := (Arr[i].Surname);
      FormDelete.StringGridDelete.Cells[3, FormDelete.StringGridDelete.RowCount - 1] := IntToStr(Arr[i].Math);
      FormDelete.StringGridDelete.Cells[4, FormDelete.StringGridDelete.RowCount - 1] := IntToStr(Arr[i].Physics);
      FormDelete.StringGridDelete.Cells[5, FormDelete.StringGridDelete.RowCount - 1] := IntToStr(Arr[i].Programming);
      FormDelete.StringGridDelete.Cells[6, FormDelete.StringGridDelete.RowCount - 1] := IntToStr(Arr[i].EGraphics);
   end;
end;

procedure PrepareOutput;
const
   NotEstated = -1;
var
   CompareFunc: TCompareFunc;
   TempArr: TStatsArr;
   i, k, j, a: Integer;
   TempFullArr: TStatsArr;
   FirstIndex, LastIndex: Integer;
begin
   CompareFunc := CompareGroups;
   TempFullArr := ReadGrdArr;
   TempFullArr := MergeSort(TempFullArr, CompareFunc);
   PrepareGroupArray(TempFullArr);
   CompareFunc := CompareMarks;
   for i := 0 to High(GroupArr) do
   begin
      TempArr := Copy(TempFullArr, GroupArr[i].FirstIndex, GroupArr[i].LastIndex - GroupArr[i].FirstIndex + 1);
      TempArr := MergeSort(TempArr, CompareFunc);
      j := 0;
      for k := GroupArr[i].FirstIndex to GroupArr[i].LastIndex do
      begin
         TempFullArr[k] := TempArr[j];
         Inc(j);
      end;
      GroupArr[i].HiMark := NotEstated;
      GroupArr[i].LowMark := NotEstated;
      a := GroupArr[i].FirstIndex;
      with  TempFullArr[a] do
      begin
         if ((Math + Physics + EGraphics + Programming)) > 27 then
         begin
            GroupArr[i].HiMark := GroupArr[i].FirstIndex;
            while (a  < GroupArr[i].LastIndex) and (((TempFullArr[a + 1].Math + TempFullArr[a + 1].Physics + TempFullArr[a + 1].Programming + TempFullArr[a + 1].EGraphics)) > 27) do
               Inc(a);
            GroupArr[i].LowMark := a;
         end;
      end;
   end;
   CompareFunc := CompareNames;
   for i := 0 to High(GroupArr) do
   begin
      if GroupArr[i].LowMark = NotEstated then
      begin
         FirstIndex := GroupArr[i].FirstIndex;
         LastIndex := GroupArr[i].LastIndex;
      end
      else
      begin
         FirstIndex := GroupArr[i].HiMark;
         LastIndex := GroupArr[i].LowMark;
      end;
      TempArr := Copy(TempFullArr, FirstIndex, LastIndex - FirstIndex + 1);
      TempArr := MergeSort(TempArr, CompareFunc);
      j := 0;
      for k := FirstIndex to LastIndex do
      begin
         TempFullArr[k] := TempArr[j];
         Inc(j);
      end;
   end;
   ReloadMainGrid(TempFullArr);
end;

procedure NoDataMsg;
begin
   MessageDlg('There is no data, you need to input data first!', mtError, [mbOk], 0);
end;

procedure ShowDeleteForm;
begin
   if not Assigned(FormDelete) then
      FormDelete := TFormDelete.Create(FormMain);
   if (FormDelete.StringGridDelete.RowCount - 1) > 0 then
   begin
      FormDelete.Visible := True;
      if FormDelete.StringGridDelete.RowCount - 1 > 9 then
         FormDelete.StringGridDelete.Width := 470*2
      else
         FormDelete.StringGridDelete.Width := 455*2;
      FormMain.Visible := False;
   end
   else
      NoDataMsg;
end;

procedure TFormMain.BtnDelClick(Sender: TObject);
begin
   ShowDeleteForm;
end;

procedure ShowViewForm;
var
   i: Integer;
begin
   if (FormDelete.StringGridDelete.RowCount - 1) = 0 then
      NoDataMsg
   else
   begin
      if not Assigned(FormView) then
         FormView := TFormView.Create(FormMain);
      if isChanged then
      begin
         PrepareOutput;
         FormView.CBGroup.Items.Clear;
         for i := 0 to High(GroupArr) do
            FormView.CBGroup.Items.Add(IntToStr(GroupArr[i].GroupNum));
         isChanged := False;
         FormView.CBGroup.ItemIndex := 0;
         if GroupArr[0].HiMark <> - 1 then
         begin
           { FormView.StringGridView.Visible := True;
            FormView.StaticTextInfoPic.Visible := False;
            FormView.StaticTextInfoPic2.Visible := False;
            FormView.ImageAnimals1.Visible := False;
            FormView.ImageAnimals2.Visible := False;
            FormView.StringGridView.RowCount := 1;}
            for i := GroupArr[0].HiMark to GroupArr[0].LowMark do
               with FormView do
               begin
                  StringGridView.RowCount := StringGridView.RowCount + 1;
                  StringGridView.Cells[0, StringGridView.RowCount - 1] := IntToStr(StringGridView.RowCount - 1);
                  StringGridView.Cells[1, StringGridView.RowCount - 1] := FormDelete.StringGridDelete.Cells[1, i + 1];
                  StringGridView.Cells[2, StringGridView.RowCount - 1] := FormDelete.StringGridDelete.Cells[2, i + 1];
                  StringGridView.Cells[3, StringGridView.RowCount - 1] := FormDelete.StringGridDelete.Cells[3, i + 1];
                  StringGridView.Cells[4, StringGridView.RowCount - 1] := FormDelete.StringGridDelete.Cells[4, i + 1];
                  StringGridView.Cells[5, StringGridView.RowCount - 1] := FormDelete.StringGridDelete.Cells[5, i + 1];
                  StringGridView.Cells[6, StringGridView.RowCount - 1] := FormDelete.StringGridDelete.Cells[6, i + 1];
                  StringGridView.Cells[7, StringGridView.RowCount - 1] := FormDelete.StringGridDelete.Cells[7, i + 1];
               end;
            if FormView.StringGridView.RowCount < 15 then
            begin

            end
            else
            begin

            end;
         end
         else
        { begin
            case Random(2) of
               0:
               begin
                  FormView.ImageAnimals1.Visible := True;
               end;
               1:
               begin
                  FormView.ImageAnimals2.Visible := True;
               end;
            end;
            FormView.StringGridView.Visible := False;
            FormView.StaticTextInfoPic.Visible := True;
            FormView.StaticTextInfoPic2.Visible := True;
         end; }
      end;
      FormView.Visible := True;
      FormView.SetFocus;
      FormMain.Visible := False;
   end;
end;

procedure TFormMain.BtnViewClick(Sender: TObject);
begin
   ShowViewForm;
end;

procedure SaveData;
var
   TempRec: TStats;
   i: Integer;
   SaveFile: file of TStats;
begin
   with FormMain do
   begin
      saveDialogMain := TSaveDialog.Create(saveDialogMain);
      saveDialogMain.Title := 'Save your file';
      saveDialogMain.InitialDir := GetCurrentDir;
      saveDialogMain.Filter := 'Typed file|*.dat|Text file|*.txt';
      saveDialogMain.DefaultExt := 'dat';
      saveDialogMain.FilterIndex := 1;
      if saveDialogMain.Execute then
      begin
         try
            AssignFile(SaveFile,saveDialogMain.FileName);
            Rewrite(SaveFile);
            if (FormDelete.StringGridDelete.RowCount - 1) > 0 then
               for i := 1 to FormDelete.StringGridDelete.RowCount - 1 do
               begin
                  TempRec.GroupNum := StrToInt(FormDelete.StringGridDelete.Cells[1, i]);
                  TempRec.Surname := (FormDelete.StringGridDelete.Cells[2, i]);
                  TempRec.Math := StrToInt(FormDelete.StringGridDelete.Cells[3, i]);
                  TempRec.Physics := StrToInt(FormDelete.StringGridDelete.Cells[4, i]);
                  TempRec.Programming := StrToInt(FormDelete.StringGridDelete.Cells[5, i]);
                  TempRec.EGraphics := StrToInt(FormDelete.StringGridDelete.Cells[6, i]);
                  Write(SaveFile, TempRec)
               end
            else
            CloseFile(SaveFile);
            isSaved := True;
         except
            MessageDlg('An error occured while saving data :( ', mtError, [mbOk], 0);
            CloseFile(SaveFile);
            isSaved:= False;
         end;
      end;
      FreeAndNil(saveDialogMain);
   end;
end;

procedure AskSaving;
var
   buttonSelected : Integer;
   strQuestion: string;
begin
   strQuestion := 'Whoops, it seems that you''ve forgot to save your document! Would you like to do it before quitting??';
   buttonSelected := MessageDlg(strQuestion , mtConfirmation, mbOKCancel, 0);
   if buttonSelected = mrOK then
      SaveData;
end;

function Confirm: Boolean;
var
   buttonSelected : Integer;
   strQuestion: string;
begin
   strQuestion := 'An error occured while loading/opening file. Would you like to load another file (ok) or to work with empty spreadsheet(Сancel)?';
   buttonSelected := MessageDlg(strQuestion , mtConfirmation, mbOKCancel, 0);
   if buttonSelected = mrOK then
      Confirm := True
   else
      Confirm := False;
end;

procedure LoadData;
const
   MaxLength = 200;
var
   TempRec: TStats;
   LoadFile: File of TStats;
begin
   FormDelete.StringGridDelete.RowCount := 1;
   FormMain.OpenDialogMain := TOpenDialog.Create(FormMain.OpenDialogMain);
   FormMain.OpenDialogMain.InitialDir := GetCurrentDir;
   if FormMain.OpenDialogMain.Execute then
   begin
      try
         AssignFile(LoadFile, FormMain.OpenDialogMain.FileName);
         Reset(LoadFile);
         if not EoF(LoadFile) then
         begin
            Seek(LoadFile, 0);
            while not EoF(LoadFile) and (FormDelete.StringGridDelete.RowCount < MaxLength + 1) do
            begin
               FormDelete.StringGridDelete.RowCount := FormDelete.StringGridDelete.RowCount + 1;
               Read(LoadFile, TempRec);
               FormDelete.StringGridDelete.Cells[0, FormDelete.StringGridDelete.RowCount - 1] := IntToStr(FormDelete.StringGridDelete.RowCount - 1);
               FormDelete.StringGridDelete.Cells[1, FormDelete.StringGridDelete.RowCount - 1] := IntToStr(TempRec.GroupNum);
               FormDelete.StringGridDelete.Cells[2, FormDelete.StringGridDelete.RowCount - 1] := (TempRec.Surname);
               FormDelete.StringGridDelete.Cells[3, FormDelete.StringGridDelete.RowCount - 1] := IntToStr(TempRec.Math);
               FormDelete.StringGridDelete.Cells[4, FormDelete.StringGridDelete.RowCount - 1] := IntToStr(TempRec.Physics);
               FormDelete.StringGridDelete.Cells[5, FormDelete.StringGridDelete.RowCount - 1] := IntToStr(TempRec.Programming);
               FormDelete.StringGridDelete.Cells[6, FormDelete.StringGridDelete.RowCount - 1] := IntToStr(TempRec.EGraphics);
            end;
            if (FormDelete.StringGridDelete.RowCount - 1 = MaxLength) and not EoF(LoadFile) then
               MessageDlg('Max number of students was exceeded. Thus the rest of file was cut.', mtInformation, [mbOk], 0);
         end
         else
            FormDelete.StringGridDelete.RowCount := 0;
         CloseFile(LoadFile);
         isChanged := True;
      except
         if not Confirm then
         begin
            FormDelete.StringGridDelete.RowCount := 0;
         end;
      end;
   end;
   FreeAndNil(FormMain.OpenDialogMain);
end;

procedure TFormMain.ButtonLoadClick(Sender: TObject);
begin
   if (FormDelete.StringGridDelete.RowCount > 0) and not isSaved then
      AskSaving;
   LoadData;
end;

procedure TFormMain.ButtonSaveClick(Sender: TObject);
begin
   SaveData;
end;

procedure TFormMain.FormCloseQuery(Sender: TObject; var CanClose: Boolean);
begin
   if not isSaved then
   begin
      AskSaving;
   end
end;

procedure TFormMain.FormCreate(Sender: TObject);
begin
   isSaved := True;
   isChanged := True;
end;

procedure TFormMain.HelpClick(Sender: TObject);
begin
   MessageDlg('Programm allows you to work with spreadsheets that represent academic performance of students [max = 200]. To learn about other functions chek their own help tabs.', mtInformation, [mbOk], 0);
end;

end.