Program lab3_4;

{$APPTYPE CONSOLE}

uses
    System.SysUtils;

Function InputFileLocation(): string;
Var
    IsCorrect: Boolean;
    Location: String;
Begin
    Repeat
        IsCorrect := false;
        WriteLn('Enter file location:');
        ReadLn(Location);
        If FileExists(Location) then
            IsCorrect := true
        Else
        Begin
            WriteLn('Please enter the correct location');
            WriteLn('');
        End;
    Until IsCorrect;
    InputFileLocation := Location;
End;


Function ChooseInput(): integer;
Var
    Line: String;
    IsCorrect: Boolean;
Begin
    Repeat
        IsCorrect := true;
        WriteLn('Do you want to input from file? (y/n)');
        ReadLn(line);
        Line := Line.ToLower();
        If(Line <> '') and (Line <> 'y') and (Line <> 'n') then
        Begin
            IsCorrect := false;
            WriteLn('Enter valid answer');
        End;
    Until IsCorrect;
    If (Line = '') or (Line = 'y') then
        ChooseInput := 0
    Else
        ChooseInput := 1;
End;

Procedure OutputToFile(Flag: Integer);
var
    TFile: TextFile;
begin
    AssignFile(TFile, InputFileLocation());
    Rewrite(TFile);
    if Flag = 0 then
        writeln(TFile, 'Баланск скобок соблюдён')
    Else
        writeln(TFile, 'Баланск скобок нарушен');
    CloseFile(TFile);
end;

Function FindBalance(Str: String): Integer;
Var
    I, Flag: Integer;
Begin
    I := 1;
    Flag := 0;
    while ((Flag >= 0) And (I <= High(Str))) do
    begin
        if Str[I] = '(' then flag := flag + 1;
        if Str[I] = ')' then flag := flag - 1;
        i:=i+1
    end;
    FindBalance := Flag;
End;

Procedure PrintToConsole(Flag: Integer);
Begin
    if Flag = 0 then
        writeln('Баланск скобок соблюдён')
    Else
        writeln('Баланск скобок нарушен');
End;

Function GetLineFromConsole(): String;
var
    IsCorrect: Boolean;
    Str: String;
begin
    repeat
        IsCorrect := true;
        ReadLn(Str);
        if Length(Str) = 0 then
        begin
            WriteLn('The line is empty, please, try to enter it one more time');
            IsCorrect := false;
        end;
    until IsCorrect;
    GetLineFromConsole := Str;
end;

Function GetLineFromFile(): String;
var
    IsCorrect: Boolean;
    TFile: TextFile;
    Str: String;
begin
    repeat
        Str := '';
        IsCorrect := true;
        AssignFile(TFile, InputFileLocation());
        Reset(TFile);
        ReadLn(TFile, Str);
        CloseFile(TFile);
        if (Length(Str) = 0) then
        begin
            WriteLn('String is empty. Enter another file location');
            IsCorrect := false;
        end;
    until IsCorrect;
    GetLineFromFile := Str;
end;

Procedure Main();
Var
    ChosenInput: Integer;
    Str: String;
    I, Flag : Integer;
Begin
    Str := '';
    WriteLn('Проверить, имеется ли в заданном тексте баланс открывающих и закрывающих скобок.');
    ChosenInput := ChooseInput();
    If (ChosenInput = 0) then
        Str := GetLineFromFile()
    Else
    Begin
        writeln('Введите строку');
        Str := GetLineFromConsole();
    End;
    writeln('Результат:');
    Flag := FindBalance(Str);
    PrintToConsole(Flag);
    WriteLn;
    OutputToFile(Flag);
    Readln;
End;

Begin
    Main();
End.