lab2_3(delphi)

program lab2_3;
{$APPTYPE CONSOLE}
{$R *.res}
uses
    System.SysUtils;
Function GetSource(What: String): String;
var
    Source: String;
begin
    Write('Select the source for '+ what + ':'  + #13#10 + '1:Console'  + #13#10 + '2:File'  + #13#10 + 'Enter 1 or 2: ');
    Readln(Source);
    while (Source <> '1') and (Source <> '2') do
    begin
        Write('Incorrect input!!!' + #13#10 + 'Select the source for '+ what + ':'  + #13#10 +
              '1:Console'  + #13#10 + '2:File'  + #13#10 + 'Enter 1 or 2: ');
        Readln(Source);
    end;
    GetSource := Source;
end;
Function GetInPath: String;
var
    Path: String;
    IsCorrect: Boolean;
begin
    Write('Enter file path: ');
    repeat
        IsCorrect := True;
        Readln(Path);
        if not FileExists(Path) then
        begin
            Write('File is not found' + #13#10 + 'Enter file path: ');
            IsCorrect := False;
        end
        else
            if ((Path[Length(Path)] <> 't') or (Path[Length(Path) - 1] <> 'x') or
                (Path[Length(Path)- 2] <> 't') or (Path[Length(Path)- 3] <> '.')) then
            begin
                Write('File is found, but it is not ".txt" type file' + #13#10 + 'Enter file path: ');
                IsCorrect := False;
            end;
    until IsCorrect;
    GetInPath := Path;
end;
Function GetOutPath: String;
var
    Path: String;
    IsCorrect: Boolean;
begin
    Write('Enter file path: ');
    repeat
        IsCorrect := True;
        Readln(Path);
        if ((Path[Length(Path)] <> 't') or (Path[Length(Path) - 1] <> 'x') or
            (Path[Length(Path)- 2] <> 't') or (Path[Length(Path) - 3] <> '.')) then
        begin
            Write('It should be a ".txt" type file' + #13#10 + 'Enter file path: ');
            IsCorrect := False;
        end;
    until IsCorrect;
    GetOutPath := Path;
end;
Function GetNumFromConsole: Integer;
var
    IsCorrect: Boolean;
    Number: Integer;
begin
    Write('Enter number: ');
    Number := 0;
    repeat
        IsCorrect := True;
        try
            Readln(Number);
        except
            Write('Incorrect input!!!' + #13#10 + 'Enter number: ');
            IsCorrect := False;
        end;
        if (IsCorrect and (Number < 1)) then
        begin
            Write('The number must be more than 0', #13#10, 'Enter number: ');
            IsCorrect := False;
        end;
    until IsCorrect;
    GetNumFromConsole := Number;
end;
Function GetNumFromFile(Path: String): Integer;
var
    InFile: TextFile;
    Number: Integer;
    IsCorrect: Boolean;
begin
    Number := 0;
    IsCorrect := True;
    AssignFile(InFile, Path);
    Reset(InFile);
    try
        Read(InFile,Number);
    except
        Writeln('Incorrect file content!!!');
        number := 0;
        IsCorrect := False;
    end;
    if IsCorrect and (not Eof(InFile)) then
    begin
        Writeln('Incorrect file content!!!');
        number := 0;
    end
    else
        if IsCorrect and (number < 1) then
        begin
            Writeln('Incorrect file content!!!(The number must be more than 0)');
            number := 0;
        end;
    CloseFile(InFile);
    GetNumFromFile := Number;
end;
Function GetNum(Source: String): Integer;
var
    InPath: String;
    Number: Integer;
begin
    if (Source = '1') then
        Number := GetNumFromConsole
    else
    begin
        InPath := GetInPath;
        Number := GetNumFromFile(InPath);
        while (Number = 0) do
        begin
            InPath := GetInPath;
            Number := GetNumFromFile(InPath);
        end;
    end;
    GetNum := Number;
end;
Function GetReverse(Number: Integer): Integer;
var
    Reverse: Integer;
begin
    Reverse := 0;
    While(Number > 0) do
    begin
        Reverse := Reverse * 10 + Number mod 10;
        Number := Number div 10;
    end;
    GetReverse := Reverse;
end;
Function GetAnswer(Number,Reverse: Integer): String;
begin
    if Number = Reverse then
        GetAnswer := 'Number is palindrome'
    else
        GetAnswer := 'Number is not palindrome';
end;
Procedure OutputToFile(Path, Answer: String);
var
    OutFile: TextFile;
begin
    AssignFile(OutFile, Path);
    Rewrite(OutFile);
    Writeln(OutFile, answer);
    CloseFile(OutFile);
    Writeln('Complete');
end;
Procedure Output(Source, Answer: String);
var
    OutPath: String;
begin
    if (Source = '1') then
        Writeln(answer)
    else
    begin
        OutPath := GetOutPath;
        OutputToFile(OutPath,Answer);
    end;
end;
var
    InputSource, OutputSource, Answer: String;
    Number, ReverseNumber: Integer;
begin
    Writeln('Welcome to the program that checks is a given number a palindrome.');
    InputSource := getSource('entering the number');
    Number := getNum(InputSource);
    ReverseNumber := getReverse(Number);
    Answer := getAnswer(Number,ReverseNumber);
    OutputSource := getSource('output');
    Output(OutputSource,Answer);
    readln;
end.