program LabWork31;

{$APPTYPE CONSOLE}

uses
  SysUtils;

type
   TStringArray = array of String;

function UserChoise(): Char;
var
   IsCorrect: Boolean;
   Choise: Char;
begin
   IsCorrect := False;
   repeat
      Write('Y/N: ');
      Readln(Choise);
      Choise := UpCase(Choise);
      if (Choise = 'Y') or (Choise = 'N') then
         begin
            IsCorrect := True;
            UserChoise := Choise;
         end
      else
         Writeln('You made an incorrect choice, please, try again clearly following the instructions');
   until IsCorrect;
end;


function InputName(): String;
var
   FileName: String;
   IsCorrect: Boolean;
begin
   Writeln('Please, enter name of the file or way to the file.');
   Writeln('Example: F:\Programming\Lab\3_1\Delphi\Input.txt');
   IsCorrect := False;
   repeat
      Readln(FileName);
      if FileExists(FileName) then
      begin
         IsCorrect := True;
         InputName := FileName;
      end
      else
         Writeln('File with the same name does not exist, please, enter name of the file again');
   until IsCorrect;
end;


function EnterStringFromFile(FileName: String): String;
var
   Input: TextFile;
   UserString: String;
begin
   AssignFile(Input, FileName);
   Reset(Input);
   Readln(Input, UserString);
   EnterStringFromFile := UserString;
end;


function CountTheDimension(UserString: String): Integer;
var
   StringIndex, Iteration : Integer;
   Dimension: Integer;
   NumberLikeString: set of Char;
begin
    NumberLikeString := ['0'..'9'];
    Iteration := length(UserString) - 1;
    StringIndex := 1;
    Dimension := 0;
    while StringIndex < Iteration do
    begin
      if (UserString[StringIndex] = '+') or (UserString[StringIndex] = '-') then
         if UserString[StringIndex + 1] in NumberLikeString then
            Dimension := Dimension + 1;
      inc(StringIndex);
    end;
    CountTheDimension := Dimension;
end;


function FindIntegers(UserString: String): TStringArray;
var
   IntegerLikeString: String;
   NumbersFromString: TStringArray;
   StringIndex, StringLen, ArrayIndex, Dimension: Integer;
   NumberLikeString : set of Char;
begin
   NumberLikeString := ['0'..'9'];
   StringLen := Length(UserString);
   Dimension := CountTheDimension(UserString);
   SetLength(NumbersFromString, Dimension);
   if Dimension <> 0 then
   begin
      StringIndex := 1;
      ArrayIndex := 0;
      while StringIndex < StringLen do
      begin
         IntegerLikeString := '';
         if (UserString[StringIndex] = '+') or (UserString[StringIndex] = '-') then
         begin
            if UserString[StringIndex] = '-' then
               IntegerLikeString := '-';
            inc(StringIndex);
            while UserString[StringIndex] in NumberLikeString do
            begin
               IntegerLikeString := IntegerLikeString + UserString[StringIndex];
               if  StringIndex <= StringLen then
                  inc(StringIndex);
            end;
            if (IntegerLikeString <>  '-') and (IntegerLikeString <> '') then
            begin
               NumbersFromString[ArrayIndex] := IntegerLikeString;
               inc(ArrayIndex);
            end;
         end
         else
            inc(StringIndex);
      end;
   end;
   FindIntegers := NumbersFromString;
end;


procedure OutputInf(NumbersFromString: TStringArray);
var
   Output: TextFile;
   FileName: String;
   Iteration, Index: Integer;
   OutputToFile, AppendOrRewrite: Char;
begin
   if Length(NumbersFromString) <> 0 then
   begin
      Writeln('There are ', length(NumbersFromString), ' integers in your string.');
      Iteration := Length(NumbersFromString) - 1;
      for Index := 0 to Iteration do
         Writeln(NumbersFromString[Index]);
      Writeln('Do you want to output data to a file?');
      OutputToFile := UserChoise();
      if OutputToFile = 'Y' then
      begin
         Writeln('Please, enter name of the file');
         Readln(FileName);
         AssignFile(Output, FileName);
         if FileExists(FileName) then
         begin
            Write('A file with this name already exists, ');
            Writeln('do you want to overwrite it');
            AppendOrRewrite := UserChoise();
            if AppendOrRewrite = 'Y' then
               Append(Output)
            else
               Rewrite(Output);
         end
         else
            Rewrite(Output);
         Writeln(Output, 'There are ', length(NumbersFromString), ' integers in your string.');
         for Index := 0 to Iteration do
         Writeln(Output, NumbersFromString[Index]);
         CloseFile(Output);
         Writeln('Write was successfully');
      end;
   end
   else
      Writeln('Your string have not integers.')
end;

procedure Main();
var
   ChoiseInput, RepeatProgram: Char;
   FileName, UserString: String;
   NumbersFromString: TStringArray;

begin
   Writeln('Hello, this program extracts integers from a string');
   repeat
      Writeln('Do you want to enter data through a file? (otherwise via console)');
      ChoiseInput := UserChoise;
      case Ord(ChoiseInput) of
         Ord('Y'):
            begin
               FileName := InputName();
               UserString := EnterStringFromFile(FileName);
            end;
         Ord('N'):
            begin
               Writeln('Please, enter your string');
               Readln(UserString);
            end;
      end;
      UserString := Trim(UserString);
      if UserString = '' then
         Writeln('Your string is empty')
      else
      begin
         NumbersFromString := FindIntegers(userString);
         OutputInf(NumbersFromString);
      end;
      Writeln('Do you want enter another string?');
      RepeatProgram := UserChoise();
   until (RepeatProgram = 'N');
   Writeln('Press enter to exit');
   Readln;
end;


begin
   Main;
end.