лаба3н1(основа)

Program laba1;

Uses
    Windows, System.SysUtils;
Var
    IsCorrect : Boolean;

Procedure PrintCondition();
Begin
    Writeln('Эта программа выводит самое короткое слово в предложении и его позицию.', #13, #10);
End;

Function CheckPath() : String;
Var
    Path : String;
    IsCorrect : Boolean;
Begin
    Writeln('Введите путь к файлу:');
    Repeat
        IsCorrect := True;
        Readln(Path);
        If Not FileExists(Path) Then
        Begin
            IsCorrect := False;
            Writeln('Такого файла не существует. Повторите ввод:');
        End
        Else If Not(ExtractFileExt(Path) = '.txt') Then
        Begin
            IsCorrect := False;
            Writeln('Неправильное расширение файла. Повторите ввод:');
        End;
    Until IsCorrect;
    CheckPath := Path;
End;

Function PathForRead() : String;
Var
    MyFile : TextFile;
    Path : String;
    IsCorrect : Boolean;
Begin
    Repeat
        IsCorrect := True;
        Path := CheckPath();
        Try
            AssignFile(MyFile, Path);
            Reset(MyFile);
        Except
            IsCorrect := False;
            Writeln('Нет доступа к файлу. Измените настройки и повторите ввод.');
        End;
    CloseFile(MyFile);
    Until IsCorrect;
    PathForRead := Path;
End;

Function CheckPermission(Path : String) : Boolean;
Var
    MyFile : TextFile;
    IsCorrect : Boolean;
Begin
    IsCorrect := True;
    AssignFile(MyFile, Path);
    Try
        Rewrite(MyFile);
    Except
        Writeln('Файл закрыт для записи.');
        IsCorrect := False;
        Readln;
    End;
    CloseFile(MyFile);
    CheckPermission := IsCorrect;
End;

Function PathForWrite() : String;
Var
    Path : String;
    MyFile : TextFile;
    IsCorrect : Boolean;
Begin
    Repeat
        IsCorrect := True;
        Path := CheckPath();
        If Not (CheckPermission(Path)) Then
            IsCorrect := False
    Until IsCorrect;
    PathForWrite := Path;
End;

Function Input(Var IsCorrect : Boolean) : String;
Var
    Sentence : String;
Begin
    Readln(Sentence);
    If Sentence = '' Then
    Begin
        IsCorrect := False;
        Writeln('Ошибка. Вы ничего не ввели.');
    End;
    Input := Sentence;
End;

Function ReadSentenceConsole() : String;
Var
    Text : String;
Begin
    Repeat
        IsCorrect := True;
        Writeln('Введите предложение:');
        Text := Input(IsCorrect);
    Until IsCorrect;
    ReadSentenceConsole := Text;
End;

Function IsSpaceCharacter(Ch: Char): Boolean;
Begin
  IsSpaceCharacter := (Ch = ' ') Or (Ch = #9);
End;

Function ExtractWords(Const Sentence: String): TArray<string>;
Var
  Words: TArray<string>;
  CurrentWord: string;
  CurrentWordStartIndex: Integer;
  I: Integer;
Begin
  SetLength(Words, 0);
  CurrentWord := '';
  CurrentWordStartIndex := 1;

  I := 1;
  While I <= Length(Sentence) Do
  Begin
    While (I <= Length(Sentence)) And IsSpaceCharacter(Sentence[I]) Do
      Inc(I);

    CurrentWordStartIndex := I;

    While (I <= Length(Sentence)) And Not IsSpaceCharacter(Sentence[I]) Do
      Inc(I);

    CurrentWord := Copy(Sentence, CurrentWordStartIndex, I - CurrentWordStartIndex);

    If CurrentWord <> '' Then
    Begin
      SetLength(Words, Length(Words) + 1);
      Words[Length(Words) - 1] := CurrentWord;
    End;
  End;

  ExtractWords := Words;
End;

Function FindShortestWord(Const Words: TArray<String>): String;
var
  ShortestWord: String;
  I: Integer;
Begin
  ShortestWord := '';

  For I := 0 To Length(Words) - 1 Do
  Begin
    If (ShortestWord = '') Or (Length(Words[I]) < Length(ShortestWord)) Then
      ShortestWord := Words[I];
  End;

  FindShortestWord := ShortestWord;
End;

Function GetWordStartPosition(Const Sentence: String; Const Word: String): Integer;
Var
  I, J: Integer;
  WordLength: Integer;
  Found: Boolean;
begin
  WordLength := Length(Word);
  I := 1;
  Found := False;

  While (Not Found) And (I <= Length(Sentence) - WordLength + 1) Do
  Begin
    J := 1;
    While (J <= WordLength) And (Sentence[I + J - 1] = Word[J]) Do
      Inc(J);

    If J > WordLength then
      Found := True
    Else
      Inc(I);
  End;

  If Found Then
    GetWordStartPosition := I
  Else
    GetWordStartPosition := -1;
End;

Function NumberToString(Number: Integer): String;
Var
  CurrentDigit: Integer;
Begin
  NumberToString := '';
  Repeat
    CurrentDigit := Number Mod 10;
    Number := Number Div 10;
    NumberToString := Chr(Ord('0') + CurrentDigit) + Result;
  Until Number = 0;
End;

Function FormatShortestWordPosition(Const ShortestWord: String; ShortestWordStartIndex: Integer): String;
Begin
  If ShortestWordStartIndex <> -1 Then
    FormatShortestWordPosition := 'Самое короткое слово: ' + ShortestWord +
      ', начинается с позиции: ' + NumberToString(ShortestWordStartIndex)
  Else
    FormatShortestWordPosition := 'В предложении нет слов.';
End;

Procedure PrintShortestWordPosition(Const ShortestWord: String; ShortestWordStartIndex: Integer);
Var
  ResultMessage: String;
Begin
  ResultMessage := FormatShortestWordPosition(ShortestWord, ShortestWordStartIndex);
  Writeln(ResultMessage);
End;


Function ReadSentenceFromFile(Var MyFile : TextFile; Var IsCorrect : Boolean) : String;
Var
    Sentence : String;
Begin
    Readln(MyFile, Sentence);
    If Sentence = '' Then
    Begin
        IsCorrect := False;
        Writeln('Ошибка. Недостаточно данных в файле.');
    End;
    ReadSentenceFromFile := Sentence;
End;

Function ReadFile() : String;
Var
    Path : String;
    MyFile : TextFile;
    Sentence : String;
    IsCorrect : Boolean;
    Words: TArray<string>;
    ShortestWord: string;
    ShortestWordStartIndex: Integer;
Begin
    Repeat
        IsCorrect := True;
        Path := PathForRead();
        AssignFile(MyFile, Path);
        ReSet(MyFile);
        Sentence := ReadSentenceFromFile(MyFile, IsCorrect);
        If IsCorrect Then
        Begin
            IsCorrect := False;
            Writeln('Ошибка. Недостаточно данных в файле.');
        End;
        CloseFile(MyFile);
    Until IsCorrect;
    Words := ExtractWords(Sentence);
    ShortestWord := FindShortestWord(Words);
    ShortestWordStartIndex := GetWordStartPosition(Sentence, ShortestWord);
    ReadFile := Sentence;
End;

Function ChooseAction() : String;
Var
    Input: String;
    IsCorrect : Boolean;
Begin
    Repeat
        IsCorrect := True;
        Readln(Input);
        Input := LowerCase(Input);
        If (Input <> 'console') And (Input <> 'file') Then
        Begin
            Writeln('Ошибка. Введите "console" или "file".');
            IsCorrect := False;
        End;
    Until IsCorrect;
    ChooseAction := Input;
End;

Function ChooseInput() : String;
Var
    Option : String;
    MyFile : TextFile;
    Sentence : String;
    Words: TArray<string>;
    ShortestWord: string;
    ShortestWordStartIndex: Integer;
Begin
    Writeln('Выберите способ ввода данных.', #13#10,
            'Введите "console", если хотите ввести данные через консоль', #13#10,
            'Введите "file", если хотите передать данные из файла');
    Option := ChooseAction();
    If Option = 'console' Then
    Begin
        Sentence := ReadSentenceConsole();
        Words := ExtractWords(Sentence);
        ShortestWord := FindShortestWord(Words);
        ShortestWordStartIndex := GetWordStartPosition(Sentence, ShortestWord);
    End
    Else
        Sentence := ReadFile();
    ChooseInput := Sentence;
End;

Procedure WriteConsole(Const ShortestWord: string; ShortestWordStartIndex: Integer);
Var
    ResultMessage: String;
Begin
    ResultMessage := FormatShortestWordPosition(ShortestWord, ShortestWordStartIndex);
    Writeln(ResultMessage);
End;

Procedure WriteFile(Const ShortestWord: string; ShortestWordStartIndex: Integer);
Var
    MyFile : TextFile;
    Path : String;
    ResultMessage : String;
Begin
    Path := PathForWrite();
    AssignFile(MyFile, Path);
    Rewrite(MyFile);
    ResultMessage := FormatShortestWordPosition(ShortestWord, ShortestWordStartIndex);
    Writeln(MyFile, ResultMessage);
    CloseFile(MyFile);
    Writeln('Результат в файле.');
End;

Procedure ChooseOutput(ShortestWord : String; ShortestWordStartIndex : Integer);
Var
    Option : String;
Begin
    Writeln('Выберите способ вывода результата.', #13#10,
            'Введите "console", если хотите вывести результат через консоль', #13#10,
            'Введите "file", если хотите передать результат в файл');
    Option := ChooseAction;
    If Option = 'console' Then
     WriteConsole(ShortestWord, ShortestWordStartIndex)
    Else
        WriteFile(ShortestWord, ShortestWordStartIndex);
End;

Var
    Sentence : String;
    ShortestWord : String;
    ResultMessage : String;
    ShortestWordStartIndex : Integer;
Begin
    SetConsoleCP(1251);
    SetConsoleOutputCP(1251);
    PrintCondition();
    Sentence := ChooseInput();
    ChooseOutput(ShortestWord, ShortestWordStartIndex);
    Readln
End.