import re


class Program:
    def __init__(self, program_from_file):
        self.dct = program_from_file

    def next_command(self, current_symbol: str, current_state: int):
        next_com = self.dct[current_symbol][current_state]
        next_sym, next_state = re.split('[<>.]', next_com, 1)
        direction = re.findall('[<>.]', next_com)[0]
        return next_sym, direction, next_state


class Parser:
    def __init__(self, path_to_file):
        self.path = path_to_file
        self._program_dct = {}

        self.parser()
        self._program = Program(self._program_dct)

    def parser(self):
        # Прочитываем файл и заносим все данные в словарь
        with open(self.path, 'r') as file:
            for line in file.readlines():
                line = line.rstrip('\n').split('\t')
                self._program_dct[line[0]] = {num: sym for num, sym in
                                              enumerate(line[1:], start=1)}

    @property
    def program(self):
        return self._program


class TuringMachine:
    def __init__(self, line: str, program: Program):
        self.line: list = list(line)
        self.head_index = line.index('q')
        del self.line[self.head_index]

        self.start_line = self.line.copy()

        self.program = program
        self.count_command = 0

        self.current_state = 1

    def run(self):
        # line = "q111X11"

        while str(self.current_state) != '0':
            self.count_command += 1
            print(f'-- COMMAND NUM: {self.count_command} --')

            viewed_symbol = self.get_viewed_symbol()
            print(f'    State: {self.current_state} -> ', end='')
            next_com = self.program.next_command(viewed_symbol,
                                                 self.current_state)
            if not next_com:
                print('--- STOP ---')
                break

            set_symbol, direction, next_state = next_com
            self.current_state = int(next_state)

            print_line = self.line.copy()
            print_line[self.head_index] = 'q' + print_line[self.head_index]
            print(f'{self.current_state}; Sym: {set_symbol}; '
                  f'Dir: {direction}; Line: "{"".join(print_line)}" -> ',
                  end='')

            self.set_symbol(set_symbol)
            self.move_head(direction)

            print_line = self.line.copy()
            print_line[self.head_index] = 'q' + print_line[self.head_index]
            print(f'"{"".join(print_line)}"')

        print(f'Convert line: "{"".join(self.start_line)}" -> '
              f'"{"".join(self.line)}"')

    def set_symbol(self, symbol):
        if symbol == "_":
            symbol = ' '
        self.line[self.head_index] = symbol

    def move_head(self, direction):
        # Пережвигаем головку машины
        if direction == '>':
            self.head_index += 1
        elif direction == '<':
            self.head_index -= 1

        # Если вышли за размеры линии, то сразу изменяем ее размер
        # (так проще всего вышло сделать для логов)
        if self.head_index >= len(self.line):
            self.line.extend([' ' for i in range(self.head_index -
                                                 (len(self.line) - 1))])
        if self.head_index < 0:
            for _ in range(abs(self.head_index)):
                self.line.insert(0, ' ')
            self.head_index = 0

    def get_viewed_symbol(self):
        symbol = ' '
        if self.head_index < len(self.line):
            symbol = self.line[self.head_index]
        return symbol

    def print_result(self):
        print(f'All viewed cell count: {len(self.line)}')
        print(f'Command count: {self.count_command}')


tur_machine = TuringMachine('111q1',
                            Parser('lab_3_programs/4.4.txt').program)
tur_machine.run()
tur_machine.print_result()