"""Валидация математической корректности задач"""

import re
from typing import Union
from fractions import Fraction


class ProbabilityValidator:
    """Валидатор для проверки корректности вероятностей"""

    @staticmethod
    def is_valid_probability(probability: Union[float, Fraction]) -> bool:
        if isinstance(probability, Fraction):
            probability = float(probability)
        return 0 <= probability <= 1

    @staticmethod
    def validate_task(task: dict) -> bool:
        try:
            required_fields = ['question', 'answer', 'solution', 'steps']
            for field in required_fields:
                if field not in task:
                    return False

            if not ProbabilityValidator.is_valid_probability(task['answer']):
                return False

            if not ProbabilityValidator.validate_grammar(task['question']):
                return False

            return True
        except Exception:
            return False

    @staticmethod
    def validate_grammar(question: str) -> bool:
        q = question.lower()

        forbidden_patterns = [
            r'\bптиц\b.*\bчай\b',
            r'\bкур\b.*\bчай\b',
            r'\bгус\b.*\bчай\b',
            r'\bшар\b.*\bчай\b',
        ]

        for pattern in forbidden_patterns:
            if re.search(pattern, q):
                return False

        if re.search(r'\bчай\b', q):
            tea_patterns = [
                r'\bчай\b.*\bпакетик\b',
                r'\bпакетик\b.*\bчай\b',
                r'\bчёрн\w*\b.*\bчай\b',
                r'\bзелён\w*\b.*\bчай\b',
            ]
            if not any(re.search(p, q) for p in tea_patterns):
                return False

        if re.search(r'\b(птиц|кур|гус|утк)\w*\b', q):
            bird_patterns = [
                r'\bферм\w*\b',
                r'\bкур\w*\b.*\bгус\w*\b',
                r'\bгус\w*\b.*\bкур\w*\b',
            ]
            if not any(re.search(p, q) for p in bird_patterns):
                return False

        return True