"""
Урок 69. Практикум 17 — весь код примеров одним файлом.

Источник: subjects/python-fundamentals/course/lessons/69-practice-17/examples.html
Файл собран автоматически (tools/build_lesson_examples.py): правьте страницу урока.
Запуск: python lesson-69.py
"""



# ====================================================================
# Полный рабочий код класса Student
# ====================================================================
from datetime import datetime, date


class Student:
    current_id: int = 1
    MIN_AGE: int = 16

    def __init__(self, name: str, birth_date: str) -> None:
        self.birth_date = datetime.strptime(birth_date, "%Y-%m-%d").date()
        if not self.is_valid_birthdate():
            raise ValueError("Student must be at least 16 years old.")

        self.name = name
        self.student_id = Student.current_id
        Student.current_id += 1

    def __str__(self) -> str:
        return f"Student: {self.name}, birth_date: {self.birth_date}, ID: {self.student_id}"

    def __repr__(self) -> str:
        return (
            f"Student(name={self.name!r}, birth_date={self.birth_date!r}, "
            f"student_id={self.student_id!r})"
        )

    def show_info(self) -> None:
        print(
            f"Student:\n\tName: {self.name}\n\tAge: {self.calculate_age()}\n\tID: {self.student_id}"
        )

    def calculate_age(self) -> int:
        today = date.today()
        return self.calculate_age_on(today)

    def calculate_age_on(self, target_date: date) -> int:
        age = target_date.year - self.birth_date.year
        if (target_date.month, target_date.day) < (self.birth_date.month, self.birth_date.day):
            age -= 1
        return age

    def is_valid_birthdate(self) -> bool:
        return self.calculate_age() >= self.MIN_AGE

    @classmethod
    def from_string(cls, data: str) -> "Student":
        name, date_string = map(str.strip, data.split(","))
        return cls(name, date_string)

    @staticmethod
    def filter_by_min_age(students: list["Student"], min_age: int) -> list["Student"]:
        return [s for s in students if s.calculate_age() >= min_age]


# Создание студентов разными способами
s1 = Student("Alice", "2005-05-10")
s2 = Student.from_string("Bob, 2001-12-03")

print(s1)
s1.show_info()
print(s2)
s2.show_info()

# Возраст на конкретную дату
some_date = date(2030, 5, 10)
print(f"Alice will be {s1.calculate_age_on(some_date)} on {some_date}")

# Фильтрация по возрасту
print("Min age 21:")
for student in Student.filter_by_min_age([s1, s2], 21):
    print("\t", student)

# Проверка валидации
try:
    Student("Bill", "2009-05-15")
except ValueError as error:
    print(f"ValueError: {error}")


# ====================================================================
# Пример 1. Парсинг даты
# ====================================================================
from datetime import datetime

birth_date = datetime.strptime("2005-05-10", "%Y-%m-%d").date()
print(birth_date)       # 2005-05-10
print(type(birth_date)) # <class 'datetime.date'>


# ====================================================================
# Пример 2. Корректный подсчёт возраста
# ====================================================================
from datetime import date

birth_date = date(2005, 5, 10)
today = date(2026, 3, 8)

age = today.year - birth_date.year
if (today.month, today.day) < (birth_date.month, birth_date.day):
    age -= 1

print(age)  # 20, а не 21, потому что день рождения ещё не наступил


# ====================================================================
# Пример 3. Альтернативный конструктор
# ====================================================================
class Student:
    def __init__(self, name: str, birth_date: str) -> None:
        self.name = name
        self.birth_date = birth_date

    @classmethod
    def from_string(cls, data: str) -> "Student":
        name, date_string = map(str.strip, data.split(","))
        return cls(name, date_string)


s = Student.from_string("Bob, 2001-12-03")
print(s.name)        # Bob
print(s.birth_date)  # 2001-12-03


# ====================================================================
# Пример 4. Статический метод фильтрации
# ====================================================================
class Student:
    def __init__(self, name: str, age: int) -> None:
        self.name = name
        self.age = age

    @staticmethod
    def filter_by_min_age(students: list["Student"], min_age: int) -> list["Student"]:
        return [s for s in students if s.age >= min_age]


s1 = Student("Alice", 19)
s2 = Student("Bob", 23)
print(Student.filter_by_min_age([s1, s2], 21))  # [Bob]