from datetime import datetime
from enum import Enum
from tokenize import group
from typing import final

from sqlalchemy import BigInteger, CheckConstraint, ForeignKey, Integer, String, Text, func
from sqlalchemy.orm import DeclarativeBase, Mapped, mapped_column, relationship


class Base(DeclarativeBase):
    pass


@final
class User(Base):
    __tablename__ = "users"
    
    id: Mapped[int] = mapped_column(BigInteger, primary_key=True)
    username: Mapped[str | None] = mapped_column(String(32))
    first_name: Mapped[str] = mapped_column(String(64))
    last_name: Mapped[str | None] = mapped_column(String(64))
    group: Mapped[int | None] = mapped_column(CheckConstraint("group >= 1000 AND group <= 9999"))
    is_admin: Mapped[bool] = mapped_column(default=False)
    created_at: Mapped[datetime] = mapped_column(server_default=func.now())
    updated_at: Mapped[datetime] = mapped_column(server_default=func.now(), onupdate=func.now())


class QuestionType(str, Enum):
    SINGLE = "single"
    MULTIPLE = "multiple"
    INPUT = "input"

@final
class Test(Base):
    __tablename__ = "tests"

    id: Mapped[int] = mapped_column(primary_key=True)
    title: Mapped[str] = mapped_column(String(255))
    description: Mapped[str | None] = mapped_column(Text)
    for_group: Mapped[int | None] = mapped_column(default=None) 
    is_active: Mapped[bool] = mapped_column(default=True)

    questions: Mapped[list["Question"]] = relationship(
        back_populates="test",
        cascade="all, delete-orphan",
        order_by="Question.position"
    )

@final
class Question(Base):
    __tablename__ = "questions"

    id: Mapped[int] = mapped_column(primary_key=True)
    test_id: Mapped[int] = mapped_column(ForeignKey("tests.id"))
    text: Mapped[str] = mapped_column(Text)
    position: Mapped[int] = mapped_column(Integer, default=0)
    question_type: Mapped[QuestionType] = mapped_column(default=QuestionType.SINGLE)
    tg_file_id: Mapped[str | None] = mapped_column(String(255))

    test: Mapped["Test"] = relationship(back_populates="questions")
    options: Mapped[list["Option"]] = relationship(
        back_populates="question",
        cascade="all, delete-orphan"
    )

@final
class Option(Base):
    __tablename__ = "options"

    id: Mapped[int] = mapped_column(primary_key=True)
    question_id: Mapped[int] = mapped_column(ForeignKey("questions.id"))
    text: Mapped[str] = mapped_column(String(255))
    is_correct: Mapped[bool] = mapped_column(default=False)
    explanation: Mapped[str | None] = mapped_column(Text)

    question: Mapped["Question"] = relationship(back_populates="options")