from datetime import datetime, timezone
from sqlalchemy import String, Text, Integer, DateTime, ForeignKey
from sqlalchemy.orm import Mapped, mapped_column, relationship

from app.database import Base


def utcnow() -> datetime:
    return datetime.now(timezone.utc)


class Problem(Base):
    __tablename__ = "problems"

    id: Mapped[int] = mapped_column(primary_key=True)
    contest_id: Mapped[int] = mapped_column(ForeignKey("contests.id", ondelete="CASCADE"), nullable=False)
    title: Mapped[str] = mapped_column(String(255), nullable=False)
    description: Mapped[str] = mapped_column(Text, nullable=False)
    input_format: Mapped[str | None] = mapped_column(Text, nullable=True)
    output_format: Mapped[str | None] = mapped_column(Text, nullable=True)
    constraints: Mapped[str | None] = mapped_column(Text, nullable=True)
    time_limit_ms: Mapped[int] = mapped_column(Integer, default=1000)
    memory_limit_kb: Mapped[int] = mapped_column(Integer, default=262144)  # 256 MB
    total_points: Mapped[int] = mapped_column(Integer, default=100)
    order_index: Mapped[int] = mapped_column(Integer, default=0)
    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), default=utcnow)

    # Relationships
    contest = relationship("Contest", back_populates="problems")
    test_cases = relationship("TestCase", back_populates="problem", cascade="all, delete-orphan")
    submissions = relationship("Submission", back_populates="problem", cascade="all, delete-orphan", passive_deletes=True)