"""
UserAnswer model for tracking individual question responses.

Represents a student's response to a single question with scoring metadata.
"""

from datetime import datetime
from typing import Literal, Union

from sqlalchemy import Boolean, CheckConstraint, DateTime, Float, ForeignKey, Index, Integer, String
from sqlalchemy.orm import Mapped, mapped_column, relationship

from app.database import Base


class UserAnswer(Base):
    """
    UserAnswer model representing a student's response to a question.

    Tracks response, correctness, scoring, and timing information.

    Attributes:
        id: Primary key
        session_id: Session identifier
        wp_user_id: WordPress user ID
        website_id: Website identifier
        tryout_id: Tryout identifier
        item_id: Item identifier
        response: User's answer (A, B, C, D)
        is_correct: Whether answer is correct
        time_spent: Time spent on this question (seconds)
        scoring_mode_used: Scoring mode used
        bobot_earned: Weight earned for this answer
        created_at: Record creation timestamp
        updated_at: Record update timestamp
        session: Session relationship
        item: Item relationship
    """

    __tablename__ = "user_answers"

    # Primary key
    id: Mapped[int] = mapped_column(primary_key=True, autoincrement=True)

    # Foreign keys
    session_id: Mapped[str] = mapped_column(
        ForeignKey("sessions.session_id", ondelete="CASCADE", onupdate="CASCADE"),
        nullable=False,
        index=True,
        comment="Session identifier",
    )
    wp_user_id: Mapped[str] = mapped_column(
        String(255), nullable=False, index=True, comment="WordPress user ID"
    )
    website_id: Mapped[int] = mapped_column(
        ForeignKey("websites.id", ondelete="CASCADE", onupdate="CASCADE"),
        nullable=False,
        index=True,
        comment="Website identifier",
    )
    tryout_id: Mapped[str] = mapped_column(
        String(255), nullable=False, index=True, comment="Tryout identifier"
    )
    item_id: Mapped[int] = mapped_column(
        ForeignKey("items.id", ondelete="CASCADE", onupdate="CASCADE"),
        nullable=False,
        index=True,
        comment="Item identifier",
    )

    # Response information
    response: Mapped[str] = mapped_column(
        String(10), nullable=False, comment="User's answer (A, B, C, D)"
    )
    is_correct: Mapped[bool] = mapped_column(
        Boolean, nullable=False, comment="Whether answer is correct"
    )
    time_spent: Mapped[int] = mapped_column(
        Integer,
        nullable=False,
        default=0,
        comment="Time spent on this question (seconds)",
    )

    # Scoring metadata
    scoring_mode_used: Mapped[Literal["ctt", "irt", "hybrid"]] = mapped_column(
        String(50),
        nullable=False,
        comment="Scoring mode used",
    )
    bobot_earned: Mapped[float] = mapped_column(
        Float,
        nullable=False,
        default=0.0,
        comment="Weight earned for this answer",
    )

    # Timestamps
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), nullable=False, server_default="NOW()"
    )
    updated_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True),
        nullable=False,
        server_default="NOW()",
        onupdate="NOW()",
    )

    # Relationships
    session: Mapped["Session"] = relationship(
        "Session", back_populates="user_answers", lazy="selectin"
    )
    item: Mapped["Item"] = relationship(
        "Item", back_populates="user_answers", lazy="selectin"
    )

    # Constraints and indexes
    __table_args__ = (
        Index("ix_user_answers_session_id", "session_id"),
        Index("ix_user_answers_wp_user_id", "wp_user_id"),
        Index("ix_user_answers_website_id", "website_id"),
        Index("ix_user_answers_tryout_id", "tryout_id"),
        Index("ix_user_answers_item_id", "item_id"),
        Index(
            "ix_user_answers_session_id_item_id",
            "session_id",
            "item_id",
            unique=True,
        ),
        # Time spent must be non-negative
        CheckConstraint("time_spent >= 0", "ck_time_spent_non_negative"),
        # Bobot earned must be non-negative
        CheckConstraint("bobot_earned >= 0", "ck_bobot_earned_non_negative"),
    )

    def __repr__(self) -> str:
        return f"<UserAnswer(id={self.id}, session_id={self.session_id}, item_id={self.item_id})>"