from __future__ import annotations
import hashlib
from datetime import datetime
from sqlalchemy import String, Integer, DateTime, ForeignKey, func, Index
from sqlalchemy.orm import Mapped, mapped_column, relationship
from shared.db.base import Base


class OAuthCode(Base):
    """Short-lived authorization code issued during OAuth flow.

    The ``code`` column is retained during migration but new codes store
    only ``code_hash``.  Lookups should use ``code_hash``.
    """
    __tablename__ = "oauth_codes"

    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
    code: Mapped[str | None] = mapped_column(String(128), nullable=True)
    code_hash: Mapped[str | None] = mapped_column(String(64), unique=True, nullable=True, index=True)
    user_id: Mapped[int] = mapped_column(ForeignKey("users.id", ondelete="CASCADE"), nullable=False, index=True)
    client_id: Mapped[str] = mapped_column(String(64), nullable=False)
    redirect_uri: Mapped[str] = mapped_column(String(512), nullable=False)
    expires_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), nullable=False)
    used_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
    grant_token: Mapped[str | None] = mapped_column(String(128), nullable=True)
    grant_token_hash: Mapped[str | None] = mapped_column(String(64), nullable=True)
    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), nullable=False, server_default=func.now())

    user = relationship("User", backref="oauth_codes")

    __table_args__ = (
        Index("ix_oauth_code_code_hash", "code_hash", unique=True),
        Index("ix_oauth_code_user", "user_id"),
    )
