import enum
import uuid
from datetime import datetime

from sqlalchemy import DateTime, Enum, ForeignKey, Text, UniqueConstraint, func
from sqlalchemy.dialects.postgresql import UUID
from sqlalchemy.orm import Mapped, mapped_column, relationship

from app.db.base_class import Base


class AcknowledgementType(str, enum.Enum):
    RECEIVED = "RECEIVED"
    READ = "READ"
    TRAINED = "TRAINED"


class Acknowledgement(Base):
    __tablename__ = "acknowledgements"
    __table_args__ = (
        UniqueConstraint("distribution_id", "user_id", "ack_type", name="uq_ack_distribution_user_type"),
    )

    id: Mapped[uuid.UUID] = mapped_column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
    distribution_id: Mapped[uuid.UUID] = mapped_column(UUID(as_uuid=True), ForeignKey("distributions.id"), nullable=False)
    user_id: Mapped[uuid.UUID] = mapped_column(UUID(as_uuid=True), ForeignKey("users.id"), nullable=False)
    site_id: Mapped[uuid.UUID | None] = mapped_column(UUID(as_uuid=True), ForeignKey("sites.id"), nullable=True)
    ack_type: Mapped[AcknowledgementType] = mapped_column(
        Enum(AcknowledgementType, name="acknowledgement_type"),
        nullable=False,
    )
    due_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
    acked_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
    note: Mapped[str | None] = mapped_column(Text, nullable=True)
    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), nullable=False, server_default=func.now())

    distribution = relationship("Distribution", back_populates="acknowledgements")