import uuid
from sqlalchemy import Column, String, Integer, BigInteger, DateTime, ForeignKey, Index
from sqlalchemy.orm import relationship
from sqlalchemy.sql import func
from app.core.database import Base


class AttachmentVersion(Base):
    __tablename__ = "pjctrl_attachment_versions"

    id = Column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
    attachment_id = Column(String(36), ForeignKey("pjctrl_attachments.id", ondelete="CASCADE"), nullable=False)
    version = Column(Integer, nullable=False)
    file_path = Column(String(1000), nullable=False)
    file_size = Column(BigInteger, nullable=False)
    checksum = Column(String(64), nullable=False)  # SHA-256
    uploaded_by = Column(String(36), ForeignKey("pjctrl_users.id", ondelete="SET NULL"), nullable=True)
    created_at = Column(DateTime, server_default=func.now(), nullable=False)

    # Relationships
    attachment = relationship("Attachment", back_populates="versions")
    uploader = relationship("User", foreign_keys=[uploaded_by])

    __table_args__ = (
        Index("idx_version_attachment", "attachment_id", "version"),
    )