from __future__ import annotations

import uuid
from datetime import datetime

from sqlalchemy import DateTime, ForeignKey, String, func
from sqlalchemy.dialects.postgresql import UUID
from sqlalchemy.orm import Mapped, mapped_column, relationship

from app.database.database import Base


class Document(Base):
    """
    Represents a logical document within a workspace.

    A document is the logical identity of a document. Each upload
    creates a new DocumentVersion while preserving the document's
    identity across revisions.
    """

    __tablename__ = "documents"

    id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True),
        primary_key=True,
        default=uuid.uuid4,
    )

    workspace_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True),
        ForeignKey("workspaces.id", ondelete="CASCADE"),
        nullable=False,
        index=True,
    )

    title: Mapped[str] = mapped_column(
        String(500),
        nullable=False,
        index=True,
    )

    document_type: Mapped[str] = mapped_column(
        String(100),
        nullable=False,
        index=True,
    )

    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True),
        nullable=False,
        server_default=func.now(),
    )

    updated_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True),
        nullable=False,
        server_default=func.now(),
        onupdate=func.now(),
    )

    # ------------------------------------------------------------------
    # Relationships
    # ------------------------------------------------------------------

    workspace: Mapped["Workspace"] = relationship(
        back_populates="documents",
    )

    versions: Mapped[list["DocumentVersion"]] = relationship(
        back_populates="document",
        cascade="all, delete-orphan",
        passive_deletes=True,
        order_by="DocumentVersion.version_number",
    )

    def __repr__(self) -> str:
        return (
            f"<Document("
            f"title='{self.title}', "
            f"type='{self.document_type}')>"
        )