from __future__ import annotations

import uuid
from datetime import datetime

from sqlalchemy import (
    DateTime,
    ForeignKey,
    Text,
    func,
)
from sqlalchemy.dialects.postgresql import JSONB, UUID
from sqlalchemy.orm import Mapped, mapped_column, relationship

from app.database.database import Base


class Commit(Base):
    """
    Represents an approved change committed to the
    Knowledge Register.

    Every commit forms part of the audit trail and
    provides a complete history of how the Knowledge
    Register evolved over time.
    """

    __tablename__ = "commits"

    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,
    )

    proposal_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True),
        ForeignKey("proposals.id", ondelete="SET NULL"),
        nullable=True,
        index=True,
    )

    committed_by: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True),
        ForeignKey("users.id", ondelete="RESTRICT"),
        nullable=False,
        index=True,
    )

    message: Mapped[str] = mapped_column(
        Text,
        nullable=False,
    )

    changes: Mapped[dict] = mapped_column(
        JSONB,
        nullable=False,
    )

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

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

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

    proposal: Mapped["Proposal | None"] = relationship()

    author: Mapped["User"] = relationship()

    def __repr__(self) -> str:
        return (
            f"<Commit("
            f"id={self.id}, "
            f"committed_at={self.committed_at})>"
        )