"""ChangeProposal — a structured diff the AI assistant (or an untrusted
contributor) proposes, which a human approves/edits/rejects. Applying it routes
each operation through the normal editing services, so the change passes the
privacy engine and is audited as the approving human's action. See
docs/design/change-proposal.md and CLAUDE.md non-negotiable #1.
"""

import uuid
from datetime import datetime

from sqlalchemy import DateTime, ForeignKey, String, Text
from sqlalchemy import Enum as SAEnum
from sqlalchemy.dialects.postgresql import JSONB
from sqlalchemy.orm import Mapped, mapped_column

from app.models.base import Base
from app.models.enums import ChangeProposalOrigin, ChangeProposalStatus
from app.models.mixins import SoftDelete, TenantScoped, Timestamps, UUIDPrimaryKey


class ChangeProposal(Base, UUIDPrimaryKey, TenantScoped, Timestamps, SoftDelete):
    __tablename__ = "change_proposals"

    status: Mapped[ChangeProposalStatus] = mapped_column(
        SAEnum(ChangeProposalStatus, name="change_proposal_status"),
        default=ChangeProposalStatus.pending,
        server_default=ChangeProposalStatus.pending.value,
        index=True,
    )
    origin: Mapped[ChangeProposalOrigin] = mapped_column(
        SAEnum(ChangeProposalOrigin, name="change_proposal_origin"),
        default=ChangeProposalOrigin.assistant,
        server_default=ChangeProposalOrigin.assistant.value,
    )
    created_by_user_id: Mapped[uuid.UUID | None] = mapped_column(
        ForeignKey("users.id", ondelete="SET NULL")
    )
    summary: Mapped[str] = mapped_column(String(512))
    rationale: Mapped[str | None] = mapped_column(Text)
    # The structured diff: a list of {op, entity_type, entity_id?, payload} dicts.
    operations: Mapped[list] = mapped_column(JSONB, nullable=False)

    reviewed_by_user_id: Mapped[uuid.UUID | None] = mapped_column(
        ForeignKey("users.id", ondelete="SET NULL")
    )
    reviewed_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True))
    review_note: Mapped[str | None] = mapped_column(String(512))
    apply_error: Mapped[str | None] = mapped_column(Text)