"""Review requests: an open question about a document, not a status

Publishing becomes the author's own action, so `pending_approval` disappears
and the delegated-approver column with it. What replaces both is a request
that can sit on a draft OR on a published document: "please check this", with
the question attached.

Revision ID: b8e14d7c05a3
Revises: f3c8d5a92b47
"""

from collections.abc import Sequence
from typing import Union

import sqlalchemy as sa

from alembic import op

revision: str = "b8e14d7c05a3"
down_revision: Union[str, Sequence[str], None] = "f3c8d5a92b47"
branch_labels: Union[str, Sequence[str], None] = None
depends_on: Union[str, Sequence[str], None] = None


def upgrade() -> None:
    op.create_table(
        "review_requests",
        sa.Column("id", sa.Uuid(), nullable=False),
        sa.Column("document_id", sa.Uuid(), nullable=False),
        sa.Column("requester_id", sa.Uuid(), nullable=True),
        sa.Column("reviewer_id", sa.Uuid(), nullable=True),
        sa.Column("question", sa.Text(), nullable=True),
        sa.Column("resolved_at", sa.DateTime(timezone=True), nullable=True),
        sa.Column("resolved_by_id", sa.Uuid(), nullable=True),
        sa.Column(
            "created_at",
            sa.DateTime(timezone=True),
            server_default=sa.text("now()"),
            nullable=False,
        ),
        sa.Column(
            "updated_at",
            sa.DateTime(timezone=True),
            server_default=sa.text("now()"),
            nullable=False,
        ),
        sa.ForeignKeyConstraint(["document_id"], ["documents.id"], ondelete="CASCADE"),
        sa.ForeignKeyConstraint(["requester_id"], ["users.id"], ondelete="SET NULL"),
        sa.ForeignKeyConstraint(["reviewer_id"], ["users.id"], ondelete="SET NULL"),
        sa.ForeignKeyConstraint(["resolved_by_id"], ["users.id"], ondelete="SET NULL"),
        sa.PrimaryKeyConstraint("id"),
    )
    op.create_index(
        "ix_review_requests_document_id", "review_requests", ["document_id"]
    )
    op.create_index(
        "ix_review_requests_reviewer_id", "review_requests", ["reviewer_id"]
    )

    # A document waiting for approval is simply an unpublished draft now; the
    # ask that used to be implied by the status is an explicit request.
    op.execute(
        "UPDATE documents SET status = 'draft' WHERE status = 'pending_approval'"
    )
    op.drop_column("documents", "reviewer_id")

    # The audit trail keeps its shape: approving WAS publishing, and
    # submitting has no counterpart in a world where the author publishes.
    op.execute(
        "UPDATE document_events SET action = 'published' WHERE action = 'approved'"
    )
    op.execute("DELETE FROM document_events WHERE action = 'submitted'")


def downgrade() -> None:
    op.add_column("documents", sa.Column("reviewer_id", sa.Uuid(), nullable=True))
    op.create_foreign_key(
        "documents_reviewer_id_fkey",
        "documents",
        "users",
        ["reviewer_id"],
        ["id"],
        ondelete="SET NULL",
    )
    op.drop_index("ix_review_requests_reviewer_id", table_name="review_requests")
    op.drop_index("ix_review_requests_document_id", table_name="review_requests")
    op.drop_table("review_requests")