"""Persist one explicitly delegated current/candidate comparison per project binding."""

import sqlalchemy as sa

from alembic import op

revision = "20260909_0033"
down_revision = "20260909_0032"
branch_labels = None
depends_on = None


def upgrade() -> None:
    op.add_column(
        "model_update_watches",
        sa.Column("enabled", sa.Boolean(), nullable=False, server_default=sa.true()),
    )
    op.add_column(
        "model_update_watches",
        sa.Column("version", sa.Integer(), nullable=False, server_default="1"),
    )
    op.create_table(
        "selected_model_comparisons",
        sa.Column("id", sa.Uuid(), primary_key=True),
        sa.Column(
            "project_binding_id",
            sa.Uuid(),
            sa.ForeignKey("project_bindings.id", ondelete="RESTRICT"),
            nullable=False,
        ),
        sa.Column(
            "consumer_client_id",
            sa.Uuid(),
            sa.ForeignKey("service_clients.id", ondelete="RESTRICT"),
            nullable=False,
        ),
        sa.Column(
            "suite_revision_id",
            sa.Uuid(),
            sa.ForeignKey("evaluation_suite_revisions.id", ondelete="RESTRICT"),
            nullable=False,
        ),
        sa.Column(
            "current_deployment_id",
            sa.Uuid(),
            sa.ForeignKey("capability_deployments.id", ondelete="RESTRICT"),
            nullable=False,
        ),
        sa.Column(
            "candidate_deployment_id",
            sa.Uuid(),
            sa.ForeignKey("capability_deployments.id", ondelete="RESTRICT"),
            nullable=False,
        ),
        sa.Column(
            "candidate_route_id",
            sa.Uuid(),
            sa.ForeignKey("capability_experiment_routes.id", ondelete="RESTRICT"),
            nullable=False,
        ),
        sa.Column("idempotency_key", sa.String(128), nullable=False),
        sa.Column("request_digest", sa.String(64), nullable=False),
        sa.Column("actor_id", sa.String(128), nullable=False),
        sa.Column("pins", sa.JSON(), nullable=False),
        sa.Column("status", sa.String(32), nullable=False),
        sa.Column("version", sa.Integer(), nullable=False, server_default="1"),
        sa.Column("current_completed_cases", sa.Integer(), nullable=False, server_default="0"),
        sa.Column("candidate_completed_cases", sa.Integer(), nullable=False, server_default="0"),
        sa.Column("expected_cases", sa.Integer(), nullable=False),
        sa.Column("claim_token_hash", sa.String(64)),
        sa.Column("claim_expires_at", sa.DateTime(timezone=True)),
        sa.Column("deadline_at", sa.DateTime(timezone=True)),
        sa.Column("claimed_at", sa.DateTime(timezone=True)),
        sa.Column("cancel_requested_at", sa.DateTime(timezone=True)),
        sa.Column("finished_at", sa.DateTime(timezone=True)),
        sa.Column("error_code", sa.String(64)),
        sa.Column("result_digest", sa.String(64)),
        sa.Column(
            "baseline_run_id", sa.Uuid(), sa.ForeignKey("evaluation_runs.id", ondelete="RESTRICT")
        ),
        sa.Column(
            "candidate_run_id", sa.Uuid(), sa.ForeignKey("evaluation_runs.id", ondelete="RESTRICT")
        ),
        sa.Column(
            "evaluation_comparison_id",
            sa.Uuid(),
            sa.ForeignKey("evaluation_comparisons.id", ondelete="RESTRICT"),
        ),
        sa.Column(
            "created_at", sa.DateTime(timezone=True), server_default=sa.func.now(), nullable=False
        ),
        sa.Column(
            "updated_at", sa.DateTime(timezone=True), server_default=sa.func.now(), nullable=False
        ),
        sa.UniqueConstraint(
            "project_binding_id", "idempotency_key", name="uq_selected_comparison_key"
        ),
        sa.CheckConstraint(
            "status IN ('pending', 'running', 'cancel_requested', 'completed', 'failed', 'cancelled', 'interrupted')",
            name="ck_selected_comparison_status",
        ),
        sa.CheckConstraint("expected_cases BETWEEN 1 AND 100", name="ck_selected_comparison_cases"),
        sa.CheckConstraint(
            "current_completed_cases BETWEEN 0 AND expected_cases AND candidate_completed_cases BETWEEN 0 AND expected_cases",
            name="ck_selected_comparison_progress",
        ),
        sa.CheckConstraint("version > 0", name="ck_selected_comparison_version"),
        sa.CheckConstraint(
            "current_deployment_id <> candidate_deployment_id",
            name="ck_selected_comparison_distinct_targets",
        ),
    )
    op.create_index(
        "uq_selected_comparison_active_binding",
        "selected_model_comparisons",
        ["project_binding_id"],
        unique=True,
        postgresql_where=sa.text("status IN ('pending', 'running', 'cancel_requested')"),
        sqlite_where=sa.text("status IN ('pending', 'running', 'cancel_requested')"),
    )
    if op.get_bind().dialect.name == "postgresql":
        op.execute(
            "REVOKE DELETE, TRUNCATE ON model_update_watches, model_update_notices FROM modelforge_runtime"
        )
        op.execute(
            "GRANT SELECT, INSERT, UPDATE ON model_update_watches, model_update_notices TO modelforge_runtime"
        )
        op.execute("REVOKE DELETE, TRUNCATE ON selected_model_comparisons FROM modelforge_runtime")
        op.execute(
            "GRANT SELECT, INSERT, UPDATE ON selected_model_comparisons TO modelforge_runtime"
        )


def downgrade() -> None:
    # Earlier deployed migrations have destructive downgrades. Never permit this
    # release to cross back into that graph while authoritative history exists.
    for table in (
        "selected_model_comparisons",
        "model_update_watches",
        "model_update_notices",
        "external_creative_allocations",
        "external_creative_resources",
        "external_creative_action_attestations",
        "external_creative_profile_observations",
    ):
        if op.get_bind().scalar(sa.select(sa.func.count()).select_from(sa.table(table))):
            raise RuntimeError(
                "Control-plane history exists; restore the pre-migration backup instead."
            )
    op.drop_index("uq_selected_comparison_active_binding", table_name="selected_model_comparisons")
    op.drop_table("selected_model_comparisons")
    op.drop_column("model_update_watches", "version")
    op.drop_column("model_update_watches", "enabled")
    # Deliberately retain the safer runtime privilege restrictions on empty old tables.