"""런타임 스키마 준비 상태 정책.

권위 스키마는 ``infra/db/init/*.sql``이다. 앱 기동 중 불완전한 스키마 보정은 로컬 개발
환경에서만 허용하고, 스테이징과 운영은 owner migration을 요구하며 fail-closed한다.
"""

from __future__ import annotations

from dataclasses import dataclass
from typing import Any, Protocol

from .config import settings


class SchemaConnection(Protocol):
    async def fetchrow(self, query: str, *args: Any) -> Any: ...


@dataclass(frozen=True, slots=True)
class RuntimeSchemaContract:
    component: str
    relations: tuple[str, ...]
    columns: tuple[str, ...] = ()
    policies: tuple[str, ...] = ()


REVIEW_SCHEMA_CONTRACT = RuntimeSchemaContract(
    component="review/evaluation",
    relations=(
        "app.session_evaluation",
        "app.case_worksheet",
        "app.live_coach_events",
        "app.safety_events",
        "app.session_review_status",
        "app.session_share_link",
        "app.session_archive_state",
    ),
    columns=(
        "app.live_coach_events.event_type",
        "app.live_coach_events.credit_delta",
        "app.live_coach_events.credit_balance",
        "app.live_coach_events.reason",
        "app.session_review_status.worksheet_status",
        "app.session_review_status.worksheet_note",
        "app.session_review_status.worksheet_reviewed_at",
    ),
    policies=(
        "app.session_evaluation.p_session_evaluation_select",
        "app.case_worksheet.p_case_worksheet_select",
        "app.live_coach_events.p_live_coach_events_select",
        "app.safety_events.p_safety_events_select",
        "app.session_review_status.p_session_review_status_select",
        "app.session_share_link.p_session_share_select",
        "app.session_archive_state.p_session_archive_select",
    ),
)

NOTIFICATION_SCHEMA_CONTRACT = RuntimeSchemaContract(
    component="notification",
    relations=("app.notification_event", "app.notification_delivery"),
    policies=(
        "app.notification_event.p_notification_event_admin_all",
        "app.notification_delivery.p_notification_delivery_admin_all",
    ),
)


async def schema_contract_ready(
    conn: SchemaConnection,
    contract: RuntimeSchemaContract,
) -> bool:
    row = await conn.fetchrow(
        """
        SELECT
          NOT EXISTS (
            SELECT 1
            FROM unnest($1::text[]) AS required(relation_name)
            WHERE to_regclass(required.relation_name) IS NULL
          )
          AND NOT EXISTS (
            SELECT 1
            FROM unnest($2::text[]) AS required(qualified_name)
            WHERE NOT EXISTS (
              SELECT 1
              FROM information_schema.columns c
              WHERE c.table_schema = split_part(required.qualified_name, '.', 1)
                AND c.table_name = split_part(required.qualified_name, '.', 2)
                AND c.column_name = split_part(required.qualified_name, '.', 3)
            )
          )
          AND NOT EXISTS (
            SELECT 1
            FROM unnest($3::text[]) AS required(qualified_name)
            WHERE NOT EXISTS (
              SELECT 1
              FROM pg_policies p
              WHERE p.schemaname = split_part(required.qualified_name, '.', 1)
                AND p.tablename = split_part(required.qualified_name, '.', 2)
                AND p.policyname = split_part(required.qualified_name, '.', 3)
            )
          ) AS ready
        """,
        list(contract.relations),
        list(contract.columns),
        list(contract.policies),
    )
    return bool(row and row["ready"])


def runtime_schema_bootstrap_required(
    contract: RuntimeSchemaContract | str,
    *,
    ready: bool,
) -> bool:
    """로컬 보정 필요 여부를 반환하고, dev 외 환경에서는 불완전 스키마를 차단한다."""
    if ready:
        return False
    component = (
        contract.component if isinstance(contract, RuntimeSchemaContract) else contract
    )
    if settings.environment != "dev":
        raise RuntimeError(
            f"{component} runtime DB schema is incomplete; run owner migration/init and "
            "scripts/check-deploy-preflight.py before starting the API"
        )
    return True