from typing import Any, cast

from sqlalchemy import MetaData, Table, insert, select, update
from sqlalchemy.ext.asyncio import AsyncSession

TABLES = frozenset(
    {
        "config_release",
        "platform_config_item",
        "model_endpoint_config",
        "model_routing_rule",
        "model_routing_fallback",
        "prompt_template_version",
        "agent_intent_config",
        "agent_reply_template",
        "agent_negative_word",
        "interaction_audit",
        "api_request_receipt",
        "svc_conversation_session",
        "svc_handover_ticket",
        "fin_knowledge_meta",
        "profile_snapshots",
    }
)


class PlatformRepository:
    """Core mappings reflected from frozen schema; resource names are a code whitelist."""

    def __init__(self, session: AsyncSession) -> None:
        self.session = session
        self.tables: dict[str, Table] = {}

    async def table(self, name: str) -> Table:
        if name not in TABLES:
            raise ValueError("unknown platform resource")
        if name not in self.tables:
            connection = await self.session.connection()
            self.tables[name] = await connection.run_sync(
                lambda sync: Table(name, MetaData(), autoload_with=sync)
            )
        return self.tables[name]

    async def get(self, name: str, row_id: int, *, lock: bool = False) -> dict[str, Any] | None:
        table = await self.table(name)
        query = select(table).where(table.c.id == row_id)
        if lock:
            query = query.with_for_update()
        row = (await self.session.execute(query)).mappings().first()
        return dict(row) if row else None

    async def rows(
        self, name: str, filters: dict[str, Any], *, before: int | None = None, limit: int = 20
    ) -> list[dict[str, Any]]:
        table = await self.table(name)
        query = select(table)
        for key, value in filters.items():
            query = query.where(table.c[key] == value)
        if before is not None:
            query = query.where(table.c.id < before)
        rows = (
            await self.session.execute(query.order_by(table.c.id.desc()).limit(limit))
        ).mappings()
        return [dict(row) for row in rows]

    async def create(self, name: str, values: dict[str, Any]) -> dict[str, Any]:
        table = await self.table(name)
        result = await self.session.execute(insert(table).values(**values))
        inserted_primary_key = cast(Any, result).inserted_primary_key
        assert inserted_primary_key is not None
        row_id = int(inserted_primary_key[0])
        row = await self.get(name, row_id)
        assert row is not None
        return row

    async def update(self, name: str, row_id: int, values: dict[str, Any]) -> dict[str, Any]:
        table = await self.table(name)
        await self.session.execute(update(table).where(table.c.id == row_id).values(**values))
        row = await self.get(name, row_id)
        assert row is not None
        return row