"""Read and update administrator-managed risk-model configuration."""

from decimal import Decimal

from sqlalchemy.ext.asyncio import AsyncSession

from app.domain.model_config import DEFAULT_FREQUENCY_CAP, DEFAULT_FREQUENCY_COEFFICIENT, DEFAULT_WEIGHTS
from app.models.entities import OperationAudit, RiskModelConfig, UserAccount
from app.schemas.model_config import ModelWeightConfigData, ModelWeightConfigUpdate


class ModelConfigService:
    def __init__(self, session: AsyncSession) -> None:
        self.session = session

    async def get(self) -> ModelWeightConfigData:
        row = await self.session.get(RiskModelConfig, 1)
        if row is None:
            return ModelWeightConfigData(
                weights=DEFAULT_WEIGHTS,
                frequency_coefficient=DEFAULT_FREQUENCY_COEFFICIENT,
                frequency_cap=DEFAULT_FREQUENCY_CAP,
            )
        return self._to_data(row)

    async def update(self, payload: ModelWeightConfigUpdate, user: UserAccount) -> ModelWeightConfigData:
        row = await self.session.get(RiskModelConfig, 1)
        if row is None:
            row = RiskModelConfig(id=1)
            self.session.add(row)
        row.weights = payload.weights
        row.frequency_coefficient = Decimal(str(payload.frequency_coefficient))
        row.frequency_cap = Decimal(str(payload.frequency_cap))
        row.updated_by = user.emp_no
        self.session.add(
            OperationAudit(
                actor_user_id=user.id,
                actor_emp_no=user.emp_no,
                action="model_weight.update",
                resource_type="risk_model_config",
                resource_id="1",
                audit_metadata=payload.model_dump(),
            )
        )
        await self.session.flush()
        await self.session.refresh(row)
        return self._to_data(row)

    @staticmethod
    def _to_data(row: RiskModelConfig) -> ModelWeightConfigData:
        return ModelWeightConfigData(
            weights={key: float(value) for key, value in row.weights.items()},
            frequency_coefficient=float(row.frequency_coefficient),
            frequency_cap=float(row.frequency_cap),
            updated_by=row.updated_by,
            updated_at=row.updated_at,
        )