package com.example.trading.gateway.grpc;

import java.util.concurrent.TimeUnit;

import com.example.trading.contracts.v1.OrderServiceGrpc.OrderServiceBlockingStub;
import com.example.trading.contracts.v1.SubmitOrderResponse;
import com.example.trading.gateway.config.GatewayOrderProperties;
import com.example.trading.gateway.order.FixToProtobufMapper;
import com.example.trading.gateway.order.IncomingOrder;
import com.example.trading.gateway.order.OrderSubmissionResult;
import com.example.trading.gateway.order.OrderSubmissionResult.Outcome;
import io.grpc.Status;
import io.grpc.StatusRuntimeException;
import org.springframework.stereotype.Component;

@Component
public class GrpcOrderClient {
    private final OrderServiceBlockingStub stub;
    private final FixToProtobufMapper mapper;
    private final long deadlineNanos;

    public GrpcOrderClient(OrderServiceBlockingStub stub, FixToProtobufMapper mapper,
            GatewayOrderProperties properties) {
        this.stub = stub;
        this.mapper = mapper;
        this.deadlineNanos = properties.deadline().toNanos();
    }

    public OrderSubmissionResult submit(IncomingOrder order) {
        try {
            // Derived immutable stubs share the Spring-managed channel. No application retries.
            SubmitOrderResponse response = stub.withDeadlineAfter(deadlineNanos, TimeUnit.NANOSECONDS)
                    .submitOrder(mapper.map(order));
            // ACCEPTED without an OMS identity is not a valid business decision.
            // Treat the malformed response as uncertain rather than failing later
            // during report creation or inventing an OMS identifier.
            if (response.getDecision() == com.example.trading.contracts.v1.OrderDecision.ACCEPTED
                    && response.getOrderId().isBlank()) {
                return new OrderSubmissionResult(Outcome.UNKNOWN_OUTCOME, "", "", Status.Code.DATA_LOSS);
            }
            return switch (response.getDecision()) {
                case ACCEPTED -> new OrderSubmissionResult(Outcome.ACCEPTED,
                        response.getOrderId(), "", Status.Code.OK);
                case REJECTED -> new OrderSubmissionResult(Outcome.REJECTED,
                        response.getOrderId(), response.getRejectReason(), Status.Code.OK);
                // An absent/future decision is not evidence of rejection.
                default -> new OrderSubmissionResult(Outcome.UNKNOWN_OUTCOME,
                        response.getOrderId(), "", Status.Code.UNKNOWN);
            };
        } catch (StatusRuntimeException failure) {
            Status.Code status = failure.getStatus().getCode();
            return new OrderSubmissionResult(status == Status.Code.INVALID_ARGUMENT
                    ? Outcome.INVALID_REQUEST : Outcome.UNKNOWN_OUTCOME, "", "", status);
        }
    }
}