package com.test.payment.service;

import com.test.payment.client.AirtelClient;
import com.test.payment.dto.AirtelCallbackPayload;
import com.test.payment.dto.AirtelPaymentRequestDto;
import com.test.payment.dto.AirtelResponseDto;
import com.test.payment.dto.CallbackAckDto;
import com.test.payment.dto.PaymentRequest;
import com.test.payment.dto.PaymentResultDto;
import com.test.payment.dto.TransactionStatusDto;
import com.test.payment.exceptions.ProviderBusyException;
import com.test.payment.models.Country;
import com.test.payment.models.Operator;
import com.test.payment.models.PaymentProviderType;
import com.test.payment.models.Status;
import com.test.payment.service.PaymentLifecycleService.CallbackData;
import com.test.payment.service.PaymentLifecycleService.ProviderResponseData;
import com.test.payment.service.PaymentLifecycleService.QueryOutcome;
import com.test.payment.service.PaymentLifecycleService.StoredResponse;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.core.env.Environment;
import org.springframework.stereotype.Service;
import reactor.core.publisher.Mono;
import tools.jackson.databind.ObjectMapper;

import java.util.UUID;

/**
 * Airtel Money USSD-push collections. Transaction status codes:
 * TIP = in progress, TS = success, TF = failed.
 */
@Service
@RequiredArgsConstructor
@Slf4j
public class AirtelService implements PaymentProviderService {

    private final AirtelClient airtelClient;
    private final PaymentLifecycleService lifecycle;
    private final ProviderMarkets markets;
    private final ProviderCallAudit audit;
    private final StatusCatalog statuses;
    private final PaymentLimitService limits;
    private final Environment environment;
    private final ObjectMapper objectMapper;

    @Override
    public PaymentProviderType provider() {
        return markets.resolve(Operator.AIRTEL);
    }

    @Override
    public Mono<PaymentResultDto> initiatePayment(PaymentRequest request) {
        return limits.enforce(provider(), request)
                .then(lifecycle.saveInitiation(provider(), request))
                .flatMap(initiation -> Mono.defer(() -> {
                            String reference = "ATL" + UUID.randomUUID().toString().replace("-", "");
                            AirtelPaymentRequestDto payload = buildRequest(request, reference);
                            ProviderCallAudit.Handle call = audit.begin(provider(), "USSD_PUSH", String.valueOf(initiation.getId()),
                                    "POST", baseUrl() + "/merchant/v1/payments/", payload);
                            audit.linkReference(call, reference);
                            return airtelClient.pay(payload)
                                    .doOnNext(response -> audit.complete(call, 200, response, null))
                                    .doOnError(ex -> audit.complete(call, null, null, ex))
                                    .map(response -> toResponseData(response, reference));
                        })
                        .flatMap(data -> lifecycle.persistResponse(initiation, data))
                        .onErrorResume(ex -> lifecycle.markFailed(initiation, ex)));
    }

    public Mono<CallbackAckDto> handleCallback(AirtelCallbackPayload payload) {
        if (payload == null || payload.getTransaction() == null) {
            log.warn("Received malformed Airtel callback payload");
            return Mono.just(CallbackAckDto.accepted("Ignored: empty callback"));
        }
        AirtelCallbackPayload.Transaction transaction = payload.getTransaction();
        boolean success = "TS".equalsIgnoreCase(transaction.getStatusCode());
        CallbackData data = new CallbackData(
                transaction.getId(),
                transaction.getStatusCode(),
                transaction.getMessage(),
                transaction.getAirtelMoneyId(),
                null, null, null,
                success);
        String raw = toJson(payload);
        audit.recordCallback(provider(), new ProviderCallAudit.CallbackAudit(
                data.providerReference(), data.resultCode(), data.resultDesc(), data.receiptNumber(),
                data.amount(), data.phoneNumber(), data.transactionDate()), raw);
        return lifecycle.applyCallback(provider(), data, raw);
    }

    @Override
    public Mono<TransactionStatusDto> checkStatus(String providerReference) {
        return lifecycle.checkStatus(provider(), providerReference, this::queryProvider);
    }

    private Mono<QueryOutcome> queryProvider(StoredResponse response) {
        ProviderCallAudit.Handle call = audit.begin(provider(), "STATUS_QUERY", String.valueOf(response.initiationId()),
                "GET", baseUrl() + "/standard/v1/payments/" + response.providerReference(), null);
        return airtelClient.status(response.providerReference())
                .doOnNext(result -> audit.complete(call, 200, result, null))
                .doOnError(ex -> audit.complete(call, null, null, ex))
                .map(result -> {
                    AirtelResponseDto.Transaction tx = result.getData() != null ? result.getData().getTransaction() : null;
                    String status = tx != null ? tx.getStatus() : null;
                    String message = tx != null && tx.getMessage() != null
                            ? tx.getMessage()
                            : (result.getStatus() != null ? result.getStatus().getMessage() : null);
                    return new QueryOutcome(mapStatus(status), status, message,
                            tx != null ? tx.getAirtelMoneyId() : null);
                })
                .onErrorResume(ProviderBusyException.class,
                        e -> Mono.just(QueryOutcome.pending(statuses.pending(), "Airtel status query rate-limited — showing last known state")));
    }

    private String baseUrl() {
        return environment.getProperty("airtel.base-url", "");
    }

    private AirtelPaymentRequestDto buildRequest(PaymentRequest request, String reference) {
        Country country = markets.resolve(Operator.AIRTEL).country();
        // the market's own currency unless airtel.currency deliberately overrides it
        String currency = environment.getProperty("airtel.currency", country.currency());
        return new AirtelPaymentRequestDto(
                request.getAccountReference(),
                new AirtelPaymentRequestDto.Subscriber(country.name(), currency, request.getPhoneNumber()),
                new AirtelPaymentRequestDto.Transaction(
                        String.valueOf(request.getAmount()), country.name(), currency, reference));
    }

    private ProviderResponseData toResponseData(AirtelResponseDto response, String reference) {
        AirtelResponseDto.Status status = response.getStatus();
        boolean accepted = status != null && Boolean.TRUE.equals(status.getSuccess());
        String transactionStatus = response.getData() != null && response.getData().getTransaction() != null
                ? response.getData().getTransaction().getStatus()
                : null;
        return new ProviderResponseData(
                reference,
                null,
                status != null ? status.getCode() : null,
                status != null ? status.getMessage() : null,
                transactionStatus,
                accepted);
    }

    private Status mapStatus(String airtelStatus) {
        if ("TS".equalsIgnoreCase(airtelStatus)) {
            return statuses.success();
        }
        if ("TF".equalsIgnoreCase(airtelStatus)) {
            return statuses.failed();
        }
        return statuses.pending(); // TIP or unknown — keep waiting
    }

    private String toJson(Object value) {
        try {
            return objectMapper.writeValueAsString(value);
        } catch (Exception e) {
            log.warn("Could not serialize callback payload: {}", e.toString());
            return null;
        }
    }
}