package com.example.trading.gateway.fix;

import java.math.BigDecimal;
import java.time.Clock;
import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.util.UUID;

import com.example.trading.gateway.order.IncomingOrder;
import com.example.trading.gateway.order.OrderSide;
import com.example.trading.gateway.order.OrderSubmissionResult;
import org.springframework.stereotype.Component;
import quickfix.field.*;
import quickfix.fix44.ExecutionReport;

/** Creates decision events only; sequence numbers and retransmission belong to QuickFIX/J. */
@Component
public class ExecutionReportFactory {
    private final Clock clock;

    public ExecutionReportFactory() {
        this(Clock.systemUTC());
    }

    ExecutionReportFactory(Clock clock) {
        this.clock = clock;
    }

    public ExecutionReport create(IncomingOrder order, OrderSubmissionResult result) {
        boolean accepted = result.outcome() == OrderSubmissionResult.Outcome.ACCEPTED;
        if (!accepted && result.outcome() != OrderSubmissionResult.Outcome.REJECTED) {
            throw new IllegalArgumentException("Only definitive OMS decisions create ExecutionReports");
        }
        if (accepted && result.orderId().isBlank()) {
            throw new IllegalArgumentException("An accepted OMS decision must have an OrderID");
        }
        ExecutionReport report = new ExecutionReport();
        // NONE means OMS did not assign an identifier. It is never a fabricated OMS ID.
        report.set(new OrderID(result.orderId().isBlank() ? "NONE" : result.orderId()));
        report.set(new ExecID(UUID.randomUUID().toString()));
        report.set(new ExecType(accepted ? ExecType.NEW : ExecType.REJECTED));
        report.set(new OrdStatus(accepted ? OrdStatus.NEW : OrdStatus.REJECTED));
        report.set(new ClOrdID(order.clientOrderId()));
        report.set(new Symbol(order.symbol()));
        report.set(new Side(order.side() == OrderSide.BUY ? Side.BUY : Side.SELL));
        report.set(new OrdType(OrdType.LIMIT));
        // QF/J 3.0.2 generated numeric fields use double. FieldMap.setDecimal writes
        // BigDecimal through DecimalConverter without a binary floating-point conversion.
        report.setDecimal(OrderQty.FIELD, BigDecimal.valueOf(order.quantity()));
        report.setDecimal(Price.FIELD, order.price());
        report.setDecimal(LeavesQty.FIELD, accepted ? BigDecimal.valueOf(order.quantity()) : BigDecimal.ZERO);
        report.setDecimal(CumQty.FIELD, BigDecimal.ZERO);
        report.setDecimal(AvgPx.FIELD, BigDecimal.ZERO);
        report.set(new TransactTime(LocalDateTime.ofInstant(clock.instant(), ZoneOffset.UTC)));
        if (!accepted) {
            String reason = result.rejectReason();
            int code = switch (reason.split(":", 2)[0].strip()) {
                case "UNSUPPORTED_SYMBOL", "UNKNOWN_SYMBOL" -> OrdRejReason.UNKNOWN_SYMBOL;
                case "MAX_ORDER_QUANTITY_EXCEEDED", "ORDER_EXCEEDS_LIMIT" -> OrdRejReason.ORDER_EXCEEDS_LIMIT;
                case "DUPLICATE_CL_ORD_ID", "DUPLICATE_ORDER" -> OrdRejReason.DUPLICATE_ORDER;
                default -> OrdRejReason.OTHER;
            };
            report.set(new OrdRejReason(code));
            // Bound free text, exclude SOH, controls, non-ASCII and log/display delimiters.
            StringBuilder sanitized = new StringBuilder();
            for (int i = 0; i < reason.length() && sanitized.length() < 256; i++) {
                char c = reason.charAt(i);
                sanitized.append(c >= 32 && c <= 126 && c != '|' ? c : ' ');
            }
            report.set(new Text(sanitized.toString().isBlank() ? "Order rejected" : sanitized.toString()));
        }
        return report;
    }
}