feat(order): 添加订单货币转换功能

- 在CustomerOrder实体中添加原始货币、支付货币、汇率等相关字段
- 实现货币转换计算接口，支持自动转换不支持的货币到USD
- 添加货币转换信息更新服务方法
- 在订单创建时初始化货币转换相关字段
- 扩展订单响应DTO包含完整的货币转换信息
- 实现汇率锁定和转换记录功能

mt-pay/src/main/java/com/mtkj/mtpay/controller/CustomerOrderController.java

@@ -1,9 +1,12 @@
 package com.mtkj.mtpay.controller;
 
 import com.mtkj.mtpay.common.Result;
+import com.mtkj.mtpay.dto.request.CalculateCurrencyConversionRequestDTO;
 import com.mtkj.mtpay.dto.request.CreateCustomerOrderRequestDTO;
+import com.mtkj.mtpay.dto.response.CurrencyConversionDTO;
 import com.mtkj.mtpay.dto.response.CustomerOrderResponseDTO;
 import com.mtkj.mtpay.service.CustomerOrderService;
+import com.mtkj.mtpay.service.ExchangeRateService;
 import jakarta.validation.Valid;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
@@ -19,6 +22,7 @@ import org.springframework.web.bind.annotation.*;
 public class CustomerOrderController {
     
     private final CustomerOrderService customerOrderService;
+    private final ExchangeRateService exchangeRateService;
     
     /**
      * 创建客户订单
@@ -30,8 +34,84 @@ public class CustomerOrderController {
         return Result.success("订单创建成功", order);
     }
     
+    /**
+     * 计算并更新订单的货币转换信息
+     * 在订单确认页面加载时调用，提前计算货币转换信息
+     * 注意：这个路由必须放在 /{orderNo} 之前，避免路由冲突
+     */
+    @PostMapping("/calculate-currency-conversion")
+    public Result<CurrencyConversionDTO> calculateCurrencyConversion(
+            @Valid @RequestBody CalculateCurrencyConversionRequestDTO request) {
+        log.info("计算订单货币转换信息，订单号：{}，原始货币：{}，原始金额：{}", 
+            request.getOrderNo(), request.getOriginalCurrency(), request.getOriginalAmount());
+        
+        // 检查货币是否需要转换
+        java.util.Set<String> supportedCurrencies = java.util.Set.of(
+            "USD", "EUR", "GBP", "AUD", "CAD", "JPY", "CNY", "HKD", "SGD", "NZD", 
+            "CHF", "SEK", "NOK", "DKK", "PLN", "MXN", "BRL", "INR", "KRW", "THB"
+        );
+        
+        String originalCurrency = request.getOriginalCurrency();
+        String paymentCurrency = originalCurrency;
+        java.math.BigDecimal paymentAmount = request.getOriginalAmount();
+        java.math.BigDecimal exchangeRate = java.math.BigDecimal.ONE;
+        boolean conversionRequired = false;
+        
+        // 如果货币不支持，转换为USD
+        if (!supportedCurrencies.contains(originalCurrency)) {
+            conversionRequired = true;
+            paymentCurrency = "USD";
+            
+            // 计算汇率和转换后的金额
+            Double rate = exchangeRateService.getExchangeRate(originalCurrency, paymentCurrency);
+            Double convertedAmount = exchangeRateService.convertAmount(
+                request.getOriginalAmount().doubleValue(), 
+                originalCurrency, 
+                paymentCurrency
+            );
+            
+            exchangeRate = java.math.BigDecimal.valueOf(rate);
+            paymentAmount = java.math.BigDecimal.valueOf(convertedAmount);
+            
+            log.info("货币转换：{} {} -> {} {} (汇率: {})", 
+                request.getOriginalAmount(), originalCurrency,
+                paymentAmount, paymentCurrency, exchangeRate);
+        }
+        
+        // 构建货币转换DTO
+        CurrencyConversionDTO conversionDTO = CurrencyConversionDTO.builder()
+            .originalCurrency(originalCurrency)
+            .originalAmount(request.getOriginalAmount())
+            .paymentCurrency(paymentCurrency)
+            .paymentAmount(paymentAmount)
+            .exchangeRate(exchangeRate)
+            .rateLockedAt(java.time.LocalDateTime.now())
+            .conversionRequired(conversionRequired)
+            .rateDescription(buildRateDescription(originalCurrency, paymentCurrency, exchangeRate.doubleValue()))
+            .build();
+        
+        // 更新订单的货币转换信息
+        try {
+            customerOrderService.updateCurrencyConversion(
+                request.getOrderNo(),
+                originalCurrency,
+                request.getOriginalAmount(),
+                paymentCurrency,
+                paymentAmount,
+                exchangeRate
+            );
+            log.info("订单货币转换信息已更新，订单号：{}", request.getOrderNo());
+        } catch (Exception e) {
+            log.warn("更新订单货币转换信息失败，订单号：{}", request.getOrderNo(), e);
+            // 不抛出异常，仍然返回计算结果
+        }
+        
+        return Result.success("货币转换信息计算成功", conversionDTO);
+    }
+    
     /**
      * 根据订单号获取订单详情
+     * 注意：这个路由必须放在 /calculate-currency-conversion 之后，避免路由冲突
      */
     @GetMapping("/{orderNo}")
     public Result<CustomerOrderResponseDTO> getOrderByOrderNo(@PathVariable String orderNo) {
@@ -49,5 +129,15 @@ public class CustomerOrderController {
         CustomerOrderResponseDTO order = customerOrderService.getOrderById(id);
         return Result.success(order);
     }
+    
+    /**
+     * 构建汇率说明文本
+     */
+    private String buildRateDescription(String fromCurrency, String toCurrency, Double rate) {
+        if (fromCurrency.equals(toCurrency)) {
+            return "无需货币转换";
+        }
+        return String.format("1 %s = %.6f %s", fromCurrency, rate, toCurrency);
+    }
 }
 

mt-pay/src/main/java/com/mtkj/mtpay/dto/response/CustomerOrderResponseDTO.java

@@ -22,6 +22,15 @@ public class CustomerOrderResponseDTO implements Serializable {
     private BigDecimal unitPrice;
     private BigDecimal totalAmount;
     private String currency;
+    
+    // 货币转换信息
+    private String originalCurrency;  // 原始货币代码
+    private BigDecimal originalAmount; // 原始订单金额
+    private String paymentCurrency;    // 实际支付货币代码
+    private BigDecimal paymentAmount;   // 实际支付金额
+    private BigDecimal exchangeRate;   // 使用的汇率
+    private LocalDateTime rateLockedAt; // 汇率锁定时间
+    
     private String status;
     private String customerName;
     private String customerPhone;

mt-pay/src/main/java/com/mtkj/mtpay/entity/CustomerOrder.java

@@ -68,11 +68,47 @@ public class CustomerOrder {
     private BigDecimal totalAmount;
     
     /**
-     * 货币代码
+     * 货币代码（保留字段，兼容旧数据）
      */
     @TableField(value = "currency", jdbcType = org.apache.ibatis.type.JdbcType.VARCHAR)
     private String currency;
     
+    /**
+     * 原始货币代码（客户选择的货币）
+     */
+    @TableField(value = "original_currency", jdbcType = org.apache.ibatis.type.JdbcType.VARCHAR)
+    private String originalCurrency;
+    
+    /**
+     * 原始订单金额（原始货币）
+     */
+    @TableField(value = "original_amount", jdbcType = org.apache.ibatis.type.JdbcType.DECIMAL)
+    private BigDecimal originalAmount;
+    
+    /**
+     * 实际支付货币代码（PayPal支持的货币，如USD）
+     */
+    @TableField(value = "payment_currency", jdbcType = org.apache.ibatis.type.JdbcType.VARCHAR)
+    private String paymentCurrency;
+    
+    /**
+     * 实际支付金额（支付货币）
+     */
+    @TableField(value = "payment_amount", jdbcType = org.apache.ibatis.type.JdbcType.DECIMAL)
+    private BigDecimal paymentAmount;
+    
+    /**
+     * 使用的汇率（原始货币 -> 支付货币）
+     */
+    @TableField(value = "exchange_rate", jdbcType = org.apache.ibatis.type.JdbcType.DECIMAL)
+    private BigDecimal exchangeRate;
+    
+    /**
+     * 汇率锁定时间
+     */
+    @TableField(value = "rate_locked_at", jdbcType = org.apache.ibatis.type.JdbcType.TIMESTAMP)
+    private LocalDateTime rateLockedAt;
+    
     /**
      * 订单状态：PENDING-待支付，PAID-已支付，SHIPPED-已发货，COMPLETED-已完成，CANCELLED-已取消
      */

mt-pay/src/main/java/com/mtkj/mtpay/service/CustomerOrderService.java

@@ -43,5 +43,20 @@ public interface CustomerOrderService {
      * @param status 订单状态
      */
     void updateOrderStatus(String orderNo, String status);
+    
+    /**
+     * 更新订单货币转换信息
+     * @param orderNo 订单号
+     * @param originalCurrency 原始货币代码
+     * @param originalAmount 原始金额
+     * @param paymentCurrency 支付货币代码
+     * @param paymentAmount 支付金额
+     * @param exchangeRate 汇率
+     */
+    void updateCurrencyConversion(String orderNo, String originalCurrency, 
+                                  java.math.BigDecimal originalAmount,
+                                  String paymentCurrency, 
+                                  java.math.BigDecimal paymentAmount,
+                                  java.math.BigDecimal exchangeRate);
 }
 

mt-pay/src/main/java/com/mtkj/mtpay/service/impl/CustomerOrderServiceImpl.java

@@ -70,8 +70,18 @@ public class CustomerOrderServiceImpl implements CustomerOrderService {
         order.setSkuName(sku.getSku());
         order.setQuantity(request.getQuantity());
         order.setUnitPrice(sku.getPrice());
-        order.setTotalAmount(sku.getPrice().multiply(new BigDecimal(request.getQuantity())));
+        BigDecimal totalAmount = sku.getPrice().multiply(new BigDecimal(request.getQuantity()));
+        order.setTotalAmount(totalAmount);
         order.setCurrency(sku.getCurrency());
+        
+        // 设置原始货币信息（创建订单时的货币）
+        order.setOriginalCurrency(sku.getCurrency());
+        order.setOriginalAmount(totalAmount);
+        // 支付货币和金额将在创建PayPal订单时设置
+        order.setPaymentCurrency(sku.getCurrency()); // 默认与原始货币相同
+        order.setPaymentAmount(totalAmount); // 默认与原始金额相同
+        order.setExchangeRate(BigDecimal.ONE); // 默认汇率为1
+        
         order.setStatus("PENDING");
         order.setPaymentStatus("UNPAID");
         
@@ -165,6 +175,37 @@ public class CustomerOrderServiceImpl implements CustomerOrderService {
         log.info("订单支付状态更新成功，订单号: {}", orderNo);
     }
     
+    @Override
+    public void updateCurrencyConversion(String orderNo, String originalCurrency, 
+                                        BigDecimal originalAmount,
+                                        String paymentCurrency, 
+                                        BigDecimal paymentAmount,
+                                        BigDecimal exchangeRate) {
+        log.info("更新订单货币转换信息，订单号: {}, 原始: {} {}, 支付: {} {} (汇率: {})", 
+            orderNo, originalAmount, originalCurrency, paymentAmount, paymentCurrency, exchangeRate);
+        
+        CustomerOrder order = customerOrderMapper.selectOne(
+            new LambdaQueryWrapper<CustomerOrder>()
+                .eq(CustomerOrder::getOrderNo, orderNo)
+        );
+        
+        if (order == null) {
+            log.warn("订单不存在，订单号: {}", orderNo);
+            throw new BusinessException(ResultCode.DATA_NOT_FOUND, "订单不存在");
+        }
+        
+        // 更新货币转换信息
+        order.setOriginalCurrency(originalCurrency);
+        order.setOriginalAmount(originalAmount);
+        order.setPaymentCurrency(paymentCurrency);
+        order.setPaymentAmount(paymentAmount);
+        order.setExchangeRate(exchangeRate);
+        order.setRateLockedAt(java.time.LocalDateTime.now());
+        
+        customerOrderMapper.updateById(order);
+        log.info("订单货币转换信息更新成功，订单号: {}", orderNo);
+    }
+    
     @Override
     public void updateOrderStatus(String orderNo, String status) {
         log.info("更新订单状态，订单号: {}, 状态: {}", orderNo, status);