refactor: 重构项目结构，迁移后端至 mengyastore-backend-go，新增 Java 后端、前端功能更新及部署文档

mengyastore-backend-go/internal/handlers/stats.go

@@ -0,0 +1,66 @@
+package handlers
+
+import (
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+
+	"mengyastore-backend/internal/storage"
+)
+
+type StatsHandler struct {
+	orderStore *storage.OrderStore
+	siteStore  *storage.SiteStore
+}
+
+func NewStatsHandler(orderStore *storage.OrderStore, siteStore *storage.SiteStore) *StatsHandler {
+	return &StatsHandler{orderStore: orderStore, siteStore: siteStore}
+}
+
+func (h *StatsHandler) GetStats(c *gin.Context) {
+	totalOrders, err := h.orderStore.Count()
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+	totalVisits, err := h.siteStore.GetTotalVisits()
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{
+		"data": gin.H{
+			"totalOrders": totalOrders,
+			"totalVisits": totalVisits,
+		},
+	})
+}
+
+func (h *StatsHandler) RecordVisit(c *gin.Context) {
+	fingerprint := buildViewerFingerprint(c)
+	totalVisits, counted, err := h.siteStore.RecordVisit(fingerprint)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{
+		"data": gin.H{
+			"totalVisits": totalVisits,
+			"counted":     counted,
+		},
+	})
+}
+
+func (h *StatsHandler) GetMaintenance(c *gin.Context) {
+	enabled, reason, err := h.siteStore.GetMaintenance()
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{
+		"data": gin.H{
+			"maintenance": enabled,
+			"reason":      reason,
+		},
+	})
+}