feat(server-go): 区域发病统计（#22，rooms.region + region-stats）

server-go/internal/handler/trace.go

@@ -3,6 +3,7 @@ package handler
 import (
 	"encoding/json"
 	"net/http"
+	"strconv"
 	"time"
 
 	"silk-server-go/internal/middleware"
@@ -18,6 +19,7 @@ func RegisterTraceRoutes(rg *gin.RouterGroup, db *gorm.DB) {
 	read := middleware.RequirePermission(db, "trace:read")
 	write := middleware.RequirePermission(db, "trace:write")
 	rg.GET("/trace-records", read, listTraceRecords(db))
+	rg.GET("/trace-records/region-stats", read, traceRegionStats(db))
 	rg.GET("/trace-records/:id", read, getTraceRecord(db))
 	rg.POST("/trace-records", write, createTraceRecord(db))
 	rg.PATCH("/trace-records/:id", write, updateTraceRecord(db))
@@ -27,6 +29,33 @@ func RegisterTraceRoutes(rg *gin.RouterGroup, db *gorm.DB) {
 	rg.POST("/trace-records/:id/checklist", write, submitTraceChecklist(db))
 }
 
+// traceRegionStats 区域发病统计（近 N 天，按蚕房 region 聚合）
+func traceRegionStats(db *gorm.DB) gin.HandlerFunc {
+	return func(c *gin.Context) {
+		days := 90
+		if d, err := strconv.Atoi(c.DefaultQuery("days", "90")); err == nil && d > 0 && d <= 365 {
+			days = d
+		}
+		q := db.Table("trace_records").
+			Select("rooms.region AS region, trace_records.disease AS disease").
+			Joins("LEFT JOIN rooms ON rooms.id = trace_records.room_id").
+			Where("trace_records.created_at >= ?", time.Now().Add(-time.Duration(days)*24*time.Hour))
+		if disease := c.Query("disease"); disease != "" {
+			q = q.Where("trace_records.disease = ?", disease)
+		}
+		var rows []struct {
+			Region  string `gorm:"column:region"`
+			Disease string `gorm:"column:disease"`
+		}
+		q.Scan(&rows)
+		entries := make([]service.RegionDiseaseEntry, 0, len(rows))
+		for _, r := range rows {
+			entries = append(entries, service.RegionDiseaseEntry{Region: r.Region, Disease: r.Disease})
+		}
+		c.JSON(http.StatusOK, service.AggregateRegionStats(entries))
+	}
+}
+
 func listTraceRecords(db *gorm.DB) gin.HandlerFunc {
 	return func(c *gin.Context) {
 		q := db.Model(&model.TraceRecord{})

server-go/internal/model/models.go

@@ -31,6 +31,7 @@ type Room struct {
 	Description *string   `json:"description,omitempty"`
 	Capacity    *int      `gorm:"type:int" json:"capacity,omitempty"`
 	Stage       *string   `gorm:"size:32" json:"stage,omitempty"`
+	Region      *string   `gorm:"size:64" json:"region,omitempty"`
 	Status      string    `gorm:"default:active" json:"status"`
 	CreatedAt   time.Time `gorm:"type:timestamptz" json:"createdAt"`
 	UpdatedAt   time.Time `gorm:"type:timestamptz" json:"updatedAt"`

server-go/internal/service/region_stat.go

@@ -0,0 +1,44 @@
+package service
+
+import "sort"
+
+// RegionDiseaseEntry 区域发病条目（trace_records 联查 rooms 得到）
+type RegionDiseaseEntry struct {
+	Region  string
+	Disease string
+}
+
+// RegionStat 区域发病统计
+type RegionStat struct {
+	Region   string         `json:"region"`
+	Total    int            `json:"total"`
+	Diseases map[string]int `json:"diseases"`
+}
+
+// AggregateRegionStats 按区域分组统计发病数与病种分布（空区域剔除，按总数降序）
+func AggregateRegionStats(entries []RegionDiseaseEntry) []RegionStat {
+	byRegion := make(map[string]*RegionStat)
+	for _, e := range entries {
+		if e.Region == "" {
+			continue
+		}
+		s, ok := byRegion[e.Region]
+		if !ok {
+			s = &RegionStat{Region: e.Region, Diseases: map[string]int{}}
+			byRegion[e.Region] = s
+		}
+		s.Total++
+		s.Diseases[e.Disease]++
+	}
+	result := make([]RegionStat, 0, len(byRegion))
+	for _, s := range byRegion {
+		result = append(result, *s)
+	}
+	sort.Slice(result, func(i, j int) bool {
+		if result[i].Total != result[j].Total {
+			return result[i].Total > result[j].Total
+		}
+		return result[i].Region < result[j].Region
+	})
+	return result
+}

server-go/internal/service/region_stat_test.go

@@ -0,0 +1,32 @@
+package service
+
+import "testing"
+
+func TestAggregateRegionStats(t *testing.T) {
+	entries := []RegionDiseaseEntry{
+		{Region: "A镇", Disease: "白僵病"},
+		{Region: "A镇", Disease: "白僵病"},
+		{Region: "A镇", Disease: "软化病"},
+		{Region: "B乡", Disease: "白僵病"},
+		{Region: "", Disease: "白僵病"},
+	}
+	stats := AggregateRegionStats(entries)
+	if len(stats) != 2 {
+		t.Fatalf("统计区域数 = %d, want 2（空区域应剔除）", len(stats))
+	}
+	if stats[0].Region != "A镇" || stats[0].Total != 3 {
+		t.Errorf("A镇应排第一且 total=3，实际 %+v", stats[0])
+	}
+	if stats[0].Diseases["白僵病"] != 2 || stats[0].Diseases["软化病"] != 1 {
+		t.Errorf("A镇病种分布不正确: %+v", stats[0].Diseases)
+	}
+	if stats[1].Region != "B乡" || stats[1].Total != 1 {
+		t.Errorf("B乡统计不正确: %+v", stats[1])
+	}
+}
+
+func TestAggregateRegionStatsEmpty(t *testing.T) {
+	if len(AggregateRegionStats(nil)) != 0 {
+		t.Error("空输入应返回空结果")
+	}
+}