推进活动系统最小成品闭环与游客体验

backend/internal/httpapi/handlers/region_options_handler.go

@@ -0,0 +1,162 @@
+package handlers
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"sort"
+	"sync"
+	"time"
+
+	"cmr-backend/internal/apperr"
+	"cmr-backend/internal/httpx"
+)
+
+type RegionOptionsHandler struct {
+	client *http.Client
+	mu     sync.Mutex
+	cache  []regionProvince
+}
+
+type regionProvince struct {
+	Code   string       `json:"code"`
+	Name   string       `json:"name"`
+	Cities []regionCity `json:"cities"`
+}
+
+type regionCity struct {
+	Code string `json:"code"`
+	Name string `json:"name"`
+}
+
+type remoteProvince struct {
+	Code string `json:"code"`
+	Name string `json:"name"`
+}
+
+type remoteCity struct {
+	Code     string `json:"code"`
+	Name     string `json:"name"`
+	Province string `json:"province"`
+}
+
+func NewRegionOptionsHandler() *RegionOptionsHandler {
+	return &RegionOptionsHandler{
+		client: &http.Client{Timeout: 12 * time.Second},
+	}
+}
+
+func (h *RegionOptionsHandler) Get(w http.ResponseWriter, r *http.Request) {
+	items, err := h.load(r.Context())
+	if err != nil {
+		httpx.WriteError(w, err)
+		return
+	}
+	httpx.WriteJSON(w, http.StatusOK, map[string]any{"data": items})
+}
+
+func (h *RegionOptionsHandler) load(ctx context.Context) ([]regionProvince, error) {
+	h.mu.Lock()
+	if len(h.cache) > 0 {
+		cached := h.cache
+		h.mu.Unlock()
+		return cached, nil
+	}
+	h.mu.Unlock()
+
+	// Data source:
+	// https://github.com/uiwjs/province-city-china
+	// Using province + city JSON only, then reducing to the province/city structure
+	// needed by ops workbench location management.
+	provinces, err := h.fetchProvinces(ctx, "https://unpkg.com/province-city-china/dist/province.json")
+	if err != nil {
+		return nil, err
+	}
+	cities, err := h.fetchCities(ctx, "https://unpkg.com/province-city-china/dist/city.json")
+	if err != nil {
+		return nil, err
+	}
+
+	cityMap := make(map[string][]regionCity)
+	for _, item := range cities {
+		if item.Province == "" || item.Code == "" {
+			continue
+		}
+		fullCode := item.Province + item.Code + "00"
+		cityMap[item.Province] = append(cityMap[item.Province], regionCity{
+			Code: fullCode,
+			Name: item.Name,
+		})
+	}
+	for key := range cityMap {
+		sort.Slice(cityMap[key], func(i, j int) bool { return cityMap[key][i].Code < cityMap[key][j].Code })
+	}
+
+	items := make([]regionProvince, 0, len(provinces))
+	for _, item := range provinces {
+		if len(item.Code) < 2 {
+			continue
+		}
+		provinceCode := item.Code[:2]
+		province := regionProvince{
+			Code: item.Code,
+			Name: item.Name,
+		}
+		if entries := cityMap[provinceCode]; len(entries) > 0 {
+			province.Cities = entries
+		} else {
+			// 直辖市 / 特殊地区没有单独的地级市列表时，退化成自身即可。
+			province.Cities = []regionCity{{
+				Code: item.Code,
+				Name: item.Name,
+			}}
+		}
+		items = append(items, province)
+	}
+
+	h.mu.Lock()
+	h.cache = items
+	h.mu.Unlock()
+	return items, nil
+}
+
+func (h *RegionOptionsHandler) fetchProvinces(ctx context.Context, url string) ([]remoteProvince, error) {
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
+	if err != nil {
+		return nil, apperr.New(http.StatusBadGateway, "region_source_unavailable", "省市数据源不可用")
+	}
+	resp, err := h.client.Do(req)
+	if err != nil {
+		return nil, apperr.New(http.StatusBadGateway, "region_source_unavailable", "省市数据源不可用")
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode != http.StatusOK {
+		return nil, apperr.New(http.StatusBadGateway, "region_source_unavailable", fmt.Sprintf("省级数据拉取失败: %d", resp.StatusCode))
+	}
+	var items []remoteProvince
+	if err := json.NewDecoder(resp.Body).Decode(&items); err != nil {
+		return nil, apperr.New(http.StatusBadGateway, "region_source_invalid", "省级数据格式无效")
+	}
+	return items, nil
+}
+
+func (h *RegionOptionsHandler) fetchCities(ctx context.Context, url string) ([]remoteCity, error) {
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
+	if err != nil {
+		return nil, apperr.New(http.StatusBadGateway, "region_source_unavailable", "省市数据源不可用")
+	}
+	resp, err := h.client.Do(req)
+	if err != nil {
+		return nil, apperr.New(http.StatusBadGateway, "region_source_unavailable", "省市数据源不可用")
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode != http.StatusOK {
+		return nil, apperr.New(http.StatusBadGateway, "region_source_unavailable", fmt.Sprintf("市级数据拉取失败: %d", resp.StatusCode))
+	}
+	var items []remoteCity
+	if err := json.NewDecoder(resp.Body).Decode(&items); err != nil {
+		return nil, apperr.New(http.StatusBadGateway, "region_source_invalid", "市级数据格式无效")
+	}
+	return items, nil
+}