package http

import (
	"context"
	"net/http"
	"strconv"
	"strings"

	"hyapp/pkg/appcode"
	"hyapp/services/gateway-service/internal/appconfig"
)

// appConfigReader 是 gateway 对后台 App 配置的只读依赖。
type appConfigReader interface {
	ListH5Links(ctx context.Context) ([]appconfig.H5Link, error)
	ListBanners(ctx context.Context, query appconfig.BannerQuery) ([]appconfig.Banner, error)
}

// listH5Links 返回后台 APP配置/H5配置 中维护的 H5 入口地址。
func (h *Handler) listH5Links(writer http.ResponseWriter, request *http.Request) {
	if h.appConfigReader == nil {
		// H5 地址来自后台配置表；未注入 reader 时不能返回空假数据。
		writeError(writer, request, http.StatusBadGateway, codeUpstreamError, "upstream service error")
		return
	}

	items, err := h.appConfigReader.ListH5Links(request.Context())
	if err != nil {
		// 配置读取失败属于服务端依赖异常，客户端只需要根据 request_id 排查。
		writeError(writer, request, http.StatusBadGateway, codeUpstreamError, "upstream service error")
		return
	}

	writeOK(writer, request, map[string]any{"items": items, "total": len(items)})
}

// listAppBanners 返回后台 APP配置/BANNER配置 中维护的首页 banner。
func (h *Handler) listAppBanners(writer http.ResponseWriter, request *http.Request) {
	if h.appConfigReader == nil {
		writeError(writer, request, http.StatusBadGateway, codeUpstreamError, "upstream service error")
		return
	}

	items, err := h.appConfigReader.ListBanners(request.Context(), appconfig.BannerQuery{
		AppCode:  appcode.FromContext(request.Context()),
		Platform: firstQueryOrHeader(request, "platform", "X-App-Platform", "X-Platform"),
		RegionID: optionalInt64Query(request, "region_id"),
		Country:  firstQueryOrHeader(request, "country", "X-Country-Code", "X-App-Country"),
	})
	if err != nil {
		writeError(writer, request, http.StatusBadGateway, codeUpstreamError, "upstream service error")
		return
	}

	writeOK(writer, request, map[string]any{"items": items, "total": len(items)})
}

func firstQueryOrHeader(request *http.Request, queryKey string, headerNames ...string) string {
	if value := strings.TrimSpace(request.URL.Query().Get(queryKey)); value != "" {
		return value
	}
	return firstHeader(request, headerNames...)
}

func optionalInt64Query(request *http.Request, key string) int64 {
	value := strings.TrimSpace(request.URL.Query().Get(key))
	if value == "" {
		return 0
	}
	parsed, err := strconv.ParseInt(value, 10, 64)
	if err != nil || parsed < 0 {
		return 0
	}
	return parsed
}