package platform

import (
	"encoding/json"
	"net/http"
	"strings"
	"time"

	"lingniu/vehicle-data-platform/apps/api/internal/httpx"
)

type Handler struct {
	service *Service
	mux     *http.ServeMux
}

func NewHandler(service *Service) *Handler {
	h := &Handler{service: service, mux: http.NewServeMux()}
	h.routes()
	return h
}

func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	h.mux.ServeHTTP(w, r)
}

func (h *Handler) routes() {
	h.mux.HandleFunc("GET /api/dashboard/summary", h.handleDashboardSummary)
	h.mux.HandleFunc("GET /api/vehicles", h.handleVehicles)
	h.mux.HandleFunc("GET /api/vehicles/detail", h.handleVehicleDetail)
	h.mux.HandleFunc("GET /api/realtime/locations", h.handleRealtimeLocations)
	h.mux.HandleFunc("GET /api/history/locations", h.handleHistoryLocations)
	h.mux.HandleFunc("GET /api/history/raw-frames", h.handleRawFramesGet)
	h.mux.HandleFunc("POST /api/history/raw-frames/query", h.handleRawFramesPost)
	h.mux.HandleFunc("GET /api/mileage/daily", h.handleDailyMileage)
	h.mux.HandleFunc("GET /api/quality/issues", h.handleQualityIssues)
	h.mux.HandleFunc("GET /api/ops/health", h.handleOpsHealth)
}

func (h *Handler) handleDashboardSummary(w http.ResponseWriter, r *http.Request) {
	data, err := h.service.DashboardSummary(r.Context())
	h.write(w, r, data, err)
}

func (h *Handler) handleVehicles(w http.ResponseWriter, r *http.Request) {
	data, err := h.service.Vehicles(r.Context(), r.URL.Query())
	h.write(w, r, data, err)
}

func (h *Handler) handleVehicleDetail(w http.ResponseWriter, r *http.Request) {
	vin := strings.TrimSpace(r.URL.Query().Get("vin"))
	if vin == "" {
		httpx.WriteError(w, http.StatusBadRequest, "VIN_REQUIRED", "VIN 不能为空", "", traceID(r))
		return
	}
	data, err := h.service.VehicleDetail(r.Context(), vin, r.URL.Query().Get("protocol"))
	h.write(w, r, data, err)
}

func (h *Handler) handleRealtimeLocations(w http.ResponseWriter, r *http.Request) {
	data, err := h.service.RealtimeLocations(r.Context(), r.URL.Query())
	h.write(w, r, data, err)
}

func (h *Handler) handleHistoryLocations(w http.ResponseWriter, r *http.Request) {
	data, err := h.service.HistoryLocations(r.Context(), r.URL.Query())
	h.write(w, r, data, err)
}

func (h *Handler) handleRawFramesGet(w http.ResponseWriter, r *http.Request) {
	q := r.URL.Query()
	query := RawFrameQuery{
		Protocol:      q.Get("protocol"),
		VIN:           q.Get("vin"),
		DateFrom:      q.Get("dateFrom"),
		DateTo:        q.Get("dateTo"),
		Fields:        splitCSV(q.Get("fields")),
		IncludeFields: q.Get("includeFields") == "true",
		Limit:         parsePositive(q.Get("limit"), 100),
		Offset:        parsePositive(q.Get("offset"), 0),
	}
	data, err := h.service.RawFrames(r.Context(), query)
	h.write(w, r, data, err)
}

func (h *Handler) handleRawFramesPost(w http.ResponseWriter, r *http.Request) {
	defer r.Body.Close()
	var query RawFrameQuery
	if err := json.NewDecoder(r.Body).Decode(&query); err != nil {
		httpx.WriteError(w, http.StatusBadRequest, "BAD_JSON", "请求 JSON 解析失败", err.Error(), traceID(r))
		return
	}
	data, err := h.service.RawFrames(r.Context(), query)
	h.write(w, r, data, err)
}

func (h *Handler) handleDailyMileage(w http.ResponseWriter, r *http.Request) {
	data, err := h.service.DailyMileage(r.Context(), r.URL.Query())
	h.write(w, r, data, err)
}

func (h *Handler) handleQualityIssues(w http.ResponseWriter, r *http.Request) {
	data, err := h.service.QualityIssues(r.Context(), r.URL.Query())
	h.write(w, r, data, err)
}

func (h *Handler) handleOpsHealth(w http.ResponseWriter, r *http.Request) {
	data, err := h.service.OpsHealth(r.Context())
	h.write(w, r, data, err)
}

func (h *Handler) write(w http.ResponseWriter, r *http.Request, data any, err error) {
	if err != nil {
		httpx.WriteError(w, http.StatusInternalServerError, "INTERNAL", "服务处理失败", err.Error(), traceID(r))
		return
	}
	httpx.WriteOK(w, traceID(r), data)
}

func traceID(r *http.Request) string {
	if value := r.Header.Get("X-Trace-Id"); value != "" {
		return value
	}
	return "trace-" + time.Now().Format("20060102150405.000000")
}

func splitCSV(value string) []string {
	if strings.TrimSpace(value) == "" {
		return nil
	}
	parts := strings.Split(value, ",")
	out := make([]string, 0, len(parts))
	for _, part := range parts {
		if trimmed := strings.TrimSpace(part); trimmed != "" {
			out = append(out, trimmed)
		}
	}
	return out
}