package handler

import (
	"errors"
	"net/http"

	"github.com/gin-gonic/gin"

	"github.com/yuxingu/digital-psychology/apps/api/internal/middleware"
	"github.com/yuxingu/digital-psychology/apps/api/internal/service/analytics"
	"github.com/yuxingu/digital-psychology/apps/api/pkg/response"
)

// AnalyticsHandler serves POST /api/v1/analytics/events (DeviceAuth).
type AnalyticsHandler struct {
	Svc *analytics.Service
}

// Register mounts analytics routes on a DeviceAuth group.
func (h *AnalyticsHandler) Register(api *gin.RouterGroup) {
	g := api.Group("/analytics")
	g.POST("/events", h.Ingest)
}

func (h *AnalyticsHandler) Ingest(c *gin.Context) {
	userID, ok := middleware.UserIDFromContext(c)
	if !ok {
		response.Fail(c, http.StatusUnauthorized, 40100, "unauthorized")
		return
	}
	deviceKey := c.GetHeader(middleware.DeviceKeyHeader)
	if deviceKey == "" {
		response.Fail(c, http.StatusBadRequest, 40020, "device key required")
		return
	}
	var body struct {
		Items []analytics.EventIn `json:"items"`
	}
	if err := c.ShouldBindJSON(&body); err != nil {
		response.Fail(c, http.StatusBadRequest, 40021, "invalid body")
		return
	}
	res, err := h.Svc.Ingest(c.Request.Context(), userID, deviceKey, body.Items)
	if err != nil {
		if errors.Is(err, analytics.ErrTooManyItems) {
			response.Fail(c, http.StatusBadRequest, 40022, "too many items")
			return
		}
		if errors.Is(err, analytics.ErrInvalidBatch) {
			response.Fail(c, http.StatusBadRequest, 40023, "invalid batch")
			return
		}
		response.Fail(c, http.StatusInternalServerError, 50020, "ingest failed")
		return
	}
	response.OK(c, res)
}