package v1

import (
	"net/http"
	"strconv"
	"time"

	"github.com/gin-gonic/gin"

	"github.com/gochat/gochat/internal/service"
	"github.com/gochat/gochat/pkg/response"
)

// ReportingEventHandler handles reporting event API endpoints.
// Reference: Chatwoot app/controllers/api/v1/accounts/reporting_events_controller.rb
type ReportingEventHandler struct {
	svc *service.ReportingEventService
}

// NewReportingEventHandler creates a new ReportingEventHandler.
func NewReportingEventHandler(svc *service.ReportingEventService) *ReportingEventHandler {
	return &ReportingEventHandler{svc: svc}
}

const chatwootReportingEventsPerPage = 25

// List retrieves reporting events for an account with Chatwoot filters and pagination.
// GET /api/v1/accounts/:account_id/reporting_events?since=...&until=...&inbox_id=...&user_id=...&name=...&page=...
func (h *ReportingEventHandler) List(c *gin.Context) {
	accountID, err := parseUintParam(c, "account_id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid account_id")
		return
	}

	filter, ok := parseReportingEventListFilter(c)
	if !ok {
		return
	}

	result, svcErr := h.svc.ListAccountEvents(c.Request.Context(), accountID, filter)
	if svcErr != nil {
		handleServiceError(c, svcErr)
		return
	}

	payload := make([]gin.H, 0, len(result.Events))
	for i := range result.Events {
		payload = append(payload, serializeReportingEvent(result.Events[i]))
	}
	c.JSON(http.StatusOK, gin.H{
		"payload": payload,
		"meta": gin.H{
			"count":        result.Total,
			"current_page": result.CurrentPage,
			"total_pages":  result.TotalPages,
		},
	})
}

func parseReportingEventListFilter(c *gin.Context) (service.ReportingEventListFilter, bool) {
	page, err := strconv.Atoi(c.DefaultQuery("page", "1"))
	if err != nil || page < 1 {
		page = 1
	}

	inboxID, err := parseOptionalUintQueryParam(c, "inbox_id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid inbox_id")
		return service.ReportingEventListFilter{}, false
	}
	userID, err := parseOptionalUintQueryParam(c, "user_id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid user_id")
		return service.ReportingEventListFilter{}, false
	}

	filter := service.ReportingEventListFilter{
		InboxID: inboxID,
		UserID:  userID,
		Name:    c.Query("name"),
		Page:    page,
		PerPage: chatwootReportingEventsPerPage,
	}

	sinceStr := c.Query("since")
	untilStr := c.Query("until")
	if sinceStr == "" || untilStr == "" {
		return filter, true
	}

	since, err := parseUnixTimestamp(sinceStr)
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid since date format")
		return service.ReportingEventListFilter{}, false
	}
	until, err := parseUnixTimestamp(untilStr)
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid until date format")
		return service.ReportingEventListFilter{}, false
	}
	filter.Since = &since
	filter.Until = &until
	return filter, true
}

func parseUnixTimestamp(value string) (time.Time, error) {
	seconds, err := strconv.ParseInt(value, 10, 64)
	if err != nil {
		return time.Time{}, err
	}
	return time.Unix(seconds, 0).UTC(), nil
}