package handlers

import (
	"encoding/base64"
	"net/http"

	"github.com/labstack/echo/v4"
	"github.com/rs/zerolog/log"

	"github.com/treytartt/casera-api/internal/services"
)

// TrackingHandler handles email tracking endpoints
type TrackingHandler struct {
	onboardingService *services.OnboardingEmailService
}

// NewTrackingHandler creates a new tracking handler
func NewTrackingHandler(onboardingService *services.OnboardingEmailService) *TrackingHandler {
	return &TrackingHandler{
		onboardingService: onboardingService,
	}
}

// 1x1 transparent GIF (43 bytes)
var transparentGIF, _ = base64.StdEncoding.DecodeString("R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7")

// TrackEmailOpen handles email open tracking via tracking pixel
// GET /api/track/open/:trackingID
func (h *TrackingHandler) TrackEmailOpen(c echo.Context) error {
	trackingID := c.Param("trackingID")

	if trackingID != "" && h.onboardingService != nil {
		// Record the open (async, don't block response)
		go func() {
			defer func() {
				if r := recover(); r != nil {
					log.Error().Interface("panic", r).Str("tracking_id", trackingID).Msg("Panic in email open tracking goroutine")
				}
			}()
			if err := h.onboardingService.RecordEmailOpened(trackingID); err != nil {
				log.Error().Err(err).Str("tracking_id", trackingID).Msg("Failed to record email open")
			}
		}()
	}

	// Return 1x1 transparent GIF
	c.Response().Header().Set("Content-Type", "image/gif")
	c.Response().Header().Set("Cache-Control", "no-store, no-cache, must-revalidate, proxy-revalidate")
	c.Response().Header().Set("Pragma", "no-cache")
	c.Response().Header().Set("Expires", "0")
	return c.Blob(http.StatusOK, "image/gif", transparentGIF)
}