package handlers

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

	"github.com/gin-gonic/gin"

	"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 *gin.Context) {
	trackingID := c.Param("trackingID")

	if trackingID != "" && h.onboardingService != nil {
		// Record the open (async, don't block response)
		go func() {
			_ = h.onboardingService.RecordEmailOpened(trackingID)
		}()
	}

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