package api

import (
	"log/slog"
	"net/http"

	"github.com/alchemistkay/guestguard/internal/notification"
)

type unsubscribeHandler struct {
	logger   *slog.Logger
	signer   *notification.UnsubscribeSigner
	suppress *notification.SuppressionRepo
}

// GET /unsubscribe/{token} — surface the email address that the token
// belongs to so the frontend can show a confirmation page. Honoured even
// before the user clicks "Confirm" so they see what's being unsubscribed.
func (h *unsubscribeHandler) preview(w http.ResponseWriter, r *http.Request) {
	if h.signer == nil {
		writeError(w, http.StatusServiceUnavailable, "unsubscribe not configured")
		return
	}
	email, err := h.signer.Verify(r.PathValue("token"))
	if err != nil {
		writeError(w, http.StatusBadRequest, "invalid unsubscribe link")
		return
	}
	writeJSON(w, http.StatusOK, map[string]string{"email": email})
}

// POST /unsubscribe/{token} — add the email to the suppression list.
// Idempotent: clicking the link twice keeps the existing entry.
func (h *unsubscribeHandler) confirm(w http.ResponseWriter, r *http.Request) {
	if h.signer == nil || h.suppress == nil {
		writeError(w, http.StatusServiceUnavailable, "unsubscribe not configured")
		return
	}
	email, err := h.signer.Verify(r.PathValue("token"))
	if err != nil {
		writeError(w, http.StatusBadRequest, "invalid unsubscribe link")
		return
	}
	if err := h.suppress.Add(r.Context(), email, "user clicked unsubscribe", notification.SuppressionUser); err != nil {
		h.logger.Error("add suppression", "err", err, "email", email)
		writeError(w, http.StatusInternalServerError, "failed to unsubscribe")
		return
	}
	writeJSON(w, http.StatusOK, map[string]string{"status": "unsubscribed", "email": email})
}