package notificationimp

import (
	"encoding/json"
	"io"
	"net/http"

	"github.com/tech/sendico/notification/internal/server/notificationimp/telegram"
	tnotifications "github.com/tech/sendico/pkg/messaging/notifications/telegram"
	"github.com/tech/sendico/pkg/model"
	"github.com/tech/sendico/pkg/mservice"
	"go.uber.org/zap"
)

const telegramWebhookMaxBody = 1 << 20

func (a *NotificationAPI) handleTelegramWebhook(w http.ResponseWriter, r *http.Request) {
	if a == nil {
		w.WriteHeader(http.StatusNoContent)
		return
	}
	if a.producer == nil {
		if a.logger != nil {
			a.logger.Warn("Telegram webhook ignored: messaging producer is not configured")
		}
		w.WriteHeader(http.StatusServiceUnavailable)
		return
	}
	var update telegram.Update
	dec := json.NewDecoder(io.LimitReader(r.Body, telegramWebhookMaxBody))
	if err := dec.Decode(&update); err != nil {
		if a.logger != nil {
			a.logger.Warn("Failed to decode telegram webhook update", zap.Error(err))
		}
		w.WriteHeader(http.StatusBadRequest)
		return
	}
	if a.logger != nil {
		fields := []zap.Field{
			zap.Int64("update_id", update.UpdateID),
			zap.Bool("has_message", update.Message != nil),
		}
		if update.Message != nil {
			fields = append(fields,
				zap.Int64("message_id", update.Message.MessageID),
				zap.Int64("chat_id", update.Message.Chat.ID),
				zap.Int("text_length", len(update.Message.Text)),
			)
			if update.Message.From != nil {
				fields = append(fields, zap.Int64("from_user_id", update.Message.From.ID))
			}
			if update.Message.ReplyToMessage != nil {
				fields = append(fields, zap.Int64("reply_to_message_id", update.Message.ReplyToMessage.MessageID))
			}
		}
		a.logger.Info("Telegram webhook update received", fields...)
	}
	payload := &model.TelegramWebhookUpdate{
		UpdateID: update.UpdateID,
	}
	if update.Message != nil {
		payload.Message = update.Message.ToModel()
	}
	env := tnotifications.TelegramUpdate(string(mservice.Notifications), payload)
	if err := a.producer.SendMessage(env); err != nil {
		if a.logger != nil {
			a.logger.Warn("Failed to publish telegram webhook update", zap.Error(err), zap.Int64("update_id", update.UpdateID))
		}
		w.WriteHeader(http.StatusServiceUnavailable)
		return
	}
	w.WriteHeader(http.StatusOK)
}