package valkey

import (
	"context"
	"encoding/json"
	"strconv"

	"git.tek.govt.hu/dowerx/chat/server/model"
	"git.tek.govt.hu/dowerx/chat/server/util"
	"github.com/valkey-io/valkey-go"
)

const CHANNEL_PREFIX string = "channel:"

type NotificationDAOVK struct {
	vkDAO
}

func (d NotificationDAOVK) SendMessage(message model.Message) *util.ChatError {
	data, err := json.Marshal(message)
	if err != nil {
		return util.MakeError(err, util.GENERAL_ERROR)
	}

	cmd := (*d.vk).B().Publish().Channel(CHANNEL_PREFIX + strconv.Itoa(message.Channel)).Message(string(data)).Build()

	return util.MakeError((*d.vk).Do(context.Background(), cmd).Error(), util.DATABASE_QUERY_FAULT)
}

func (d NotificationDAOVK) SubscribeToChannel(ctx context.Context, id int) (<-chan model.Message, <-chan *util.ChatError) {
	cmd := (*d.vk).B().Subscribe().Channel(CHANNEL_PREFIX + strconv.Itoa(id)).Build()

	var messages chan model.Message = make(chan model.Message, 1)
	var errChan chan *util.ChatError = make(chan *util.ChatError, 1)

	go func() {
		err := (*d.vk).Receive(ctx, cmd, func(msg valkey.PubSubMessage) {
			go func() {
				message := model.Message{}
				err := json.Unmarshal([]byte(msg.Message), &message)
				if err != nil {
					return
				}

				messages <- message
			}()
		})
		defer close(messages)

		errChan <- util.MakeError(err, util.DATABASE_QUERY_FAULT)
	}()

	return messages, errChan
}

func MakeNotificationDAO() (NotificationDAOVK, *util.ChatError) {
	dao := NotificationDAOVK{}
	conn, err := getClient()
	if err != nil {
		return dao, err
	}

	dao.vk = conn
	return dao, nil
}