IM_NEW/MessageService.WebApi/Application/EventHandlers/MessageHandler.cs

using IM.Commons.IntegrationEvents;
using MassTransit;
using MediatR;
using MessageService.Domain.Events;
using MessageService.Domain.IReposities;
using MessageService.Infrastructure;

namespace MessageService.WebApi.Application.EventHandlers
{
    public class MessageHandler : INotificationHandler<MessageCreatedDomainEvent>, INotificationHandler<MessageWithdrawDomainEvent>
    {
        private readonly IPublishEndpoint endpoint;
        private readonly IConversationReposity reposity;
        private readonly MessageDbContext messageDb;

        public MessageHandler(IPublishEndpoint endpoint, IConversationReposity reposity, MessageDbContext messageDb)
        {
            this.endpoint = endpoint;
            this.reposity = reposity;
            this.messageDb = messageDb;
        }

        public async Task Handle(MessageCreatedDomainEvent notification, CancellationToken cancellationToken)
        {
            var message = notification.Message;

            if(message.ChatType == Domain.Enums.ChatType.PRIVATE)
            {
                var list = await reposity.FindByStreamKeyAsync(message.StreamKey);
                var owner = list.First(x => x.UserId == message.SenderId);
                var target = list.First(x => x.UserId == message.TargetId);

                owner.Update(message.SequenceId, 0, message.Content.Fallback);
                target.Update(target.LastReadSequenceId, target.UnreadCount + 1, message.Content.Fallback);

                messageDb.Conversations.UpdateRange(owner,target);
                await messageDb.SaveChangesAsync(cancellationToken);
            }

            await endpoint.Publish(message.ToIntegrationEvent());
        }

        public async Task Handle(MessageWithdrawDomainEvent notification, CancellationToken cancellationToken)
        {
            var message = notification.Message;
            await endpoint.Publish(new MsgWithdrawEvent(message.Id, message.State.ToString(), message.StreamKey), cancellationToken);
        }
    }
}