using Domain.AggregateModel.AppAggregate;
using Domain.AggregateModel.LinkAggregate;
using Domain.Exceptions;
using MediatR;
using Microsoft.Extensions.Logging;
using QRCodeService.Services;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace QRCodeService.Application.Commands
{
    public class CreateLinkCommandHandler : IRequestHandler<CreateLinkCommand, Link>
    {

        readonly ILogger<CreateLinkCommandHandler> logger;
        readonly IAppRepository appRepository;
        private readonly IShortCodeService shortCodeService;
        readonly ILinkRepository linkRepository;

        public CreateLinkCommandHandler(IShortCodeService shortCodeService,ILinkRepository linkRepository, IAppRepository appRepository, ILogger<CreateLinkCommandHandler> logger)
        {
            this.shortCodeService = shortCodeService;
            this.linkRepository = linkRepository;
            this.appRepository = appRepository;
            this.logger = logger;
        }

        async Task<Link> IRequestHandler<CreateLinkCommand, Link>.Handle(CreateLinkCommand request, CancellationToken cancellationToken)
        {
            var app =  await appRepository.GetAsync(request.AppId);
            if (app == null)
            {
                throw new DomainException("app not found");
            }
            var fullUrl = new Uri(new Uri(app.BaseUrl), request.SuffixUrl).ToString();
            var shortCode = await shortCodeService.GenShortCode(fullUrl);
            var dbLink = await linkRepository.GetAsync(shortCode);
            if (dbLink != null)
            {
                logger.LogDebug("use exist link");
                return dbLink;
            }
            var link = new Link(app.BaseUrl, request.SuffixUrl,fullUrl, request.AppId, shortCode);
            link = linkRepository.Add(link);
            await linkRepository.UnitOfWork.SaveEntitiesAsync();
            return link;
        }
    }
}