Initial commit

ErsatzTV.Application/MediaCollections/Commands/CreateSimpleMediaCollectionHandler.cs

@@ -0,0 +1,49 @@
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using ErsatzTV.Core;
+using ErsatzTV.Core.Domain;
+using ErsatzTV.Core.Interfaces.Repositories;
+using LanguageExt;
+using MediatR;
+using static ErsatzTV.Application.MediaCollections.Mapper;
+using static LanguageExt.Prelude;
+
+namespace ErsatzTV.Application.MediaCollections.Commands
+{
+    public class CreateSimpleMediaCollectionHandler : IRequestHandler<CreateSimpleMediaCollection,
+        Either<BaseError, MediaCollectionViewModel>>
+    {
+        private readonly IMediaCollectionRepository _mediaCollectionRepository;
+
+        public CreateSimpleMediaCollectionHandler(IMediaCollectionRepository mediaCollectionRepository) =>
+            _mediaCollectionRepository = mediaCollectionRepository;
+
+        public Task<Either<BaseError, MediaCollectionViewModel>> Handle(
+            CreateSimpleMediaCollection request,
+            CancellationToken cancellationToken) =>
+            Validate(request).MapT(PersistCollection).Bind(v => v.ToEitherAsync());
+
+        private Task<MediaCollectionViewModel> PersistCollection(SimpleMediaCollection c) =>
+            _mediaCollectionRepository.Add(c).Map(ProjectToViewModel);
+
+        private Task<Validation<BaseError, SimpleMediaCollection>> Validate(CreateSimpleMediaCollection request) =>
+            ValidateName(request).MapT(name => new SimpleMediaCollection { Name = name });
+
+        private async Task<Validation<BaseError, string>> ValidateName(CreateSimpleMediaCollection createCollection)
+        {
+            List<string> allNames = await _mediaCollectionRepository.GetSimpleMediaCollections()
+                .Map(list => list.Map(c => c.Name).ToList());
+
+            Validation<BaseError, string> result1 = createCollection.NotEmpty(c => c.Name)
+                .Bind(_ => createCollection.NotLongerThan(50)(c => c.Name));
+
+            var result2 = Optional(createCollection.Name)
+                .Filter(name => !allNames.Contains(name))
+                .ToValidation<BaseError>("Media collection name must be unique");
+
+            return (result1, result2).Apply((_, _) => createCollection.Name);
+        }
+    }
+}