settings rework (#144)

* add hdhr tuner count setting

* code cleanup

ErsatzTV.Application/HDHR/Commands/UpdateHDHRTunerCount.cs

@@ -0,0 +1,7 @@
+using ErsatzTV.Core;
+using LanguageExt;
+
+namespace ErsatzTV.Application.HDHR.Commands
+{
+    public record UpdateHDHRTunerCount(int TunerCount) : MediatR.IRequest<Either<BaseError, Unit>>;
+}

ErsatzTV.Application/HDHR/Commands/UpdateHDHRTunerCountHandler.cs

@@ -0,0 +1,45 @@
+using System.Threading;
+using System.Threading.Tasks;
+using ErsatzTV.Core;
+using ErsatzTV.Core.Domain;
+using ErsatzTV.Core.Interfaces.Repositories;
+using LanguageExt;
+using static LanguageExt.Prelude;
+
+namespace ErsatzTV.Application.HDHR.Commands
+{
+    public class UpdateHDHRTunerCountHandler : MediatR.IRequestHandler<UpdateHDHRTunerCount, Either<BaseError, Unit>>
+    {
+        private readonly IConfigElementRepository _configElementRepository;
+
+        public UpdateHDHRTunerCountHandler(IConfigElementRepository configElementRepository) =>
+            _configElementRepository = configElementRepository;
+
+        public Task<Either<BaseError, Unit>> Handle(
+            UpdateHDHRTunerCount request,
+            CancellationToken cancellationToken) =>
+            Validate(request)
+                .MapT(_ => Upsert(ConfigElementKey.HDHRTunerCount, request.TunerCount.ToString()))
+                .Bind(v => v.ToEitherAsync());
+
+        private Task<Validation<BaseError, Unit>> Validate(UpdateHDHRTunerCount request) =>
+            Optional(request.TunerCount)
+                .Filter(tc => tc > 0)
+                .Map(_ => Unit.Default)
+                .ToValidation<BaseError>("Tuner count must be greater than zero")
+                .AsTask();
+
+        private Task<Unit> Upsert(ConfigElementKey key, string value) =>
+            _configElementRepository.Get(key).Match(
+                ce =>
+                {
+                    ce.Value = value;
+                    return _configElementRepository.Update(ce);
+                },
+                () =>
+                {
+                    var ce = new ConfigElement { Key = key.Key, Value = value };
+                    return _configElementRepository.Add(ce);
+                }).ToUnit();
+    }
+}

ErsatzTV.Application/HDHR/Queries/GetHDHRTunerCount.cs

@@ -0,0 +1,6 @@
+using MediatR;
+
+namespace ErsatzTV.Application.HDHR.Queries
+{
+    public record GetHDHRTunerCount : IRequest<int>;
+}

ErsatzTV.Application/HDHR/Queries/GetHDHRTunerCountHandler.cs

@@ -0,0 +1,21 @@
+using System.Threading;
+using System.Threading.Tasks;
+using ErsatzTV.Core.Domain;
+using ErsatzTV.Core.Interfaces.Repositories;
+using LanguageExt;
+using MediatR;
+
+namespace ErsatzTV.Application.HDHR.Queries
+{
+    public class GetHDHRTunerCountHandler : IRequestHandler<GetHDHRTunerCount, int>
+    {
+        private readonly IConfigElementRepository _configElementRepository;
+
+        public GetHDHRTunerCountHandler(IConfigElementRepository configElementRepository) =>
+            _configElementRepository = configElementRepository;
+
+        public Task<int> Handle(GetHDHRTunerCount request, CancellationToken cancellationToken) =>
+            _configElementRepository.GetValue<int>(ConfigElementKey.HDHRTunerCount)
+                .Map(result => result.IfNone(2));
+    }
+}