enforce unique schedule name (#47)

ErsatzTV.Application/ProgramSchedules/Commands/CreateProgramScheduleHandler.cs

@@ -1,4 +1,6 @@
-using System.Threading;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading;
 using System.Threading.Tasks;
 using ErsatzTV.Core;
 using ErsatzTV.Core.Domain;
@@ -6,6 +8,7 @@ using ErsatzTV.Core.Interfaces.Repositories;
 using LanguageExt;
 using MediatR;
 using static ErsatzTV.Application.ProgramSchedules.Mapper;
+using static LanguageExt.Prelude;
 
 namespace ErsatzTV.Application.ProgramSchedules.Commands
 {
@@ -22,22 +25,33 @@ namespace ErsatzTV.Application.ProgramSchedules.Commands
             CreateProgramSchedule request,
             CancellationToken cancellationToken) =>
             Validate(request)
-                .Map(PersistProgramSchedule)
-                .ToEitherAsync();
+                .MapT(PersistProgramSchedule)
+                .Bind(v => v.ToEitherAsync());
 
         private Task<ProgramScheduleViewModel> PersistProgramSchedule(ProgramSchedule c) =>
             _programScheduleRepository.Add(c).Map(ProjectToViewModel);
 
-        private Validation<BaseError, ProgramSchedule> Validate(CreateProgramSchedule request) =>
+        private Task<Validation<BaseError, ProgramSchedule>> Validate(CreateProgramSchedule request) =>
             ValidateName(request)
-                .Map(
+                .MapT(
                     name => new ProgramSchedule
                     {
                         Name = name, MediaCollectionPlaybackOrder = request.MediaCollectionPlaybackOrder
                     });
 
-        private Validation<BaseError, string> ValidateName(CreateProgramSchedule createProgramSchedule) =>
-            createProgramSchedule.NotEmpty(c => c.Name)
+        private async Task<Validation<BaseError, string>> ValidateName(CreateProgramSchedule createProgramSchedule)
+        {
+            List<string> allNames = await _programScheduleRepository.GetAll()
+                .Map(list => list.Map(c => c.Name).ToList());
+
+            Validation<BaseError, string> result1 = createProgramSchedule.NotEmpty(c => c.Name)
                 .Bind(_ => createProgramSchedule.NotLongerThan(50)(c => c.Name));
+
+            var result2 = Optional(createProgramSchedule.Name)
+                .Filter(name => !allNames.Contains(name))
+                .ToValidation<BaseError>("Schedule name must be unique");
+
+            return (result1, result2).Apply((_, _) => createProgramSchedule.Name);
+        }
     }
 }

ErsatzTV/Pages/ScheduleEditor.razor

@@ -81,7 +81,7 @@
             errorMessage.HeadOrNone().Match(
                 error =>
                 {
-                    Snackbar.Add(error.Value);
+                    Snackbar.Add(error.Value, Severity.Error);
                     Logger.LogError("Unexpected error saving schedule: {Error}", error.Value);
                 },
                 () => NavigationManager.NavigateTo("/schedules"));