fix adding channel with no watermark (#265)

CHANGELOG.md

@@ -4,6 +4,8 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ## [Unreleased]
+### Fixed
+- Fix ui crash adding a channel without a watermark
 
 ## [0.0.46-prealpha] - 2021-06-14
 ### Added
@@ -18,7 +20,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
   - This allows easy watermark reuse across channels
 
 ### Fixed
-- Fix crash adding or editing schedule items due to Artist with no name
+- Fix ui crash adding or editing schedule items due to Artist with no name
 - Fix many potential sources of inconsistent data in UI
 
 ## [0.0.45-prealpha] - 2021-06-12

ErsatzTV.Application/Channels/Commands/CreateChannelHandler.cs

@@ -38,7 +38,7 @@ namespace ErsatzTV.Application.Channels.Commands
             return new CreateChannelResult(channel.Id);
         }
 
-        private async Task<Validation<BaseError, Channel>> Validate(TvContext dbContext, CreateChannel request) =>
+        private static async Task<Validation<BaseError, Channel>> Validate(TvContext dbContext, CreateChannel request) =>
             (ValidateName(request), await ValidateNumber(dbContext, request),
                 await FFmpegProfileMustExist(dbContext, request),
                 ValidatePreferredLanguage(request),
@@ -66,10 +66,14 @@ namespace ErsatzTV.Application.Channels.Commands
                         FFmpegProfileId = ffmpegProfileId,
                         StreamingMode = request.StreamingMode,
                         Artwork = artwork,
-                        PreferredLanguageCode = preferredLanguageCode,
+                        PreferredLanguageCode = preferredLanguageCode
-                        WatermarkId = watermarkId
                     };
 
+                    foreach (int id in watermarkId)
+                    {
+                        channel.WatermarkId = id;
+                    }
+
                     return channel;
                 });
 
@@ -111,20 +115,20 @@ namespace ErsatzTV.Application.Channels.Commands
                 .MapT(_ => createChannel.FFmpegProfileId)
                 .Map(o => o.ToValidation<BaseError>($"FFmpegProfile {createChannel.FFmpegProfileId} does not exist."));
 
-        private static async Task<Validation<BaseError, int?>> WatermarkMustExist(
+        private static async Task<Validation<BaseError, Option<int>>> WatermarkMustExist(
             TvContext dbContext,
             CreateChannel createChannel)
         {
             if (createChannel.WatermarkId is null)
             {
-                return createChannel.WatermarkId;
+                return Option<int>.None;
             }
 
             return await dbContext.ChannelWatermarks
                 .CountAsync(w => w.Id == createChannel.WatermarkId)
                 .Map(Optional)
                 .Filter(c => c > 0)
-                .MapT(_ => createChannel.WatermarkId)
+                .MapT(_ => Optional(createChannel.WatermarkId))
                 .Map(o => o.ToValidation<BaseError>($"Watermark {createChannel.WatermarkId} does not exist."));
         }
     }