fix watermark validation (#2301)

CHANGELOG.md

@@ -42,6 +42,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Fix channel playout mode `On Demand` for Block and YAML schedules
 - Fix QSV transitions when remote streaming from a media server
 - Fix green output when padding with VAAPI accel and i965 driver
+- Fix watermark custom image validation
+- Fix playback when using any watermarks that were saved with invalid state (no image)
 
 ### Changed
 - Allow multiple watermarks in playback troubleshooting

ErsatzTV.Core/FFmpeg/FFmpegProcessService.cs

@@ -190,6 +190,15 @@ public class FFmpegProcessService
                             Option<int>.None,
                             false);
                     case ChannelWatermarkImageSource.Custom:
+                        // bad form validation makes this possible
+                        if (string.IsNullOrWhiteSpace(watermark.Image))
+                        {
+                            _logger.LogWarning(
+                                "Watermark {Name} has custom image configured with no image; ignoring",
+                                watermark.Name);
+                            break;
+                        }
+
                         string customPath = _imageCache.GetPathForImage(
                             watermark.Image,
                             ArtworkKind.Watermark,

ErsatzTV/Pages/WatermarkEditor.razor

@@ -72,6 +72,10 @@
                         <MudElement HtmlTag="img" src="@($"artwork/watermarks/{_model.Image.UrlWithContentType}")" />
                     </div>
                 }
+                else
+                {
+                    <MudTextField Disabled="true" For="@(() => _model.Image.Path)" />
+                }
             </MudStack>
             <MudStack Row="true" Breakpoint="Breakpoint.SmAndDown" Class="form-field-stack gap-md-8 mb-5">
                 <div class="d-flex">

ErsatzTV/Validators/WatermarkEditViewModelValidator.cs

@@ -12,7 +12,7 @@ public class WatermarkEditViewModelValidator : AbstractValidator<WatermarkEditVi
     {
         RuleFor(x => x.Name).NotEmpty();
 
-        RuleFor(x => x.Image)
+        RuleFor(x => x.Image.Path)
             .NotEmpty()
             .WithMessage("Watermark image is required!")
             .When(vm => vm.ImageSource == ChannelWatermarkImageSource.Custom);