add remote resource support

src/SIL.Harmony.Core/EntityNotFoundException.cs

@@ -0,0 +1,3 @@
+namespace SIL.Harmony.Core;
+
+public class EntityNotFoundException(string message) : Exception(message);

src/SIL.Harmony.Core/IRemoteResourceService.cs

@@ -0,0 +1,27 @@
+namespace SIL.Harmony.Core;
+
+/// <summary>
+/// interface to facilitate downloading of resources, typically implemented in application code
+/// the remote Id is opaque to the CRDT lib and could be a URL or some other identifier provided by the backend
+/// the local path returned for the application code to use as required, it could be a URL if needed also.
+/// </summary>
+public interface IRemoteResourceService
+{
+    /// <summary>
+    /// instructs application code to download a resource from the remote server
+    /// the service is responsible for downloading the resource and returning the local path
+    /// </summary>
+    /// <param name="remoteId">ID used to identify the remote resource, could be a URL</param>
+    /// <param name="localResourceCachePath">path defined by the CRDT config where the resource should be stored</param>
+    /// <returns>download result containing the path to the downloaded file, this is stored in the local db and not synced</returns>
+    Task<DownloadResult> DownloadResource(string remoteId, string localResourceCachePath);
+    /// <summary>
+    /// upload a resource to the remote server
+    /// </summary>
+    /// <param name="localPath">full path to the resource on the local machine</param>
+    /// <returns>an upload result with the remote id, the id will be stored and transmitted to other clients so they can also download the resource</returns>
+    Task<UploadResult> UploadResource(string localPath);
+}
+
+public record DownloadResult(string LocalPath);
+public record UploadResult(string RemoteId);

src/SIL.Harmony.Sample/Changes/AddWordImageChange.cs

@@ -0,0 +1,15 @@
+using SIL.Harmony.Changes;
+using SIL.Harmony.Entities;
+using SIL.Harmony.Sample.Models;
+
+namespace SIL.Harmony.Sample.Changes;
+
+public class AddWordImageChange(Guid entityId, Guid imageId) : EditChange<Word>(entityId), ISelfNamedType<AddWordImageChange>
+{
+    public Guid ImageId { get; } = imageId;
+
+    public override async ValueTask ApplyChange(Word entity, ChangeContext context)
+    {
+        if (!await context.IsObjectDeleted(ImageId)) entity.ImageResourceId = ImageId;
+    }
+}

src/SIL.Harmony.Sample/CrdtSampleKernel.cs

@@ -36,6 +36,7 @@ public static IServiceCollection AddCrdtDataSample(this IServiceCollection servi
         services.AddCrdtData<SampleDbContext>(config =>
         {
             config.EnableProjectedTables = true;
+            config.AddRemoteResourceEntity();
             config.ChangeTypeListBuilder
                 .Add<NewWordChange>()
                 .Add<NewDefinitionChange>()
@@ -44,6 +45,7 @@ public static IServiceCollection AddCrdtDataSample(this IServiceCollection servi
                 .Add<SetWordTextChange>()
                 .Add<SetWordNoteChange>()
                 .Add<AddAntonymReferenceChange>()
+                .Add<AddWordImageChange>()
                 .Add<SetOrderChange<Definition>>()
                 .Add<SetDefinitionPartOfSpeechChange>()
                 .Add<DeleteChange<Word>>()

src/SIL.Harmony.Sample/Models/Word.cs

@@ -10,10 +10,17 @@ public class Word : IObjectBase<Word>
     public Guid Id { get; init; }
     public DateTimeOffset? DeletedAt { get; set; }
     public Guid? AntonymId { get; set; }
+    public Guid? ImageResourceId { get; set; }
 
     public Guid[] GetReferences()
     {
-        return AntonymId is null ? [] : [AntonymId.Value];
+        return Refs().ToArray();
+
+        IEnumerable<Guid> Refs()
+        {
+            if (AntonymId.HasValue) yield return AntonymId.Value;
+            if (ImageResourceId.HasValue) yield return ImageResourceId.Value;
+        }
     }
 
     public void RemoveReference(Guid id, Commit commit)

src/SIL.Harmony.Tests/DbContextTests.VerifyModel.verified.txt

@@ -81,6 +81,40 @@
       Relational:TableName: Snapshots
       Relational:ViewName: 
       Relational:ViewSchema: 
+  EntityType: LocalResource
+    Properties: 
+      Id (Guid) Required PK AfterSave:Throw ValueGenerated.OnAdd
+      LocalPath (string) Required
+    Keys: 
+      Id PK
+    Annotations: 
+      DiscriminatorProperty: 
+      Relational:FunctionName: 
+      Relational:Schema: 
+      Relational:SqlQuery: 
+      Relational:TableName: LocalResource
+      Relational:ViewName: 
+      Relational:ViewSchema: 
+  EntityType: RemoteResource
+    Properties: 
+      Id (Guid) Required PK AfterSave:Throw ValueGenerated.OnAdd
+      DeletedAt (DateTimeOffset?)
+      RemoteId (string)
+      SnapshotId (no field, Guid?) Shadow FK Index
+    Keys: 
+      Id PK
+    Foreign keys: 
+      RemoteResource {'SnapshotId'} -> ObjectSnapshot {'Id'} Unique SetNull
+    Indexes: 
+      SnapshotId Unique
+    Annotations: 
+      DiscriminatorProperty: 
+      Relational:FunctionName: 
+      Relational:Schema: 
+      Relational:SqlQuery: 
+      Relational:TableName: RemoteResource
+      Relational:ViewName: 
+      Relational:ViewSchema: 
   EntityType: Definition
     Properties: 
       Id (Guid) Required PK AfterSave:Throw ValueGenerated.OnAdd
@@ -133,6 +167,7 @@
       Id (Guid) Required PK AfterSave:Throw ValueGenerated.OnAdd
       AntonymId (Guid?)
       DeletedAt (DateTimeOffset?)
+      ImageResourceId (Guid?)
       Note (string)
       SnapshotId (no field, Guid?) Shadow FK Index
       Text (string) Required

src/SIL.Harmony.Tests/ResourceTests/RemoteResourcesTests.cs

@@ -0,0 +1,139 @@
+using System.Runtime.CompilerServices;
+using Microsoft.Extensions.DependencyInjection;
+using SIL.Harmony.Resource;
+
+namespace SIL.Harmony.Tests.ResourceTests;
+
+public class RemoteResourcesTests : DataModelTestBase
+{
+    private RemoteServiceMock _remoteServiceMock = new();
+    private ResourceService _resourceService => _services.GetRequiredService<ResourceService>();
+
+    public RemoteResourcesTests()
+    {
+    }
+
+    private string CreateFile(string contents, [CallerMemberName] string fileName = "")
+    {
+        var filePath = Path.GetFullPath(fileName + ".txt");
+        File.WriteAllText(filePath, contents);
+        return filePath;
+    }
+
+    private async Task<(Guid resourceId, string remoteId)> SetupRemoteResource(string fileContents)
+    {
+        var remoteId = _remoteServiceMock.CreateRemoteResource(fileContents);
+        var resourceId = Guid.NewGuid();
+        await DataModel.AddChange(_localClientId, new CreateRemoteResourceChange(resourceId, remoteId));
+        return (resourceId, remoteId);
+    }
+
+    private async Task<(Guid resourceId, string localPath)> SetupLocalFile(string contents, [CallerMemberName] string fileName = "")
+    {
+        var file = CreateFile(contents, fileName);
+        //because resource service is null the file is not uploaded
+        var resourceId = await _resourceService.AddLocalResource(file, _localClientId, resourceService: null);
+        return (resourceId, file);
+    }
+
+    [Fact]
+    public async Task CreatingAResourceResultsInPendingLocalResources()
+    {
+        var (_, file) = await SetupLocalFile("contents");
+
+        //act
+        var pending = await _resourceService.ListResourcesPendingUpload();
+
+
+        pending.Should().ContainSingle().Which.LocalPath.Should().Be(file);
+    }
+
+    [Fact]
+    public async Task ResourcesNotLocalShouldShowUpAsNotDownloaded()
+    {
+        var (resourceId, remoteId) = await SetupRemoteResource("test");
+
+        //act
+        var pending = await _resourceService.ListResourcesPendingDownload();
+
+
+        var remoteResource = pending.Should().ContainSingle().Subject;
+        remoteResource.RemoteId.Should().Be(remoteId);
+        remoteResource.Id.Should().Be(resourceId);
+    }
+
+    [Fact]
+    public async Task CanUploadFileToRemote()
+    {
+        var fileContents = "resource";
+        var localFile = CreateFile(fileContents);
+
+        //act
+        var resourceId =
+            await _resourceService.AddLocalResource(localFile, _localClientId, resourceService: _remoteServiceMock);
+
+
+        var resource = await DataModel.GetLatest<RemoteResource>(resourceId);
+        ArgumentNullException.ThrowIfNull(resource);
+        ArgumentNullException.ThrowIfNull(resource.RemoteId);
+        _remoteServiceMock.ReadFile(resource.RemoteId).Should().Be(fileContents);
+        var pendingUpload = await _resourceService.ListResourcesPendingUpload();
+        pendingUpload.Should().BeEmpty();
+    }
+
+    [Fact]
+    public async Task WillUploadMultiplePendingLocalFilesAtOnce()
+    {
+        await SetupLocalFile("file1", "file1");
+        await SetupLocalFile("file2", "file2");
+
+        //act
+        await _resourceService.UploadPendingResources(_localClientId, _remoteServiceMock);
+
+
+        _remoteServiceMock.ListFiles()
+            .Select(Path.GetFileName)
+            .Should()
+            .Contain(["file1.txt", "file2.txt"]);
+    }
+
+    [Fact]
+    public async Task CanDownloadFileFromRemote()
+    {
+        var fileContents = "resource";
+        var (resourceId, _) = await SetupRemoteResource(fileContents);
+
+        //act
+        var localResource = await _resourceService.DownloadResource(resourceId, _remoteServiceMock);
+
+
+        localResource.Id.Should().Be(resourceId);
+        var actualFileContents = await File.ReadAllTextAsync(localResource.LocalPath);
+        actualFileContents.Should().Be(fileContents);
+        var pendingDownloads = await _resourceService.ListResourcesPendingDownload();
+        pendingDownloads.Should().BeEmpty();
+    }
+
+    [Fact]
+    public async Task CanGetALocalResourceGivenAnId()
+    {
+        var file = CreateFile("resource");
+        //because resource service is null the file is not uploaded
+        var resourceId = await _resourceService.AddLocalResource(file, _localClientId, resourceService: null);
+
+        //act
+        var localResource = await _resourceService.GetLocalResource(resourceId);
+
+
+        localResource.Should().NotBeNull();
+        localResource!.LocalPath.Should().Be(file);
+    }
+
+    [Fact]
+    public async Task LocalResourceIsNullIfNotDownloaded()
+    {
+        var (resourceId, _) = await SetupRemoteResource("test");
+        var localResource = await _resourceService.GetLocalResource(resourceId);
+        localResource.Should().BeNull();
+    }
+}

src/SIL.Harmony.Tests/ResourceTests/RemoteServiceMock.cs

@@ -0,0 +1,45 @@
+using SIL.Harmony.Core;
+
+namespace SIL.Harmony.Tests.ResourceTests;
+
+public class RemoteServiceMock : IRemoteResourceService
+{
+    public static readonly string RemotePath = Directory.CreateTempSubdirectory("RemoteServiceMock").FullName;
+
+    /// <summary>
+    /// directly creates a remote resource
+    /// </summary>
+    /// <returns>the remote id</returns>
+    public string CreateRemoteResource(string contents)
+    {
+        var filePath = Path.Combine(RemotePath, Guid.NewGuid().ToString("N") + ".txt");
+        File.WriteAllText(filePath, contents);
+        return filePath;
+    }
+
+    public Task<DownloadResult> DownloadResource(string remoteId, string localResourceCachePath)
+    {
+        var fileName = Path.GetFileName(remoteId);
+        var localPath = Path.Combine(localResourceCachePath, fileName);
+        Directory.CreateDirectory(localResourceCachePath);
+        File.Copy(remoteId, localPath);
+        return Task.FromResult(new DownloadResult(localPath));
+    }
+
+    public Task<UploadResult> UploadResource(string localPath)
+    {
+        var remoteId = Path.Combine(RemotePath, Path.GetFileName(localPath));
+        File.Copy(localPath, remoteId);
+        return Task.FromResult(new UploadResult(remoteId));
+    }
+
+    public string ReadFile(string remoteId)
+    {
+        return File.ReadAllText(remoteId);
+    }
+
+    public IEnumerable<string> ListFiles()
+    {
+        return Directory.GetFiles(RemotePath);
+    }
+}

src/SIL.Harmony.Tests/ResourceTests/WordResourceTests.cs

@@ -0,0 +1,41 @@
+using System.Runtime.CompilerServices;
+using Microsoft.Extensions.DependencyInjection;
+using SIL.Harmony.Sample.Changes;
+using SIL.Harmony.Sample.Models;
+
+namespace SIL.Harmony.Tests.ResourceTests;
+
+public class WordResourceTests: DataModelTestBase
+{
+    private RemoteServiceMock _remoteServiceMock = new();
+    private ResourceService _resourceService => _services.GetRequiredService<ResourceService>();
+    private readonly Guid _entity1Id = Guid.NewGuid();
+
+    private string CreateFile(string contents, [CallerMemberName] string fileName = "")
+    {
+        var filePath = Path.GetFullPath(fileName + ".txt");
+        File.WriteAllText(filePath, contents);
+        return filePath;
+    }
+
+    [Fact]
+    public async Task CanReferenceAResourceFromAWord()
+    {
+        await WriteNextChange(SetWord(_entity1Id, "test-value"));
+        var imageFile = CreateFile("not image data");
+        //set commit date for add local resource
+        MockTimeProvider.SetNextDateTime(NextDate());
+        var resourceId = await _resourceService.AddLocalResource(imageFile, Guid.NewGuid(), resourceService: _remoteServiceMock);
+        await WriteNextChange(new AddWordImageChange(_entity1Id, resourceId));
+
+        var word = await DataModel.GetLatest<Word>(_entity1Id);
+        word.Should().NotBeNull();
+        word!.ImageResourceId.Should().Be(resourceId);
+
+
+        var localResource = await _resourceService.GetLocalResource(word.ImageResourceId!.Value);
+        localResource.Should().NotBeNull();
+        localResource!.LocalPath.Should().Be(imageFile);
+        (await File.ReadAllTextAsync(localResource.LocalPath)).Should().Be("not image data");
+    }
+}

src/SIL.Harmony/Changes/EditChange.cs

@@ -1,4 +1,4 @@
-namespace SIL.Harmony.Changes;
+namespace SIL.Harmony.Changes;
 
 public abstract class EditChange<T>(Guid entityId) : Change<T>(entityId)
     where T : class