From 8b1237e2c49f12997fa72541900f0933a74daf7b Mon Sep 17 00:00:00 2001
From: Kevin Hahn <kevin_hahn@sil.org>
Date: Tue, 15 Oct 2024 10:05:33 +0700
Subject: [PATCH] allow multiple object adapters

---
 .../Adapters/CustomAdapterProvider.cs         |  8 +++-
 .../Adapters/DefaultAdapterProvider.cs        |  8 +++-
 .../Adapters/IObjectAdapterProvider.cs        |  3 +-
 src/SIL.Harmony/CrdtConfig.cs                 | 41 +++++++++++++------
 4 files changed, 41 insertions(+), 19 deletions(-)

diff --git a/src/SIL.Harmony/Adapters/CustomAdapterProvider.cs b/src/SIL.Harmony/Adapters/CustomAdapterProvider.cs
index 53231cc..81a2252 100644
--- a/src/SIL.Harmony/Adapters/CustomAdapterProvider.cs
+++ b/src/SIL.Harmony/Adapters/CustomAdapterProvider.cs
@@ -12,8 +12,7 @@ public class CustomAdapterProvider<TCommonInterface, TCustomAdapter> : IObjectAd
 {
     private readonly ObjectTypeListBuilder _objectTypeListBuilder;
     private readonly List<AdapterRegistration> _objectTypes = new();
-    private Dictionary<Type, List<JsonDerivedType>> JsonTypes { get; } = [];
-    Dictionary<Type, List<JsonDerivedType>> IObjectAdapterProvider.JsonTypes => JsonTypes;
+    private Dictionary<Type, List<JsonDerivedType>> JsonTypes => _objectTypeListBuilder.JsonTypes;
 
     public CustomAdapterProvider(ObjectTypeListBuilder objectTypeListBuilder)
     {
@@ -55,6 +54,11 @@ IObjectBase IObjectAdapterProvider.Adapt(object obj)
     {
         return TCustomAdapter.Create((TCommonInterface)obj);
     }
+
+    public bool CanAdapt(object obj)
+    {
+        return obj is TCommonInterface;
+    }
 }
 
 // it's possible to implement this without a Common interface
diff --git a/src/SIL.Harmony/Adapters/DefaultAdapterProvider.cs b/src/SIL.Harmony/Adapters/DefaultAdapterProvider.cs
index 53bea0f..b764ba9 100644
--- a/src/SIL.Harmony/Adapters/DefaultAdapterProvider.cs
+++ b/src/SIL.Harmony/Adapters/DefaultAdapterProvider.cs
@@ -38,6 +38,10 @@ IObjectBase IObjectAdapterProvider.Adapt(object obj)
             $"Object is of type {obj.GetType().Name} which does not implement {nameof(IObjectBase)}");
     }
 
-    private Dictionary<Type, List<JsonDerivedType>> JsonTypes { get; } = [];
-    Dictionary<Type, List<JsonDerivedType>> IObjectAdapterProvider.JsonTypes => JsonTypes;
+    public bool CanAdapt(object obj)
+    {
+        return obj is IObjectBase;
+    }
+
+    private Dictionary<Type, List<JsonDerivedType>> JsonTypes => objectTypeListBuilder.JsonTypes;
 }
\ No newline at end of file
diff --git a/src/SIL.Harmony/Adapters/IObjectAdapterProvider.cs b/src/SIL.Harmony/Adapters/IObjectAdapterProvider.cs
index 6504c0a..98b21dd 100644
--- a/src/SIL.Harmony/Adapters/IObjectAdapterProvider.cs
+++ b/src/SIL.Harmony/Adapters/IObjectAdapterProvider.cs
@@ -11,6 +11,5 @@ internal interface IObjectAdapterProvider
 {
     IEnumerable<AdapterRegistration> GetRegistrations();
     IObjectBase Adapt(object obj);
-
-    Dictionary<Type, List<JsonDerivedType>> JsonTypes { get; }
+    bool CanAdapt(object obj);
 }
\ No newline at end of file
diff --git a/src/SIL.Harmony/CrdtConfig.cs b/src/SIL.Harmony/CrdtConfig.cs
index 1c24f12..da54811 100644
--- a/src/SIL.Harmony/CrdtConfig.cs
+++ b/src/SIL.Harmony/CrdtConfig.cs
@@ -75,12 +75,12 @@ public void AddRemoteResourceEntity(string? cachePath = null)
     {
         RemoteResourcesEnabled = true;
         LocalResourceCachePath = cachePath ?? LocalResourceCachePath;
-        ObjectTypeListBuilder.Add<RemoteResource>();
+        ObjectTypeListBuilder.DefaultAdapter().Add<RemoteResource>();
         ChangeTypeListBuilder.Add<RemoteResourceUploadedChange>();
         ChangeTypeListBuilder.Add<CreateRemoteResourceChange>();
         ChangeTypeListBuilder.Add<CreateRemoteResourcePendingUploadChange>();
         ChangeTypeListBuilder.Add<DeleteChange<RemoteResource>>();
-        ObjectTypeListBuilder.AddDbModelConfig(builder =>
+        ObjectTypeListBuilder.ModelConfigurations.Add((builder, config) =>
         {
             var entity = builder.Entity<LocalResource>();
             entity.HasKey(lr => lr.Id);
@@ -127,8 +127,7 @@ public void Freeze()
     {
         if (_frozen) return;
         _frozen = true;
-        JsonTypes = AdapterProvider.JsonTypes;
-        foreach (var registration in AdapterProvider.GetRegistrations())
+        foreach (var registration in AdapterProviders.SelectMany(a => a.GetRegistrations()))
         {
             ModelConfigurations.Add((builder, config) =>
             {
@@ -147,19 +146,18 @@ internal void CheckFrozen()
         if (_frozen) throw new InvalidOperationException($"{nameof(ObjectTypeListBuilder)} is frozen");
     }
 
-    internal Dictionary<Type, List<JsonDerivedType>>? JsonTypes { get; set; }
+    internal Dictionary<Type, List<JsonDerivedType>> JsonTypes { get; } = [];
 
     internal List<Action<ModelBuilder, CrdtConfig>> ModelConfigurations { get; } = [];
 
-    internal IObjectAdapterProvider AdapterProvider => _adapterProvider ?? throw new InvalidOperationException("No adapter has been added to the builder");
-    private IObjectAdapterProvider? _adapterProvider;
+    internal List<IObjectAdapterProvider> AdapterProviders { get; } = [];
 
     public DefaultAdapterProvider DefaultAdapter()
     {
         CheckFrozen();
-        if (_adapterProvider is not null) throw new InvalidOperationException("adapter has already been added");
-        var adapter = new DefaultAdapterProvider(this);
-        _adapterProvider = adapter;
+        if (AdapterProviders.OfType<DefaultAdapterProvider>().SingleOrDefault() is {} adapter) return adapter;
+        adapter = new DefaultAdapterProvider(this);
+        AdapterProviders.Add(adapter);
         return adapter;
     }
     
@@ -182,9 +180,26 @@ public CustomAdapterProvider<TCommonInterface, TAdapter> CustomAdapter<TCommonIn
         where TCommonInterface : class where TAdapter : class, ICustomAdapter<TAdapter, TCommonInterface>, IPolyType
     {
         CheckFrozen();
-        if (_adapterProvider is not null) throw new InvalidOperationException("adapter has already been added");
-        var adapter = new CustomAdapterProvider<TCommonInterface, TAdapter>(this);
-        _adapterProvider = adapter;
+        if (AdapterProviders.OfType<CustomAdapterProvider<TCommonInterface, TAdapter>>().SingleOrDefault() is {} adapter) return adapter;
+        adapter = new CustomAdapterProvider<TCommonInterface, TAdapter>(this);
+        AdapterProviders.Add(adapter);
         return adapter;
     }
+
+    internal IObjectBase Adapt(object obj)
+    {
+        if (AdapterProviders is [{ } defaultAdapter])
+        {
+            return defaultAdapter.Adapt(obj);
+        }
+
+        foreach (var objectAdapterProvider in AdapterProviders)
+        {
+            if (objectAdapterProvider.CanAdapt(obj))
+            {
+                return objectAdapterProvider.Adapt(obj);
+            }
+        }
+        throw new ArgumentException($"Unable to adapt object of type {obj.GetType()}");
+    }
 }