use timestamp to identify model changes

src/CoreCraft.SourceGeneration/Generators/ModelShardGenerator.cs

@@ -458,7 +458,7 @@ void ImplementUpdateMethod(ModelShard modelShard)
 
         void ImplementSaveMethod(ModelShard modelShard)
         {
-            code.WriteLine($"public void Save(int changeId, IHistoryRepository repository)");
+            code.WriteLine($"public void Save(long changeId, IHistoryRepository repository)");
             code.Block(() =>
             {
                 foreach (var collection in modelShard.Collections)
@@ -476,7 +476,7 @@ void ImplementSaveMethod(ModelShard modelShard)
 
         void ImplementLoadMethod(ModelShard modelShard)
         {
-            code.WriteLine($"public void Load(int changeId, IHistoryRepository repository)");
+            code.WriteLine($"public void Load(long changeId, IHistoryRepository repository)");
             code.Block(() =>
             {
                 foreach (var collection in modelShard.Collections)

src/CoreCraft.Storage.Json/JsonRepository.cs

@@ -138,14 +138,14 @@ public void Save<TParent, TChild>(IRelation<TParent, TChild> relation)
         }
     }
 
-    public void Save<TEntity, TProperties>(int changeId, ICollectionChangeSet<TEntity, TProperties> changes)
+    public void Save<TEntity, TProperties>(long changeId, ICollectionChangeSet<TEntity, TProperties> changes)
         where TEntity : Entity
         where TProperties : Properties
     {
         throw new NotImplementedException();
     }
 
-    public void Save<TParent, TChild>(int changeId, IRelationChangeSet<TParent, TChild> changes)
+    public void Save<TParent, TChild>(long changeId, IRelationChangeSet<TParent, TChild> changes)
         where TParent : Entity
         where TChild : Entity
     {
@@ -204,14 +204,14 @@ public void Load<TParent, TChild>(IMutableRelation<TParent, TChild> relation, IE
         }
     }
 
-    public void Load<TEntity, TProperties>(int changeId, ICollectionChangeSet<TEntity, TProperties> changes)
+    public void Load<TEntity, TProperties>(long changeId, ICollectionChangeSet<TEntity, TProperties> changes)
         where TEntity : Entity
         where TProperties : Properties
     {
         throw new NotImplementedException();
     }
 
-    public void Load<TParent, TChild>(int changeId, IRelationChangeSet<TParent, TChild> changes)
+    public void Load<TParent, TChild>(long changeId, IRelationChangeSet<TParent, TChild> changes)
         where TParent : Entity
         where TChild : Entity
     {

src/CoreCraft.Storage.Sqlite/ISqliteRepository.cs

@@ -1,4 +1,6 @@
-using CoreCraft.Persistence;
+using CoreCraft.ChangesTracking;
+using CoreCraft.Core;
+using CoreCraft.Persistence;
 using CoreCraft.Persistence.History;
 using System.Data;
 
@@ -31,7 +33,7 @@ public interface ISqliteRepository : IRepository, IHistoryRepository, IDisposabl
     ///     TODO: Write documentation
     /// </summary>
     /// <returns>TODO: Write documentation</returns>
-    int GetMaxChangeId();
+    IEnumerable<IModelChanges> LoadChanges(IEnumerable<IModelShard> shards);
 
     /// <summary>
     ///     Sets new database version

src/CoreCraft.Storage.Sqlite/QueryBuilder.cs

@@ -53,7 +53,7 @@ internal static class History
             CREATE TABLE IF NOT EXISTS [__CollectionHistory] (
                 [Id] INTEGER NOT NULL,
                 [Collection] TEXT NOT NULL,
-                [ChangeId] INTEGER NOT NULL,
+                [ChangeId] NUMERIC NOT NULL,
                 [Action] INTEGER NOT NULL,
                 [EntityId] TEXT NOT NULL,
                 [OldProperties] TEXT,
@@ -62,17 +62,6 @@ PRIMARY KEY([Id])
             );
             """;
 
-        internal const string SelectMaxChangeId = """
-            SELECT [ChangeId]
-            FROM (
-                SELECT [ChangeId] FROM [__CollectionHistory]
-                UNION ALL
-                SELECT [ChangeId] FROM [__RelationHistory]
-            )
-            ORDER BY [ChangeId] DESC
-            LIMIT 1;
-            """;
-
         internal const string InsertIntoCollectionTable = """
             INSERT INTO [__CollectionHistory] ([Collection], [ChangeId], [Action], [EntityId], [OldProperties], [NewProperties])
             VALUES ($Collection, $ChangeId, $Action, $EntityId, $OldProperties, $NewProperties);
@@ -82,7 +71,7 @@ INSERT INTO [__CollectionHistory] ([Collection], [ChangeId], [Action], [EntityId
             CREATE TABLE IF NOT EXISTS [__RelationHistory] (
                 [Id] INTEGER NOT NULL,
                 [Relation] TEXT NOT NULL,
-                [ChangeId] INTEGER NOT NULL,
+                [ChangeId] NUMERIC NOT NULL,
                 [Action] INTEGER NOT NULL,
                 [ParentId] TEXT NOT NULL,
                 [ChildId] TEXT NOT NULL,
@@ -95,17 +84,29 @@ INSERT INTO [__RelationHistory] ([Relation], [ChangeId], [Action], [ParentId], [
             VALUES ($Relation, $ChangeId, $Action, $ParentId, $ChildId);
             """;
 
-        internal static string SelectCollectionTable(int changeId, string collection) => $"""
+        internal static string SelectCollectionTable(long changeId, string collection) => $"""
             SELECT [Action], [EntityId], [OldProperties], [NewProperties]
             FROM [__CollectionHistory]
             WHERE [ChangeId] = {changeId} AND [Collection] = '{collection}';
             """;
 
-        internal static string SelectRelationTable(int changeId, string relation) => $"""
+        internal static string SelectRelationTable(long changeId, string relation) => $"""
             SELECT [Action], [ParentId], [ChildId]
             FROM [__RelationHistory]
             WHERE [ChangeId] = {changeId} AND [Relation] = '{relation}';
             """;
+
+        internal const string SelectChangeIds = """
+            SELECT DISTINCT *
+            FROM (
+                SELECT [ChangeId]
+                FROM [__CollectionHistory]
+                UNION ALL
+                SELECT [ChangeId]
+                FROM [__RelationHistory]
+            )
+            ORDER BY [ChangeId] ASC;
+            """;
     }
 
     internal static class Migrations

src/CoreCraft.Storage.Sqlite/SqliteRepository.cs

@@ -184,7 +184,7 @@ public void Save<TParent, TChild>(IRelation<TParent, TChild> relation)
         }
     }
 
-    public void Save<TEntity, TProperties>(int changeId, ICollectionChangeSet<TEntity, TProperties> changes)
+    public void Save<TEntity, TProperties>(long changeId, ICollectionChangeSet<TEntity, TProperties> changes)
         where TEntity : Entity
         where TProperties : Properties
     {
@@ -218,7 +218,7 @@ public void Save<TEntity, TProperties>(int changeId, ICollectionChangeSet<TEntit
         }
     }
 
-    public void Save<TParent, TChild>(int changeId, IRelationChangeSet<TParent, TChild> changes)
+    public void Save<TParent, TChild>(long changeId, IRelationChangeSet<TParent, TChild> changes)
         where TParent : Entity
         where TChild : Entity
     {
@@ -305,7 +305,7 @@ public void Load<TParent, TChild>(IMutableRelation<TParent, TChild> relation, IE
         }
     }
 
-    public void Load<TEntity, TProperties>(int changeId, ICollectionChangeSet<TEntity, TProperties> changes)
+    public void Load<TEntity, TProperties>(long changeId, ICollectionChangeSet<TEntity, TProperties> changes)
         where TEntity : Entity
         where TProperties : Properties
     {
@@ -325,7 +325,7 @@ public void Load<TEntity, TProperties>(int changeId, ICollectionChangeSet<TEntit
         }
     }
 
-    public void Load<TParent, TChild>(int changeId, IRelationChangeSet<TParent, TChild> changes)
+    public void Load<TParent, TChild>(long changeId, IRelationChangeSet<TParent, TChild> changes)
         where TParent : Entity
         where TChild : Entity
     {
@@ -344,21 +344,36 @@ public void Load<TParent, TChild>(int changeId, IRelationChangeSet<TParent, TChi
         }
     }
 
-    public int GetMaxChangeId()
+    public IEnumerable<IModelChanges> LoadChanges(IEnumerable<IModelShard> shards)
     {
-        var command = CreateCommand(History.SelectMaxChangeId);
+        var changes = new List<IModelChanges>();
+        using var command = CreateCommand(History.SelectChangeIds);
 
         Log(command);
 
         using var reader = command.ExecuteReader();
-        if (reader.Read())
+        while (reader.Read())
         {
-            var changeId = reader.GetInt32(0);
+            var timestamp = reader.GetInt64(0);
+            var modelChanges = new ModelChanges(timestamp);
 
-            return changeId;
+            foreach (var shard in shards.Cast<IFrameFactory>())
+            {
+                var change = (IChangesFrameEx)shard.Create();
+                change.Load(timestamp, this);
+                if (change.HasChanges())
+                {
+                    modelChanges.AddOrGet(change);
+                }
+            }
+
+            if (modelChanges.Any())
+            {
+                changes.Add(modelChanges);
+            }
         }
 
-        return 0;
+        return changes;
     }
 
     internal bool Exists(CollectionInfo collection)

src/CoreCraft.Storage.Sqlite/SqliteStorage.cs

@@ -63,13 +63,9 @@ public void Save(IEnumerable<IModelChanges> modelChanges)
             repository.ExecuteNonQuery(QueryBuilder.History.CreateCollectionTable);
             repository.ExecuteNonQuery(QueryBuilder.History.CreateRelationTable);
 
-            var baseId = repository.GetMaxChangeId();
-            foreach (var (idx, change) in modelChanges.Select((c, idx) => (idx, c)))
+            foreach (var change in modelChanges)
             {
-                foreach (var frame in change.Cast<IChangesFrameEx>())
-                {
-                    frame.Save(baseId + idx, repository);
-                }
+                change.Save(repository);
             }
         });
     }
@@ -121,30 +117,7 @@ public IEnumerable<IModelChanges> Load(IEnumerable<IModelShard> modelShards)
         repository.ExecuteNonQuery(QueryBuilder.History.CreateCollectionTable);
         repository.ExecuteNonQuery(QueryBuilder.History.CreateRelationTable);
 
-        var changes = new List<IModelChanges>();
-        var numOfChanges = repository.GetMaxChangeId();
-
-        for (int i = 0; i <= numOfChanges; i++)
-        {
-            var modelChanges = new ModelChanges();
-
-            foreach (var shard in modelShards.Cast<IFrameFactory>())
-            {
-                var change = (IChangesFrameEx)shard.Create();
-                change.Load(i, repository);
-                if (change.HasChanges())
-                {
-                    modelChanges.AddOrGet(change);
-                }
-            }
-
-            if (modelChanges.Any())
-            {
-                changes.Add(modelChanges);
-            }
-        }
-
-        return changes;
+        return repository.LoadChanges(modelShards);
     }
 
     private void Transaction(string path, Action<ISqliteRepository> action)

src/CoreCraft/ChangesTracking/IChangesFrameEx.cs

@@ -69,7 +69,7 @@ public interface IChangesFrameEx : IChangesFrame
     ///     - The `changeId` parameter allows for associating the changes with a specific event or action.
     ///     - The `repository` parameter is an <see cref="IHistoryRepository" /> instance responsible for handling the storage and retrieval of history data.
     /// </remarks>
-    void Save(int changeId, IHistoryRepository repository);
+    void Save(long changeId, IHistoryRepository repository);
 
     /// <summary>
     ///     Loads changes history from the specified repository for the given change identifier.
@@ -81,5 +81,5 @@ public interface IChangesFrameEx : IChangesFrame
     ///     - The `changeId` parameter specifies the unique identifier of the change set to be loaded.
     ///     - The `repository` parameter is an <see cref="IHistoryRepository" /> instance responsible for providing access to changes.
     /// </remarks>
-    void Load(int changeId, IHistoryRepository repository);
+    void Load(long changeId, IHistoryRepository repository);
 }

src/CoreCraft/ChangesTracking/IModelChanges.cs

@@ -1,4 +1,6 @@
-namespace CoreCraft.ChangesTracking;
+using CoreCraft.Persistence.History;
+
+namespace CoreCraft.ChangesTracking;
 
 /// <summary>
 ///     A collection of changes for a model
@@ -36,4 +38,10 @@ bool TryGetFrame<T>(out T frame)
     /// </summary>
     /// <returns>A new inverted changes</returns>
     IModelChanges Invert();
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="repository"></param>
+    void Save(IHistoryRepository repository);
 }

src/CoreCraft/ChangesTracking/ModelChanges.cs

@@ -1,4 +1,5 @@
 using System.Collections;
+using CoreCraft.Persistence.History;
 
 namespace CoreCraft.ChangesTracking;
 
@@ -7,16 +8,19 @@ public sealed class ModelChanges : IMutableModelChanges
 {
     private readonly HashSet<IChangesFrameEx> _frames;
 
+    private long _timestamp;
+
     /// <summary>
     ///     Ctor
     /// </summary>
-    public ModelChanges()
-        : this(new HashSet<IChangesFrameEx>(ChangesFrameComparer.Instance))
+    public ModelChanges(long timestamp)
+        : this(timestamp, new HashSet<IChangesFrameEx>(ChangesFrameComparer.Instance))
     {
     }
 
-    private ModelChanges(HashSet<IChangesFrameEx> frames)
+    private ModelChanges(long timestamp, HashSet<IChangesFrameEx> frames)
     {
+        _timestamp = timestamp;
         _frames = frames;
     }
 
@@ -45,7 +49,7 @@ public IModelChanges Invert()
     {
         var frames = _frames.Select(x => x.Invert()).Cast<IChangesFrameEx>();
 
-        return new ModelChanges(new HashSet<IChangesFrameEx>(frames, ChangesFrameComparer.Instance));
+        return new ModelChanges(_timestamp, new HashSet<IChangesFrameEx>(frames, ChangesFrameComparer.Instance));
     }
 
     /// <inheritdoc />
@@ -71,7 +75,16 @@ public IMutableModelChanges Merge(IModelChanges changes)
             }
         }
 
-        return new ModelChanges(result);
+        return new ModelChanges(_timestamp, result);
+    }
+
+    /// <inheritdoc />
+    public void Save(IHistoryRepository repository)
+    {
+        foreach (var frame in _frames)
+        {
+            frame.Save(_timestamp, repository);
+        }
     }
 
     /// <inheritdoc />

src/CoreCraft/Core/IFeature.cs

@@ -26,11 +26,11 @@ public interface IFeature
     /// </summary>
     /// <typeparam name="TEntity">A type of an entity</typeparam>
     /// <typeparam name="TProperties">A type of properties</typeparam>
-    /// <param name="context">A context with utility methods</param>
+    /// <param name="factory">A factory for changes frames</param>
     /// <param name="collection">A base collection which will be wrapped in this method</param>
     /// <returns>A new collection with adjusted behavior</returns>
     IMutableCollection<TEntity, TProperties> Decorate<TEntity, TProperties>(
-        IFrameFactory context,
+        IFrameFactory factory,
         IMutableCollection<TEntity, TProperties> collection)
         where TEntity : Entity
         where TProperties : Properties;
@@ -40,11 +40,11 @@ IMutableCollection<TEntity, TProperties> Decorate<TEntity, TProperties>(
     /// </summary>
     /// <typeparam name="TParent">A type of a parent entity</typeparam>
     /// <typeparam name="TChild">A type of a child entity</typeparam>
-    /// <param name="context">A context with utility methods</param>
+    /// <param name="factory">A factory for changes frames</param>
     /// <param name="relation">A base relation which will be wrapped in this method</param>
     /// <returns>A new relation with adjusted behavior</returns>
     IMutableRelation<TParent, TChild> Decorate<TParent, TChild>(
-        IFrameFactory context,
+        IFrameFactory factory,
         IMutableRelation<TParent, TChild> relation)
         where TParent : Entity
         where TChild : Entity;