diff --git a/LibMatrix/Homeservers/ImplementationDetails/Synapse/Models/Responses/SynapseCollectionResult.cs b/LibMatrix/Homeservers/ImplementationDetails/Synapse/Models/Responses/SynapseCollectionResult.cs
new file mode 100644
index 0000000..36a5596
--- /dev/null
+++ b/LibMatrix/Homeservers/ImplementationDetails/Synapse/Models/Responses/SynapseCollectionResult.cs
@@ -0,0 +1,250 @@
+using System.Buffers;
+using System.Text;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+using ArcaneLibs.Extensions;
+
+namespace LibMatrix.Homeservers.ImplementationDetails.Synapse.Models.Responses;
+
+public class SynapseNextTokenTotalCollectionResult {
+ [JsonPropertyName("total")]
+ public int Total { get; set; }
+
+ [JsonPropertyName("next_token")]
+ public string? NextToken { get; set; }
+}
+
+// [JsonConverter(typeof(SynapseCollectionJsonConverter<>))]
+public class SynapseCollectionResult<T>(string chunkKey = "chunk", string prevTokenKey = "prev_token", string nextTokenKey = "next_token", string totalKey = "total") {
+ public int? Total { get; set; }
+ public string? PrevToken { get; set; }
+ public string? NextToken { get; set; }
+ public List<T> Chunk { get; set; } = [];
+
+ // TODO: figure out how to provide an IAsyncEnumerable<T> for this
+ // https://learn.microsoft.com/en-us/dotnet/standard/serialization/system-text-json/use-utf8jsonreader#read-from-a-stream-using-utf8jsonreader
+
+ // public async IAsyncEnumerable<T> FromJsonAsync(Stream stream) {
+ //
+ // }
+
+ public SynapseCollectionResult<T> FromJson(Stream stream, Action<T> action) {
+ byte[] buffer = new byte[4096];
+ _ = stream.Read(buffer);
+ var reader = new Utf8JsonReader(buffer, isFinalBlock: false, state: default);
+
+ try {
+ FromJsonInternal(stream, ref buffer, ref reader, action);
+ }
+ catch (JsonException e) {
+ Console.WriteLine($"Caught a JsonException: {e}");
+ int hexdumpWidth = 64;
+ Console.WriteLine($"Check hexdump line {reader.BytesConsumed / hexdumpWidth} index {reader.BytesConsumed % hexdumpWidth}");
+ buffer.HexDump(64);
+ }
+ finally { }
+
+ return this;
+ }
+
+ private void FromJsonInternal(Stream stream, ref byte[] buffer, ref Utf8JsonReader reader, Action<T> action) {
+ while (!reader.IsFinalBlock) {
+ while (!reader.Read()) {
+ GetMoreBytesFromStream(stream, ref buffer, ref reader);
+ }
+
+ if (reader.TokenType == JsonTokenType.PropertyName) {
+ var propName = reader.GetString();
+ Console.WriteLine($"SynapseCollectionResult: encountered property name: {propName}");
+
+ while (!reader.Read()) {
+ GetMoreBytesFromStream(stream, ref buffer, ref reader);
+ }
+
+ Console.WriteLine($"{reader.BytesConsumed}/{stream.Position} {reader.TokenType}");
+
+ if (propName == totalKey && reader.TokenType == JsonTokenType.Number) {
+ Total = reader.GetInt32();
+ }
+ else if (propName == prevTokenKey && reader.TokenType == JsonTokenType.String) {
+ PrevToken = reader.GetString();
+ }
+ else if (propName == nextTokenKey && reader.TokenType == JsonTokenType.String) {
+ NextToken = reader.GetString();
+ }
+ else if (propName == chunkKey) {
+ if (reader.TokenType == JsonTokenType.StartArray) {
+ while (reader.Read() && reader.TokenType != JsonTokenType.EndArray) {
+ // if (reader.TokenType == JsonTokenType.EndArray) {
+ // break;
+ // }
+ // Console.WriteLine($"Encountered token in chunk: {reader.TokenType}");
+ // var _buf = reader.ValueSequence.ToArray();
+ // try {
+ // var item = JsonSerializer.Deserialize<T>(_buf);
+ // action(item);
+ // Chunk.Add(item);
+ // }
+ // catch(JsonException e) {
+ // Console.WriteLine($"Caught a JsonException: {e}");
+ // int hexdumpWidth = 64;
+ //
+ // // Console.WriteLine($"Check hexdump line {reader.BytesConsumed / hexdumpWidth} index {reader.BytesConsumed % hexdumpWidth}");
+ // Console.WriteLine($"Buffer length: {_buf.Length}");
+ // _buf.HexDump(64);
+ // throw;
+ // }
+ var item = ReadItem(stream, ref buffer, ref reader);
+ action(item);
+ Chunk.Add(item);
+ }
+ }
+ }
+ }
+ }
+ }
+
+ private T ReadItem(Stream stream, ref byte[] buffer, ref Utf8JsonReader reader) {
+ while (!reader.Read()) {
+ GetMoreBytesFromStream(stream, ref buffer, ref reader);
+ }
+
+ // handle nullable types
+ if (typeof(T).IsGenericType && typeof(T).GetGenericTypeDefinition() == typeof(Nullable<>)) {
+ if (reader.TokenType == JsonTokenType.Null) {
+ return default(T);
+ }
+ }
+
+ // if(typeof(T) == typeof(string)) {
+ // return (T)(object)reader.GetString();
+ // }
+ // else if(typeof(T) == typeof(int)) {
+ // return (T)(object)reader.GetInt32();
+ // }
+ // else {
+ // var _buf = reader.ValueSequence.ToArray();
+ // return JsonSerializer.Deserialize<T>(_buf);
+ // }
+
+ // default branch uses "object?" cast to avoid compiler error
+ // add more branches here as nessesary
+ // reader.Read();
+ var call = typeof(T) switch {
+ Type t when t == typeof(string) => reader.GetString(),
+ _ => ReadObject<T>(stream, ref buffer, ref reader)
+ };
+
+ object ReadObject<T>(Stream stream, ref byte[] buffer, ref Utf8JsonReader reader) {
+ if (reader.TokenType != JsonTokenType.PropertyName) {
+ throw new JsonException();
+ }
+
+ List<byte> objBuffer = [(byte)'{', ..reader.ValueSequence.ToArray()];
+ var currentDepth = reader.CurrentDepth;
+ while (reader.CurrentDepth >= currentDepth) {
+ while (!reader.Read()) {
+ GetMoreBytesFromStream(stream, ref buffer, ref reader);
+ }
+
+ if (reader.TokenType == JsonTokenType.EndObject && reader.CurrentDepth == currentDepth) {
+ break;
+ }
+
+ objBuffer.AddRange(reader.ValueSpan);
+ }
+
+ return JsonSerializer.Deserialize<T>(objBuffer.ToArray());
+ }
+
+ return (T)call;
+
+ // return JsonSerializer.Deserialize<T>(ref reader);
+ }
+
+ private static void GetMoreBytesFromStream(Stream stream, ref byte[] buffer, ref Utf8JsonReader reader) {
+ int bytesRead;
+ if (reader.BytesConsumed < buffer.Length) {
+ ReadOnlySpan<byte> leftover = buffer.AsSpan((int)reader.BytesConsumed);
+
+ if (leftover.Length == buffer.Length) {
+ Array.Resize(ref buffer, buffer.Length * 2);
+ Console.WriteLine($"Increased buffer size to {buffer.Length}");
+ }
+
+ leftover.CopyTo(buffer);
+ bytesRead = stream.Read(buffer.AsSpan(leftover.Length));
+ }
+ else {
+ bytesRead = stream.Read(buffer);
+ }
+
+ // Console.WriteLine($"String in buffer is: {Encoding.UTF8.GetString(buffer)}");
+ reader = new Utf8JsonReader(buffer, isFinalBlock: bytesRead == 0, reader.CurrentState);
+ }
+}
+
+public partial class SynapseCollectionJsonConverter<T> : JsonConverter<SynapseCollectionResult<T>> {
+ public override SynapseCollectionResult<T>? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options) {
+ if (reader.TokenType != JsonTokenType.StartObject) {
+ throw new JsonException();
+ }
+
+ var result = new SynapseCollectionResult<T>();
+ while (reader.Read()) {
+ if (reader.TokenType == JsonTokenType.EndObject) {
+ break;
+ }
+
+ if (reader.TokenType != JsonTokenType.PropertyName) {
+ throw new JsonException();
+ }
+
+ var propName = reader.GetString();
+ reader.Read();
+ if (propName == "total") {
+ result.Total = reader.GetInt32();
+ }
+ else if (propName == "prev_token") {
+ result.PrevToken = reader.GetString();
+ }
+ else if (propName == "next_token") {
+ result.NextToken = reader.GetString();
+ }
+ else if (propName == "chunk") {
+ if (reader.TokenType != JsonTokenType.StartArray) {
+ throw new JsonException();
+ }
+
+ while (reader.Read()) {
+ if (reader.TokenType == JsonTokenType.EndArray) {
+ break;
+ }
+
+ var item = JsonSerializer.Deserialize<T>(ref reader, options);
+ result.Chunk.Add(item);
+ }
+ }
+ }
+
+ return result;
+ }
+
+ public override void Write(Utf8JsonWriter writer, SynapseCollectionResult<T> value, JsonSerializerOptions options) {
+ writer.WriteStartObject();
+ if (value.Total is not null)
+ writer.WriteNumber("total", value.Total ?? 0);
+ if (value.PrevToken is not null)
+ writer.WriteString("prev_token", value.PrevToken);
+ if (value.NextToken is not null)
+ writer.WriteString("next_token", value.NextToken);
+
+ writer.WriteStartArray("chunk");
+ foreach (var item in value.Chunk) {
+ JsonSerializer.Serialize(writer, item, options);
+ }
+
+ writer.WriteEndArray();
+ writer.WriteEndObject();
+ }
+}
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