# Glossary

Core terminology for the AyCode framework. Read this before working on unfamiliar areas.

## Core Abstractions

| Term | Definition |
|---|---|
| **IId<T>** | Generic identity interface (`T` = `Guid` or `int`). Foundation of the entity system. |
| **TrackingState** | Client-side change tracking enum: Added, Modified, Deleted, Unchanged. Not related to EF Core tracking. |
| **IForeignKey** | Marker interface for navigation property foreign keys. |
| **IForeignCollection<T>** | Marker for collection navigation properties. |

## Serialization Formats

| Term | Definition |
|---|---|
| **AcBinary** | High-performance binary serializer. Two-phase: scan (collect metadata) then serialize. Supports reference tracking, string interning, ID-based deduplication. |
| **Toon** | Token-Oriented Object Notation. LLM-optimized format with @meta (schema) and @data (values) sections. Designed for maximum LLM comprehension accuracy. |
| **AcJson** | Newtonsoft.Json wrapper with $id/$ref reference handling, IId-based resolution, and chain deserialization API. |
| **Chain API** | Fluent deserialization: `CreateDeserializeChain<T>().ThenDeserialize<U>()...Execute()`. Resolves cross-references across multiple types. |
| **String Interning** | Binary serializer deduplicates repeated strings. Controlled via `[AcStringIntern]` attribute or `StringInterningMode`. See `AyCode.Core/docs/BINARY_FEATURES.md`. |

## Binary Wire Format

For full specification see `AyCode.Core/docs/BINARY_FORMAT.md`.

| Term | Definition |
|---|---|
| **BinaryTypeCode** | Single-byte marker that identifies the type of the next value in the binary stream. 100+ codes defined in `BinaryTypeCode.cs`. |
| **FixObj** | Compact object marker (0–63). The byte itself is the type slot index — no additional identifier needed. |
| **FixStr** | Compact string marker (103–134). Encodes type + length in one byte for ASCII strings ≤31 bytes. |
| **TinyInt** | Compact integer marker (192–255). Encodes small integers (−16 to 47) in a single byte. |
| **VarInt / VarUInt** | Variable-length integer encoding. LEB128 for unsigned, ZigZag + LEB128 for signed. |
| **HeaderFlags** | Byte at stream position 1 encoding serialization options: metadata, reference handling mode, cache count presence. Base `0x90`. |
| **Two-Phase Serialization** | Scan pass detects multi-referenced objects, serialize pass writes output using reference table. Required for `ReferenceHandling.All`. |

## Serialization Attributes

| Attribute | Purpose |
|---|---|
| **[AcBinarySerializable]** | Marks type for source generator. Feature flags: enableMetadata, enableIdTracking, enableRefHandling, enableInternString. |
| **[AcStringIntern]** | Marks string property for deduplication during binary serialization. |
| **[ToonDescription]** | Per-property description for Toon @meta output. |

## Architecture Layers

| Layer | Projects | Role |
|---|---|---|
| **Interfaces** | AyCode.Interfaces, .Server | Contracts only — no implementation |
| **Entities** | AyCode.Entities, .Server | Abstract generic base classes |
| **Models** | AyCode.Models, .Server | DTOs, view models |
| **Services** | AyCode.Services, .Server | Business logic, SignalR |
| **Database** | AyCode.Database | EF Core DAL with Session/Transaction pattern |
| **Core** | AyCode.Core, .Server | Serializers, compression, logging, constants |
| **Utils** | AyCode.Utils, .Server | Zero-dependency utilities |

## Database Patterns

| Term | Definition |
|---|---|
| **DAL (Data Access Layer)** | `AcDalBase` — mutex-protected, supports Session (read) and Transaction (write) patterns. |
| **PooledDal** | Singleton pool managing DAL instances by SessionId/PlayerId. |
| **Session** | Read-only database operation pattern. No transaction, no mutex lock on DbContext. |
| **Transaction** | Write operation pattern with auto-rollback on failure. |

## SignalR Infrastructure

For full architecture see `AyCode.Services/docs/SIGNALR.md`.

| Term | Definition |
|---|---|
| **OnReceiveMessage** | The single SignalR method for all communication. Signature: `(int messageTag, int? requestId, SignalReceiveParams receiveParams, byte[] data)`. Metadata and payload are separate hub arguments — `byte[]` uses protocol zero-copy fast-path. |
| **SignalReceiveParams** | Lightweight metadata sent alongside message payload as separate hub argument. Contains `Status` (SignalResponseStatus). Implements `ISignalParams`. AcBinary serialized. |
| **Message Tag** | Integer identifier mapping to a method via `[SignalR(tag)]` or `[SignalRSendToClient(tag)]` attributes. |
| **DynamicMethodRegistry** | Resolves message tags to `MethodInfo` at runtime. Static `ConcurrentDictionary` cache with lazy scan on miss. |
| **SignalRCrudTags** | Sealed class bundling 5 independent tag integers (getAllTag, getItemTag, addTag, updateTag, removeTag) for entity CRUD. See `AyCode.Services.Server/docs/SIGNALR_DATASOURCE.md`. |
| **AcBinaryHubProtocol** | Custom `IHubProtocol` replacing SignalR's JSON+Base64 with `AcBinarySerializer`. Protocol name: `"acbinary"`. Uses `BufferWriterBinaryOutput` for zero-copy writes to the SignalR pipe. |
| **SignalResponseDataMessage** | Internal DTO for callback routing (not serialized on wire). Constructed in-memory from `receiveParams` + `data`. Supports Binary or JSON+GZip via `GetResponseData<T>()`. |
| **SignalPostJsonDataMessage** | ⚠️ TECH DEBT — request params serialized to JSON inside Binary envelope. Planned for pure Binary replacement. |
| **AcSignalRDataSource** | Generic real-time `IList<T>` with change tracking, CRUD via SignalRCrudTags, binary merge, rollback, sync state. |
| **TrackingItem** | Wraps a modified DataSource item with `TrackingState` (Add/Update/Remove) + `OriginalValue` for rollback. |
| **SendToClientType** | Enum controlling broadcast scope: None, Others, Caller, All. |
| **AcWebSignalRHubBase** | Abstract server hub. Receives `OnReceiveMessage`, dispatches via DynamicMethodRegistry, responds/broadcasts via `SendMessageToClient` (metadata + payload as separate args, no envelope). |
| **AcSignalRClientBase** | Abstract client. Manages `HubConnection`, request/response correlation via `requestId`, pooled `SignalRRequestModel`. |
| **AcSessionService** | `ConcurrentDictionary`-based session tracker for connected SignalR clients. |
| **AcSignalRSendToClientService** | Server-push service: `SendMessageToAllClients`, `SendMessageToConnection`, `SendMessageToUser`. |
| **Working Reference List** | DataSource feature: `SetWorkingReferenceList()` allows external list to become inner storage (zero-copy). |

## Logging

For full architecture see `AyCode.Core/docs/LOGGING.md`.

| Term | Definition |
|---|---|
| **LogLevel** | Byte enum: Detail(0), Trace(5), Debug(10), Info(15), Suggest(17), Warning(20), Error(25), Disabled(255). Values are DB-synced — do NOT renumber. |
| **AcLoggerBase** | Abstract logger with multi-writer fan-out. Two-level filtering: logger-level + per-writer level. Implements both `IAcLogWriterBase` and MS `ILogger`. |
| **AcLogWriterBase** | Abstract writer base. Own `LogLevel` loaded from appsettings by `AssemblyQualifiedName` match. Two branches: text (`AcTextLogWriterBase`) and structured (`AcLogItemWriterBase<T>`). |
| **AcTextLogWriterBase** | Text formatting base. Format: `[HH:mm:ss.fff] [AppType[0]] [Level] [Category->Method] [ThreadId] Text`. |
| **AcConsoleLogWriter** | Colored console writer. Gray=≤Trace, Cyan=Suggest, Yellow=Warning, Red=≥Error. Thread-safe via static lock. |
| **AcLogItemWriterBase\<T\>** | Abstract structured writer. ThreadPool dispatch + Mutex serialization. `Activator.CreateInstance<T>()` factory for log items. |
| **GlobalLogger** | Server-side singleton wrapping `AcGlobalLoggerBase`. Static methods for all log levels. Default category: `"GLOBAL_LOGGER"`. |
| **AcLoggerProvider\<T\>** | `ILoggerProvider` implementation with `ConcurrentDictionary<string, T>` per-category cache. Registered via `AddAcLogger<T>()` or `UseOnlyAcLogger<T>()`. |
| **IAcLogItemClient** | Structured log item DTO interface. Fields: TimeStampUtc, AppType, LogLevel, ThreadId, CategoryName, CallerName, Text, Exception, ErrorType. |
| **AcLogItemClient** | `[MessagePackObject]` implementation of `IAcLogItemClient`. Client-side transport entity. |
| **AcLogItem** | Server-side entity extending `AcLogItemClient`. `[Table("LogItem")]` with auto-generated `Id` and `LogHeaderId`. |
| **AcLoggerSignalRHub\<T\>** | Server hub receiving log items via `AddLogItem(AcLogItem)`. Simple `Hub` (not tag-based dispatch). |
| **IAcLogWriterClientBase** | Empty marker interface for client-side writers (`: IAcLogWriterBase`). |