# CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

## Overview

MARTe2 component library providing real-time signal streaming (`UDPStreamer` DataSource → StreamHub → web/ImGui oscilloscopes) and zero-code-change debugging (`DebugService` Interface: trace/force/breakpoint via registry-patched broker wrappers). See `ARCHITECTURE.md` for full detail and `Docs/` for per-component references.

## Build & Test

Requires MARTe2 and MARTe2-components built externally; `env.sh` sets `MARTe2_DIR`, `MARTe2_Components_DIR`, `TARGET=x86-linux`, and `LD_LIBRARY_PATH` (needed both for building and for running anything).

```bash
source env.sh

make -f Makefile.gcc core    # all C++ MARTe2 components
make -f Makefile.gcc apps    # StreamHub standalone app
make -f Makefile.gcc test    # build GTest + Integration tests
make -f Makefile.gcc clean

# Run tests (after source env.sh)
./Build/x86-linux/GTest/MainGTest.ex                          # unit tests (UDPStreamer)
./Build/x86-linux/GTest/MainGTest.ex --gtest_filter='Name*'   # single test
./Build/x86-linux/Test/Integration/Integration/IntegrationTests.ex  # DebugService integration tests

# Build a single component (each component dir has its own Makefile.gcc)
make -C Source/Components/DataSources/UDPStreamer -f Makefile.gcc

# Go clients
cd Common/Client/go && go build ./...
cd Client/debugger && go build ./...

# ImGui desktop client (not a MARTe2 component; needs SDL2)
cd Client/streamhub && cmake -B build -DCMAKE_BUILD_TYPE=Release && cmake --build build
```

End-to-end demo scripts (build + launch full stack, see headers for ports/options): `./run_combined_test.sh`, `./run_streamhub.sh`.

Build output goes to `Build/x86-linux/` (shared libs per component, `.ex` executables).

## Architecture

Two independent data paths:

1. **Streaming path**: `UDPStreamer` DataSource serialises signals each RT cycle to UDPS binary packets (UDP 44500, unicast/multicast) → `StreamHub` (`Source/Applications/StreamHub/`, headless C++ app: ring buffers, LTTB decimation, trigger FSM) → WebSocket 8090 → browser (`Client/udpstreamer`, Go) or native ImGui client (`Client/streamhub`).
2. **Debug path**: `DebugService` patches the `ClassRegistryDatabase` at `Initialise()` so subsequent `ConfigureApplication()` instantiates `DebugBrokerWrapper<T>` around all `MemoryMap*Broker` types — no application changes. RT hot path goes through `DebugServiceI` (abstract singleton in `DebugServiceI.h`) for forcing/tracing/breakpoints. Exposes TCP 8080 (text commands), UDP 8081 (trace telemetry), works with `TcpLogger` on 8082. Web UI: `Client/debugger` (Go).

**Shared wire format**: `Common/UDP/UDPSProtocol.h` defines the UDPS binary protocol (17-byte packed header, 136-byte signal descriptors, little-endian). It is deliberately MARTe2-free so it's shared by C++ producers (`UDPStreamer`, `DebugService`), the C++ consumer (`Source/Components/Interfaces/UDPStream/UDPSClient`), and the Go decoder (`Common/Client/go/udpsprotocol`). Changes to the protocol must be mirrored across all of these, plus the JS client parsers.

**StreamHub WebSocket protocol**: JSON text frames for commands/events, binary frames for data pushes — spec in `ARCHITECTURE.md` §6. The Go hub (`Client/udpstreamer`) and C++ StreamHub implement the identical protocol; both clients (browser JS and ImGui) must stay compatible with both.

**StreamHub History**: `HistoryWriter` (`Source/Applications/StreamHub/HistoryWriter.{h,cpp}`) provides disk-backed circular storage of signal data. Each signal is stored in a separate `.shist` binary file with a 64-byte header and pre-allocated circular data region of `(float64 time, float64 value)` pairs. Configured via a `+History` block in the StreamHub config with keys: `Directory` (required), `DurationHours` (default 1), `Decimation` (default 1), `FlushIntervalSec` (default 5), `MinDiskFreeMB` (default 500). WS commands: `historyInfo` (returns metadata), `historyZoom` (reads time range from disk). Both the web SPA (`Client/udpstreamer/static/app.js`) and ImGui client support history zoom queries alongside in-memory ring zoom.

## Conventions

- **No STL in MARTe2 components** (`Source/Components/`): use MARTe2 types (`StreamString`, `FastPollingMutexSem`, fixed arrays). STL/C++17 is fine in `Client/streamhub/` and `Source/Applications/StreamHub/` follows MARTe2 style but links MARTe2 core.
- `FastPollingMutexSem` on RT hot paths (never OS mutexes).
- Each component dir has `Makefile.gcc` (wrapper), `Makefile.inc` (sources/includes), and `depends.x86-linux`/`dependsRaw.x86-linux` (generated dependency files).
- EUPL v1.1 license headers on C++ sources.