voice-cat/CLAUDE.md

# CLAUDE.md — agent hub for VoiceCat

Auto-loaded each session. This is the **map**: build commands, architecture at a glance, and
where everything is. For the *working method* read [`AGENTS.md`](AGENTS.md); for *what's done
and what's next* read [`PROGRESS.md`](PROGRESS.md); for *design* read [`docs/`](docs/).

> **One-line status:** M1 control plane is complete and verified (`ctest --preset m1-dev`
> green — 5/5 tests including full TLS auth + text relay integration test). Next up is
> **M2** (UDP media, Opus, jitter buffer). See [`PROGRESS.md`](PROGRESS.md).

VoiceCat = self-hosted native voice & text chat (TeamSpeak/Mumble-style). Plain TCP (control)
+ UDP (media), no WebRTC, encrypted by default. A shared C++ core (`libvoicecat`) drives
native clients (Swift on macOS/iOS, C# on Windows) and the server.

---

## Build & test commands

The **M0 skeleton builds with no third-party dependencies** — just CMake + Ninja + a C++20
compiler. Deps (vcpkg) are off until a subsystem needs them.

```bash
# Configure + build the skeleton (default; no vcpkg needed)
cmake --preset dev
cmake --build --preset dev

# Run the tests (behavior smoke test today; grows per milestone)
ctest --preset dev                      # or: ctest --test-dir build/dev --output-on-failure

# Run the binaries (Windows adds .exe; Linux/macOS no extension)
./build/dev/bin/vccli                    # headless test client
./build/dev/bin/voicecat-server --help
./build/dev/bin/voicecat-server --name "My Server"

# Build a single target / be verbose
cmake --build --preset dev --target vccli
cmake --build --preset dev --verbose

# Clean
rm -rf build/dev                         # nuke; or:
cmake --build --preset dev --target clean
```

When you start a subsystem that needs real libraries (mbedTLS, libsodium, opus, protobuf, …),
turn vcpkg deps on:

```bash
# one-time: git clone https://github.com/microsoft/vcpkg && ./vcpkg/bootstrap-vcpkg.sh  (.bat on Windows)
export VCPKG_ROOT=/path/to/vcpkg         # works on Linux / macOS / Windows
cmake --preset server-release            # auto-installs deps pinned in vcpkg.json
cmake --build --preset server-release
```

Other useful toggles (pass with `-D` at configure time):

```bash
cmake --preset dev -DVOICECAT_BUILD_SHARED=ON     # build libvoicecat as a .dll/.so/.dylib (for the C# client)
cmake --preset dev -DVOICECAT_BUILD_SERVER=OFF     # core + tools only
cmake --preset dev -DVOICECAT_BUILD_TESTS=OFF
```

Formatting: `clang-format` config is `.clang-format` (Google base, 100 cols, 4-space).

```bash
git ls-files '*.cpp' '*.h' | xargs clang-format -i
```

---

## Architecture at a glance

Full detail: [`docs/architecture.md`](docs/architecture.md). The short version:

```
 Swift (macOS/iOS)  ─┐                                    ┌─ C# (Windows)
                     ├──▶  libvoicecat  (C ABI: voicecat.h) ◀──┤
 voicecat-server  ───┘   net · crypto · codec · protocol ·     └─ all UIs are thin
   (links core)          session · audio                          the core owns audio
```

- **One core, many faces.** Protocol, Opus, crypto, networking, jitter buffer, and mixing
  live once in C++. Clients call the **C ABI** (`core/include/voicecat.h`); the server links
  the same core, so framing/crypto never drift between ends.
- **Two transports.** TCP + **TLS 1.3** (control, protobuf `Envelope`) and UDP + **exported-key
  ChaCha20-Poly1305 AEAD** (media, fixed binary voice frame). Encryption is mandatory.
- **Threading.** Real-time audio threads never allocate/lock/block; they exchange data with
  the net thread via lock-free ring buffers; a worker pool absorbs blocking work.

### Subsystem map (code ↔ design doc)

| Path | Subsystem | Design |
|------|-----------|--------|
| `core/include/voicecat.h` | The C ABI (client/server contract) | architecture.md §4 |
| `core/proto/voicecat.proto` | Control-plane wire format (source of truth) | protocol.md |
| `core/src/net/` | Asio TCP/UDP transport, `[u32 len][payload]` framing | protocol.md §1, voice.md §2 |
| `core/src/crypto/` | TLS 1.3 (mbedTLS), media AEAD (libsodium), anti-replay | security.md |
| `core/src/codec/` | Opus encode/decode, FEC/DTX | voice.md §3–4 |
| `core/src/protocol/` | Envelope (de)serialize, request/response, dispatch | protocol.md |
| `core/src/session/` | Channels, users, streams, permissions, ephemeral text | protocol.md §5 |
| `core/src/audio/` | miniaudio I/O, APM DSP, jitter buffer, mixer | voice.md §8–11 |
| `core/src/core/` | `vc_client` — the handle behind the C ABI | architecture.md §4 |
| `server/` | Connection mgr, session registry, SFU relay, SQLite | architecture.md §5 |
| `tools/vccli/` | Headless client that drives/verifies the protocol | — |
| `clients/apple/`, `clients/windows/` | Native GUIs (M4) | architecture.md §4 |

---

## Documentation index (source of truth)

Read [`docs/`](docs/) before changing behavior. Order:

1. [docs/README.md](docs/README.md) — overview, locked decisions, glossary
2. [docs/architecture.md](docs/architecture.md) — core, C ABI, threading, server
3. [docs/protocol.md](docs/protocol.md) — control plane, Envelope, message catalog
4. [docs/voice.md](docs/voice.md) — UDP media, Opus, multi-stream, two-sided NR, VAD/PTT
5. [docs/security.md](docs/security.md) — mandatory encryption, TLS+AEAD, accounts, threat model
6. [docs/tech-stack.md](docs/tech-stack.md) — libraries, permissive-license rule, tooling
7. [docs/deployment.md](docs/deployment.md) — zero-config self-host (Docker / binary / source)
8. [docs/roadmap.md](docs/roadmap.md) — milestones + resolved decisions

---

## Keeping track of progress

**[`PROGRESS.md`](PROGRESS.md) is the living status file.** When you finish a task, check it
off there and note the next step, so the next agent can pick up instantly. Treat it as part of
the work, not an afterthought — update it in the same commit as the code.

---

## House rules (hard constraints)

- **A clean compile is the floor, not the goal.** "Done" = the milestone's observable exit
  criterion in [`docs/roadmap.md`](docs/roadmap.md) passes (e.g. M1 = two `vccli` actually chat
  over TLS). Encode it as a test. See [`AGENTS.md`](AGENTS.md).
- **No GPL/LGPL dependencies, ever** (closed-source redistribution is a goal). docs/tech-stack.md §5.
- **Encryption is mandatory** — never add a plaintext transport path. docs/security.md.
- **Real-time audio threads** never allocate, lock, or block. docs/architecture.md §3.
- **Keep docs + code in sync.** Changing a wire format (`voicecat.proto`) or the C ABI
  (`voicecat.h`) is a deliberate, versioned act — update the doc in the same commit (protocol.md §8).
- Every commit must build (`cmake --build --preset dev`) and pass `ctest --preset dev`.