# Backend & Infrastructure

Semua implementasi I/O ada di `apps/infrastructure/src/`. Layer ini mengimplementasikan port/trait yang didefinisikan di `apps/domain/`.

## LLM Client (`infrastructure/src/llm/`)

Wrapper di atas provider OpenAI-compatible:

- **`provider/`** — `LlmClient`: HTTP client dengan `reqwest::blocking` (sync) untuk agent turn, dan async streaming untuk preview
- **Request/Response** — `ChatMessage`, `ChatCompletionRequest`, `ChatCompletionResponse` dengan support tool calls
- **Streaming** — SSE event parser untuk streaming response
- **Usage tracking** — `tokens_in`, `tokens_out`, `last_tokens_in`, `last_tokens_out` per panggilan
- **Provider defaults** — DeepSeek v4 flash free via OpenCode AI proxy (default)

```rust
// Contoh penggunaan di turn.rs
let result = client.chat_with_tools_non_streaming(
    &mut messages,
    Some(tool_defs),
    Some(4096),  // max_tokens
    Some(0.7),   // temperature
    None,        // abort flag
);
```

## Tool System (`infrastructure/src/tools/`)

37 tool yang mengimplementasikan trait `Tool` dari domain:

```rust
pub trait Tool: Send + Sync {
    fn name(&self) -> &'static str;
    fn description(&self) -> &'static str;
    fn parameters(&self) -> Value;         // JSON Schema
    fn run(&self, ctx: &ToolCtx, args: &Value) -> Result<String>;
}
```

### Kategori Tool

| Kategori | Tools |
|----------|-------|
| **File System** | `read`, `write`, `edit`, `delete`, `dir_list`, `dir_cache_update` |
| **Shell** | `bash`, `bash_interactive`, `bash_kill`, `bash_output` |
| **Git** | `git_operator`, `git_cred`, `git_worktree` |
| **Search** | `search`, `grep`, `glob`, `semantic_search` |
| **LSP** | `lsp_connect`, `lsp_hover`, `lsp_completion`, `lsp_definition`, `lsp_references`, `lsp_diagnostics`, `lsp_disconnect` |
| **Memory** | `remember`, `recall`, `forget` |
| **Workflow** | `spawn_agents`, `spawn_pipeline`, `plan`, `sequential_think`, `hive_mind` |
| **Utility** | `todo_write`, `todo_finish`, `pong`, `cd` |
| **Background** | `bash_bg_cancel`, `bash_bg_status`, `bash_bg_list` |

`ToolCtx` berisi:
- `session_dir: PathBuf` — direktori sesi aktif
- `workspaces: Vec<PathBuf>` — root workspace yang dibuka

## Background Shell Jobs (`infrastructure/src/bgbash/`)

Manajemen proses shell jangka panjang:
- **Spawn** dengan Unix process groups (untuk kill seluruh tree)
- **Output buffering** — collect stdout/stderr secara async
- **Cancel/status/list** — kontrol via tool calls
- **Progress monitoring** — track state: `Running`, `Completed`, `Failed`

## MCP Manager (`infrastructure/src/mcp/`)

Integrasi **Model Context Protocol**:
- Menggunakan crate `rmcp` (v2.2)
- Transport: **stdio** (child process) dan **streamable HTTP**
- `list_tools()` → tool discovery otomatis → registrasi ke tool harness
- Persistent connection management

## LSP Integration (`infrastructure/src/lsp/`)

Integrasi **Language Server Protocol**:
- **Auto-provisioner** — deteksi bahasa dari file extension, start LSP server yang sesuai
- Mendukung: `rust-analyzer`, `typescript-language-server`, `pyright`, `gopls`, dan lainnya
- **JSON-RPC client** — typed notifications + request/response
- 7 tools LSP yang diekspose ke LLM

## Persistence (`infrastructure/src/persistence/`)

### SQLite Message Log

Session database dengan `rusqlite` (bundled):
- Per-session isolation
- Table: `messages`, `sessions`
- CRUD, query/filter, blob storage

### Settings Repository

`JsonSettingsRepository` — simpan/load `Settings` dari `settings.json`:
- `provider`: nama provider LLM
- `model`: model ID
- `max_tokens`: override context window (default: 256k jika tidak diset)
- `temperature`, `concise_output`, dll

### Memory Files

File-based memory di `~/.local/share/zesdex/memories/`:
- Setiap memory = satu `.md` dengan frontmatter YAML
- Fields: `name`, `description`, `type` (`user`/`feedback`/`project`/`reference`)
- Index di `MEMORY.md`

## Session Management (`infrastructure/src/session/`)

- Setiap sesi memiliki UUID, direktori sendiri di `sessions/<uuid>/`
- `.lock` file untuk cegah concurrent access
- `session.json` — metadata (waktu mulai, workspace, model yang dipakai)

## Utils

| Util | Fungsi |
|------|--------|
| `utils::write_osc52` | Tulis teks ke clipboard via OSC52 escape sequence |
| `Toast` / `ToastKind` | Notifikasi sementara (Success/Warning/Error/Info/Lesson) |
| `TurnEvent` | Event dari background agent ke TUI (queue-based) |
| `DirCache` | Cache async listing direktori untuk `@mention` autocomplete |
| `MentionIndex` | Index file workspace untuk fuzzy autocomplete |
| `SessionRuntime` | Runtime state: messages history, usage stats, session start time |

## OAuth 2.0

Flow PKCE untuk provider LLM:
1. Generate code verifier + challenge
2. Open browser ke authorization URL
3. Start localhost HTTP server untuk tangkap redirect
4. Exchange code → access + refresh token
5. Simpan token di settings