---
name: zenbu-hg-web
description: Use this skill when changing hg-web, the Mercurial repository browser, including the C API server, hg proxying, React/TypeScript frontend, markdown rendering, graph views, or static asset bundle.
---

# Hg Web

Use this skill for `hg-web/`, a GitHub-style Mercurial repository browser backed by a C server and a TypeScript frontend.

## Structure

- `hg-web/main.c`: C server, routes, Mercurial proxy APIs, wire protocol streaming.
- `hg-web/src/main.tsx`: frontend entry.
- `hg-web/src/components/`: React/TypeScript UI components.
- `hg-web/src/index.html`, `index.css`, `base.css`: shell and styles.
- `hg-web/BUILD`: Bun bundle, static assets, C server, and release bundle.
- `hg-web/deploy.sh`: deployment entry point.

The server depends on `//seobeo:seobeo`. The frontend bundle includes `markdown_converter:markdown_to_html_wasm` and `third_party/highlight:js`.

## Backend model

The C backend proxies to local `hg serve` at:

```c
#define HG_SERVE_HOST "127.0.0.1"
#define HG_SERVE_PORT "4444"
```

Public endpoints include:

- `GET /`
- `GET /directories`
- `GET /graph`
- `GET /api/repo/list?path=...`
- `GET /api/repo/file?path=...`
- `GET /api/repo/readme?path=...`
- `GET /api/graph/:graph_id?...`
- `GET /repo` and `POST /repo` streaming Mercurial wire protocol proxy.

Use `sanitize_path` and `Seobeo_Url_Decode` patterns for any path-derived endpoint. Never pass raw path input to an hg path.

## Frontend model

Prefer editing components under `hg-web/src/components/`. Keep API paths aligned with backend registrations in `main.c`. The frontend should be able to handle:

- directory listings from `/api/repo/list`,
- file contents from `/api/repo/file`,
- README markdown rendering through the WASM markdown converter,
- syntax highlighting through highlight.js,
- graph data via `/api/graph/:graph_id`.

## Build

```bash
bazel build //hg-web:hg_web_server
bazel build //hg-web:hg_web_server_bundle
```

If changing shared networking behavior, also run the relevant seobeo tests.

## Safety checklist

- Prefer Dowa aliases (`uint8`, `uint32`, `boolean`, `TRUE`/`FALSE`) over
  `<stdint.h>` `_t` types and `<stdbool.h>` `bool` in first-party C.
- Preserve binary-safe streaming in `StreamHgWireProtocol`; Mercurial bundle data can contain null bytes.
- Do not buffer large wire-protocol responses through the normal HTTP client path unless the task explicitly requires it.
- Validate and sanitize all path and graph inputs.
- Keep content types accurate: JSON for API listing responses, `text/plain` or source-specific content for file/graph proxy responses, `text/html` for the app shell.
- If changing route names, update both backend registrations and frontend fetch/navigation code.