# WrNexus

> WrNexus is an SSR-first, **Bun-native** full-stack web framework. UI is written in
> `.wrn` files (its own component language — NOT React/JSX/Vue). Routing is file-based.
> This document teaches an AI how to write correct WrNexus code. It is private and
> post-dates model training data, so rely on THIS document, not prior web-framework
> assumptions.

## Golden rules

- **Pages, components, and layouts are `.wrn` files.** Do NOT write `.tsx`/`.jsx`/React
  for UI. Do NOT use `useState`, hooks, JSX, or a client bundler.
- **Routing is file-based** under `app/`. The filename is the route. No router config.
- **Interactivity** lives in `state` + `{expr}` + `@event` inside `.wrn`. Components render
  on the server and hydrate automatically — you never write client-side JS islands.
- **Runtime is Bun only** (uses `Bun.serve`, `bun:sqlite`, `Bun.password`, …). Node is not supported.
- To add files, prefer the CLI: `wrnexus generate page <Name>` / `component <name>` / `api <path>` / `schema <name>`.

## Project layout

```
app/
  pages/       *.wrn  → routes: index.wrn = "/", about.wrn = "/about", blog/[slug].wrn = "/blog/:slug"
  components/  *.wrn  → reusable UI, mounted in a page/component via <div data-component="name" ...props>
  layouts/     *.wrn  → named layouts; a page opts in with  layout = "name"
  api/         *.ts   → HTTP handlers: export const GET/POST/PUT/PATCH/DELETE = async (ctx) => Response
  middleware/  *.ts   → export default async (ctx, next) => next()
  realtime/    *.ts   → export default defineRoom({ ... }) from "@wrnexus/core"  (ws://host/realtime/<name>)
  schemas/     *.ts   → validation schemas (the `v` builder), used by forms + parseBody
  locales/     *.json → i18n messages per language
  db/          schema.ts, queries/*.sql, migrations/*.sql
  styles/      global.css  → Tailwind (default) or plain CSS
wrnexus.config.ts    → app config (AppConfig from "@wrnexus/styles")
public/              → static assets served at /
```

## `.wrn` page

```wrn
page Home {
  layout = "public"          // optional: a component in app/layouts/<name>.wrn ("none" to skip)

  state count = 0            // optional: seeds client-reactive state (omit for pure SSR)

  seo {
    title = "Home"
    description = "..."
    canonical = "/"
  }

  view {
    <h1>Hello</h1>
    <p>Count is {count}, doubled is {count * 2}.</p>
    <button @click="count++">Increment</button>
    <div data-component="counter" start="5" label="Clicks"></div>
  }

  style {
    h1 { color: var(--wrn-color-text); }
  }
}
```

## `.wrn` component

```wrn
component Counter {
  props {                    // props come from mount attributes; each is coerced to the
    start = 0                // TYPE of its default (so start="5" arrives as the number 5)
    label = "Count"
  }
  state count = start        // state may reference props
  view {
    <button @click="count++">{label}: {count}</button>
  }
}
```

Mount it from any page/component: `<div data-component="counter" start="0" label="Clicks"></div>`.
Components render on the server with their props, then hydrate — no per-component JS.

## The `view { }` block (plain HTML + a few directives)

- `{expr}` — interpolate a JS expression. Reactive if it references `state`: `{count}`, `{count * 2}`, `{user.name}`.
- `@event="expr"` — bind a DOM event; the expression runs in the reactive scope: `@click="count++"`, `@input="name = event.target.value"`.
- `<div data-component="name" prop="v">` — mount a component (attrs become string props, coerced).
- `<slot></slot>` / `<slot name="x"></slot>` — component/layout slots; fill with `<div data-slot="x">…</div>`.
- **Server loop (DB/list/table):** `{#each <list> as <item>[, <i>]} …rows… {:empty} …fallback… {/each}` — iterates SSR data on the server and renders markup per item. `{item.field}` interpolates (HTML-escaped, XSS-safe). `<list>` is a JS expression, usually an `ssr` data binding (see "Data-driven tables" below). This is how you render a database table in `.wrn`.
- **Server conditional:** `{#if <expr>} … {:else if <expr>} … {:else} … {/if}` — renders the first truthy branch on the server. `<expr>` can reference `ssr` data, or the `item`/`index` of an enclosing `{#each}`. Works at page level and inside loops (e.g. `{#if r.active}<span>●</span>{:else}<span>○</span>{/if}` per row). For client-side show/hide based on reactive `state`, use `data-show="expr"` instead.
- i18n: `{t:home.title}` in text, `t:placeholder="form.name"` on attributes — resolved per request from `app/locales/`.
- Theme: any element with `data-wrn-theme-toggle` toggles light/dark; `data-wrn-theme-set="dark"` sets it.
- Void/self-closing tags are fine: `<br />`, `<img src="..." />`.
- Only `{` and `}` are special (interpolation). Don't use a bare `}` in view text.

## Data-driven tables / lists (server-rendered `.wrn`)

Use an `ssr` data binding to fetch rows on the server, then `{#each}` to render them.
This renders on the **server** (SSR-first) and is HTML-escaped by default.

```wrn
page Admin {
  layout = "dashboard"

  // Fetch on the server. The api handler at /api/contacts returns { contacts: [...] };
  // this block's `return contacts` exposes that array (via `$data`) as the binding `rows`.
  ssr {
    api rows GET /api/contacts { return contacts }
  }

  view {
    <table>
      <tbody>
        {#each rows as r, i}
          <tr>
            <td>#{i}</td>
            <td>{r.name}</td>
            <td><a href="mailto:{r.email}">{r.email}</a></td>
          </tr>
        {:empty}
          <tr><td colspan="3">No submissions yet.</td></tr>
        {/each}
      </tbody>
    </table>
  }
}
```

The matching API returns the array under a key the `ssr` block reads:

```ts
// app/api/contacts.ts  → GET /api/contacts
import { getDb } from "@wrnexus/db";
export const GET = async () => {
  const contacts = await getDb().all("SELECT id, name, email FROM contacts ORDER BY id DESC");
  return Response.json({ contacts });   // ssr block does `return contacts`
};
```

**Prefer this `.wrn` + `{#each}` approach for DB-backed tables and lists.** (`.ts`/`.tsx`
pages returning an HTML string are also supported for fully-custom programmatic rendering,
but a `.wrn` page with `ssr` data + `{#each}` is the idiomatic, SSR-first way.)

## API routes (`app/api/*.ts`)

```ts
// app/api/users/list.ts  → GET /api/users/list
import { getDb } from "@wrnexus/db";

export const GET = async (ctx) => {
  return Response.json({ users: await ListUsers(getDb()) });
};

export const POST = async (ctx) => {
  const body = await ctx.req.json();
  return Response.json({ ok: true, body }, { status: 201 });
};
```

`ctx` (the `Context` from `@wrnexus/core`) has:
`req: Request`, `url: URL`, `params: Record<string,string>` (dynamic route params, e.g. `/users/[id]` → `ctx.params.id`),
`lang: string`, `t(key, params?)` (i18n), `cookies` (get/set), `session` (get/set). Auth: `getUser(ctx)` after `sessionAuth`/`logIn`.

When an SSO forward-auth verifier needs the URL that originally reached the gateway, use
`@wrnexus/helpers` instead of constructing it from untrusted headers:

```ts
import { redirectToLogin } from "@wrnexus/helpers";

return redirectToLogin(ctx, "/login", {
  allowedHosts: ["admin.localhost:3000", "reports.localhost:3000"],
});
```

The package also exports `getOriginalRequestUrl`, `getOriginalRequestOrigin`,
`getOriginalRequestPath`, and `getOriginalRequestMethod`. Always pass `allowedHosts` when
using forwarded gateway URLs; the helper rejects untrusted redirect destinations.

## Middleware & realtime

```ts
// app/middleware/logger.ts
export default async function logger(ctx, next) {
  console.log(ctx.req.method, ctx.url.pathname);
  return next();               // return a Response WITHOUT calling next() to short-circuit
}
```

```ts
// app/realtime/chat.ts  → ws://host/realtime/chat
import { defineRoom } from "@wrnexus/core";
export default defineRoom({
  onConnect(client) { client.send({ type: "system", text: "connected" }); },
  onMessage(client, msg) { client.room.broadcast({ type: "message", data: msg }); },
});
```
Client side: a page opts in with `data-room="chat"` (handled by the realtime runtime).

## Config (`wrnexus.config.ts`)

```ts
import type { AppConfig } from "@wrnexus/styles";
const config: AppConfig = {
  seo: { title: "App", titleTemplate: "%s | App", description: "..." },
  styles: { entry: "app/styles/global.css", process: async ({ entryPath, mode }) => /* Tailwind */ "" },
  fonts: { sans: '"Inter", system-ui, sans-serif', google: [{ family: "Inter", weights: [400, 600] }] },
  theme: { default: "dark", themes: { light: { "color-primary": "#2563eb" } } },
  i18n: { default: "en", locales: ["en", "es"] },
  db: { driver: "sqlite", url: "file:./dev.db" },
  security: { cors: { enabled: true, origin: ["http://localhost:5173"] } },
  // profiles: { production: { db: { driver: "postgres", url: process.env.DATABASE_URL } } },
};
export default config;
```

## Database (`@wrnexus/db`)

```ts
// app/db/schema.ts
import { v, table } from "@wrnexus/db";
export const users = table("users", {
  id: v.id(),
  name: v.string(),
  email: v.string().unique(),
  createdAt: v.timestamp(),
});
```
- Queries: write `app/db/queries/*.sql` with `-- name: ListUsers :many` blocks; `wrnexus db generate` emits typed functions.
- Access at runtime: `import { getDb } from "@wrnexus/db"; const rows = await ListUsers(getDb());`
- Migrations in `app/db/migrations/`; run `wrnexus db migrate` (dev auto-migrates sqlite).

## Validation (`@wrnexus/validation`)

```ts
// app/schemas/login.ts
import { v } from "@wrnexus/validation";
export default v.object({
  email: v.string().email(),
  password: v.string().min(8),
});
```
In an API route: `import s from "../schemas/login"; import { parseBody } from "@wrnexus/validation"; const r = await parseBody(s, ctx.req);` → `r.ok ? r.value : r.response`.
In a form: `<form data-schema="login" action="/api/login" method="post">` + `<span data-error="email"></span>` (client + server validation connected automatically).

## AI / LLM (`@wrnexus/ai`)

```ts
// app/api/ai.ts
import { createAI } from "@wrnexus/ai";
const ai = createAI();                     // reads ANTHROPIC_API_KEY; default model claude-opus-4-8
export const POST = async (ctx) => {
  const { prompt } = await ctx.req.json();
  return ai.streamResponse(prompt);        // or: return Response.json({ text: await ai.generate(prompt) })
};
```

## CLI

```
wrnexus dev .                 # dev server + HMR
wrnexus build .               # production build → dist/server.js
bun dist/server.js            # run the production server (or npm start)
wrnexus create <name>         # scaffold a new app
wrnexus update --latest       # deps + syntax/config migrations + verification
wrnexus generate page <Name>  # scaffold a page   (aliases: g p)
wrnexus generate component <name> | api <path> | schema <name>
wrnexus db migrate | rollback | status | new [--from-models] | generate | seed
wrnexus eject <component>     # copy a WrNexus UI component's .wrn into app/components to customize
```

## When asked to "create a page/component/feature"

1. Create the `.wrn` file under `app/pages/` (or `app/components/`) with a `page`/`component` block — or run `wrnexus generate page <Name>`.
2. Put markup in `view { }`, interactive bits in `state` + `{expr}` + `@event`, reusable UI as components mounted via `data-component`.
3. For data, add an `app/api/*.ts` route and `getDb()`; for forms, add an `app/schemas/*.ts` and `data-schema`.
4. Style with Tailwind utility classes in the view, or theme tokens (`var(--wrn-*)`), or `style { }`.
5. Never emit React/JSX, a manual router, or client-side island JS — the framework handles hydration.
