# hypen-server

Rust server SDK for building [Hypen](https://hypen.space) applications.

Hypen is a declarative UI language and reactive runtime for building cross-platform applications. This SDK provides a type-safe, idiomatic Rust API for defining stateful modules, handling actions, managing routing, and discovering components.

## Quick Start

```rust
use hypen_server::prelude::*;
use serde::{Deserialize, Serialize};

#[derive(Clone, Default, Serialize, Deserialize)]
struct Counter { count: i32 }

#[derive(Deserialize)]
struct AddPayload { amount: i32 }

let module = ModuleBuilder::new("Counter")
    .state(Counter { count: 0 })
    .ui(r#"
        Column {
            Text("Count: ${state.count}")
            Button("@actions.increment") { Text("+") }
        }
    "#)
    .on_action::<()>("increment", |state, _, _ctx| {
        state.count += 1;
    })
    .on_action::<AddPayload>("add", |state, payload, _ctx| {
        state.count += payload.amount;
    })
    .build();
```

## Action Handling

Actions always take a type parameter for the payload and a string name. Use `()` for actions with no payload.

```rust
// No payload
.on_action::<()>("increment", |state, _, _ctx| {
    state.count += 1;
})

// Typed payload (just needs #[derive(Deserialize)])
#[derive(Deserialize)]
struct SetValue { value: i32 }

.on_action::<SetValue>("set_value", |state, payload, _ctx| {
    state.count = payload.value;
})

// Raw JSON access
.on_action::<serde_json::Value>("raw", |state, raw, _ctx| {
    if let Some(n) = raw.as_i64() { state.count = n as i32; }
})
```

## Routing

```rust
let app = HypenApp::builder()
    .route("/", home_module)
    .route("/counter", counter_module)
    .components_dir("./components")
    .build();

app.navigate("/counter");
```

## Features

- **Typed state** with automatic JSON diffing and path-based change detection
- **Typed action payloads** via `serde::Deserialize` (no custom traits needed)
- **Lifecycle hooks**: `on_created`, `on_destroyed`
- **URL router** with pattern matching and parameter extraction
- **Component discovery** from `.hypen` files on the filesystem
- **Cross-module communication** via `GlobalContext` and `EventEmitter`
- **Patch-based rendering** compatible with all Hypen renderers (DOM, Canvas, iOS, Android)

## License

MIT
