//! WebSocket gateway example.
//!
//! Starts a native node with some demo actors and a WebSocket gateway.
//! Browser clients connect via WebSocket to send/receive messages.
//!
//! ```bash
//! cargo run --example ws_gateway --features transport
//! ```
//!
//! Then open `crates/wasm/www/index.html` in a browser.

use std::sync::Arc;
use std::time::Duration;

use swactor::actor::{ActorAddress, ActorInterface};
use swactor::runtime::{Ctx, Runtime, RuntimeConfig};
use swactor::transport::{
    Codec, CodecRegistry, NetworkMessage, TransportRouter,
};
use swactor::Error;

use swactor_gateway::WsGateway;

// ─── Messages ────────────────────────────────────────────────────────────────

/// A simple echo request: the payload + who to reply to.
#[derive(Clone, Debug)]
struct EchoRequest {
    payload: String,
    reply_to: ActorAddress,
}

impl NetworkMessage for EchoRequest {
    fn type_tag() -> &'static str {
        "example::EchoRequest"
    }
}

/// Echo response — just the echoed payload.
#[derive(Clone, Debug)]
struct EchoResponse {
    payload: String,
}

impl NetworkMessage for EchoResponse {
    fn type_tag() -> &'static str {
        "example::EchoResponse"
    }
}

// ─── JSON codec for the demo messages ────────────────────────────────────────

struct JsonCodec;

impl Codec<EchoRequest> for JsonCodec {
    fn encode(&self, msg: &EchoRequest) -> Result<Vec<u8>, Error> {
        let mut buf = Vec::new();
        buf.extend_from_slice(&msg.reply_to.0);
        buf.extend_from_slice(msg.payload.as_bytes());
        Ok(buf)
    }
    fn decode(&self, bytes: &[u8]) -> Result<EchoRequest, Error> {
        if bytes.len() < 32 {
            return Err(Error::from("EchoRequest too short"));
        }
        let mut addr = [0u8; 32];
        addr.copy_from_slice(&bytes[..32]);
        let payload = String::from_utf8_lossy(&bytes[32..]).to_string();
        Ok(EchoRequest {
            payload,
            reply_to: ActorAddress(addr),
        })
    }
}

impl Codec<EchoResponse> for JsonCodec {
    fn encode(&self, msg: &EchoResponse) -> Result<Vec<u8>, Error> {
        Ok(msg.payload.as_bytes().to_vec())
    }
    fn decode(&self, bytes: &[u8]) -> Result<EchoResponse, Error> {
        Ok(EchoResponse {
            payload: String::from_utf8_lossy(bytes).to_string(),
        })
    }
}

// Also register the JsMessage type that the browser uses
#[derive(Clone, Debug)]
struct JsMessage {
    type_tag: String,
    payload: String,
}

impl NetworkMessage for JsMessage {
    fn type_tag() -> &'static str {
        "swactor::JsMessage"
    }
}

struct JsMessageCodec;

impl Codec<JsMessage> for JsMessageCodec {
    fn encode(&self, msg: &JsMessage) -> Result<Vec<u8>, Error> {
        Ok(msg.payload.as_bytes().to_vec())
    }
    fn decode(&self, bytes: &[u8]) -> Result<JsMessage, Error> {
        Ok(JsMessage {
            type_tag: "js".to_string(),
            payload: String::from_utf8_lossy(bytes).to_string(),
        })
    }
}

// ─── Echo actor ──────────────────────────────────────────────────────────────

struct EchoActor;

impl ActorInterface for EchoActor {
    type Incoming = JsMessage;
    type Response = ();

    fn handle(&mut self, ctx: &Ctx, msg: JsMessage) {
        println!("[echo] Received: type_tag={}, payload={}", msg.type_tag, msg.payload);
        // Echo back to sender — in a real app, the payload would contain
        // the reply_to address. For the demo, we just log it.
        let _ = msg;
        let _ = ctx;
    }
}

// ─── Main ────────────────────────────────────────────────────────────────────

const WS_ADDR: &str = "127.0.0.1:9000";

fn main() {
    println!("[gateway] Starting WebSocket gateway on ws://{WS_ADDR}");
    println!("[gateway] Open crates/wasm/www/index.html in a browser to connect.\n");

    // Build codec registry
    let mut codecs = CodecRegistry::new();
    codecs.register::<EchoRequest, _>(JsonCodec);
    codecs.register::<EchoResponse, _>(JsonCodec);
    codecs.register::<JsMessage, _>(JsMessageCodec);
    let codecs = Arc::new(codecs);

    // Build runtime with an echo actor
    let transport_router = Arc::new(TransportRouter::new());
    let mut rt = Runtime::new(RuntimeConfig {
        num_threads: 1,
        ..RuntimeConfig::default()
    });
    rt.set_codec_registry(codecs.clone());
    rt.set_transport_router(transport_router.clone());

    let echo_addr = rt.spawn(EchoActor).unwrap();
    rt.tick(); // drain spawn queue
    println!("[gateway] EchoActor spawned at {echo_addr}");

    // Start WebSocket gateway
    let mut gateway = WsGateway::bind(WS_ADDR.parse().unwrap())
        .expect("failed to bind WebSocket gateway");
    println!("[gateway] Listening on ws://{}", gateway.local_addr());
    println!();

    // Event loop
    loop {
        let n = gateway.tick(&rt, &codecs, &transport_router);
        if n > 0 {
            println!("[gateway] Processed {n} envelope(s)");
        }
        rt.tick();
        std::thread::sleep(Duration::from_millis(16)); // ~60 ticks/sec
    }
}