use crate::axon::AxonEvent;
use tokio::sync::broadcast;

/// SSE channel — broadcasts AxonEvents to all connected SSE clients.
#[derive(Clone)]
pub struct SseChannel {
    sender: broadcast::Sender<String>,
}

impl SseChannel {
    pub fn new(capacity: usize) -> Self {
        let (sender, _) = broadcast::channel(capacity);
        Self { sender }
    }

    /// Send an event to all subscribers.
    pub fn send(&self, event: &AxonEvent) -> Result<(), String> {
        let json = serde_json::to_string(event).map_err(|e| e.to_string())?;
        // Ignore errors when no receivers are connected
        let _ = self.sender.send(json);
        Ok(())
    }

    /// Subscribe to the SSE channel.
    pub fn subscribe(&self) -> broadcast::Receiver<String> {
        self.sender.subscribe()
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[tokio::test]
    async fn sse_channel_broadcast() {
        let ch = SseChannel::new(16);
        let mut rx = ch.subscribe();

        let event = AxonEvent::new("test", serde_json::json!({ "msg": "hello" }));
        ch.send(&event).unwrap();

        let received = rx.recv().await.unwrap();
        let parsed: serde_json::Value = serde_json::from_str(&received).unwrap();
        assert_eq!(parsed["event_type"], "test");
        assert_eq!(parsed["payload"]["msg"], "hello");
    }
}