/*
    This file is part of gnix (https://codeberg.org/metamuffin/gnix)
    which is licensed under the GNU Affero General Public License (version 3); see /COPYING.
    Copyright (C) 2025 metamuffin <metamuffin.org>
*/
use super::{Node, NodeContext, NodeKind, NodeRequest, NodeResponse};
use crate::{config::DynNode, error::ServiceError};
use anyhow::Result;
use serde::Deserialize;
use serde_yml::Value;
use std::{
    future::Future,
    pin::Pin,
    sync::Arc,
};
use tokio::sync::Semaphore;

pub struct SemaphoreKind;

#[derive(Deserialize)]
struct SemaphoreConfig {
    permits: usize,
    next: DynNode,
}

struct SemaphoreState {
    config: SemaphoreConfig,
    semaphore: Semaphore,
}

impl NodeKind for SemaphoreKind {
    fn name(&self) -> &'static str {
        "semaphore"
    }
    fn instanciate(&self, config: Value) -> Result<Arc<dyn Node>> {
        let config = serde_yml::from_value::<SemaphoreConfig>(config)?;
        Ok(Arc::new(SemaphoreState {
            semaphore: Semaphore::new(config.permits),
            config,
        }))
    }
}
impl Node for SemaphoreState {
    fn handle<'a>(
        &'a self,
        context: &'a mut NodeContext,
        request: NodeRequest,
    ) -> Pin<Box<dyn Future<Output = Result<NodeResponse, ServiceError>> + Send + Sync + 'a>> {
        Box::pin(async move {
            let _permit = self.semaphore.acquire().await;
            let resp = self.config.next.handle(context, request).await?;
            drop(_permit);
            Ok(resp)
        })
    }
}