/*
    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 futures::Future;
use hyper::{
    header::{HeaderName, HeaderValue},
    HeaderMap,
};
use serde::Deserialize;
use std::{collections::BTreeMap, pin::Pin, str::FromStr, sync::Arc};

pub struct HeadersKind;

#[derive(Deserialize)]
pub struct Headers {
    #[serde(default)]
    request: HeaderMapWrap,
    #[serde(default)]
    response: HeaderMapWrap,
    next: DynNode,
}

impl NodeKind for HeadersKind {
    fn name(&self) -> &'static str {
        "headers"
    }
    fn instanciate(&self, config: serde_yml::Value) -> Result<Arc<dyn Node>> {
        Ok(Arc::new(serde_yml::from_value::<Headers>(config)?))
    }
}

impl Node for Headers {
    fn handle<'a>(
        &'a self,
        context: &'a mut NodeContext,
        mut request: NodeRequest,
    ) -> Pin<Box<dyn Future<Output = Result<NodeResponse, ServiceError>> + Send + Sync + 'a>> {
        Box::pin(async move {
            request
                .headers_mut()
                .extend(self.request.0.clone());
            let mut response = self.next.handle(context, request).await?;
            response
                .headers_mut()
                .extend(self.response.0.clone());
            Ok(response)
        })
    }
}

#[derive(Default)]
struct HeaderMapWrap(HeaderMap);
impl<'de> Deserialize<'de> for HeaderMapWrap {
    fn deserialize<D>(deserializer: D) -> std::result::Result<Self, D::Error>
    where
        D: serde::Deserializer<'de>,
    {
        let headers = BTreeMap::<String, String>::deserialize(deserializer)?;
        let mut hm = HeaderMap::new();
        for (k, v) in headers {
            hm.insert(
                HeaderName::from_str(&k).map_err(|e| serde::de::Error::custom(format!("{e}")))?,
                HeaderValue::from_str(&v).map_err(|e| serde::de::Error::custom(format!("{e}")))?,
            );
        }
        Ok(HeaderMapWrap(hm))
    }
}