use super::{Node, NodeContext, NodeKind, NodeRequest, NodeResponse};
use crate::{config::DynNode, error::ServiceError};
use anyhow::Result;
use http::Request;
use http_body_util::{combinators::BoxBody, BodyExt, Full};
use serde::Deserialize;
use serde_yml::Value;
use std::{future::Future, pin::Pin, sync::Arc};

pub struct FallbackKind;

#[derive(Deserialize)]
struct Fallback(Vec<DynNode>);

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

impl Node for Fallback {
    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 (parts, body) = request.into_parts();
            let body = body
                .collect()
                .await
                .map_err(|_| ServiceError::Other)?
                .to_bytes();

            for (i, h) in self.0.iter().enumerate() {
                let last = i == self.0.len() - 1;
                let res = h
                    .handle(
                        context,
                        Request::from_parts(
                            parts.clone(),
                            BoxBody::new(Full::new(body.clone()).map_err(|x| match x {})),
                        ),
                    )
                    .await;
                if last {
                    return res;
                }
                if let Ok(resp) = res {
                    if resp.status().is_success()
                        || resp.status().is_redirection()
                        || resp.status().is_informational()
                    {
                        return Ok(resp);
                    }
                }
            }
            Err(ServiceError::CustomStatic(
                "fallback module without any handlers",
            ))
        })
    }
}