use std::future::Future;
use std::pin::Pin;
use std::sync::{Arc, Mutex, atomic::{AtomicUsize, Ordering}};
use std::time::{Duration/*, Instant*/};

use hyper::{Body, Client, Request, Response, Server, Version};
use hyper::client::HttpConnector;
use hyper::service::{make_service_fn, service_fn};

pub use std::net::SocketAddr;
pub use futures_util::{future, FutureExt as _, StreamExt as _, TryFutureExt as _, TryStreamExt as _};
pub use hyper::{HeaderMap, StatusCode};

macro_rules! t {
    (
        $name:ident,
        parallel: $range:expr
    ) => (
        #[test]
        fn $name() {

            let mut c = vec![];
            let mut s = vec![];

            for _i in $range {
                c.push((
                    __CReq {
                        uri: "/",
                        body: vec![b'x'; 8192],
                        ..Default::default()
                    },
                    __CRes {
                        body: vec![b'x'; 8192],
                        ..Default::default()
                    },
                ));
                s.push((
                    __SReq {
                        uri: "/",
                        body: vec![b'x'; 8192],
                        ..Default::default()
                    },
                    __SRes {
                        body: vec![b'x'; 8192],
                        ..Default::default()
                    },
                ));
            }

            __run_test(__TestConfig {
                client_version: 2,
                client_msgs: c.clone(),
                server_version: 2,
                server_msgs: s.clone(),
                parallel: true,
                connections: 1,
                proxy: false,
            });

            __run_test(__TestConfig {
                client_version: 2,
                client_msgs: c,
                server_version: 2,
                server_msgs: s,
                parallel: true,
                connections: 1,
                proxy: true,
            });
        }
    );
    (
        $name:ident,
        client: $(
            request: $(
                $c_req_prop:ident: $c_req_val:tt,
            )*;
            response: $(
                $c_res_prop:ident: $c_res_val:tt,
            )*;
        )*
        server: $(
            request: $(
                $s_req_prop:ident: $s_req_val:tt,
            )*;
            response: $(
                $s_res_prop:ident: $s_res_val:tt,
            )*;
        )*
    ) => (
        #[test]
        fn $name() {
            let c = vec![$((
                __CReq {
                    $($c_req_prop: __internal_map_prop!($c_req_prop: $c_req_val),)*
                    ..Default::default()
                },
                __CRes {
                    $($c_res_prop: __internal_eq_prop!($c_res_prop: $c_res_val),)*
                    ..Default::default()
                }
            ),)*];
            let s = vec![$((
                __SReq {
                    $($s_req_prop: __internal_eq_prop!($s_req_prop: $s_req_val),)*
                    ..Default::default()
                },
                __SRes {
                    $($s_res_prop: __internal_map_prop!($s_res_prop: $s_res_val),)*
                    ..Default::default()
                }
            ),)*];

            __run_test(__TestConfig {
                client_version: 1,
                client_msgs: c.clone(),
                server_version: 1,
                server_msgs: s.clone(),
                parallel: false,
                connections: 1,
                proxy: false,
            });

            __run_test(__TestConfig {
                client_version: 2,
                client_msgs: c.clone(),
                server_version: 2,
                server_msgs: s.clone(),
                parallel: false,
                connections: 1,
                proxy: false,
            });

            __run_test(__TestConfig {
                client_version: 1,
                client_msgs: c.clone(),
                server_version: 1,
                server_msgs: s.clone(),
                parallel: false,
                connections: 1,
                proxy: true,
            });

            __run_test(__TestConfig {
                client_version: 2,
                client_msgs: c,
                server_version: 2,
                server_msgs: s,
                parallel: false,
                connections: 1,
                proxy: true,
            });
        }
    );
}

macro_rules! __internal_map_prop {
    (headers: $map:tt) => ({
        #[allow(unused_mut)]
        {
        let mut headers = HeaderMap::new();
        __internal_headers_map!(headers, $map);
        headers
        }
    });
    ($name:tt: $val:tt) => ({
        __internal_req_res_prop!($name: $val)
    });
}

macro_rules! __internal_eq_prop {
    (headers: $map:tt) => ({
        #[allow(unused_mut)]
        {
        let mut headers = Vec::new();
        __internal_headers_eq!(headers, $map);
        headers
        }
    });
    ($name:tt: $val:tt) => ({
        __internal_req_res_prop!($name: $val)
    });
}

macro_rules! __internal_req_res_prop {
    (method: $prop_val:expr) => (
        $prop_val
    );
    (status: $prop_val:expr) => (
        StatusCode::from_u16($prop_val).expect("status code")
    );
    ($prop_name:ident: $prop_val:expr) => (
        From::from($prop_val)
    )
}

macro_rules! __internal_headers_map {
    ($headers:ident, { $($name:expr => $val:expr,)* }) => {
        $(
        $headers.insert($name, $val.to_string().parse().expect("header value"));
        )*
    }
}

macro_rules! __internal_headers_eq {
    (@pat $name: expr, $pat:pat) => {
        ::std::sync::Arc::new(move |__hdrs: &hyper::HeaderMap| {
            match __hdrs.get($name) {
                $pat => (),
                other => panic!("headers[{}] was not {}: {:?}", stringify!($name), stringify!($pat), other),
            }
        }) as ::std::sync::Arc<dyn Fn(&hyper::HeaderMap) + Send + Sync>
    };
    (@val $name: expr, NONE) => {
        __internal_headers_eq!(@pat $name, None);
    };
    (@val $name: expr, SOME) => {
        __internal_headers_eq!(@pat $name, Some(_));
    };
    (@val $name: expr, $val:expr) => ({
        let __val = Option::from($val);
        ::std::sync::Arc::new(move |__hdrs: &hyper::HeaderMap| {
            if let Some(ref val) = __val {
                assert_eq!(__hdrs.get($name).expect(stringify!($name)), val.to_string().as_str(), stringify!($name));
            } else {
                assert_eq!(__hdrs.get($name), None, stringify!($name));
            }
        }) as ::std::sync::Arc<dyn Fn(&hyper::HeaderMap) + Send + Sync>
    });
    ($headers:ident, { $($name:expr => $val:tt,)* }) => {
        $(
        $headers.push(__internal_headers_eq!(@val $name, $val));
        )*
    }
}

#[derive(Clone, Debug)]
pub struct __CReq {
    pub method: &'static str,
    pub uri: &'static str,
    pub headers: HeaderMap,
    pub body: Vec<u8>,
}

impl Default for __CReq {
    fn default() -> __CReq {
        __CReq {
            method: "GET",
            uri: "/",
            headers: HeaderMap::new(),
            body: Vec::new(),
        }
    }
}

#[derive(Clone, Default)]
pub struct __CRes {
    pub status: hyper::StatusCode,
    pub body: Vec<u8>,
    pub headers: __HeadersEq,
}

#[derive(Clone)]
pub struct __SReq {
    pub method: &'static str,
    pub uri: &'static str,
    pub headers: __HeadersEq,
    pub body: Vec<u8>,
}

impl Default for __SReq {
    fn default() -> __SReq {
        __SReq {
            method: "GET",
            uri: "/",
            headers: Vec::new(),
            body: Vec::new(),
        }
    }
}

#[derive(Clone, Debug, Default)]
pub struct __SRes {
    pub status: hyper::StatusCode,
    pub body: Vec<u8>,
    pub headers: HeaderMap,
}

pub type __HeadersEq = Vec<Arc<dyn Fn(&HeaderMap) + Send + Sync>>;

pub struct __TestConfig {
    pub client_version: usize,
    pub client_msgs: Vec<(__CReq, __CRes)>,

    pub server_version: usize,
    pub server_msgs: Vec<(__SReq, __SRes)>,

    pub parallel: bool,
    pub connections: usize,
    pub proxy: bool,
}

pub fn __run_test(cfg: __TestConfig) {
    let _ = pretty_env_logger::try_init();
    tokio::runtime::Builder::new()
        .enable_io()
        .enable_time()
        .basic_scheduler()
        .build()
        .expect("new rt")
        .block_on(async_test(cfg));
}

async fn async_test(cfg: __TestConfig) {
    assert_eq!(cfg.client_version, cfg.server_version);

    let version = if cfg.client_version == 2 {
        Version::HTTP_2
    } else {
        Version::HTTP_11
    };

    let connector = HttpConnector::new();
    let client = Client::builder()
        .keep_alive_timeout(Duration::from_secs(10))
        .http2_only(cfg.client_version == 2)
        .build::<_, Body>(connector);

    let serve_handles = Arc::new(Mutex::new(
        cfg.server_msgs
    ));

    let expected_connections = cfg.connections;
    let mut cnt = 0;
    let new_service = make_service_fn(move |_| {
        cnt += 1;
        assert!(
            cnt <= expected_connections,
            "server expected {} connections, received {}",
            expected_connections,
            cnt
        );

        // Move a clone into the service_fn
        let serve_handles = serve_handles.clone();
        future::ok::<_, hyper::Error>(service_fn(move |req: Request<Body>| {
            let (sreq, sres) = serve_handles.lock()
                .unwrap()
                .remove(0);

            assert_eq!(req.uri().path(), sreq.uri, "client path");
            assert_eq!(req.method(), &sreq.method, "client method");
            assert_eq!(req.version(), version, "client version");
            for func in &sreq.headers {
                func(&req.headers());
            }
            let sbody = sreq.body;
            concat(req.into_body())
                .map_ok(move |body| {
                    assert_eq!(body.as_ref(), sbody.as_slice(), "client body");

                    let mut res = Response::builder()
                        .status(sres.status)
                        .body(Body::from(sres.body))
                        .expect("Response::build");
                    *res.headers_mut() = sres.headers;
                    res
                })
        }))
    });

    let server = hyper::Server::bind(&SocketAddr::from(([127, 0, 0, 1], 0)))
        .http2_only(cfg.server_version == 2)
        .serve(new_service);

    let mut addr = server.local_addr();

    tokio::task::spawn(server.map(|result| {
        let _ = result.expect("server error");
    }));

    if cfg.proxy {
        let (proxy_addr, proxy) = naive_proxy(ProxyConfig {
            connections: cfg.connections,
            dst: addr,
            version: cfg.server_version,
        });
        tokio::task::spawn(proxy);
        addr = proxy_addr;
    }

    let make_request = Arc::new(move |client: &Client<HttpConnector>, creq: __CReq, cres: __CRes| {
        let uri = format!("http://{}{}", addr, creq.uri);
        let mut req = Request::builder()
            .method(creq.method)
            .uri(uri)
            //.headers(creq.headers)
            .body(creq.body.into())
            .expect("Request::build");
        *req.headers_mut() = creq.headers;
        let cstatus = cres.status;
        let cheaders = cres.headers;
        let cbody = cres.body;

        client.request(req)
            .and_then(move |res| {
                assert_eq!(res.status(), cstatus, "server status");
                assert_eq!(res.version(), version, "server version");
                for func in &cheaders {
                    func(&res.headers());
                }
                concat(res.into_body())
            })
            .map_ok(move |body| {
                assert_eq!(body.as_ref(), cbody.as_slice(), "server body");
            })
            .map(|res| res.expect("client error"))
    });


    let client_futures: Pin<Box<dyn Future<Output = ()> + Send>> = if cfg.parallel {
        let mut client_futures = vec![];
        for (creq, cres) in cfg.client_msgs {
            client_futures.push(make_request(&client, creq, cres));
        }
        drop(client);
        Box::pin(future::join_all(client_futures).map(|_| ()))
    } else {
        let mut client_futures: Pin<Box<dyn Future<Output=Client<HttpConnector>> + Send>> =
            Box::pin(future::ready(client));
        for (creq, cres) in cfg.client_msgs {
            let mk_request = make_request.clone();
            client_futures = Box::pin(
                client_futures
                .then(move |client| {
                    let fut = mk_request(&client, creq, cres);
                    fut.map(move |()| client)
                })
            );
        }
        Box::pin(client_futures.map(|_| ()))
    };

    client_futures.await;
}

struct ProxyConfig {
    connections: usize,
    dst: SocketAddr,
    version: usize,
}

fn naive_proxy(cfg: ProxyConfig) -> (SocketAddr, impl Future<Output = ()>) {
    let client = Client::builder()
        .keep_alive_timeout(Duration::from_secs(10))
        .http2_only(cfg.version == 2)
        .build_http::<Body>();

    let dst_addr = cfg.dst;
    let max_connections = cfg.connections;
    let counter = AtomicUsize::new(0);

    let srv = Server::bind(&([127, 0, 0, 1], 0).into())
        .serve(make_service_fn(move |_| {
            let prev = counter.fetch_add(1, Ordering::Relaxed);
            assert!(max_connections >= prev + 1, "proxy max connections");
            let client = client.clone();
            future::ok::<_, hyper::Error>(service_fn(move |mut req| {
                let uri = format!("http://{}{}", dst_addr, req.uri().path())
                    .parse()
                    .expect("proxy new uri parse");
                *req.uri_mut() = uri;
                client.request(req)
            }))
        }));
    let proxy_addr = srv.local_addr();
    (proxy_addr, srv.map(|res| res.expect("proxy error")))
}

async fn concat(mut body: Body) -> Result<hyper::Chunk, hyper::Error> {
    let mut vec = Vec::new();
    while let Some(chunk) = body.next().await {
        vec.extend_from_slice(&chunk?);
    }
    Ok(vec.into())
}