use std::future::Future;
use std::str::FromStr;

use async_graphql::http::{WebSocketProtocols, WsMessage};
use async_graphql::{Data, ObjectType, Result, Schema, SubscriptionType};
use futures_util::{future, StreamExt};
use warp::filters::ws;
use warp::ws::WebSocket;
use warp::{Filter, Rejection, Reply};

/// GraphQL subscription filter
///
/// # Examples
///
/// ```no_run
/// use async_graphql::*;
/// use async_graphql_warp::*;
/// use warp::Filter;
/// use futures_util::stream::{Stream, StreamExt};
/// use std::time::Duration;
///
/// struct QueryRoot;
///
/// #[Object]
/// impl QueryRoot {
///     async fn value(&self) -> i32 {
///         // A GraphQL Object type must define one or more fields.
///         100
///     }
/// }
///
/// struct SubscriptionRoot;
///
/// #[Subscription]
/// impl SubscriptionRoot {
///     async fn tick(&self) -> impl Stream<Item = String> {
///         async_stream::stream! {
///             let mut interval = tokio::time::interval(Duration::from_secs(1));
///             loop {
///                 let n = interval.tick().await;
///                 yield format!("{}", n.elapsed().as_secs_f32());
///             }
///         }
///     }
/// }
///
/// tokio::runtime::Runtime::new().unwrap().block_on(async {
///     let schema = Schema::new(QueryRoot, EmptyMutation, SubscriptionRoot);
///     let filter = async_graphql_warp::graphql_subscription(schema)
///         .or(warp::any().map(|| "Hello, World!"));
///     warp::serve(filter).run(([0, 0, 0, 0], 8000)).await;
/// });
/// ```
pub fn graphql_subscription<Query, Mutation, Subscription>(
    schema: Schema<Query, Mutation, Subscription>,
) -> impl Filter<Extract = (impl Reply,), Error = Rejection> + Clone
where
    Query: ObjectType + Sync + Send + 'static,
    Mutation: ObjectType + Sync + Send + 'static,
    Subscription: SubscriptionType + Send + Sync + 'static,
{
    graphql_subscription_with_data(schema, |_| async { Ok(Default::default()) })
}

/// GraphQL subscription filter
///
/// Specifies that a function converts the init payload to data.
pub fn graphql_subscription_with_data<Query, Mutation, Subscription, F, R>(
    schema: Schema<Query, Mutation, Subscription>,
    initializer: F,
) -> impl Filter<Extract = (impl Reply,), Error = Rejection> + Clone
where
    Query: ObjectType + 'static,
    Mutation: ObjectType + 'static,
    Subscription: SubscriptionType + 'static,
    F: FnOnce(serde_json::Value) -> R + Clone + Send + 'static,
    R: Future<Output = Result<Data>> + Send + 'static,
{
    warp::ws()
        .and(graphql_protocol())
        .map(move |ws: ws::Ws, protocol| {
            let schema = schema.clone();
            let initializer = initializer.clone();

            let reply = ws.on_upgrade(move |websocket| {
                graphql_subscription_upgrade_with_data(websocket, protocol, schema, initializer)
            });

            warp::reply::with_header(
                reply,
                "Sec-WebSocket-Protocol",
                protocol.sec_websocket_protocol(),
            )
        })
}

/// Create a `Filter` that parse [WebSocketProtocols] from `sec-websocket-protocol` header.
pub fn graphql_protocol() -> impl Filter<Extract = (WebSocketProtocols,), Error = Rejection> + Clone
{
    warp::header::optional::<String>("sec-websocket-protocol").map(|protocols: Option<String>| {
        protocols
            .and_then(|protocols| {
                protocols
                    .split(',')
                    .find_map(|p| WebSocketProtocols::from_str(p.trim()).ok())
            })
            .unwrap_or(WebSocketProtocols::SubscriptionsTransportWS)
    })
}

/// Handle the WebSocket subscription.
///
/// If you want to control the WebSocket subscription more finely, you can use this function,
/// otherwise it is more convenient to use [graphql_subscription].
///
/// # Examples
///
/// ```no_run
/// use async_graphql::*;
/// use async_graphql_warp::*;
/// use warp::Filter;
/// use futures_util::stream::{Stream, StreamExt};
/// use std::time::Duration;
///
/// struct QueryRoot;
///
/// #[Object]
/// impl QueryRoot {
///     async fn value(&self) -> i32 {
///         // A GraphQL Object type must define one or more fields.
///         100
///     }
/// }
///
/// struct SubscriptionRoot;
///
/// #[Subscription]
/// impl SubscriptionRoot {
///     async fn tick(&self) -> impl Stream<Item = String> {
///         async_stream::stream! {
///             let mut interval = tokio::time::interval(Duration::from_secs(1));
///             loop {
///                 let n = interval.tick().await;
///                 yield format!("{}", n.elapsed().as_secs_f32());
///             }
///         }
///     }
/// }
///
/// tokio::runtime::Runtime::new().unwrap().block_on(async {
///     let schema = Schema::new(QueryRoot, EmptyMutation, SubscriptionRoot);
///     let filter = warp::ws()
///         .and(graphql_protocol())
///         .map(move |ws: warp::ws::Ws, protocol| {
///             let schema = schema.clone();
///             let reply = ws.on_upgrade( move |websocket| {
///                 graphql_subscription_upgrade(websocket, protocol, schema)
///             });
///             warp::reply::with_header(
///                reply,
///                "Sec-WebSocket-Protocol",
///                protocol.sec_websocket_protocol(),
///            )
///         });
///     warp::serve(filter).run(([0, 0, 0, 0], 8000)).await;
/// });
/// ```
pub async fn graphql_subscription_upgrade<Query, Mutation, Subscription>(
    websocket: WebSocket,
    protocol: WebSocketProtocols,
    schema: Schema<Query, Mutation, Subscription>,
) where
    Query: ObjectType + 'static,
    Mutation: ObjectType + 'static,
    Subscription: SubscriptionType + 'static,
{
    graphql_subscription_upgrade_with_data(websocket, protocol, schema, |_| async {
        Ok(Default::default())
    })
    .await
}

/// Handle the WebSocket subscription.
///
/// Specifies that a function converts the init payload to data.
pub async fn graphql_subscription_upgrade_with_data<Query, Mutation, Subscription, F, R>(
    websocket: WebSocket,
    protocol: WebSocketProtocols,
    schema: Schema<Query, Mutation, Subscription>,
    initializer: F,
) where
    Query: ObjectType + 'static,
    Mutation: ObjectType + 'static,
    Subscription: SubscriptionType + 'static,
    F: FnOnce(serde_json::Value) -> R + Clone + Send + 'static,
    R: Future<Output = Result<Data>> + Send + 'static,
{
    let (ws_sender, ws_receiver) = websocket.split();
    let _ = async_graphql::http::WebSocket::with_data(
        schema,
        ws_receiver
            .take_while(|msg| future::ready(msg.is_ok()))
            .map(Result::unwrap)
            .filter(|msg| future::ready(msg.is_text() || msg.is_binary()))
            .map(ws::Message::into_bytes),
        initializer,
        protocol,
    )
    .map(|msg| match msg {
        WsMessage::Text(text) => ws::Message::text(text),
        WsMessage::Close(code, status) => ws::Message::close_with(code, status),
    })
    .map(Ok)
    .forward(ws_sender)
    .await;
}