#![feature(min_specialization)]
#![feature(str_split_remainder)]
#![feature(arbitrary_self_types)]
#![feature(arbitrary_self_types_pointers)]

pub mod html;
mod http;
pub mod introspect;
mod invalidation;
pub mod source;
pub mod update;

use std::{
    collections::VecDeque,
    future::Future,
    net::{SocketAddr, TcpListener},
    pin::Pin,
    sync::Arc,
    time::{Duration, Instant},
};

use anyhow::{Context, Result};
use hyper::{
    Request, Response, Server,
    server::{Builder, conn::AddrIncoming},
    service::{make_service_fn, service_fn},
};
use parking_lot::Mutex;
use socket2::{Domain, Protocol, Socket, Type};
use tokio::task::JoinHandle;
use tracing::{Instrument, Level, Span, event, info_span};
use turbo_tasks::{
    Effects, NonLocalValue, OperationVc, PrettyPrintError, TurboTasksApi, Vc, run_once_with_reason,
    take_effects, trace::TraceRawVcs, util::FormatDuration,
};
use turbopack_core::issue::{IssueReporter, IssueSeverity, handle_issues};

use self::{source::ContentSource, update::UpdateServer};
use crate::{
    invalidation::{ServerRequest, ServerRequestSideEffects},
    source::ContentSourceSideEffect,
};

pub trait SourceProvider: Send + Clone + 'static {
    /// must call a turbo-tasks function internally
    fn get_source(&self) -> OperationVc<Box<dyn ContentSource>>;
}

impl<T> SourceProvider for T
where
    T: Fn() -> OperationVc<Box<dyn ContentSource>> + Send + Clone + 'static,
{
    fn get_source(&self) -> OperationVc<Box<dyn ContentSource>> {
        self()
    }
}

#[turbo_tasks::value(serialization = "skip")]
struct ContentSourceWithIssues {
    source_op: OperationVc<Box<dyn ContentSource>>,
    effects: Effects,
}

#[turbo_tasks::function(operation)]
async fn get_source_with_issues_operation(
    source_op: OperationVc<Box<dyn ContentSource>>,
) -> Result<Vc<ContentSourceWithIssues>> {
    let _ = source_op.resolve().strongly_consistent().await?;
    let effects = take_effects(source_op).await?;
    Ok(ContentSourceWithIssues { source_op, effects }.cell())
}

#[derive(TraceRawVcs, Debug, NonLocalValue)]
pub struct DevServerBuilder {
    #[turbo_tasks(trace_ignore)]
    pub addr: SocketAddr,
    #[turbo_tasks(trace_ignore)]
    server: Builder<AddrIncoming>,
}

#[derive(TraceRawVcs, NonLocalValue)]
pub struct DevServer {
    #[turbo_tasks(trace_ignore)]
    pub addr: SocketAddr,
    #[turbo_tasks(trace_ignore)]
    pub future: Pin<Box<dyn Future<Output = Result<()>> + Send + 'static>>,
}

impl DevServer {
    pub fn listen(addr: SocketAddr) -> Result<DevServerBuilder, anyhow::Error> {
        // This is annoying. The hyper::Server doesn't allow us to know which port was
        // bound (until we build it with a request handler) when using the standard
        // `server::try_bind` approach. This is important when binding the `0` port,
        // because the OS will remap that to an actual free port, and we need to know
        // that port before we build the request handler. So we need to construct a
        // real TCP listener, see if it bound, and get its bound address.
        let socket = Socket::new(Domain::for_address(addr), Type::STREAM, Some(Protocol::TCP))
            .context("unable to create socket")?;
        // Allow the socket to be reused immediately after closing. This ensures that
        // the dev server can be restarted on the same address without a buffer time for
        // the OS to release the socket.
        // https://docs.microsoft.com/en-us/windows/win32/winsock/using-so-reuseaddr-and-so-exclusiveaddruse
        #[cfg(not(windows))]
        let _ = socket.set_reuse_address(true);
        if matches!(addr, SocketAddr::V6(_)) {
            // When possible bind to v4 and v6, otherwise ignore the error
            let _ = socket.set_only_v6(false);
        }
        let sock_addr = addr.into();
        socket
            .bind(&sock_addr)
            .context("not able to bind address")?;
        socket.listen(128).context("not able to listen on socket")?;

        let listener: TcpListener = socket.into();
        let addr = listener
            .local_addr()
            .context("not able to get bound address")?;
        let server = Server::from_tcp(listener).context("Not able to start server")?;
        Ok(DevServerBuilder { addr, server })
    }
}

impl DevServerBuilder {
    pub fn serve(
        self,
        turbo_tasks: Arc<dyn TurboTasksApi>,
        source_provider: impl SourceProvider + NonLocalValue + TraceRawVcs + Sync,
        get_issue_reporter: Arc<dyn Fn() -> Vc<Box<dyn IssueReporter>> + Send + Sync>,
    ) -> DevServer {
        let ongoing_side_effects = Arc::new(Mutex::new(VecDeque::<
            Arc<tokio::sync::Mutex<Option<JoinHandle<Result<()>>>>>,
        >::with_capacity(16)));
        let make_svc = make_service_fn(move |_| {
            let tt = turbo_tasks.clone();
            let source_provider = source_provider.clone();
            let get_issue_reporter = get_issue_reporter.clone();
            let ongoing_side_effects = ongoing_side_effects.clone();
            async move {
                let handler = move |request: Request<hyper::Body>| {
                    let request_span = info_span!(parent: None, "request", name = ?request.uri());
                    let start = Instant::now();
                    let tt = tt.clone();
                    let get_issue_reporter = get_issue_reporter.clone();
                    let ongoing_side_effects = ongoing_side_effects.clone();
                    let source_provider = source_provider.clone();
                    let future = async move {
                        event!(parent: Span::current(), Level::DEBUG, "request start");
                        // Wait until all ongoing side effects are completed
                        // We only need to wait for the ongoing side effects that were started
                        // before this request. Later added side effects are not relevant for this.
                        let current_ongoing_side_effects = {
                            // Cleanup the ongoing_side_effects list
                            let mut guard = ongoing_side_effects.lock();
                            while let Some(front) = guard.front() {
                                let Ok(front_guard) = front.try_lock() else {
                                    break;
                                };
                                if front_guard.is_some() {
                                    break;
                                }
                                drop(front_guard);
                                guard.pop_front();
                            }
                            // Get a clone of the remaining list
                            (*guard).clone()
                        };
                        // Wait for the side effects to complete
                        for side_effect_mutex in current_ongoing_side_effects {
                            let mut guard = side_effect_mutex.lock().await;
                            if let Some(join_handle) = guard.take() {
                                join_handle.await??;
                            }
                            drop(guard);
                        }
                        let reason = ServerRequest {
                            method: request.method().clone(),
                            uri: request.uri().clone(),
                        };
                        let side_effects_reason = ServerRequestSideEffects {
                            method: request.method().clone(),
                            uri: request.uri().clone(),
                        };
                        run_once_with_reason(tt.clone(), reason, async move {
                            // TODO: `get_issue_reporter` should be an `OperationVc`, as there's a
                            // risk it could be a task-local Vc, which is not safe for us to await.
                            let issue_reporter = get_issue_reporter();

                            if hyper_tungstenite::is_upgrade_request(&request) {
                                let uri = request.uri();
                                let path = uri.path();

                                if path == "/turbopack-hmr" {
                                    let (response, websocket) =
                                        hyper_tungstenite::upgrade(request, None)?;
                                    let update_server =
                                        UpdateServer::new(source_provider, issue_reporter);
                                    update_server.run(&*tt, websocket);
                                    return Ok(response);
                                }

                                println!("[404] {path} (WebSocket)");
                                if path == "/_next/hmr" {
                                    // Special-case requests to hmr as these are made by
                                    // Next.js clients built
                                    // without turbopack, which may be making requests in
                                    // development.
                                    println!(
                                        "A non-turbopack next.js client is trying to connect."
                                    );
                                    println!(
                                        "Make sure to reload/close any browser window which has \
                                         been opened without --turbo."
                                    );
                                }

                                return Ok(Response::builder()
                                    .status(404)
                                    .body(hyper::Body::empty())?);
                            }

                            let uri = request.uri();
                            let path = uri.path().to_string();
                            let source_with_issues_op =
                                get_source_with_issues_operation(source_provider.get_source());
                            let ContentSourceWithIssues { source_op, effects } =
                                &*source_with_issues_op.read_strongly_consistent().await?;
                            effects.apply().await?;
                            handle_issues(
                                source_with_issues_op,
                                issue_reporter,
                                IssueSeverity::Fatal,
                                Some(&path),
                                Some("get source"),
                            )
                            .await?;
                            let (response, side_effects) =
                                http::process_request_with_content_source(
                                    // HACK: pass `source` here (instead of `resolved_source`
                                    // because the underlying API wants to do it's own
                                    // `.resolve().strongly_consistent()` call.
                                    //
                                    // It's unlikely (the calls happen one-after-another), but this
                                    // could cause inconsistency between the reported issues and
                                    // the generated HTTP response.
                                    *source_op,
                                    request,
                                    issue_reporter,
                                )
                                .await?;
                            let status = response.status().as_u16();
                            let is_error = response.status().is_client_error()
                                || response.status().is_server_error();
                            let elapsed = start.elapsed();
                            if is_error
                                || (cfg!(feature = "log_request_stats")
                                    && elapsed > Duration::from_secs(1))
                            {
                                println!(
                                    "[{status}] {path} ({duration})",
                                    duration = FormatDuration(elapsed)
                                );
                            }
                            if !side_effects.is_empty() {
                                let join_handle = tokio::spawn(run_once_with_reason(
                                    tt.clone(),
                                    side_effects_reason,
                                    async move {
                                        for side_effect in side_effects {
                                            side_effect.apply().await?;
                                        }
                                        Ok(())
                                    },
                                ));
                                ongoing_side_effects.lock().push_back(Arc::new(
                                    tokio::sync::Mutex::new(Some(join_handle)),
                                ));
                            }
                            Ok(response)
                        })
                        .await
                    };
                    async move {
                        match future.await {
                            Ok(r) => Ok::<_, hyper::http::Error>(r),
                            Err(e) => {
                                println!(
                                    "[500] error ({}): {}",
                                    FormatDuration(start.elapsed()),
                                    PrettyPrintError(&e),
                                );
                                Ok(Response::builder()
                                    .status(500)
                                    .body(hyper::Body::from(format!("{}", PrettyPrintError(&e))))?)
                            }
                        }
                    }
                    .instrument(request_span)
                };
                anyhow::Ok(service_fn(handler))
            }
        });
        let server = self.server.serve(make_svc);

        DevServer {
            addr: self.addr,
            future: Box::pin(async move {
                server.await?;
                Ok(())
            }),
        }
    }
}