// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.

use crate::io::TcpStreamResource;
use crate::ops::IpAddr;
use crate::ops::TlsHandshakeInfo;
use crate::raw::NetworkListenerResource;
use crate::resolve_addr::resolve_addr;
use crate::resolve_addr::resolve_addr_sync;
use crate::tcp::TcpListener;
use crate::DefaultTlsOptions;
use crate::NetPermissions;
use crate::UnsafelyIgnoreCertificateErrors;
use deno_core::error::bad_resource;
use deno_core::error::custom_error;
use deno_core::error::generic_error;
use deno_core::error::invalid_hostname;
use deno_core::error::AnyError;
use deno_core::op2;
use deno_core::v8;
use deno_core::AsyncRefCell;
use deno_core::AsyncResult;
use deno_core::CancelHandle;
use deno_core::CancelTryFuture;
use deno_core::OpState;
use deno_core::RcRef;
use deno_core::Resource;
use deno_core::ResourceId;
use deno_tls::create_client_config;
use deno_tls::load_certs;
use deno_tls::load_private_keys;
use deno_tls::rustls::Certificate;
use deno_tls::rustls::PrivateKey;
use deno_tls::rustls::ServerConfig;
use deno_tls::rustls::ServerName;
use deno_tls::SocketUse;
use deno_tls::TlsKey;
use deno_tls::TlsKeys;
use rustls_tokio_stream::TlsStreamRead;
use rustls_tokio_stream::TlsStreamWrite;
use serde::Deserialize;
use std::borrow::Cow;
use std::cell::RefCell;
use std::convert::From;
use std::convert::TryFrom;
use std::fs::File;
use std::io::BufReader;
use std::io::ErrorKind;
use std::io::Read;
use std::net::SocketAddr;
use std::num::NonZeroUsize;
use std::path::Path;
use std::rc::Rc;
use std::sync::Arc;
use tokio::io::AsyncReadExt;
use tokio::io::AsyncWriteExt;
use tokio::net::TcpStream;

pub use rustls_tokio_stream::TlsStream;

pub(crate) const TLS_BUFFER_SIZE: Option<NonZeroUsize> =
  NonZeroUsize::new(65536);

pub struct TlsListener {
  pub(crate) tcp_listener: TcpListener,
  pub(crate) tls_config: Arc<ServerConfig>,
}

impl TlsListener {
  pub async fn accept(&self) -> std::io::Result<(TlsStream, SocketAddr)> {
    let (tcp, addr) = self.tcp_listener.accept().await?;
    let tls =
      TlsStream::new_server_side(tcp, self.tls_config.clone(), TLS_BUFFER_SIZE);
    Ok((tls, addr))
  }
  pub fn local_addr(&self) -> std::io::Result<SocketAddr> {
    self.tcp_listener.local_addr()
  }
}

#[derive(Debug)]
pub struct TlsStreamResource {
  rd: AsyncRefCell<TlsStreamRead>,
  wr: AsyncRefCell<TlsStreamWrite>,
  // `None` when a TLS handshake hasn't been done.
  handshake_info: RefCell<Option<TlsHandshakeInfo>>,
  cancel_handle: CancelHandle, // Only read and handshake ops get canceled.
}

impl TlsStreamResource {
  pub fn new((rd, wr): (TlsStreamRead, TlsStreamWrite)) -> Self {
    Self {
      rd: rd.into(),
      wr: wr.into(),
      handshake_info: RefCell::new(None),
      cancel_handle: Default::default(),
    }
  }

  pub fn into_inner(self) -> (TlsStreamRead, TlsStreamWrite) {
    (self.rd.into_inner(), self.wr.into_inner())
  }

  pub async fn read(
    self: Rc<Self>,
    data: &mut [u8],
  ) -> Result<usize, AnyError> {
    let mut rd = RcRef::map(&self, |r| &r.rd).borrow_mut().await;
    let cancel_handle = RcRef::map(&self, |r| &r.cancel_handle);
    Ok(rd.read(data).try_or_cancel(cancel_handle).await?)
  }

  pub async fn write(self: Rc<Self>, data: &[u8]) -> Result<usize, AnyError> {
    let mut wr = RcRef::map(self, |r| &r.wr).borrow_mut().await;
    let nwritten = wr.write(data).await?;
    wr.flush().await?;
    Ok(nwritten)
  }

  pub async fn shutdown(self: Rc<Self>) -> Result<(), AnyError> {
    let mut wr = RcRef::map(self, |r| &r.wr).borrow_mut().await;
    wr.shutdown().await?;
    Ok(())
  }

  pub async fn handshake(
    self: &Rc<Self>,
  ) -> Result<TlsHandshakeInfo, AnyError> {
    if let Some(tls_info) = &*self.handshake_info.borrow() {
      return Ok(tls_info.clone());
    }

    let mut wr = RcRef::map(self, |r| &r.wr).borrow_mut().await;
    let cancel_handle = RcRef::map(self, |r| &r.cancel_handle);
    let handshake = wr.handshake().try_or_cancel(cancel_handle).await?;

    let alpn_protocol = handshake.alpn.map(|alpn| alpn.into());
    let tls_info = TlsHandshakeInfo { alpn_protocol };
    self.handshake_info.replace(Some(tls_info.clone()));
    Ok(tls_info)
  }
}

impl Resource for TlsStreamResource {
  deno_core::impl_readable_byob!();
  deno_core::impl_writable!();

  fn name(&self) -> Cow<str> {
    "tlsStream".into()
  }

  fn shutdown(self: Rc<Self>) -> AsyncResult<()> {
    Box::pin(self.shutdown())
  }

  fn close(self: Rc<Self>) {
    self.cancel_handle.cancel();
  }
}

#[derive(Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct ConnectTlsArgs {
  cert_file: Option<String>,
  ca_certs: Vec<String>,
  alpn_protocols: Option<Vec<String>>,
}

#[derive(Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct StartTlsArgs {
  rid: ResourceId,
  ca_certs: Vec<String>,
  hostname: String,
  alpn_protocols: Option<Vec<String>>,
}

#[op2]
pub fn op_tls_key_null<'s>(
  scope: &mut v8::HandleScope<'s>,
) -> Result<v8::Local<'s, v8::Object>, AnyError> {
  Ok(deno_core::cppgc::make_cppgc_object(scope, TlsKeys::Null))
}

#[op2]
pub fn op_tls_key_static<'s>(
  scope: &mut v8::HandleScope<'s>,
  #[string] cert: String,
  #[string] key: String,
) -> Result<v8::Local<'s, v8::Object>, AnyError> {
  let cert = load_certs(&mut BufReader::new(cert.as_bytes()))?;
  let key = load_private_keys(key.as_bytes())?
    .into_iter()
    .next()
    .unwrap();
  Ok(deno_core::cppgc::make_cppgc_object(
    scope,
    TlsKeys::Static(TlsKey(cert, key)),
  ))
}

/// Legacy op -- will be removed in Deno 2.0.
#[op2]
pub fn op_tls_key_static_from_file<'s, NP>(
  state: &mut OpState,
  scope: &mut v8::HandleScope<'s>,
  #[string] api: String,
  #[string] cert_file: String,
  #[string] key_file: String,
) -> Result<v8::Local<'s, v8::Object>, AnyError>
where
  NP: NetPermissions + 'static,
{
  {
    let permissions = state.borrow_mut::<NP>();
    permissions.check_read(Path::new(&cert_file), &api)?;
    permissions.check_read(Path::new(&key_file), &api)?;
  }

  let cert = load_certs_from_file(&cert_file)?;
  let key = load_private_keys_from_file(&key_file)?
    .into_iter()
    .next()
    .unwrap();
  Ok(deno_core::cppgc::make_cppgc_object(
    scope,
    TlsKeys::Static(TlsKey(cert, key)),
  ))
}

#[op2]
#[serde]
pub fn op_tls_start<NP>(
  state: Rc<RefCell<OpState>>,
  #[serde] args: StartTlsArgs,
) -> Result<(ResourceId, IpAddr, IpAddr), AnyError>
where
  NP: NetPermissions + 'static,
{
  let rid = args.rid;
  let hostname = match &*args.hostname {
    "" => "localhost",
    n => n,
  };

  {
    let mut s = state.borrow_mut();
    let permissions = s.borrow_mut::<NP>();
    permissions.check_net(&(hostname, Some(0)), "Deno.startTls()")?;
  }

  let ca_certs = args
    .ca_certs
    .into_iter()
    .map(|s| s.into_bytes())
    .collect::<Vec<_>>();

  let hostname_dns =
    ServerName::try_from(hostname).map_err(|_| invalid_hostname(hostname))?;

  let unsafely_ignore_certificate_errors = state
    .borrow()
    .try_borrow::<UnsafelyIgnoreCertificateErrors>()
    .and_then(|it| it.0.clone());

  let root_cert_store = state
    .borrow()
    .borrow::<DefaultTlsOptions>()
    .root_cert_store()?;

  let resource_rc = state
    .borrow_mut()
    .resource_table
    .take::<TcpStreamResource>(rid)?;
  // This TCP connection might be used somewhere else. If it's the case, we cannot proceed with the
  // process of starting a TLS connection on top of this TCP connection, so we just return a bad
  // resource error. See also: https://github.com/denoland/deno/pull/16242
  let resource = Rc::try_unwrap(resource_rc)
    .map_err(|_| bad_resource("TCP stream is currently in use"))?;
  let (read_half, write_half) = resource.into_inner();
  let tcp_stream = read_half.reunite(write_half)?;

  let local_addr = tcp_stream.local_addr()?;
  let remote_addr = tcp_stream.peer_addr()?;

  let mut tls_config = create_client_config(
    root_cert_store,
    ca_certs,
    unsafely_ignore_certificate_errors,
    None,
    SocketUse::GeneralSsl,
  )?;

  if let Some(alpn_protocols) = args.alpn_protocols {
    tls_config.alpn_protocols =
      alpn_protocols.into_iter().map(|s| s.into_bytes()).collect();
  }

  let tls_config = Arc::new(tls_config);
  let tls_stream = TlsStream::new_client_side(
    tcp_stream,
    tls_config,
    hostname_dns,
    TLS_BUFFER_SIZE,
  );

  let rid = {
    let mut state_ = state.borrow_mut();
    state_
      .resource_table
      .add(TlsStreamResource::new(tls_stream.into_split()))
  };

  Ok((rid, IpAddr::from(local_addr), IpAddr::from(remote_addr)))
}

#[op2(async)]
#[serde]
pub async fn op_net_connect_tls<NP>(
  state: Rc<RefCell<OpState>>,
  #[serde] addr: IpAddr,
  #[serde] args: ConnectTlsArgs,
  #[cppgc] key_pair: &TlsKeys,
) -> Result<(ResourceId, IpAddr, IpAddr), AnyError>
where
  NP: NetPermissions + 'static,
{
  let cert_file = args.cert_file.as_deref();
  let unsafely_ignore_certificate_errors = state
    .borrow()
    .try_borrow::<UnsafelyIgnoreCertificateErrors>()
    .and_then(|it| it.0.clone());

  {
    let mut s = state.borrow_mut();
    let permissions = s.borrow_mut::<NP>();
    permissions
      .check_net(&(&addr.hostname, Some(addr.port)), "Deno.connectTls()")?;
    if let Some(path) = cert_file {
      permissions.check_read(Path::new(path), "Deno.connectTls()")?;
    }
  }

  let mut ca_certs = args
    .ca_certs
    .into_iter()
    .map(|s| s.into_bytes())
    .collect::<Vec<_>>();

  if let Some(path) = cert_file {
    let mut buf = Vec::new();
    File::open(path)?.read_to_end(&mut buf)?;
    ca_certs.push(buf);
  };

  let root_cert_store = state
    .borrow()
    .borrow::<DefaultTlsOptions>()
    .root_cert_store()?;
  let hostname_dns = ServerName::try_from(&*addr.hostname)
    .map_err(|_| invalid_hostname(&addr.hostname))?;
  let connect_addr = resolve_addr(&addr.hostname, addr.port)
    .await?
    .next()
    .ok_or_else(|| generic_error("No resolved address found"))?;
  let tcp_stream = TcpStream::connect(connect_addr).await?;
  let local_addr = tcp_stream.local_addr()?;
  let remote_addr = tcp_stream.peer_addr()?;

  let cert_and_key = match key_pair {
    TlsKeys::Null => None,
    TlsKeys::Static(key) => Some(key.clone()),
  };
  let mut tls_config = create_client_config(
    root_cert_store,
    ca_certs,
    unsafely_ignore_certificate_errors,
    cert_and_key,
    SocketUse::GeneralSsl,
  )?;

  if let Some(alpn_protocols) = args.alpn_protocols {
    tls_config.alpn_protocols =
      alpn_protocols.into_iter().map(|s| s.into_bytes()).collect();
  }

  let tls_config = Arc::new(tls_config);

  let tls_stream = TlsStream::new_client_side(
    tcp_stream,
    tls_config,
    hostname_dns,
    TLS_BUFFER_SIZE,
  );

  let rid = {
    let mut state_ = state.borrow_mut();
    state_
      .resource_table
      .add(TlsStreamResource::new(tls_stream.into_split()))
  };

  Ok((rid, IpAddr::from(local_addr), IpAddr::from(remote_addr)))
}

fn load_certs_from_file(path: &str) -> Result<Vec<Certificate>, AnyError> {
  let cert_file = File::open(path)?;
  let reader = &mut BufReader::new(cert_file);
  load_certs(reader)
}

fn load_private_keys_from_file(
  path: &str,
) -> Result<Vec<PrivateKey>, AnyError> {
  let key_bytes = std::fs::read(path)?;
  load_private_keys(&key_bytes)
}

#[derive(Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct ListenTlsArgs {
  alpn_protocols: Option<Vec<String>>,
  reuse_port: bool,
}

#[op2]
#[serde]
pub fn op_net_listen_tls<NP>(
  state: &mut OpState,
  #[serde] addr: IpAddr,
  #[serde] args: ListenTlsArgs,
  #[cppgc] keys: &TlsKeys,
) -> Result<(ResourceId, IpAddr), AnyError>
where
  NP: NetPermissions + 'static,
{
  if args.reuse_port {
    super::check_unstable(state, "Deno.listenTls({ reusePort: true })");
  }

  {
    let permissions = state.borrow_mut::<NP>();
    permissions
      .check_net(&(&addr.hostname, Some(addr.port)), "Deno.listenTls()")?;
  }

  let tls_config = ServerConfig::builder()
    .with_safe_defaults()
    .with_no_client_auth();

  let mut tls_config = match keys {
    TlsKeys::Null => {
      unreachable!()
    }
    TlsKeys::Static(TlsKey(cert, key)) => {
      tls_config.with_single_cert(cert.clone(), key.clone())
    }
  }
  .map_err(|e| {
    custom_error(
      "InvalidData",
      format!("Error creating TLS certificate: {:?}", e),
    )
  })?;

  if let Some(alpn_protocols) = args.alpn_protocols {
    tls_config.alpn_protocols =
      alpn_protocols.into_iter().map(|s| s.into_bytes()).collect();
  }

  let bind_addr = resolve_addr_sync(&addr.hostname, addr.port)?
    .next()
    .ok_or_else(|| generic_error("No resolved address found"))?;

  let tcp_listener = TcpListener::bind_direct(bind_addr, args.reuse_port)?;
  let local_addr = tcp_listener.local_addr()?;

  let tls_listener_resource = NetworkListenerResource::new(TlsListener {
    tcp_listener,
    tls_config: tls_config.into(),
  });

  let rid = state.resource_table.add(tls_listener_resource);

  Ok((rid, IpAddr::from(local_addr)))
}

#[op2(async)]
#[serde]
pub async fn op_net_accept_tls(
  state: Rc<RefCell<OpState>>,
  #[smi] rid: ResourceId,
) -> Result<(ResourceId, IpAddr, IpAddr), AnyError> {
  let resource = state
    .borrow()
    .resource_table
    .get::<NetworkListenerResource<TlsListener>>(rid)
    .map_err(|_| bad_resource("Listener has been closed"))?;

  let cancel_handle = RcRef::map(&resource, |r| &r.cancel);
  let listener = RcRef::map(&resource, |r| &r.listener)
    .try_borrow_mut()
    .ok_or_else(|| custom_error("Busy", "Another accept task is ongoing"))?;

  let (tls_stream, remote_addr) =
    match listener.accept().try_or_cancel(&cancel_handle).await {
      Ok(tuple) => tuple,
      Err(err) if err.kind() == ErrorKind::Interrupted => {
        // FIXME(bartlomieju): compatibility with current JS implementation.
        return Err(bad_resource("Listener has been closed"));
      }
      Err(err) => return Err(err.into()),
    };

  let local_addr = tls_stream.local_addr()?;
  let rid = {
    let mut state_ = state.borrow_mut();
    state_
      .resource_table
      .add(TlsStreamResource::new(tls_stream.into_split()))
  };

  Ok((rid, IpAddr::from(local_addr), IpAddr::from(remote_addr)))
}

#[op2(async)]
#[serde]
pub async fn op_tls_handshake(
  state: Rc<RefCell<OpState>>,
  #[smi] rid: ResourceId,
) -> Result<TlsHandshakeInfo, AnyError> {
  let resource = state
    .borrow()
    .resource_table
    .get::<TlsStreamResource>(rid)
    .map_err(|_| bad_resource("Listener has been closed"))?;
  resource.handshake().await
}