// Take a look at the license at the top of the repository in the LICENSE file.

use crate::Cancellable;
use crate::Socket;
use crate::SocketAddress;
use glib::object::{Cast, IsA};
use glib::translate::*;
use std::cell::RefCell;
use std::mem::transmute;
#[cfg(all(not(unix), feature = "dox"))]
use std::os::raw::c_int;
#[cfg(all(not(windows), feature = "dox"))]
use std::os::raw::c_void;
use std::pin::Pin;
use std::ptr;

use futures_core::stream::Stream;

#[cfg(unix)]
use std::os::unix::io::{AsRawFd, FromRawFd, IntoRawFd, RawFd};

#[cfg(windows)]
use std::os::windows::io::{AsRawSocket, FromRawSocket, IntoRawSocket, RawSocket};

impl Socket {
    /// Creates a new [`Socket`][crate::Socket] from a native file descriptor
    /// or winsock SOCKET handle.
    ///
    /// This reads all the settings from the file descriptor so that
    /// all properties should work. Note that the file descriptor
    /// will be set to non-blocking mode, independent on the blocking
    /// mode of the [`Socket`][crate::Socket].
    ///
    /// On success, the returned [`Socket`][crate::Socket] takes ownership of `fd`. On failure, the
    /// caller must close `fd` themselves.
    ///
    /// Since GLib 2.46, it is no longer a fatal error to call this on a non-socket
    /// descriptor. Instead, a GError will be set with code [`IOErrorEnum::Failed`][crate::IOErrorEnum::Failed]
    /// ## `fd`
    /// a native socket file descriptor.
    ///
    /// # Returns
    ///
    /// a [`Socket`][crate::Socket] or [`None`] on error.
    ///  Free the returned object with `g_object_unref()`.
    #[cfg(any(unix, feature = "dox"))]
    pub unsafe fn from_fd(fd: impl IntoRawFd) -> Result<Socket, glib::Error> {
        let fd = fd.into_raw_fd();
        let mut error = ptr::null_mut();
        let ret = ffi::g_socket_new_from_fd(fd, &mut error);
        if error.is_null() {
            Ok(from_glib_full(ret))
        } else {
            Err(from_glib_full(error))
        }
    }
    #[cfg(any(windows, feature = "dox"))]
    pub unsafe fn from_socket(socket: impl IntoRawSocket) -> Result<Socket, glib::Error> {
        let socket = socket.into_raw_socket();
        let mut error = ptr::null_mut();
        let ret = ffi::g_socket_new_from_fd(socket as i32, &mut error);
        if error.is_null() {
            Ok(from_glib_full(ret))
        } else {
            Err(from_glib_full(error))
        }
    }
}

#[cfg(any(unix, feature = "dox"))]
impl AsRawFd for Socket {
    fn as_raw_fd(&self) -> RawFd {
        unsafe { ffi::g_socket_get_fd(self.to_glib_none().0) as _ }
    }
}

#[cfg(any(windows, feature = "dox"))]
impl AsRawSocket for Socket {
    fn as_raw_socket(&self) -> RawSocket {
        unsafe { ffi::g_socket_get_fd(self.to_glib_none().0) as _ }
    }
}

pub trait SocketExtManual: Sized {
    /// Receive data (up to `size` bytes) from a socket. This is mainly used by
    /// connection-oriented sockets; it is identical to [`SocketExtManual::receive_from()`][crate::prelude::SocketExtManual::receive_from()]
    /// with `address` set to [`None`].
    ///
    /// For [`SocketType::Datagram`][crate::SocketType::Datagram] and [`SocketType::Seqpacket`][crate::SocketType::Seqpacket] sockets,
    /// [`SocketExtManual::receive()`][crate::prelude::SocketExtManual::receive()] will always read either 0 or 1 complete messages from
    /// the socket. If the received message is too large to fit in `buffer`, then
    /// the data beyond `size` bytes will be discarded, without any explicit
    /// indication that this has occurred.
    ///
    /// For [`SocketType::Stream`][crate::SocketType::Stream] sockets, [`SocketExtManual::receive()`][crate::prelude::SocketExtManual::receive()] can return any
    /// number of bytes, up to `size`. If more than `size` bytes have been
    /// received, the additional data will be returned in future calls to
    /// [`SocketExtManual::receive()`][crate::prelude::SocketExtManual::receive()].
    ///
    /// If the socket is in blocking mode the call will block until there
    /// is some data to receive, the connection is closed, or there is an
    /// error. If there is no data available and the socket is in
    /// non-blocking mode, a [`IOErrorEnum::WouldBlock`][crate::IOErrorEnum::WouldBlock] error will be
    /// returned. To be notified when data is available, wait for the
    /// [`glib::IOCondition::IN`][crate::glib::IOCondition::IN] condition.
    ///
    /// On error -1 is returned and `error` is set accordingly.
    /// ## `cancellable`
    /// a `GCancellable` or [`None`]
    ///
    /// # Returns
    ///
    /// Number of bytes read, or 0 if the connection was closed by
    /// the peer, or -1 on error
    ///
    /// ## `buffer`
    ///
    ///  a buffer to read data into (which should be at least `size` bytes long).
    #[doc(alias = "g_socket_receive")]
    fn receive<B: AsMut<[u8]>, C: IsA<Cancellable>>(
        &self,
        buffer: B,
        cancellable: Option<&C>,
    ) -> Result<usize, glib::Error>;
    /// Receive data (up to `size` bytes) from a socket.
    ///
    /// If `address` is non-[`None`] then `address` will be set equal to the
    /// source address of the received packet.
    /// `address` is owned by the caller.
    ///
    /// See [`SocketExtManual::receive()`][crate::prelude::SocketExtManual::receive()] for additional information.
    /// ## `cancellable`
    /// a `GCancellable` or [`None`]
    ///
    /// # Returns
    ///
    /// Number of bytes read, or 0 if the connection was closed by
    /// the peer, or -1 on error
    ///
    /// ## `address`
    /// a pointer to a [`SocketAddress`][crate::SocketAddress]
    ///  pointer, or [`None`]
    ///
    /// ## `buffer`
    ///
    ///  a buffer to read data into (which should be at least `size` bytes long).
    #[doc(alias = "g_socket_receive_from")]
    fn receive_from<B: AsMut<[u8]>, C: IsA<Cancellable>>(
        &self,
        buffer: B,
        cancellable: Option<&C>,
    ) -> Result<(usize, SocketAddress), glib::Error>;
    /// This behaves exactly the same as [`SocketExtManual::receive()`][crate::prelude::SocketExtManual::receive()], except that
    /// the choice of blocking or non-blocking behavior is determined by
    /// the `blocking` argument rather than by `self`'s properties.
    /// ## `blocking`
    /// whether to do blocking or non-blocking I/O
    /// ## `cancellable`
    /// a `GCancellable` or [`None`]
    ///
    /// # Returns
    ///
    /// Number of bytes read, or 0 if the connection was closed by
    /// the peer, or -1 on error
    ///
    /// ## `buffer`
    ///
    ///  a buffer to read data into (which should be at least `size` bytes long).
    #[doc(alias = "g_socket_receive_with_blocking")]
    fn receive_with_blocking<B: AsMut<[u8]>, C: IsA<Cancellable>>(
        &self,
        buffer: B,
        blocking: bool,
        cancellable: Option<&C>,
    ) -> Result<usize, glib::Error>;

    /// Tries to send `size` bytes from `buffer` on the socket. This is
    /// mainly used by connection-oriented sockets; it is identical to
    /// [`SocketExtManual::send_to()`][crate::prelude::SocketExtManual::send_to()] with `address` set to [`None`].
    ///
    /// If the socket is in blocking mode the call will block until there is
    /// space for the data in the socket queue. If there is no space available
    /// and the socket is in non-blocking mode a [`IOErrorEnum::WouldBlock`][crate::IOErrorEnum::WouldBlock] error
    /// will be returned. To be notified when space is available, wait for the
    /// [`glib::IOCondition::OUT`][crate::glib::IOCondition::OUT] condition. Note though that you may still receive
    /// [`IOErrorEnum::WouldBlock`][crate::IOErrorEnum::WouldBlock] from [`SocketExtManual::send()`][crate::prelude::SocketExtManual::send()] even if you were previously
    /// notified of a [`glib::IOCondition::OUT`][crate::glib::IOCondition::OUT] condition. (On Windows in particular, this is
    /// very common due to the way the underlying APIs work.)
    ///
    /// On error -1 is returned and `error` is set accordingly.
    /// ## `buffer`
    /// the buffer
    ///  containing the data to send.
    /// ## `cancellable`
    /// a `GCancellable` or [`None`]
    ///
    /// # Returns
    ///
    /// Number of bytes written (which may be less than `size`), or -1
    /// on error
    #[doc(alias = "g_socket_send")]
    fn send<B: AsRef<[u8]>, C: IsA<Cancellable>>(
        &self,
        buffer: B,
        cancellable: Option<&C>,
    ) -> Result<usize, glib::Error>;
    /// Tries to send `size` bytes from `buffer` to `address`. If `address` is
    /// [`None`] then the message is sent to the default receiver (set by
    /// [`SocketExt::connect()`][crate::prelude::SocketExt::connect()]).
    ///
    /// See [`SocketExtManual::send()`][crate::prelude::SocketExtManual::send()] for additional information.
    /// ## `address`
    /// a [`SocketAddress`][crate::SocketAddress], or [`None`]
    /// ## `buffer`
    /// the buffer
    ///  containing the data to send.
    /// ## `cancellable`
    /// a `GCancellable` or [`None`]
    ///
    /// # Returns
    ///
    /// Number of bytes written (which may be less than `size`), or -1
    /// on error
    #[doc(alias = "g_socket_send_to")]
    fn send_to<B: AsRef<[u8]>, P: IsA<SocketAddress>, C: IsA<Cancellable>>(
        &self,
        address: Option<&P>,
        buffer: B,
        cancellable: Option<&C>,
    ) -> Result<usize, glib::Error>;
    /// This behaves exactly the same as [`SocketExtManual::send()`][crate::prelude::SocketExtManual::send()], except that
    /// the choice of blocking or non-blocking behavior is determined by
    /// the `blocking` argument rather than by `self`'s properties.
    /// ## `buffer`
    /// the buffer
    ///  containing the data to send.
    /// ## `blocking`
    /// whether to do blocking or non-blocking I/O
    /// ## `cancellable`
    /// a `GCancellable` or [`None`]
    ///
    /// # Returns
    ///
    /// Number of bytes written (which may be less than `size`), or -1
    /// on error
    #[doc(alias = "g_socket_send_with_blocking")]
    fn send_with_blocking<B: AsRef<[u8]>, C: IsA<Cancellable>>(
        &self,
        buffer: B,
        blocking: bool,
        cancellable: Option<&C>,
    ) -> Result<usize, glib::Error>;

    /// Returns the underlying OS socket object. On unix this
    /// is a socket file descriptor, and on Windows this is
    /// a Winsock2 SOCKET handle. This may be useful for
    /// doing platform specific or otherwise unusual operations
    /// on the socket.
    ///
    /// # Returns
    ///
    /// the file descriptor of the socket.
    #[cfg(any(unix, feature = "dox"))]
    #[cfg_attr(feature = "dox", doc(cfg(unix)))]
    #[doc(alias = "get_fd")]
    #[doc(alias = "g_socket_get_fd")]
    fn fd<T: FromRawFd>(&self) -> T;

    #[cfg(any(windows, feature = "dox"))]
    #[cfg_attr(feature = "dox", doc(cfg(windows)))]
    #[doc(alias = "get_socket")]
    #[doc(alias = "g_socket_get_fd")]
    fn socket<T: FromRawSocket>(&self) -> T;

    #[doc(alias = "g_socket_create_source")]
    fn create_source<F, C>(
        &self,
        condition: glib::IOCondition,
        cancellable: Option<&C>,
        name: Option<&str>,
        priority: glib::Priority,
        func: F,
    ) -> glib::Source
    where
        F: FnMut(&Self, glib::IOCondition) -> glib::Continue + 'static,
        C: IsA<Cancellable>;

    fn create_source_future<C: IsA<Cancellable>>(
        &self,
        condition: glib::IOCondition,
        cancellable: Option<&C>,
        priority: glib::Priority,
    ) -> Pin<Box<dyn std::future::Future<Output = glib::IOCondition> + 'static>>;

    fn create_source_stream<C: IsA<Cancellable>>(
        &self,
        condition: glib::IOCondition,
        cancellable: Option<&C>,
        priority: glib::Priority,
    ) -> Pin<Box<dyn Stream<Item = glib::IOCondition> + 'static>>;
}

impl<O: IsA<Socket>> SocketExtManual for O {
    fn receive<B: AsMut<[u8]>, C: IsA<Cancellable>>(
        &self,
        mut buffer: B,
        cancellable: Option<&C>,
    ) -> Result<usize, glib::Error> {
        let cancellable = cancellable.map(|c| c.as_ref());
        let gcancellable = cancellable.to_glib_none();
        let buffer = buffer.as_mut();
        let buffer_ptr = buffer.as_mut_ptr();
        let count = buffer.len();
        unsafe {
            let mut error = ptr::null_mut();
            let ret = ffi::g_socket_receive(
                self.as_ref().to_glib_none().0,
                buffer_ptr,
                count,
                gcancellable.0,
                &mut error,
            );
            if error.is_null() {
                Ok(ret as usize)
            } else {
                Err(from_glib_full(error))
            }
        }
    }

    fn receive_from<B: AsMut<[u8]>, C: IsA<Cancellable>>(
        &self,
        mut buffer: B,
        cancellable: Option<&C>,
    ) -> Result<(usize, SocketAddress), glib::Error> {
        let cancellable = cancellable.map(|c| c.as_ref());
        let gcancellable = cancellable.to_glib_none();
        let buffer = buffer.as_mut();
        let buffer_ptr = buffer.as_mut_ptr();
        let count = buffer.len();
        unsafe {
            let mut error = ptr::null_mut();
            let mut addr_ptr = ptr::null_mut();

            let ret = ffi::g_socket_receive_from(
                self.as_ref().to_glib_none().0,
                &mut addr_ptr,
                buffer_ptr,
                count,
                gcancellable.0,
                &mut error,
            );
            if error.is_null() {
                Ok((ret as usize, from_glib_full(addr_ptr)))
            } else {
                Err(from_glib_full(error))
            }
        }
    }

    fn receive_with_blocking<B: AsMut<[u8]>, C: IsA<Cancellable>>(
        &self,
        mut buffer: B,
        blocking: bool,
        cancellable: Option<&C>,
    ) -> Result<usize, glib::Error> {
        let cancellable = cancellable.map(|c| c.as_ref());
        let gcancellable = cancellable.to_glib_none();
        let buffer = buffer.as_mut();
        let buffer_ptr = buffer.as_mut_ptr();
        let count = buffer.len();
        unsafe {
            let mut error = ptr::null_mut();
            let ret = ffi::g_socket_receive_with_blocking(
                self.as_ref().to_glib_none().0,
                buffer_ptr,
                count,
                blocking.into_glib(),
                gcancellable.0,
                &mut error,
            );
            if error.is_null() {
                Ok(ret as usize)
            } else {
                Err(from_glib_full(error))
            }
        }
    }

    fn send<B: AsRef<[u8]>, C: IsA<Cancellable>>(
        &self,
        buffer: B,
        cancellable: Option<&C>,
    ) -> Result<usize, glib::Error> {
        let cancellable = cancellable.map(|c| c.as_ref());
        let gcancellable = cancellable.to_glib_none();
        let (count, buffer_ptr) = {
            let slice = buffer.as_ref();
            (slice.len(), slice.as_ptr())
        };
        unsafe {
            let mut error = ptr::null_mut();
            let ret = ffi::g_socket_send(
                self.as_ref().to_glib_none().0,
                mut_override(buffer_ptr),
                count,
                gcancellable.0,
                &mut error,
            );
            if error.is_null() {
                Ok(ret as usize)
            } else {
                Err(from_glib_full(error))
            }
        }
    }

    fn send_to<B: AsRef<[u8]>, P: IsA<SocketAddress>, C: IsA<Cancellable>>(
        &self,
        address: Option<&P>,
        buffer: B,
        cancellable: Option<&C>,
    ) -> Result<usize, glib::Error> {
        let cancellable = cancellable.map(|c| c.as_ref());
        let gcancellable = cancellable.to_glib_none();
        let (count, buffer_ptr) = {
            let slice = buffer.as_ref();
            (slice.len(), slice.as_ptr())
        };
        unsafe {
            let mut error = ptr::null_mut();

            let ret = ffi::g_socket_send_to(
                self.as_ref().to_glib_none().0,
                address.map(|p| p.as_ref()).to_glib_none().0,
                mut_override(buffer_ptr),
                count,
                gcancellable.0,
                &mut error,
            );
            if error.is_null() {
                Ok(ret as usize)
            } else {
                Err(from_glib_full(error))
            }
        }
    }

    fn send_with_blocking<B: AsRef<[u8]>, C: IsA<Cancellable>>(
        &self,
        buffer: B,
        blocking: bool,
        cancellable: Option<&C>,
    ) -> Result<usize, glib::Error> {
        let cancellable = cancellable.map(|c| c.as_ref());
        let gcancellable = cancellable.to_glib_none();
        let (count, buffer_ptr) = {
            let slice = buffer.as_ref();
            (slice.len(), slice.as_ptr())
        };
        unsafe {
            let mut error = ptr::null_mut();
            let ret = ffi::g_socket_send_with_blocking(
                self.as_ref().to_glib_none().0,
                mut_override(buffer_ptr),
                count,
                blocking.into_glib(),
                gcancellable.0,
                &mut error,
            );
            if error.is_null() {
                Ok(ret as usize)
            } else {
                Err(from_glib_full(error))
            }
        }
    }

    #[cfg(any(unix, feature = "dox"))]
    #[cfg_attr(feature = "dox", doc(cfg(unix)))]
    fn fd<T: FromRawFd>(&self) -> T {
        unsafe { FromRawFd::from_raw_fd(ffi::g_socket_get_fd(self.as_ref().to_glib_none().0)) }
    }

    #[cfg(any(windows, feature = "dox"))]
    #[cfg_attr(feature = "dox", doc(cfg(windows)))]
    fn socket<T: FromRawSocket>(&self) -> T {
        unsafe {
            FromRawSocket::from_raw_socket(ffi::g_socket_get_fd(self.as_ref().to_glib_none().0) as _)
        }
    }

    fn create_source<F, C>(
        &self,
        condition: glib::IOCondition,
        cancellable: Option<&C>,
        name: Option<&str>,
        priority: glib::Priority,
        func: F,
    ) -> glib::Source
    where
        F: FnMut(&Self, glib::IOCondition) -> glib::Continue + 'static,
        C: IsA<Cancellable>,
    {
        unsafe extern "C" fn trampoline<
            O: IsA<Socket>,
            F: FnMut(&O, glib::IOCondition) -> glib::Continue + 'static,
        >(
            socket: *mut ffi::GSocket,
            condition: glib::ffi::GIOCondition,
            func: glib::ffi::gpointer,
        ) -> glib::ffi::gboolean {
            let func: &RefCell<F> = &*(func as *const RefCell<F>);
            let mut func = func.borrow_mut();
            (*func)(
                Socket::from_glib_borrow(socket).unsafe_cast_ref(),
                from_glib(condition),
            )
            .into_glib()
        }
        unsafe extern "C" fn destroy_closure<O, F>(ptr: glib::ffi::gpointer) {
            let _ = Box::<RefCell<F>>::from_raw(ptr as *mut _);
        }
        let cancellable = cancellable.map(|c| c.as_ref());
        let gcancellable = cancellable.to_glib_none();
        unsafe {
            let source = ffi::g_socket_create_source(
                self.as_ref().to_glib_none().0,
                condition.into_glib(),
                gcancellable.0,
            );
            let trampoline = trampoline::<O, F> as glib::ffi::gpointer;
            glib::ffi::g_source_set_callback(
                source,
                Some(transmute::<
                    _,
                    unsafe extern "C" fn(glib::ffi::gpointer) -> glib::ffi::gboolean,
                >(trampoline)),
                Box::into_raw(Box::new(RefCell::new(func))) as glib::ffi::gpointer,
                Some(destroy_closure::<O, F>),
            );
            glib::ffi::g_source_set_priority(source, priority.into_glib());

            if let Some(name) = name {
                glib::ffi::g_source_set_name(source, name.to_glib_none().0);
            }

            from_glib_full(source)
        }
    }

    fn create_source_future<C: IsA<Cancellable>>(
        &self,
        condition: glib::IOCondition,
        cancellable: Option<&C>,
        priority: glib::Priority,
    ) -> Pin<Box<dyn std::future::Future<Output = glib::IOCondition> + 'static>> {
        let cancellable: Option<Cancellable> = cancellable.map(|c| c.as_ref()).cloned();

        let obj = self.clone();
        Box::pin(glib::SourceFuture::new(move |send| {
            let mut send = Some(send);
            obj.create_source(
                condition,
                cancellable.as_ref(),
                None,
                priority,
                move |_, condition| {
                    let _ = send.take().unwrap().send(condition);
                    glib::Continue(false)
                },
            )
        }))
    }

    fn create_source_stream<C: IsA<Cancellable>>(
        &self,
        condition: glib::IOCondition,
        cancellable: Option<&C>,
        priority: glib::Priority,
    ) -> Pin<Box<dyn Stream<Item = glib::IOCondition> + 'static>> {
        let cancellable: Option<Cancellable> = cancellable.map(|c| c.as_ref()).cloned();

        let obj = self.clone();
        Box::pin(glib::SourceStream::new(move |send| {
            let send = Some(send);
            obj.create_source(
                condition,
                cancellable.as_ref(),
                None,
                priority,
                move |_, condition| {
                    if send.as_ref().unwrap().unbounded_send(condition).is_err() {
                        glib::Continue(false)
                    } else {
                        glib::Continue(true)
                    }
                },
            )
        }))
    }
}

#[cfg(all(not(unix), feature = "dox"))]
pub trait IntoRawFd {
    fn into_raw_fd(self) -> c_int;
}

#[cfg(all(not(unix), feature = "dox"))]
pub trait FromRawFd {
    unsafe fn from_raw_fd(fd: c_int) -> Self;
}

#[cfg(all(not(unix), feature = "dox"))]
pub trait AsRawFd {
    fn as_raw_fd(&self) -> RawFd;
}

#[cfg(all(not(unix), feature = "dox"))]
pub type RawFd = c_int;

#[cfg(all(not(windows), feature = "dox"))]
pub trait IntoRawSocket {
    fn into_raw_socket(self) -> u64;
}

#[cfg(all(not(windows), feature = "dox"))]
pub trait FromRawSocket {
    unsafe fn from_raw_socket(sock: u64) -> Self;
}

#[cfg(all(not(windows), feature = "dox"))]
pub trait AsRawSocket {
    fn as_raw_socket(&self) -> RawSocket;
}

#[cfg(all(not(windows), feature = "dox"))]
pub type RawSocket = *mut c_void;