// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

//! UDP (User Datagram Protocol) network connections.
//!
//! This module contains the ability to open a UDP stream to a socket address.
//! The destination and binding addresses can either be an IPv4 or IPv6
//! address. There is no corresponding notion of a server because UDP is a
//! datagram protocol.

use clone::Clone;
use io::net::ip::{SocketAddr, IpAddr};
use io::{Reader, Writer, IoResult, IoError};
use kinds::Send;
use boxed::Box;
use option::Option;
use result::{Ok, Err};
use rt::rtio::{RtioSocket, RtioUdpSocket, IoFactory, LocalIo};
use rt::rtio;

/// A User Datagram Protocol socket.
///
/// This is an implementation of a bound UDP socket. This supports both IPv4 and
/// IPv6 addresses, and there is no corresponding notion of a server because UDP
/// is a datagram protocol.
///
/// # Example
///
/// ```rust,no_run
/// # #![allow(unused_must_use)]
/// use std::io::net::udp::UdpSocket;
/// use std::io::net::ip::{Ipv4Addr, SocketAddr};
///
/// let addr = SocketAddr { ip: Ipv4Addr(127, 0, 0, 1), port: 34254 };
/// let mut socket = match UdpSocket::bind(addr) {
///     Ok(s) => s,
///     Err(e) => fail!("couldn't bind socket: {}", e),
/// };
///
/// let mut buf = [0, ..10];
/// match socket.recv_from(buf) {
///     Ok((amt, src)) => {
///         // Send a reply to the socket we received data from
///         let buf = buf.mut_slice_to(amt);
///         buf.reverse();
///         socket.send_to(buf, src);
///     }
///     Err(e) => println!("couldn't receive a datagram: {}", e)
/// }
/// drop(socket); // close the socket
/// ```
pub struct UdpSocket {
    obj: Box<RtioUdpSocket + Send>,
}

impl UdpSocket {
    /// Creates a UDP socket from the given socket address.
    pub fn bind(addr: SocketAddr) -> IoResult<UdpSocket> {
        let SocketAddr { ip, port } = addr;
        LocalIo::maybe_raise(|io| {
            let addr = rtio::SocketAddr { ip: super::to_rtio(ip), port: port };
            io.udp_bind(addr).map(|s| UdpSocket { obj: s })
        }).map_err(IoError::from_rtio_error)
    }

    /// Receives data from the socket. On success, returns the number of bytes
    /// read and the address from whence the data came.
    pub fn recv_from(&mut self, buf: &mut [u8])
                    -> IoResult<(uint, SocketAddr)> {
        match self.obj.recv_from(buf) {
            Ok((amt, rtio::SocketAddr { ip, port })) => {
                Ok((amt, SocketAddr { ip: super::from_rtio(ip), port: port }))
            }
            Err(e) => Err(IoError::from_rtio_error(e)),
        }
    }

    #[allow(missing_doc)]
    #[deprecated = "renamed to `recv_from`"]
    pub fn recvfrom(&mut self, buf: &mut [u8])
                    -> IoResult<(uint, SocketAddr)> {
        self.recv_from(buf)
    }

    /// Sends data on the socket to the given address. Returns nothing on
    /// success.
    pub fn send_to(&mut self, buf: &[u8], dst: SocketAddr) -> IoResult<()> {
        self.obj.send_to(buf, rtio::SocketAddr {
            ip: super::to_rtio(dst.ip),
            port: dst.port,
        }).map_err(IoError::from_rtio_error)
    }

    #[allow(missing_doc)]
    #[deprecated = "renamed to `send_to`"]
    pub fn sendto(&mut self, buf: &[u8], dst: SocketAddr) -> IoResult<()> {
        self.send_to(buf, dst)
    }

    /// Creates a `UdpStream`, which allows use of the `Reader` and `Writer`
    /// traits to receive and send data from the same address. This transfers
    /// ownership of the socket to the stream.
    ///
    /// Note that this call does not perform any actual network communication,
    /// because UDP is a datagram protocol.
    pub fn connect(self, other: SocketAddr) -> UdpStream {
        UdpStream {
            socket: self,
            connected_to: other,
        }
    }

    /// Returns the socket address that this socket was created from.
    pub fn socket_name(&mut self) -> IoResult<SocketAddr> {
        match self.obj.socket_name() {
            Ok(a) => Ok(SocketAddr { ip: super::from_rtio(a.ip), port: a.port }),
            Err(e) => Err(IoError::from_rtio_error(e))
        }
    }

    /// Joins a multicast IP address (becomes a member of it)
    #[experimental]
    pub fn join_multicast(&mut self, multi: IpAddr) -> IoResult<()> {
        let e = self.obj.join_multicast(super::to_rtio(multi));
        e.map_err(IoError::from_rtio_error)
    }

    /// Leaves a multicast IP address (drops membership from it)
    #[experimental]
    pub fn leave_multicast(&mut self, multi: IpAddr) -> IoResult<()> {
        let e = self.obj.leave_multicast(super::to_rtio(multi));
        e.map_err(IoError::from_rtio_error)
    }

    /// Set the multicast loop flag to the specified value
    ///
    /// This lets multicast packets loop back to local sockets (if enabled)
    #[experimental]
    pub fn set_multicast_loop(&mut self, on: bool) -> IoResult<()> {
        if on {
            self.obj.loop_multicast_locally()
        } else {
            self.obj.dont_loop_multicast_locally()
        }.map_err(IoError::from_rtio_error)
    }

    /// Sets the multicast TTL
    #[experimental]
    pub fn set_multicast_ttl(&mut self, ttl: int) -> IoResult<()> {
        self.obj.multicast_time_to_live(ttl).map_err(IoError::from_rtio_error)
    }

    /// Sets this socket's TTL
    #[experimental]
    pub fn set_ttl(&mut self, ttl: int) -> IoResult<()> {
        self.obj.time_to_live(ttl).map_err(IoError::from_rtio_error)
    }

    /// Sets the broadcast flag on or off
    #[experimental]
    pub fn set_broadcast(&mut self, broadcast: bool) -> IoResult<()> {
        if broadcast {
            self.obj.hear_broadcasts()
        } else {
            self.obj.ignore_broadcasts()
        }.map_err(IoError::from_rtio_error)
    }

    /// Sets the broadcast flag on or off
    #[deprecated="renamed to `set_broadcast`"]
    pub fn set_broadast(&mut self, broadcast: bool) -> IoResult<()> {
        self.set_broadcast(broadcast)
    }

    /// Sets the read/write timeout for this socket.
    ///
    /// For more information, see `TcpStream::set_timeout`
    #[experimental = "the timeout argument may change in type and value"]
    pub fn set_timeout(&mut self, timeout_ms: Option<u64>) {
        self.obj.set_timeout(timeout_ms)
    }

    /// Sets the read timeout for this socket.
    ///
    /// For more information, see `TcpStream::set_timeout`
    #[experimental = "the timeout argument may change in type and value"]
    pub fn set_read_timeout(&mut self, timeout_ms: Option<u64>) {
        self.obj.set_read_timeout(timeout_ms)
    }

    /// Sets the write timeout for this socket.
    ///
    /// For more information, see `TcpStream::set_timeout`
    #[experimental = "the timeout argument may change in type and value"]
    pub fn set_write_timeout(&mut self, timeout_ms: Option<u64>) {
        self.obj.set_write_timeout(timeout_ms)
    }
}

impl Clone for UdpSocket {
    /// Creates a new handle to this UDP socket, allowing for simultaneous
    /// reads and writes of the socket.
    ///
    /// The underlying UDP socket will not be closed until all handles to the
    /// socket have been deallocated. Two concurrent reads will not receive
    /// the same data. Instead, the first read will receive the first packet
    /// received, and the second read will receive the second packet.
    fn clone(&self) -> UdpSocket {
        UdpSocket {
            obj: self.obj.clone(),
        }
    }
}

/// A type that allows convenient usage of a UDP stream connected to one
/// address via the `Reader` and `Writer` traits.
pub struct UdpStream {
    socket: UdpSocket,
    connected_to: SocketAddr
}

impl UdpStream {
    /// Allows access to the underlying UDP socket owned by this stream. This
    /// is useful to, for example, use the socket to send data to hosts other
    /// than the one that this stream is connected to.
    pub fn as_socket<T>(&mut self, f: |&mut UdpSocket| -> T) -> T {
        f(&mut self.socket)
    }

    /// Consumes this UDP stream and returns out the underlying socket.
    pub fn disconnect(self) -> UdpSocket {
        self.socket
    }
}

impl Reader for UdpStream {
    fn read(&mut self, buf: &mut [u8]) -> IoResult<uint> {
        let peer = self.connected_to;
        self.as_socket(|sock| {
            match sock.recv_from(buf) {
                Ok((_nread, src)) if src != peer => Ok(0),
                Ok((nread, _src)) => Ok(nread),
                Err(e) => Err(e),
            }
        })
    }
}

impl Writer for UdpStream {
    fn write(&mut self, buf: &[u8]) -> IoResult<()> {
        let connected_to = self.connected_to;
        self.as_socket(|sock| sock.send_to(buf, connected_to))
    }
}

#[cfg(test)]
#[allow(experimental)]
mod test {
    use super::*;
    use io::net::ip::{SocketAddr};

    // FIXME #11530 this fails on android because tests are run as root
    iotest!(fn bind_error() {
        let addr = SocketAddr { ip: Ipv4Addr(0, 0, 0, 0), port: 1 };
        match UdpSocket::bind(addr) {
            Ok(..) => fail!(),
            Err(e) => assert_eq!(e.kind, PermissionDenied),
        }
    } #[ignore(cfg(windows))] #[ignore(cfg(target_os = "android"))])

    iotest!(fn socket_smoke_test_ip4() {
        let server_ip = next_test_ip4();
        let client_ip = next_test_ip4();
        let (tx1, rx1) = channel();
        let (tx2, rx2) = channel();

        spawn(proc() {
            match UdpSocket::bind(client_ip) {
                Ok(ref mut client) => {
                    rx1.recv();
                    client.send_to([99], server_ip).unwrap()
                }
                Err(..) => fail!()
            }
            tx2.send(());
        });

        match UdpSocket::bind(server_ip) {
            Ok(ref mut server) => {
                tx1.send(());
                let mut buf = [0];
                match server.recv_from(buf) {
                    Ok((nread, src)) => {
                        assert_eq!(nread, 1);
                        assert_eq!(buf[0], 99);
                        assert_eq!(src, client_ip);
                    }
                    Err(..) => fail!()
                }
            }
            Err(..) => fail!()
        }
        rx2.recv();
    })

    iotest!(fn socket_smoke_test_ip6() {
        let server_ip = next_test_ip6();
        let client_ip = next_test_ip6();
        let (tx, rx) = channel::<()>();

        spawn(proc() {
            match UdpSocket::bind(client_ip) {
                Ok(ref mut client) => {
                    rx.recv();
                    client.send_to([99], server_ip).unwrap()
                }
                Err(..) => fail!()
            }
        });

        match UdpSocket::bind(server_ip) {
            Ok(ref mut server) => {
                tx.send(());
                let mut buf = [0];
                match server.recv_from(buf) {
                    Ok((nread, src)) => {
                        assert_eq!(nread, 1);
                        assert_eq!(buf[0], 99);
                        assert_eq!(src, client_ip);
                    }
                    Err(..) => fail!()
                }
            }
            Err(..) => fail!()
        }
    })

    iotest!(fn stream_smoke_test_ip4() {
        let server_ip = next_test_ip4();
        let client_ip = next_test_ip4();
        let (tx1, rx1) = channel();
        let (tx2, rx2) = channel();

        spawn(proc() {
            match UdpSocket::bind(client_ip) {
                Ok(client) => {
                    let client = box client;
                    let mut stream = client.connect(server_ip);
                    rx1.recv();
                    stream.write([99]).unwrap();
                }
                Err(..) => fail!()
            }
            tx2.send(());
        });

        match UdpSocket::bind(server_ip) {
            Ok(server) => {
                let server = box server;
                let mut stream = server.connect(client_ip);
                tx1.send(());
                let mut buf = [0];
                match stream.read(buf) {
                    Ok(nread) => {
                        assert_eq!(nread, 1);
                        assert_eq!(buf[0], 99);
                    }
                    Err(..) => fail!()
                }
            }
            Err(..) => fail!()
        }
        rx2.recv();
    })

    iotest!(fn stream_smoke_test_ip6() {
        let server_ip = next_test_ip6();
        let client_ip = next_test_ip6();
        let (tx1, rx1) = channel();
        let (tx2, rx2) = channel();

        spawn(proc() {
            match UdpSocket::bind(client_ip) {
                Ok(client) => {
                    let client = box client;
                    let mut stream = client.connect(server_ip);
                    rx1.recv();
                    stream.write([99]).unwrap();
                }
                Err(..) => fail!()
            }
            tx2.send(());
        });

        match UdpSocket::bind(server_ip) {
            Ok(server) => {
                let server = box server;
                let mut stream = server.connect(client_ip);
                tx1.send(());
                let mut buf = [0];
                match stream.read(buf) {
                    Ok(nread) => {
                        assert_eq!(nread, 1);
                        assert_eq!(buf[0], 99);
                    }
                    Err(..) => fail!()
                }
            }
            Err(..) => fail!()
        }
        rx2.recv();
    })

    pub fn socket_name(addr: SocketAddr) {
        let server = UdpSocket::bind(addr);

        assert!(server.is_ok());
        let mut server = server.unwrap();

        // Make sure socket_name gives
        // us the socket we binded to.
        let so_name = server.socket_name();
        assert!(so_name.is_ok());
        assert_eq!(addr, so_name.unwrap());
    }

    iotest!(fn socket_name_ip4() {
        socket_name(next_test_ip4());
    })

    iotest!(fn socket_name_ip6() {
        socket_name(next_test_ip6());
    })

    iotest!(fn udp_clone_smoke() {
        let addr1 = next_test_ip4();
        let addr2 = next_test_ip4();
        let mut sock1 = UdpSocket::bind(addr1).unwrap();
        let sock2 = UdpSocket::bind(addr2).unwrap();

        spawn(proc() {
            let mut sock2 = sock2;
            let mut buf = [0, 0];
            assert_eq!(sock2.recv_from(buf), Ok((1, addr1)));
            assert_eq!(buf[0], 1);
            sock2.send_to([2], addr1).unwrap();
        });

        let sock3 = sock1.clone();

        let (tx1, rx1) = channel();
        let (tx2, rx2) = channel();
        spawn(proc() {
            let mut sock3 = sock3;
            rx1.recv();
            sock3.send_to([1], addr2).unwrap();
            tx2.send(());
        });
        tx1.send(());
        let mut buf = [0, 0];
        assert_eq!(sock1.recv_from(buf), Ok((1, addr2)));
        rx2.recv();
    })

    iotest!(fn udp_clone_two_read() {
        let addr1 = next_test_ip4();
        let addr2 = next_test_ip4();
        let mut sock1 = UdpSocket::bind(addr1).unwrap();
        let sock2 = UdpSocket::bind(addr2).unwrap();
        let (tx1, rx) = channel();
        let tx2 = tx1.clone();

        spawn(proc() {
            let mut sock2 = sock2;
            sock2.send_to([1], addr1).unwrap();
            rx.recv();
            sock2.send_to([2], addr1).unwrap();
            rx.recv();
        });

        let sock3 = sock1.clone();

        let (done, rx) = channel();
        spawn(proc() {
            let mut sock3 = sock3;
            let mut buf = [0, 0];
            sock3.recv_from(buf).unwrap();
            tx2.send(());
            done.send(());
        });
        let mut buf = [0, 0];
        sock1.recv_from(buf).unwrap();
        tx1.send(());

        rx.recv();
    })

    iotest!(fn udp_clone_two_write() {
        let addr1 = next_test_ip4();
        let addr2 = next_test_ip4();
        let mut sock1 = UdpSocket::bind(addr1).unwrap();
        let sock2 = UdpSocket::bind(addr2).unwrap();

        let (tx, rx) = channel();
        let (serv_tx, serv_rx) = channel();

        spawn(proc() {
            let mut sock2 = sock2;
            let mut buf = [0, 1];

            rx.recv();
            match sock2.recv_from(buf) {
                Ok(..) => {}
                Err(e) => fail!("failed receive: {}", e),
            }
            serv_tx.send(());
        });

        let sock3 = sock1.clone();

        let (done, rx) = channel();
        let tx2 = tx.clone();
        spawn(proc() {
            let mut sock3 = sock3;
            match sock3.send_to([1], addr2) {
                Ok(..) => { let _ = tx2.send_opt(()); }
                Err(..) => {}
            }
            done.send(());
        });
        match sock1.send_to([2], addr2) {
            Ok(..) => { let _ = tx.send_opt(()); }
            Err(..) => {}
        }
        drop(tx);

        rx.recv();
        serv_rx.recv();
    })

    iotest!(fn recv_from_timeout() {
        let addr1 = next_test_ip4();
        let addr2 = next_test_ip4();
        let mut a = UdpSocket::bind(addr1).unwrap();

        let (tx, rx) = channel();
        let (tx2, rx2) = channel();
        spawn(proc() {
            let mut a = UdpSocket::bind(addr2).unwrap();
            assert_eq!(a.recv_from([0]), Ok((1, addr1)));
            assert_eq!(a.send_to([0], addr1), Ok(()));
            rx.recv();
            assert_eq!(a.send_to([0], addr1), Ok(()));

            tx2.send(());
        });

        // Make sure that reads time out, but writes can continue
        a.set_read_timeout(Some(20));
        assert_eq!(a.recv_from([0]).err().unwrap().kind, TimedOut);
        assert_eq!(a.recv_from([0]).err().unwrap().kind, TimedOut);
        assert_eq!(a.send_to([0], addr2), Ok(()));

        // Cloned handles should be able to block
        let mut a2 = a.clone();
        assert_eq!(a2.recv_from([0]), Ok((1, addr2)));

        // Clearing the timeout should allow for receiving
        a.set_timeout(None);
        tx.send(());
        assert_eq!(a2.recv_from([0]), Ok((1, addr2)));

        // Make sure the child didn't die
        rx2.recv();
    })

    iotest!(fn send_to_timeout() {
        let addr1 = next_test_ip4();
        let addr2 = next_test_ip4();
        let mut a = UdpSocket::bind(addr1).unwrap();
        let _b = UdpSocket::bind(addr2).unwrap();

        a.set_write_timeout(Some(1000));
        for _ in range(0u, 100) {
            match a.send_to([0, ..4*1024], addr2) {
                Ok(()) | Err(IoError { kind: ShortWrite(..), .. }) => {},
                Err(IoError { kind: TimedOut, .. }) => break,
                Err(e) => fail!("other error: {}", e),
            }
        }
    })
}