// Copyright 2014 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.

use std::c_str::CString;
use std::cast;
use std::io;
use std::libc;
use std::mem;
use std::rt::rtio;
use std::sync::arc::UnsafeArc;
use std::unstable::intrinsics;

use super::{IoResult, retry};
use super::file::{keep_going, fd_t};

fn unix_socket(ty: libc::c_int) -> IoResult<fd_t> {
    match unsafe { libc::socket(libc::AF_UNIX, ty, 0) } {
        -1 => Err(super::last_error()),
        fd => Ok(fd)
    }
}

fn addr_to_sockaddr_un(addr: &CString) -> IoResult<(libc::sockaddr_storage, uint)> {
    // the sun_path length is limited to SUN_LEN (with null)
    assert!(mem::size_of::<libc::sockaddr_storage>() >=
            mem::size_of::<libc::sockaddr_un>());
    let mut storage: libc::sockaddr_storage = unsafe { intrinsics::init() };
    let s: &mut libc::sockaddr_un = unsafe { cast::transmute(&mut storage) };

    let len = addr.len();
    if len > s.sun_path.len() - 1 {
        return Err(io::IoError {
            kind: io::InvalidInput,
            desc: "path must be smaller than SUN_LEN",
            detail: None,
        })
    }
    s.sun_family = libc::AF_UNIX as libc::sa_family_t;
    for (slot, value) in s.sun_path.mut_iter().zip(addr.iter()) {
        *slot = value;
    }

    // count the null terminator
    let len = mem::size_of::<libc::sa_family_t>() + len + 1;
    return Ok((storage, len));
}

fn sockaddr_to_unix(storage: &libc::sockaddr_storage,
                    len: uint) -> IoResult<CString> {
    match storage.ss_family as libc::c_int {
        libc::AF_UNIX => {
            assert!(len as uint <= mem::size_of::<libc::sockaddr_un>());
            let storage: &libc::sockaddr_un = unsafe {
                cast::transmute(storage)
            };
            unsafe {
                Ok(CString::new(storage.sun_path.as_ptr(), false).clone())
            }
        }
        _ => Err(io::standard_error(io::InvalidInput))
    }
}

struct Inner {
    fd: fd_t,
}

impl Drop for Inner {
    fn drop(&mut self) { unsafe { let _ = libc::close(self.fd); } }
}

fn connect(addr: &CString, ty: libc::c_int) -> IoResult<Inner> {
    let (addr, len) = try!(addr_to_sockaddr_un(addr));
    let inner = Inner { fd: try!(unix_socket(ty)) };
    let addrp = &addr as *libc::sockaddr_storage;
    match retry(|| unsafe {
        libc::connect(inner.fd, addrp as *libc::sockaddr,
                      len as libc::socklen_t)
    }) {
        -1 => Err(super::last_error()),
        _  => Ok(inner)
    }
}

fn bind(addr: &CString, ty: libc::c_int) -> IoResult<Inner> {
    let (addr, len) = try!(addr_to_sockaddr_un(addr));
    let inner = Inner { fd: try!(unix_socket(ty)) };
    let addrp = &addr as *libc::sockaddr_storage;
    match unsafe {
        libc::bind(inner.fd, addrp as *libc::sockaddr, len as libc::socklen_t)
    } {
        -1 => Err(super::last_error()),
        _  => Ok(inner)
    }
}

////////////////////////////////////////////////////////////////////////////////
// Unix Streams
////////////////////////////////////////////////////////////////////////////////

pub struct UnixStream {
    priv inner: UnsafeArc<Inner>,
}

impl UnixStream {
    pub fn connect(addr: &CString) -> IoResult<UnixStream> {
        connect(addr, libc::SOCK_STREAM).map(|inner| {
            UnixStream { inner: UnsafeArc::new(inner) }
        })
    }

    fn fd(&self) -> fd_t { unsafe { (*self.inner.get()).fd } }
}

impl rtio::RtioPipe for UnixStream {
    fn read(&mut self, buf: &mut [u8]) -> IoResult<uint> {
        let ret = retry(|| unsafe {
            libc::recv(self.fd(),
                       buf.as_ptr() as *mut libc::c_void,
                       buf.len() as libc::size_t,
                       0) as libc::c_int
        });
        if ret == 0 {
            Err(io::standard_error(io::EndOfFile))
        } else if ret < 0 {
            Err(super::last_error())
        } else {
            Ok(ret as uint)
        }
    }

    fn write(&mut self, buf: &[u8]) -> IoResult<()> {
        let ret = keep_going(buf, |buf, len| unsafe {
            libc::send(self.fd(),
                       buf as *mut libc::c_void,
                       len as libc::size_t,
                       0) as i64
        });
        if ret < 0 {
            Err(super::last_error())
        } else {
            Ok(())
        }
    }

    fn clone(&self) -> ~rtio::RtioPipe {
        ~UnixStream { inner: self.inner.clone() } as ~rtio::RtioPipe
    }
}

////////////////////////////////////////////////////////////////////////////////
// Unix Datagram
////////////////////////////////////////////////////////////////////////////////

pub struct UnixDatagram {
    priv inner: UnsafeArc<Inner>,
}

impl UnixDatagram {
    pub fn connect(addr: &CString) -> IoResult<UnixDatagram> {
        connect(addr, libc::SOCK_DGRAM).map(|inner| {
            UnixDatagram { inner: UnsafeArc::new(inner) }
        })
    }

    pub fn bind(addr: &CString) -> IoResult<UnixDatagram> {
        bind(addr, libc::SOCK_DGRAM).map(|inner| {
            UnixDatagram { inner: UnsafeArc::new(inner) }
        })
    }

    fn fd(&self) -> fd_t { unsafe { (*self.inner.get()).fd } }

    pub fn recvfrom(&mut self, buf: &mut [u8]) -> IoResult<(uint, CString)> {
        let mut storage: libc::sockaddr_storage = unsafe { intrinsics::init() };
        let storagep = &mut storage as *mut libc::sockaddr_storage;
        let mut addrlen: libc::socklen_t =
                mem::size_of::<libc::sockaddr_storage>() as libc::socklen_t;
        let ret = retry(|| unsafe {
            libc::recvfrom(self.fd(),
                           buf.as_ptr() as *mut libc::c_void,
                           buf.len() as libc::size_t,
                           0,
                           storagep as *mut libc::sockaddr,
                           &mut addrlen) as libc::c_int
        });
        if ret < 0 { return Err(super::last_error()) }
        sockaddr_to_unix(&storage, addrlen as uint).and_then(|addr| {
            Ok((ret as uint, addr))
        })
    }

    pub fn sendto(&mut self, buf: &[u8], dst: &CString) -> IoResult<()> {
        let (dst, len) = try!(addr_to_sockaddr_un(dst));
        let dstp = &dst as *libc::sockaddr_storage;
        let ret = retry(|| unsafe {
            libc::sendto(self.fd(),
                         buf.as_ptr() as *libc::c_void,
                         buf.len() as libc::size_t,
                         0,
                         dstp as *libc::sockaddr,
                         len as libc::socklen_t) as libc::c_int
        });
        match ret {
            -1 => Err(super::last_error()),
            n if n as uint != buf.len() => {
                Err(io::IoError {
                    kind: io::OtherIoError,
                    desc: "couldn't send entire packet at once",
                    detail: None,
                })
            }
            _ => Ok(())
        }
    }

    pub fn clone(&mut self) -> UnixDatagram {
        UnixDatagram { inner: self.inner.clone() }
    }
}

////////////////////////////////////////////////////////////////////////////////
// Unix Listener
////////////////////////////////////////////////////////////////////////////////

pub struct UnixListener {
    priv inner: Inner,
}

impl UnixListener {
    pub fn bind(addr: &CString) -> IoResult<UnixListener> {
        bind(addr, libc::SOCK_STREAM).map(|fd| UnixListener { inner: fd })
    }

    fn fd(&self) -> fd_t { self.inner.fd }

    pub fn native_listen(self, backlog: int) -> IoResult<UnixAcceptor> {
        match unsafe { libc::listen(self.fd(), backlog as libc::c_int) } {
            -1 => Err(super::last_error()),
            _ => Ok(UnixAcceptor { listener: self })
        }
    }
}

impl rtio::RtioUnixListener for UnixListener {
    fn listen(~self) -> IoResult<~rtio::RtioUnixAcceptor> {
        self.native_listen(128).map(|a| ~a as ~rtio::RtioUnixAcceptor)
    }
}

pub struct UnixAcceptor {
    priv listener: UnixListener,
}

impl UnixAcceptor {
    fn fd(&self) -> fd_t { self.listener.fd() }

    pub fn native_accept(&mut self) -> IoResult<UnixStream> {
        let mut storage: libc::sockaddr_storage = unsafe { intrinsics::init() };
        let storagep = &mut storage as *mut libc::sockaddr_storage;
        let size = mem::size_of::<libc::sockaddr_storage>();
        let mut size = size as libc::socklen_t;
        match retry(|| unsafe {
            libc::accept(self.fd(),
                         storagep as *mut libc::sockaddr,
                         &mut size as *mut libc::socklen_t) as libc::c_int
        }) {
            -1 => Err(super::last_error()),
            fd => Ok(UnixStream { inner: UnsafeArc::new(Inner { fd: fd }) })
        }
    }
}

impl rtio::RtioUnixAcceptor for UnixAcceptor {
    fn accept(&mut self) -> IoResult<~rtio::RtioPipe> {
        self.native_accept().map(|s| ~s as ~rtio::RtioPipe)
    }
}
