////////////////////////////////////////////////////////////////////////////////
//                                                                            //
//  Copyright (c) 2015 Mohd Tarmizi Mohd Affandi                              //
//                                                                            //
//  Permission is hereby granted, free of charge, to any person obtaining a   //
//  copy of this software and associated documentation files (the             //
//  "Software"), to deal in the Software without restriction, including       //
//  without limitation the rights to use, copy, modify, merge, publish,       //
//  distribute, sublicense, and/or sell copies of the Software, and to        //
//  permit persons to whom the Software is furnished to do so, subject to     //
//  the following conditions:                                                 //
//                                                                            //
//  The above copyright notice and this permission notice shall be included   //
//  in all copies or substantial portions of the Software.                    //
//                                                                            //
//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS   //
//  OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF                //
//  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.    //
//  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY      //
//  CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,      //
//  TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE         //
//  SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                    //
//                                                                            //
////////////////////////////////////////////////////////////////////////////////

use libc as c;
use std::io::{self, Read, Write};
use std::mem;
use std::net::{Ipv4Addr, Ipv6Addr};
use std::os::unix::io::RawFd;
use std::ptr::{null_mut};

const LISTENSOCK_FILENO: c::c_int = 0;

pub struct Transport {
    inner: c::c_int,
}

impl Transport {
    pub fn new() -> Self {
        Self::from_raw_fd(LISTENSOCK_FILENO)
    }

    pub fn from_raw_fd(raw_fd: RawFd) -> Self {
        Transport { inner: raw_fd }
    }

    pub fn is_fastcgi(&self) -> bool {
        let res = unsafe { c::getpeername(self.inner, null_mut(), null_mut()) };
        res == -1 && io::Error::last_os_error().raw_os_error() == Some(c::ENOTCONN)
    }

    pub fn accept(&mut self) -> io::Result<Socket> {
        let res = unsafe {
            c::accept(self.inner, 0 as *mut _, 0 as *mut _)
        };
        if res == -1 {
            Err(io::Error::last_os_error())
        } else {
            Ok(Socket { inner: res })
        }
    }
}

pub struct Socket {
    inner: c::c_int,
}

impl Socket {
    pub fn peer(&self) -> io::Result<String> {
        unsafe {
            let mut ss = mem::zeroed::<c::sockaddr_storage>();
            let mut len = mem::size_of::<c::sockaddr_storage>() as c::socklen_t;
            let res = c::getpeername(
                self.inner,
                &mut ss as *mut _ as *mut c::sockaddr,
                &mut len
            );
            if res == -1 {
                return Err(io::Error::last_os_error());
            }
            match ss.ss_family as c::c_int {
                c::AF_INET => {
                    let sin = *(&ss as *const _ as *const c::sockaddr_in);
                    let ip = mem::transmute::<c::in_addr, [u8; 4]>(sin.sin_addr);
                    Ok(Ipv4Addr::new(ip[0], ip[1], ip[2], ip[3]).to_string())
                },
                c::AF_INET6 => {
                    let sin = *(&ss as *const _ as *const c::sockaddr_in6);
                    let ip = mem::transmute::<c::in6_addr, [u16; 8]>(sin.sin6_addr);
                    Ok(Ipv6Addr::new(
                            ip[0], ip[1], ip[2], ip[3],
                            ip[4], ip[5], ip[6], ip[7]
                        ).to_string()
                    )
                },
                c::AF_UNIX => Ok(String::new()),
                _ => Err(io::Error::new(
                    io::ErrorKind::InvalidInput,
                    "Unsupported FastCGI socket"
                )),
            }
        }
    }
}

impl Drop for Socket {
    fn drop(&mut self) {
        unsafe { c::shutdown(self.inner, c::SHUT_WR); }
        let mut buf = Vec::new();
        self.read_to_end(&mut buf).ok();
        unsafe { c::close(self.inner); }
    }
}

impl<'a> Read for &'a Socket {
    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
        let res = unsafe {
            c::read(
                self.inner,
                buf.as_mut_ptr() as *mut c::c_void,
                buf.len() as c::size_t
            )
        };
        if res == -1 {
            Err(io::Error::last_os_error())
        } else {
            Ok(res as usize)
        }
    }
}

impl<'a> Write for &'a Socket {
    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
        let res = unsafe {
            c::write(
                self.inner,
                buf.as_ptr() as *const c::c_void,
                buf.len() as c::size_t
            )
        };
        if res == -1 {
            Err(io::Error::last_os_error())
        } else {
            Ok(res as usize)
        }
    }

    fn flush(&mut self) -> io::Result<()> { Ok(()) }
}

impl Read for Socket {
    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
        (&*self).read(buf)
    }
}

impl Write for Socket {
    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
        (&*self).write(buf)
    }

    fn flush(&mut self) -> io::Result<()> {
        (&*self).flush()
    }
}