use nix::Error;
use nix::errno::*;
use nix::fcntl::{openat, open, OFlag, readlink, readlinkat, renameat};
use nix::sys::stat::Mode;
use nix::unistd::{close, read};
use tempfile::{self, NamedTempFile};
use std::fs::File;
use std::io::prelude::*;
use std::os::unix::fs;

#[test]
fn test_openat() {
    const CONTENTS: &[u8] = b"abcd";
    let mut tmp = NamedTempFile::new().unwrap();
    tmp.write_all(CONTENTS).unwrap();

    let dirfd = open(tmp.path().parent().unwrap(),
                     OFlag::empty(),
                     Mode::empty()).unwrap();
    let fd = openat(dirfd,
                    tmp.path().file_name().unwrap(),
                    OFlag::O_RDONLY,
                    Mode::empty()).unwrap();

    let mut buf = [0u8; 1024];
    assert_eq!(4, read(fd, &mut buf).unwrap());
    assert_eq!(CONTENTS, &buf[0..4]);

    close(fd).unwrap();
    close(dirfd).unwrap();
}

#[test]
fn test_renameat() {
    let old_dir = tempfile::tempdir().unwrap();
    let old_dirfd = open(old_dir.path(), OFlag::empty(), Mode::empty()).unwrap();
    let old_path = old_dir.path().join("old");
    File::create(&old_path).unwrap();
    let new_dir = tempfile::tempdir().unwrap();
    let new_dirfd = open(new_dir.path(), OFlag::empty(), Mode::empty()).unwrap();
    renameat(Some(old_dirfd), "old", Some(new_dirfd), "new").unwrap();
    assert_eq!(renameat(Some(old_dirfd), "old", Some(new_dirfd), "new").unwrap_err(),
               Error::Sys(Errno::ENOENT));
    close(old_dirfd).unwrap();
    close(new_dirfd).unwrap();
    assert!(new_dir.path().join("new").exists());
}

#[test]
fn test_readlink() {
    let tempdir = tempfile::tempdir().unwrap();
    let src = tempdir.path().join("a");
    let dst = tempdir.path().join("b");
    println!("a: {:?}, b: {:?}", &src, &dst);
    fs::symlink(&src.as_path(), &dst.as_path()).unwrap();
    let dirfd = open(tempdir.path(),
                     OFlag::empty(),
                     Mode::empty()).unwrap();
    let expected_dir = src.to_str().unwrap();

    assert_eq!(readlink(&dst).unwrap().to_str().unwrap(), expected_dir);
    assert_eq!(readlinkat(dirfd, "b").unwrap().to_str().unwrap(), expected_dir);

}

#[cfg(any(target_os = "linux", target_os = "android"))]
mod linux_android {
    use std::fs::File;
    use std::io::prelude::*;
    use std::io::{BufRead, BufReader, SeekFrom};
    use std::os::unix::prelude::*;

    use libc::loff_t;

    use nix::fcntl::*;
    use nix::sys::stat::fstat;
    use nix::sys::uio::IoVec;
    use nix::unistd::{close, pipe, read, write};

    use tempfile::{tempfile, NamedTempFile};

    /// This test creates a temporary file containing the contents
    /// 'foobarbaz' and uses the `copy_file_range` call to transfer
    /// 3 bytes at offset 3 (`bar`) to another empty file at offset 0. The
    /// resulting file is read and should contain the contents `bar`.
    /// The from_offset should be updated by the call to reflect
    /// the 3 bytes read (6).
    ///
    /// FIXME: This test is disabled for linux based builds, because Travis
    /// Linux version is too old for `copy_file_range`.
    #[test]
    #[ignore]
    fn test_copy_file_range() {
        const CONTENTS: &[u8] = b"foobarbaz";

        let mut tmp1 = tempfile().unwrap();
        let mut tmp2 = tempfile().unwrap();

        tmp1.write_all(CONTENTS).unwrap();
        tmp1.flush().unwrap();

        let mut from_offset: i64 = 3;
        copy_file_range(
            tmp1.as_raw_fd(),
            Some(&mut from_offset),
            tmp2.as_raw_fd(),
            None,
            3,
        )
        .unwrap();

        let mut res: String = String::new();
        tmp2.seek(SeekFrom::Start(0)).unwrap();
        tmp2.read_to_string(&mut res).unwrap();

        assert_eq!(res, String::from("bar"));
        assert_eq!(from_offset, 6);
    }

    #[test]
    fn test_splice() {
        const CONTENTS: &[u8] = b"abcdef123456";
        let mut tmp = tempfile().unwrap();
        tmp.write_all(CONTENTS).unwrap();

        let (rd, wr) = pipe().unwrap();
        let mut offset: loff_t = 5;
        let res = splice(tmp.as_raw_fd(), Some(&mut offset),
            wr, None, 2, SpliceFFlags::empty()).unwrap();

        assert_eq!(2, res);

        let mut buf = [0u8; 1024];
        assert_eq!(2, read(rd, &mut buf).unwrap());
        assert_eq!(b"f1", &buf[0..2]);
        assert_eq!(7, offset);

        close(rd).unwrap();
        close(wr).unwrap();
    }

    #[test]
    fn test_tee() {
        let (rd1, wr1) = pipe().unwrap();
        let (rd2, wr2) = pipe().unwrap();

        write(wr1, b"abc").unwrap();
        let res = tee(rd1, wr2, 2, SpliceFFlags::empty()).unwrap();

        assert_eq!(2, res);

        let mut buf = [0u8; 1024];

        // Check the tee'd bytes are at rd2.
        assert_eq!(2, read(rd2, &mut buf).unwrap());
        assert_eq!(b"ab", &buf[0..2]);

        // Check all the bytes are still at rd1.
        assert_eq!(3, read(rd1, &mut buf).unwrap());
        assert_eq!(b"abc", &buf[0..3]);

        close(rd1).unwrap();
        close(wr1).unwrap();
        close(rd2).unwrap();
        close(wr2).unwrap();
    }

    #[test]
    fn test_vmsplice() {
        let (rd, wr) = pipe().unwrap();

        let buf1 = b"abcdef";
        let buf2 = b"defghi";
        let mut iovecs = Vec::with_capacity(2);
        iovecs.push(IoVec::from_slice(&buf1[0..3]));
        iovecs.push(IoVec::from_slice(&buf2[0..3]));

        let res = vmsplice(wr, &iovecs[..], SpliceFFlags::empty()).unwrap();

        assert_eq!(6, res);

        // Check the bytes can be read at rd.
        let mut buf = [0u8; 32];
        assert_eq!(6, read(rd, &mut buf).unwrap());
        assert_eq!(b"abcdef", &buf[0..6]);

        close(rd).unwrap();
        close(wr).unwrap();
    }

    #[test]
    fn test_fallocate() {
        let tmp = NamedTempFile::new().unwrap();

        let fd = tmp.as_raw_fd();
        fallocate(fd, FallocateFlags::empty(), 0, 100).unwrap();

        // Check if we read exactly 100 bytes
        let mut buf = [0u8; 200];
        assert_eq!(100, read(fd, &mut buf).unwrap());
    }

    // The tests below are disabled for the listed targets
    // due to OFD locks not being available in the kernel/libc
    // versions used in the CI environment, probably because
    // they run under QEMU.

    #[test]
    #[cfg(not(any(target_arch = "aarch64",
                  target_arch = "arm",
                  target_arch = "armv7",
                  target_arch = "x86",
                  target_arch = "mips",
                  target_arch = "mips64",
                  target_arch = "mips64el",
                  target_arch = "powerpc64",
                  target_arch = "powerpc64le")))]
    fn test_ofd_write_lock() {
        let tmp = NamedTempFile::new().unwrap();

        let fd = tmp.as_raw_fd();
        let inode = fstat(fd).expect("fstat failed").st_ino as usize;

        let mut flock = libc::flock {
            l_type: libc::F_WRLCK as libc::c_short,
            l_whence: libc::SEEK_SET as libc::c_short,
            l_start: 0,
            l_len: 0,
            l_pid: 0,
        };
        fcntl(fd, FcntlArg::F_OFD_SETLKW(&flock)).expect("write lock failed");
        assert_eq!(
            Some(("OFDLCK".to_string(), "WRITE".to_string())),
            lock_info(inode)
        );

        flock.l_type = libc::F_UNLCK as libc::c_short;
        fcntl(fd, FcntlArg::F_OFD_SETLKW(&flock)).expect("write unlock failed");
        assert_eq!(None, lock_info(inode));
    }

    #[test]
    #[cfg(not(any(target_arch = "aarch64",
                  target_arch = "arm",
                  target_arch = "armv7",
                  target_arch = "x86",
                  target_arch = "mips",
                  target_arch = "mips64",
                  target_arch = "mips64el",
                  target_arch = "powerpc64",
                  target_arch = "powerpc64le")))]
    fn test_ofd_read_lock() {
        let tmp = NamedTempFile::new().unwrap();

        let fd = tmp.as_raw_fd();
        let inode = fstat(fd).expect("fstat failed").st_ino as usize;

        let mut flock = libc::flock {
            l_type: libc::F_RDLCK as libc::c_short,
            l_whence: libc::SEEK_SET as libc::c_short,
            l_start: 0,
            l_len: 0,
            l_pid: 0,
        };
        fcntl(fd, FcntlArg::F_OFD_SETLKW(&flock)).expect("read lock failed");
        assert_eq!(
            Some(("OFDLCK".to_string(), "READ".to_string())),
            lock_info(inode)
        );

        flock.l_type = libc::F_UNLCK as libc::c_short;
        fcntl(fd, FcntlArg::F_OFD_SETLKW(&flock)).expect("read unlock failed");
        assert_eq!(None, lock_info(inode));
    }

    fn lock_info(inode: usize) -> Option<(String, String)> {
        let file = File::open("/proc/locks").expect("open /proc/locks failed");
        let buf = BufReader::new(file);

        for line in buf.lines() {
            let line = line.unwrap();
            let parts: Vec<_> = line.split_whitespace().collect();
            let lock_type = parts[1];
            let lock_access = parts[3];
            let ino_parts: Vec<_> = parts[5].split(':').collect();
            let ino: usize = ino_parts[2].parse().unwrap();
            if ino == inode {
                return Some((lock_type.to_string(), lock_access.to_string()));
            }
        }
        None
    }
}

#[cfg(any(target_os = "linux",
          target_os = "android",
          target_os = "emscripten",
          target_os = "fuchsia",
          any(target_os = "wasi", target_env = "wasi"),
          target_env = "uclibc",
          target_env = "freebsd"))]
mod test_posix_fadvise {

    use tempfile::NamedTempFile;
    use std::os::unix::io::{RawFd, AsRawFd};
    use nix::errno::Errno;
    use nix::fcntl::*;
    use nix::unistd::pipe;

    #[test]
    fn test_success() {
        let tmp = NamedTempFile::new().unwrap();
        let fd = tmp.as_raw_fd();
        let res = posix_fadvise(fd, 0, 100, PosixFadviseAdvice::POSIX_FADV_WILLNEED).unwrap();

        assert_eq!(res, 0);
    }

    #[test]
    fn test_errno() {
        let (rd, _wr) = pipe().unwrap();
        let errno = posix_fadvise(rd as RawFd, 0, 100, PosixFadviseAdvice::POSIX_FADV_WILLNEED)
                                 .unwrap();
        assert_eq!(errno, Errno::ESPIPE as i32);
    }
}

#[cfg(any(target_os = "linux",
          target_os = "android",
          target_os = "emscripten",
          target_os = "fuchsia",
          any(target_os = "wasi", target_env = "wasi"),
          target_os = "freebsd"))]
mod test_posix_fallocate {

    use tempfile::NamedTempFile;
    use std::{io::Read, os::unix::io::{RawFd, AsRawFd}};
    use nix::errno::Errno;
    use nix::fcntl::*;
    use nix::unistd::pipe;

    #[test]
    fn success() {
        const LEN: usize = 100;
        let mut tmp = NamedTempFile::new().unwrap();
        let fd = tmp.as_raw_fd();
        let res = posix_fallocate(fd, 0, LEN as libc::off_t);
        match res {
            Ok(_) => {
                let mut data = [1u8; LEN];
                assert_eq!(tmp.read(&mut data).expect("read failure"), LEN);
                assert_eq!(&data[..], &[0u8; LEN][..]);
            }
            Err(nix::Error::Sys(Errno::EINVAL)) => {
                // POSIX requires posix_fallocate to return EINVAL both for
                // invalid arguments (i.e. len < 0) and if the operation is not
                // supported by the file system.
                // There's no way to tell for sure whether the file system
                // supports posix_fallocate, so we must pass the test if it
                // returns EINVAL.
            }
            _ => res.unwrap(),
        }
    }

    #[test]
    fn errno() {
        let (rd, _wr) = pipe().unwrap();
        let err = posix_fallocate(rd as RawFd, 0, 100).unwrap_err();
        use nix::Error::Sys;
        match err {
            Sys(Errno::EINVAL)
                | Sys(Errno::ENODEV)
                | Sys(Errno::ESPIPE)
                | Sys(Errno::EBADF) => (),
            errno =>
                panic!(
                    "unexpected errno {}",
                    errno,
                ),
        }
    }
}