#![allow(missing_docs)]
use crate::errno::Errno;
use crate::{NixPath, Result};
use libc::{self, c_int, c_ulong};

libc_bitflags!(
    pub struct MsFlags: c_ulong {
        /// Mount read-only
        MS_RDONLY;
        /// Ignore suid and sgid bits
        MS_NOSUID;
        /// Disallow access to device special files
        MS_NODEV;
        /// Disallow program execution
        MS_NOEXEC;
        /// Writes are synced at once
        MS_SYNCHRONOUS;
        /// Alter flags of a mounted FS
        MS_REMOUNT;
        /// Allow mandatory locks on a FS
        MS_MANDLOCK;
        /// Directory modifications are synchronous
        MS_DIRSYNC;
        /// Do not update access times
        MS_NOATIME;
        /// Do not update directory access times
        MS_NODIRATIME;
        /// Linux 2.4.0 - Bind directory at different place
        MS_BIND;
        MS_MOVE;
        MS_REC;
        MS_SILENT;
        MS_POSIXACL;
        MS_UNBINDABLE;
        MS_PRIVATE;
        MS_SLAVE;
        MS_SHARED;
        MS_RELATIME;
        MS_KERNMOUNT;
        MS_I_VERSION;
        MS_STRICTATIME;
        MS_LAZYTIME;
        MS_ACTIVE;
        MS_NOUSER;
        MS_RMT_MASK;
        MS_MGC_VAL;
        MS_MGC_MSK;
    }
);

libc_bitflags!(
    pub struct MntFlags: c_int {
        MNT_FORCE;
        MNT_DETACH;
        MNT_EXPIRE;
        UMOUNT_NOFOLLOW;
    }
);

pub fn mount<
    P1: ?Sized + NixPath,
    P2: ?Sized + NixPath,
    P3: ?Sized + NixPath,
    P4: ?Sized + NixPath,
>(
    source: Option<&P1>,
    target: &P2,
    fstype: Option<&P3>,
    flags: MsFlags,
    data: Option<&P4>,
) -> Result<()> {
    fn with_opt_nix_path<P, T, F>(p: Option<&P>, f: F) -> Result<T>
    where
        P: ?Sized + NixPath,
        F: FnOnce(*const libc::c_char) -> T,
    {
        match p {
            Some(path) => path.with_nix_path(|p_str| f(p_str.as_ptr())),
            None => Ok(f(std::ptr::null())),
        }
    }

    let res = with_opt_nix_path(source, |s| {
        target.with_nix_path(|t| {
            with_opt_nix_path(fstype, |ty| {
                with_opt_nix_path(data, |d| unsafe {
                    libc::mount(
                        s,
                        t.as_ptr(),
                        ty,
                        flags.bits,
                        d as *const libc::c_void,
                    )
                })
            })
        })
    })????;

    Errno::result(res).map(drop)
}

pub fn umount<P: ?Sized + NixPath>(target: &P) -> Result<()> {
    let res =
        target.with_nix_path(|cstr| unsafe { libc::umount(cstr.as_ptr()) })?;

    Errno::result(res).map(drop)
}

pub fn umount2<P: ?Sized + NixPath>(target: &P, flags: MntFlags) -> Result<()> {
    let res = target.with_nix_path(|cstr| unsafe {
        libc::umount2(cstr.as_ptr(), flags.bits)
    })?;

    Errno::result(res).map(drop)
}