// Take a look at the license at the top of the repository in the LICENSE file.

#[cfg(unix)]
use std::os::unix::io::{AsRawFd, IntoRawFd, RawFd};
use std::{mem, ptr};

use glib::{prelude::*, translate::*};
#[cfg(all(not(unix), docsrs))]
use socket::{AsRawFd, IntoRawFd, RawFd};

use crate::UnixFDList;

impl UnixFDList {
    /// Creates a new [`UnixFDList`][crate::UnixFDList] containing the file descriptors given in
    /// `fds`. The file descriptors become the property of the new list and
    /// may no longer be used by the caller. The array itself is owned by
    /// the caller.
    ///
    /// Each file descriptor in the array should be set to close-on-exec.
    ///
    /// If `n_fds` is -1 then `fds` must be terminated with -1.
    /// ## `fds`
    /// the initial list of file descriptors
    ///
    /// # Returns
    ///
    /// a new [`UnixFDList`][crate::UnixFDList]
    #[doc(alias = "g_unix_fd_list_new_from_array")]
    pub fn from_array(fds: impl IntoIterator<Item = impl IntoRawFd>) -> UnixFDList {
        let fds = fds.into_iter().map(|t| t.into_raw_fd()).collect::<Vec<_>>();
        unsafe {
            from_glib_full(ffi::g_unix_fd_list_new_from_array(
                fds.to_glib_none().0,
                fds.len() as i32,
            ))
        }
    }
}

mod sealed {
    pub trait Sealed {}
    impl<T: super::IsA<super::UnixFDList>> Sealed for T {}
}

pub trait UnixFDListExtManual: sealed::Sealed + IsA<UnixFDList> + Sized {
    /// Adds a file descriptor to `self`.
    ///
    /// The file descriptor is duplicated using `dup()`. You keep your copy
    /// of the descriptor and the copy contained in `self` will be closed
    /// when `self` is finalized.
    ///
    /// A possible cause of failure is exceeding the per-process or
    /// system-wide file descriptor limit.
    ///
    /// The index of the file descriptor in the list is returned. If you use
    /// this index with [`UnixFDListExtManual::get()`][crate::prelude::UnixFDListExtManual::get()] then you will receive back a
    /// duplicated copy of the same file descriptor.
    /// ## `fd`
    /// a valid open file descriptor
    ///
    /// # Returns
    ///
    /// the index of the appended fd in case of success, else -1
    ///  (and `error` is set)
    #[doc(alias = "g_unix_fd_list_append")]
    fn append<T: AsRawFd>(&self, fd: T) -> Result<i32, glib::Error> {
        unsafe {
            let mut error = ptr::null_mut();
            let ret = ffi::g_unix_fd_list_append(
                self.as_ref().to_glib_none().0,
                fd.as_raw_fd(),
                &mut error,
            );
            if error.is_null() {
                Ok(ret)
            } else {
                Err(from_glib_full(error))
            }
        }
    }

    /// Gets a file descriptor out of `self`.
    ///
    /// `index_` specifies the index of the file descriptor to get. It is a
    /// programmer error for `index_` to be out of range; see
    /// [`UnixFDListExt::length()`][crate::prelude::UnixFDListExt::length()].
    ///
    /// The file descriptor is duplicated using `dup()` and set as
    /// close-on-exec before being returned. You must call `close()` on it
    /// when you are done.
    ///
    /// A possible cause of failure is exceeding the per-process or
    /// system-wide file descriptor limit.
    /// ## `index_`
    /// the index into the list
    ///
    /// # Returns
    ///
    /// the file descriptor, or -1 in case of error
    #[doc(alias = "g_unix_fd_list_get")]
    fn get(&self, index_: i32) -> Result<RawFd, glib::Error> {
        unsafe {
            let mut error = ptr::null_mut();
            let ret = ffi::g_unix_fd_list_get(self.as_ref().to_glib_none().0, index_, &mut error);
            if error.is_null() {
                Ok(ret)
            } else {
                Err(from_glib_full(error))
            }
        }
    }

    #[doc(alias = "g_unix_fd_list_peek_fds")]

    /// Returns the array of file descriptors that is contained in this
    /// object.
    ///
    /// After this call, the descriptors remain the property of `self`. The
    /// caller must not close them and must not free the array. The array is
    /// valid only until `self` is changed in any way.
    ///
    /// If `length` is non-[`None`] then it is set to the number of file
    /// descriptors in the returned array. The returned array is also
    /// terminated with -1.
    ///
    /// This function never returns [`None`]. In case there are no file
    /// descriptors contained in `self`, an empty array is returned.
    ///
    /// # Returns
    ///
    /// an array of file
    ///  descriptors
    fn peek_fds(&self) -> Vec<RawFd> {
        unsafe {
            let mut length = mem::MaybeUninit::uninit();
            let ret = FromGlibContainer::from_glib_none_num(
                ffi::g_unix_fd_list_peek_fds(self.as_ref().to_glib_none().0, length.as_mut_ptr()),
                length.assume_init() as usize,
            );
            ret
        }
    }
    /// Returns the array of file descriptors that is contained in this
    /// object.
    ///
    /// After this call, the descriptors are no longer contained in
    /// `self`. Further calls will return an empty list (unless more
    /// descriptors have been added).
    ///
    /// The return result of this function must be freed with `g_free()`.
    /// The caller is also responsible for closing all of the file
    /// descriptors. The file descriptors in the array are set to
    /// close-on-exec.
    ///
    /// If `length` is non-[`None`] then it is set to the number of file
    /// descriptors in the returned array. The returned array is also
    /// terminated with -1.
    ///
    /// This function never returns [`None`]. In case there are no file
    /// descriptors contained in `self`, an empty array is returned.
    ///
    /// # Returns
    ///
    /// an array of file
    ///  descriptors
    #[doc(alias = "g_unix_fd_list_steal_fds")]
    fn steal_fds(&self) -> Vec<RawFd> {
        unsafe {
            let mut length = mem::MaybeUninit::uninit();
            let ret = FromGlibContainer::from_glib_full_num(
                ffi::g_unix_fd_list_steal_fds(self.as_ref().to_glib_none().0, length.as_mut_ptr()),
                length.assume_init() as usize,
            );
            ret
        }
    }
}

impl<O: IsA<UnixFDList>> UnixFDListExtManual for O {}