use crate::FileTime;
use libc::{time_t, timespec};
use std::fs;
use std::os::unix::prelude::*;

cfg_if::cfg_if! {
    if #[cfg(target_os = "linux")] {
        mod utimes;
        mod linux;
        pub use self::linux::*;
    } else if #[cfg(target_os = "android")] {
        mod android;
        pub use self::android::*;
    } else if #[cfg(target_os = "macos")] {
        mod utimes;
        mod macos;
        pub use self::macos::*;
    } else if #[cfg(any(target_os = "aix",
                        target_os = "solaris",
                        target_os = "illumos",
                        target_os = "emscripten",
                        target_os = "freebsd",
                        target_os = "netbsd",
                        target_os = "openbsd",
                        target_os = "haiku"))] {
        mod utimensat;
        pub use self::utimensat::*;
    } else {
        mod utimes;
        pub use self::utimes::*;
    }
}

#[allow(dead_code)]
fn to_timespec(ft: &Option<FileTime>) -> timespec {
    cfg_if::cfg_if! {
        if #[cfg(any(target_os = "macos",
                     target_os = "illumos",
                     target_os = "freebsd"))] {
            // https://github.com/apple/darwin-xnu/blob/a449c6a3b8014d9406c2ddbdc81795da24aa7443/bsd/sys/stat.h#L541
            // https://github.com/illumos/illumos-gate/blob/master/usr/src/boot/sys/sys/stat.h#L312
            // https://svnweb.freebsd.org/base/head/sys/sys/stat.h?view=markup#l359
            const UTIME_OMIT: i64 = -2;
        } else if #[cfg(target_os = "openbsd")] {
            // https://github.com/openbsd/src/blob/master/sys/sys/stat.h#L189
            const UTIME_OMIT: i64 = -1;
        } else if #[cfg(target_os = "haiku")] {
            // https://git.haiku-os.org/haiku/tree/headers/posix/sys/stat.h?#n106
            const UTIME_OMIT: i64 = 1000000001;
        } else if #[cfg(target_os = "aix")] {
            // AIX hasn't disclosed system header files yet.
            // https://github.com/golang/go/blob/master/src/cmd/vendor/golang.org/x/sys/unix/zerrors_aix_ppc64.go#L1007
            const UTIME_OMIT: i64 = -3;
        } else {
            // http://cvsweb.netbsd.org/bsdweb.cgi/src/sys/sys/stat.h?annotate=1.68.30.1
            // https://github.com/emscripten-core/emscripten/blob/master/system/include/libc/sys/stat.h#L71
            const UTIME_OMIT: i64 = 1_073_741_822;
        }
    }

    let mut ts: timespec = unsafe { std::mem::zeroed() };
    if let &Some(ft) = ft {
        ts.tv_sec = ft.seconds() as time_t;
        ts.tv_nsec = ft.nanoseconds() as _;
    } else {
        ts.tv_sec = 0;
        ts.tv_nsec = UTIME_OMIT as _;
    }

    ts
}

pub fn from_last_modification_time(meta: &fs::Metadata) -> FileTime {
    FileTime {
        seconds: meta.mtime(),
        nanos: meta.mtime_nsec() as u32,
    }
}

pub fn from_last_access_time(meta: &fs::Metadata) -> FileTime {
    FileTime {
        seconds: meta.atime(),
        nanos: meta.atime_nsec() as u32,
    }
}

pub fn from_creation_time(meta: &fs::Metadata) -> Option<FileTime> {
    #[cfg(target_os = "bitrig")]
    {
        use std::os::bitrig::fs::MetadataExt;
        Some(FileTime {
            seconds: meta.st_birthtime(),
            nanos: meta.st_birthtime_nsec() as u32,
        })
    }

    #[cfg(not(target_os = "bitrig"))]
    {
        meta.created().map(|i| i.into()).ok()
    }
}