//! Utility functions.
use std::{fs, io, path::Path};

#[cfg(unix)]
use nix::unistd::{self, Gid, Uid};

use super::error::Result;

#[cfg(not(unix))]
pub mod nix {
    //! Stub mod on non-unix systems.
    pub mod unistd {
        pub enum Uid {}
        pub enum Gid {}
    }
}

/// Recursively copy the *contents* of the given directory to the given path.
pub fn copy_recursive<S: AsRef<Path>, D: AsRef<Path>>(source: S, destination: D) -> io::Result<()> {
    copy_inner(source.as_ref(), destination.as_ref())
}

fn copy_inner(source: &Path, destination: &Path) -> io::Result<()> {
    for item in fs::read_dir(source)? {
        let item = item?;
        let metadata = item.metadata()?;
        let item_destination = destination.join(item.file_name());
        if metadata.is_file() {
            fs::copy(&item.path(), &item_destination)?;
        } else if metadata.is_dir() {
            fs::create_dir(&item_destination)?;
            copy_inner(&item.path(), &item_destination)?;
        }
    }
    Ok(())
}

/// Recursively change the owner of the given path to the given ones.
///
/// Note that this function only works on Unix systems. **It will panic on other systems!**
pub fn chown_recursive<P: AsRef<Path>>(path: P, uid: Option<Uid>, gid: Option<Gid>) -> Result<()> {
    chown_inner(path.as_ref(), uid, gid)
}

#[cfg(unix)]
fn chown_inner(path: &Path, uid: Option<Uid>, gid: Option<Gid>) -> Result<()> {
    unistd::chown(path, uid, gid)?;

    let metadata = fs::metadata(path)?;
    if metadata.is_dir() {
        for item in fs::read_dir(path)? {
            let item = item?;
            chown_inner(&item.path(), uid, gid)?;
        }
    }
    Ok(())
}

#[cfg(not(unix))]
fn chown_inner(_: &Path, _: Option<Uid>, _: Option<Gid>) -> Result<()> {
    panic!("chown() is not available on non-Unix systems!");
}