//! File utilities.

use crate::{err::*, machdr};
use std::{fs, path::Path, io::{SeekFrom, prelude::*}};

/// Confirms that the path `p` is a folder.
pub fn validate_folder_path(p: &str) -> ResultS<()>
{
	let at = fs::metadata(p)?;
	if at.is_dir() {
		Ok(())
	} else {
		Err(err_msg("not a directory"))
	}
}

/// Opens the file at `path` and skips past any macintosh headers.
pub fn open_mac<P: AsRef<Path>>(path: P) -> ResultS<fs::File>
{
	let mut fp = fs::File::open(path)?;

	machdr::skip_mac_header(&mut fp);

	Ok(fp)
}

impl<T> Drop for SeekBackToStart<T>
	where T: Seek
{
	fn drop(&mut self) {if self.fl {let _ = self.seek(SeekFrom::Start(0));}}
}

impl<T> std::ops::Deref for SeekBackToStart<T>
	where T: Seek
{
	type Target = T;

	fn deref(&self) -> &Self::Target {&self.sc}
}

impl<T> std::ops::DerefMut for SeekBackToStart<T>
	where T: Seek
{
	fn deref_mut(&mut self) -> &mut Self::Target {&mut self.sc}
}

impl<T> SeekBackToStart<T>
	where T: Seek
{
	/// Creates a new `SeekBackToStart` object.
	pub fn new(sc: T) -> Self {Self{sc, fl: true}}

	/// Sets the seek-back flag.
	pub fn set_seek(&mut self, fl: bool) {self.fl = fl;}

	/// Returns the seek-back flag.
	pub fn get_seek(&self) -> bool {self.fl}
}

/// Seeks back to the starting position of the inner object when losing scope,
/// unless a flag is set.
pub struct SeekBackToStart<T: Seek> {
	sc: T,
	fl: bool,
}

// EOF