//! Handle deletion
//!
//! # Handling paths
//! Deletion of single files is trivial, deletion of directories is not as trivial.
//! Other types of filesystem object are ignored.
//!
//! ## Directories
//! With directories the deletion processes all files containing recursively.
//! See `restore` for restoration of directories
use super::*;
use std::{
    path::{
	Path,
    },
};
use tokio::{
    fs,
    task::JoinHandle,
};
use futures::{
    prelude::*,
    future::BoxFuture,
};

/// Process a single file.
///
/// `path` is known to be a file at this point.
async fn process_single(state: Arc<state::State>, path: impl AsRef<Path>) -> eyre::Result<()>
{
    let path = path.as_ref();
    #[cfg(debug_assertions)] {
	if !path.is_file() {
	    panic!("process_single() expected a file, but {:?} is not one.", path);
	}
    }
    
    let _g = state.lock().await;
    debug!("{:?} Processing", path);
    //TODO: Actual processing
    Ok(())
}

/// Process this path
///
/// This will not return until all its children finish too (if any)
pub async fn process<'a, P>(state: Arc<state::State>, path: P) -> eyre::Result<()>
where P: 'a + Send + AsRef<Path> 
{
    let path = path.as_ref();
    if path.is_dir() {
	let read = fs::read_dir(path).await?;
	fn proc_dir(state: Arc<state::State>,  mut read: fs::ReadDir) -> BoxFuture<'static, JoinHandle<Result<(), eyre::Report>>>
	{
	    async move {
		tokio::spawn(async move {
		    while let Some(entry) = read.next_entry().await?
		    {
			process(Arc::clone(&state), entry.path()).await?;
		    }
		    Ok::<_, eyre::Report>(())
		})
	    }.boxed()
	}
	let handle = proc_dir(state, read).await;
	let res = handle.await
	    .wrap_err(eyre!("Child exited abnormally"))?;
	res.wrap_err(eyre!("Failed to process children"))
    } else if path.is_file() {
	process_single(state, path).await
    } else {
	Err(eyre!("Invalid/unsupported FSO"))
    }.with_section(|| format!("{:?}", path).header("Path was"))
}