//
use actix::prelude::*;

use actix::Recipient;
use anyhow::{Context, Result};
use notify::{event::ModifyKind, Watcher};
use tracing::{error, info};

use std::{
    path::PathBuf,
    sync::{
        atomic::{AtomicBool, Ordering},
        Arc,
    },
    time::Duration,
};

#[derive(Debug, Message)]
#[rtype(result = "()")]
pub struct FileUpdated;

#[derive(Debug, thiserror::Error)]
pub enum Error {
    #[error("io")]
    Io(#[from] std::io::Error),
}
pub fn watch_file(path: PathBuf, recipient: Recipient<FileUpdated>) -> Result<Arc<AtomicBool>> {
    let (tx, rx) = std::sync::mpsc::channel();
    let shutdown = Arc::new(AtomicBool::default());

    let mut handler = notify::recommended_watcher(tx).context("file watcher")?;
    handler
        .watch(&path, notify::RecursiveMode::NonRecursive)
        .with_context(|| format!("Watching: {path:?}"))?;
    let thread_shutdown = shutdown.clone();
    actix_rt::task::spawn_blocking(move || {
        loop {
            if thread_shutdown.load(Ordering::Relaxed) {
                drop(handler);
                break;
            }
            for result in rx.try_iter() {
                match result {
                    Ok(event) => match event.kind {
                        notify::EventKind::Modify(ModifyKind::Data(_)) => {
                            info!("File modified");
                            recipient.do_send(FileUpdated);
                            break;
                        }
                        notify::EventKind::Modify(_)
                        | notify::EventKind::Create(_)
                        | notify::EventKind::Remove(_)
                        | notify::EventKind::Any
                        | notify::EventKind::Access(_)
                        | notify::EventKind::Other => { /* do nothing */ }
                    },
                    Err(err) => {
                        error!(?err, "Watching file: {path:?}");
                    }
                }
            }
            std::thread::sleep(Duration::from_millis(1000));
        }
    });
    Ok(shutdown)
}