// Copyright (c) 2017 fd developers
// Licensed under the Apache License, Version 2.0
// <LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0>
// or the MIT license <LICENSE-MIT or http://opensource.org/licenses/MIT>,
// at your option. All files in the project carrying such
// notice may not be copied, modified, or distributed except
// according to those terms.

use super::CommandTemplate;
use crate::exit_codes::{ExitCode, merge_exitcodes};
use crate::walk::WorkerResult;
use std::path::PathBuf;
use std::sync::mpsc::Receiver;
use std::sync::{Arc, Mutex};

/// An event loop that listens for inputs from the `rx` receiver. Each received input will
/// generate a command with the supplied command template. The generated command will then
/// be executed, and this process will continue until the receiver's sender has closed.
pub fn job(
    rx: Arc<Mutex<Receiver<WorkerResult>>>,
    cmd: Arc<CommandTemplate>,
    out_perm: Arc<Mutex<()>>,
    show_filesystem_errors: bool,
) -> ExitCode {
    let mut results: Vec<ExitCode> = Vec::new();
    loop {
        // Create a lock on the shared receiver for this thread.
        let lock = rx.lock().unwrap();

        // Obtain the next result from the receiver, else if the channel
        // has closed, exit from the loop
        let value: PathBuf = match lock.recv() {
            Ok(WorkerResult::Entry(val)) => val,
            Ok(WorkerResult::Error(err)) => {
                if show_filesystem_errors {
                    print_error!("{}", err);
                }
                continue;
            }
            Err(_) => break,
        };

        // Drop the lock so that other threads can read from the receiver.
        drop(lock);
        // Generate a command, execute it and store its exit code.
        results.push(cmd.generate_and_execute(&value, Arc::clone(&out_perm)))
    }
    // Returns error in case of any error.
    merge_exitcodes(results)
}

pub fn batch(
    rx: Receiver<WorkerResult>,
    cmd: &CommandTemplate,
    show_filesystem_errors: bool,
) -> ExitCode {
    let paths = rx.iter().filter_map(|value| match value {
        WorkerResult::Entry(val) => Some(val),
        WorkerResult::Error(err) => {
            if show_filesystem_errors {
                print_error!("{}", err);
            }
            None
        }
    });
    cmd.generate_and_execute_batch(paths)
}