use alloc::collections::VecDeque;
use spin::{Lazy, Mutex};

pub static SCHEDULER: Lazy<Mutex<Scheduler>> = Lazy::new(|| Mutex::new(Scheduler::default()));

pub enum Task {
    Suspended(u64),
    Spawn(fn()),
}

#[derive(Default)]
pub struct Scheduler {
    task_queue: VecDeque<Task>,
}

impl Scheduler {
    pub fn enqueue_spawn(&mut self, f: fn()) {
        self.task_queue.push_back(Task::Spawn(f));
    }

    pub fn enqueue_suspended(&mut self, sp: u64) {
        self.task_queue.push_back(Task::Suspended(sp));
    }

    pub fn pop(&mut self) -> Option<Task> {
        self.task_queue.pop_front()
    }
}