// Copyright (c) 2019 Stefan Lankes, RWTH Aachen University
//
// Licensed under the Apache License, Version 2.0, <LICENSE-APACHE or
// http://apache.org/licenses/LICENSE-2.0> or the MIT license <LICENSE-MIT or
// http://opensource.org/licenses/MIT>, at your option. This file may not be
// copied, modified, or distributed except according to those terms.

use crate::arch::kernel::percore::*;
use crate::scheduler::task::TaskHandle;
use crate::synch::semaphore::*;
use crate::synch::spinlock::SpinlockIrqSave;
use alloc::collections::BTreeMap;

static NET_SEM: Semaphore = Semaphore::new(0);
static NIC_QUEUE: SpinlockIrqSave<BTreeMap<usize, TaskHandle>> =
	SpinlockIrqSave::new(BTreeMap::new());

pub fn netwakeup() {
	NET_SEM.release();
}

pub fn netwait_and_wakeup(handles: &[usize], millis: Option<u64>) {
	{
		let mut guard = NIC_QUEUE.lock();

		for i in handles {
			if let Some(task) = guard.remove(i) {
				core_scheduler().custom_wakeup(task);
			}
		}
	}

	NET_SEM.acquire(millis);
}

pub fn netwait(handle: usize, millis: Option<u64>) {
	let wakeup_time = match millis {
		Some(ms) => Some(crate::arch::processor::get_timer_ticks() + ms * 1000),
		_ => None,
	};
	let mut guard = NIC_QUEUE.lock();
	let core_scheduler = core_scheduler();

	// Block the current task and add it to the wakeup queue.
	core_scheduler.block_current_task(wakeup_time);
	guard.insert(handle, core_scheduler.get_current_task_handle());

	// release lock
	drop(guard);

	// Switch to the next task.
	core_scheduler.reschedule();

	// if the timer is expired, we have still the task in the btreemap
	// => remove it from the btreemap
	if millis.is_some() {
		let mut guard = NIC_QUEUE.lock();

		guard.remove(&handle);
	}
}