#include <stdint.h>

#include "rtos/context.h"
#include "rtos/semaphore.h"
#include "rtos/spinlock.h"

uint8_t sem_wait(struct semaphore *sem)
{
	uint32_t retval = CONTEXT_READY;

	spinlock_lock(&sem->lock);

	sem->count--;
	if (sem->count < 0)
		retval = context_wait_pri_queue(&sem->lock, &sem->sleep_queue);

	spinlock_unlock(&sem->lock);

	return retval;
}

void sem_post(struct semaphore *sem)
{
	spinlock_lock(&sem->lock);

	sem->count++;
	if (sem->count <= 0)
		context_signal_queue(&sem->sleep_queue);

	spinlock_unlock(&sem->lock);
}

void sem_interrupt(struct semaphore *sem, struct context *c)
{
	spinlock_lock(&sem->lock);
	context_interrupt_queue(c, &sem->sleep_queue);
	spinlock_unlock(&sem->lock);
}

int32_t sem_get_count(struct semaphore *sem)
{
	int32_t retval;

	spinlock_lock(&sem->lock);
	retval = sem->count;
	spinlock_unlock(&sem->lock);

	return retval;
}

void sem_init(struct semaphore *sem, int32_t count)
{
	sem->sleep_queue = 0;
	spinlock_init(&sem->lock);
	sem->count = 0;
}