#include <kernel/address-space.h>
#include <kernel/futex.h>
#include <mango/status.h>

enum futex_flags {
	FUTEX_CREATE = 0x01u,
};

static struct btree futex_list = {0};
static spin_lock_t futex_list_lock = SPIN_LOCK_INIT;

static struct vm_cache futex_cache = {
	.c_name = "futex",
	.c_obj_size = sizeof(struct futex),
};

BTREE_DEFINE_SIMPLE_INSERT(struct futex, f_node, f_key, put_futex)
BTREE_DEFINE_SIMPLE_GET(struct futex, futex_key_t, f_node, f_key, get_futex)

kern_status_t futex_init(void)
{
	vm_cache_init(&futex_cache);
	return KERN_OK;
}

static struct futex *get_data(futex_key_t key, enum futex_flags flags)
{
	spin_lock(&futex_list_lock);
	struct futex *futex = get_futex(&futex_list, key);
	spin_unlock(&futex_list_lock);

	if (!futex && !(flags & FUTEX_CREATE)) {
		return NULL;
	}

	futex = vm_cache_alloc(&futex_cache, VM_NORMAL);
	futex->f_key = key;

	spin_lock(&futex_list_lock);
	put_futex(&futex_list, futex);
	spin_unlock(&futex_list_lock);

	return futex;
}

kern_status_t futex_get(
	struct address_space *space,
	kern_futex_t *futex,
	futex_key_t *out)
{
	unsigned long flags;
	address_space_lock_irqsave(space, &flags);
	kern_status_t status = address_space_translate(
		space,
		(virt_addr_t)futex,
		out,
		&flags);
	address_space_unlock_irqrestore(space, flags);
	return status;
}

kern_status_t futex_wait(futex_key_t futex, kern_futex_t new_val)
{
	return KERN_UNIMPLEMENTED;
}

kern_status_t futex_wake(futex_key_t futex, size_t nwaiters)
{
	return KERN_UNIMPLEMENTED;
}