#include <vhex/keyboard.h>
#include <vhex/drivers/cpu.h>

/* Internal cache, used like chained list.
   @note:
   The KEYSC have 6 key data 16-bits registers this is why we used 6 * 16 = 96
   cache slots. */
struct keycache_s keycache[96];
struct keycache_s *keylist;

//---
// Private functions
//---

/* keycache_alloc() : Try to alloc a new keycache node */
static struct keycache_s *keycache_alloc(int keycode, int keyframe)
{
	void *node;

	cpu_atomic_start();

	node = NULL;
	for (int i = 0; i < 96 ; ++i) {
		if (keycache[i].keycode == KEY_UNUSED) {
			keycache[i].keycode = keycode;
			keycache[i].keyframe = keyframe;
			keycache[i].repeated = 0;
			node = &keycache[i];
			break;
		}
	}

	cpu_atomic_end();
	return (node);
}

//---
// Secret entries
//---

/* keycache_init() : keycache constructor */
void keycache_init(void)
{
	for (int i = 0; i < 96 ; ++i) {
		keycache[i].keycode = KEY_UNUSED;
		keycache[i].next = NULL;
	}
	keylist = NULL;
}

//---
// Public API
//---

/* keycache_update() : Add / update key code node */
void keycache_update(int row, int column, uint8_t keyframe)
{
	struct keycache_s *node;
	uint8_t keycode;

	keycode = KEYCODE_GEN(row, column);

	cpu_atomic_start();

	node = keylist;
	while (node != NULL) {
		if (node->keycode == keycode) {
			node->keyframe = keyframe;
			break;
		}
		node = node->next;
	}

	if (node == NULL) {
		node = keycache_alloc(keycode, keyframe);
		if (node != NULL) {
			node->next = keylist;
			keylist = node;
		}
	}

	cpu_atomic_end();
}

/* keycache_clean() : Remove dirty node */
void keycache_clean(int keyframe)
{
	struct keycache_s **current_node;

	cpu_atomic_start();

	current_node = &keylist;
	while (*current_node != NULL) {
		if ((*current_node)->keyframe != keyframe) {
			(*current_node)->keycode = KEY_UNUSED;
			*current_node = (*current_node)->next;
			continue;
		}
		(*current_node)->repeated = (*current_node)->repeated + 1;
		current_node = &(*current_node)->next;
	}

	cpu_atomic_end();
}