#include <stddef.h>
#include <string.h>

#include "vec.h"
#include "alloc.h"

static enum LEO_Vec_Error LEO_Vec_grow(struct LEO_Vec *vec)
{
	size_t new_capacity = vec->capacity
		* LEO_Vec_GROWTH_FACTOR_NUMER
		/ LEO_Vec_GROWTH_FACTOR_DENOM;

	if (new_capacity <= vec->capacity)
		return LEO_Vec_TOO_BIG;

	vec->capacity = new_capacity;
	vec->data = vec->allocator.realloc(vec->data,
					   vec->capacity * vec->item_size);

	if (vec->data == NULL)
		return LEO_Vec_ALLOCATION_FAILURE;

	return LEO_Vec_OK;
}

enum LEO_Vec_Error LEO_Vec_init(struct LEO_Vec *vec, size_t item_size,
				struct LEO_Allocator allocator)
{
	if (vec == NULL)
		return LEO_Vec_NULL_VEC_POINTER;
	if (item_size == 0)
		return LEO_Vec_INVALID_ITEM_SIZE;

	vec->allocator = allocator;
	vec->item_size = item_size;
	vec->length = 0;
	vec->capacity = LEO_Vec_DEFAULT_CAPACITY;
	vec->data = vec->allocator.alloc(vec->capacity * vec->item_size);

	if (!vec->data)
		return LEO_Vec_ALLOCATION_FAILURE;

	return LEO_Vec_OK;
}

void LEO_Vec_free(struct LEO_Vec *vec)
{
	if (vec == NULL)
		return;

	vec->allocator.free(vec->data);
	vec->data = NULL;
}

enum LEO_Vec_Error LEO_Vec_push(struct LEO_Vec *vec, const void *item)
{
	if (vec == NULL)
		return LEO_Vec_NULL_VEC_POINTER;
	if (item == NULL)
		return LEO_Vec_NULL_ITEM_POINTER;

	if (vec->length >= vec->capacity) {
		enum LEO_Vec_Error result = LEO_Vec_grow(vec);
		if (result != LEO_Vec_OK)
			return result;
	}

	unsigned char *dest = (unsigned char *)vec->data + (vec->length++) * vec->item_size;
	memcpy(dest, item, vec->item_size);

	return LEO_Vec_OK;
}

enum LEO_Vec_Error LEO_Vec_pop(struct LEO_Vec *vec, void *item)
{
	if (vec == NULL)
		return LEO_Vec_NULL_VEC_POINTER;
	if (vec->length == 0)
		return LEO_Vec_OUT_OF_BOUNDS;

	void *src = vec->data + (vec->length--) * vec->item_size;
	memcpy(item, src, vec->item_size);

	return LEO_Vec_OK;
}

enum LEO_Vec_Error LEO_Vec_get(struct LEO_Vec *vec, size_t i, void *item)
{
	if (vec == NULL)
		return LEO_Vec_NULL_VEC_POINTER;
	if (i >= vec->length)
		return LEO_Vec_OUT_OF_BOUNDS;

	unsigned char *src = (unsigned char *) vec->data + i * vec->item_size;
	memcpy(item, src, vec->item_size);

	return LEO_Vec_OK;
}