#include <rte_memcpy.h>

#include <sc_metrics.h>

/**
 * @brief Round up a value to the nearest multiple of 8.
 * Note: This function is not thread-safe.
 *
 * @param value The value to round up.
 * @return The rounded up value.
 */
uint16_t round_up_to_multiple_of_8(uint16_t value)
{
    return (value + 7) & ~7;
}

/**
 * @brief Create and initialize a new SC metrics handle.
 *
 * This function allocates and initializes a new SC metrics handle with the
 * specified capacity. It ensures that the capacity is rounded up to the
 * nearest multiple of 8. The handle includes memory for storing metrics
 * values based on the rounded capacity.
 *
 * @param capacity The number of metrics values that the handle should be able
 *                 to store. This value is rounded up to the nearest multiple
 *                 of 8.
 *
 * @return Pointer to the newly created SC metrics handle, or NULL if memory
 *         allocation fails or if an invalid capacity is provided (0).
 */
struct sc_metrics_handle * sc_metrics_handle_create(uint16_t capacity)
{
    if (capacity == 0)
    {
        MR_ERROR("Error allocating stats handle: invalid input parameters.");
        return NULL;
    }
    else if (capacity > SC_METRICS_MAX_CAPACITY)
    {
        MR_ERROR("Error allocating stats handle: capacity exceeds maximum limit.");
        return NULL;
    }

    struct sc_metrics_handle * metrics_handle = (struct sc_metrics_handle *)ZMALLOC(sizeof(struct sc_metrics_handle));
    MR_VERIFY_MALLOC(metrics_handle);

    metrics_handle->capacity = round_up_to_multiple_of_8(capacity);

    metrics_handle->values = (volatile uint64_t *)ZMALLOC(sizeof(uint64_t) * metrics_handle->capacity);
    MR_VERIFY_MALLOC(metrics_handle->values);

    return metrics_handle;
}

/**
 * @brief Delete and free an SC metrics handle.
 *
 * This function deallocates the memory associated with an SC metrics handle,
 * including its values array. After freeing the memory, it sets the pointers
 * to NULL to avoid dangling pointers.
 *
 * @param metrics_handle Pointer to the SC metrics handle to be deleted.
 *                       If this pointer is NULL, no action is taken.
 *
 * @return Return value indicating success or failure:
 *         - RT_SUCCESS (0) if the handle is successfully deleted.
 *         - RT_ERR (-1) if the handle is NULL and cannot be deleted.
 */
int sc_metrics_handle_delete(struct sc_metrics_handle * metrics_handle)
{
    if (metrics_handle == NULL)
    {
        MR_ERROR("Error deleting stats handle: invalid input parameters.");
        return RT_ERR;
    }

    FREE((void *)metrics_handle->values);
    metrics_handle->values = NULL;

    FREE((void *)metrics_handle);

    return RT_SUCCESS;
}

/**
 * @brief Set the values for the SC metrics handle.
 *
 * This function copies an array of metric values into the SC metrics handle.
 * It ensures that the provided capacity does not exceed the handle's allocated
 * capacity. The function uses `rte_memcpy` to perform the copy operation.
 *
 * @param metrics_handle Pointer to the SC metrics handle where the values will
 *                       be set. This handle must be valid and initialized.
 * @param stats Array of metric values to be copied into the handle.
 * @param capacity Number of metric values to copy from the `stats` array.
 *                 This should not exceed the handle's allocated capacity.
 *
 * @return Return value indicating success:
 *         - RT_SUCCESS (0) if the values are successfully copied.
 */
int sc_metrics_values_set(struct sc_metrics_handle * metrics_handle, uint64_t values[], uint16_t capacity)
{
    assert(metrics_handle != NULL);
    assert(metrics_handle->values != NULL);
    assert(capacity <= metrics_handle->capacity);

    rte_memcpy((void *)metrics_handle->values, values, sizeof(uint64_t) * capacity);
    return RT_SUCCESS;
}

/**
 * @brief Get the values from the SC metrics handle.
 *
 * This function copies the metric values from the SC metrics handle into the
 * provided array. It ensures that the provided capacity does not exceed the
 * handle's allocated capacity. The function uses `rte_memcpy` to perform the
 * copy operation.
 *
 * @param metrics_handle Pointer to the SC metrics handle from which the values
 *                       will be retrieved. This handle must be valid and initialized.
 * @param values Array where the metric values will be copied.
 * @param capacity Number of metric values to copy into the `values` array.
 *                 This should not exceed the handle's allocated capacity.
 *
 * @return Return value indicating success:
 *         - RT_SUCCESS (0) if the values are successfully copied.
 */
int sc_metrics_values_get(struct sc_metrics_handle * metrics_handle, uint64_t values[], uint16_t capacity)
{
    assert(metrics_handle != NULL);
    assert(metrics_handle->values != NULL);
    assert(capacity <= metrics_handle->capacity);

    rte_memcpy(values, (void *)metrics_handle->values, sizeof(uint64_t) * capacity);
    return RT_SUCCESS;
}

/**
 * @brief Get a single value from the SC metrics handle.
 *
 * This function retrieves a single metric value from the SC metrics handle at
 * the specified key. The function ensures that the key is within the handle's
 * allocated capacity. The value is directly read from the handle's values array
 * at the specified key.
 *
 * @param metrics_handle Pointer to the SC metrics handle from which the value
 *                       will be retrieved. This handle must be valid and initialized.
 * @param value Pointer to the variable where the metric value will be stored.
 * @param key The key from which to retrieve the metric value. This key must be
 *            within the handle's allocated capacity.
 *
 * @return Return value indicating success:
 *         - RT_SUCCESS (0) if the value is successfully retrieved.
 */
int sc_metrics_value_get(struct sc_metrics_handle * metrics_handle, uint64_t * value, uint16_t key)
{
    assert(value != NULL);
    assert(metrics_handle != NULL);
    assert(metrics_handle->values != NULL);
    assert(key < metrics_handle->capacity);

    *value = metrics_handle->values[key];
    return RT_SUCCESS;
}

/**
 * @brief Reset all values in the SC metrics handle to zero.
 *
 * This function sets all values in the SC metrics handle to zero. It uses
 * `memset` to overwrite the entire allocated space for metric values with zeros.
 * This operation effectively resets the metrics handle to its initial state.
 *
 * @param metrics_handle Pointer to the SC metrics handle to be reset.
 *                       This handle must be valid and initialized.
 *
 * @return Return value indicating success:
 *         - RT_SUCCESS (0) if the values are successfully reset.
 */
int sc_metrics_values_reset(struct sc_metrics_handle * metrics_handle)
{
    assert(metrics_handle != NULL);
    assert(metrics_handle->values != NULL);

    memset((void *)metrics_handle->values, 0, sizeof(uint64_t) * metrics_handle->capacity);
    return RT_SUCCESS;
}

/**
 * @brief Accumulate values into the SC metrics handle.
 *
 * This function adds values from the `inc_values` array to the existing values
 * in the SC metrics handle. The accumulation is performed element-wise for
 * the specified `capacity`. The function ensures that the provided capacity
 * does not exceed the handle's allocated capacity.
 *
 * @param metrics_handle Pointer to the SC metrics handle where the values
 *                       will be accumulated. This handle must be valid and
 *                       initialized.
 * @param inc_values Array of values to be added to the current values in
 *                   the handle.
 * @param capacity Number of values to accumulate. This should not exceed
 *                 the handle's allocated capacity.
 *
 * @return Return value indicating success:
 *         - RT_SUCCESS (0) if the values are successfully accumulated.
 */
int sc_metrics_accumulate(struct sc_metrics_handle * metrics_handle, uint64_t inc_values[], uint16_t capacity)
{
    assert(metrics_handle != NULL);
    assert(metrics_handle->values != NULL);
    assert(capacity <= metrics_handle->capacity);

    volatile uint64_t * values = metrics_handle->values;

    for (uint16_t i = 0; i < capacity; i++)
    {
        values[i] += inc_values[i];
    }

    return RT_SUCCESS;
}