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#ifndef NABLA_INTEGRAL_COMPUTE_API_H
#define NABLA_INTEGRAL_COMPUTE_API_H

#include <stddef.h>

#include "../macros.h"
#include "../types/cuest_types.h"
#include "../types/cuest_parameter_types.h"
#include "../types/workspace_api.h"

#ifdef __cplusplus
extern "C" {
#endif

/**
 * @brief Compute the atomic orbital nabla matrix using the provided \c cuestOEIntPlan_t plan.
 * @ingroup Nabla
 * @since v0.2.0
 *
 * The output buffer must be preallocated and sized for nao × nao elements, where nao is the
 * number of atomic orbitals in the basis. Temporary workspace must be allocated using size
 * returned by \c cuestNablaComputeWorkspaceQuery.
 *
 * @param[in]  handle             cuEST handle. Must not be NULL.
 * @param[in]  plan               One-electron integral computation plan (opaque handle). Must not be NULL.
 * @param[in]  parameters         Compute parameters (\c cuestNablaComputeParameters_t). Must not be NULL
 * @param[in]  temporaryWorkspace Temporary workspace buffers for computation (preallocated). Must not be NULL.
 * @param[in]  component          Enum (\c cuestNablaComputeParametersComponent_t) defining the nabla operator (i.e. \f$\nabla_x\f$, \f$\nabla_y\f$, or \f$\nabla_z\f$).
 * @param[out] outMatrix          Output GPU buffer for computed nabla matrix elements [size: nao × nao]. Must not be NULL.
 *                                Elements of this array are overwritten by the calculation results.
 *
 * @return
 *   - \c CUEST_STATUS_SUCCESS on success;
 *   - \c CUEST_STATUS_INVALID_HANDLE if the cuEST handle is NULL;
 *   - \c CUEST_STATUS_NULL_POINTER if any required pointer is NULL;
 *   - \c CUEST_STATUS_INVALID_TYPE if opaque handles are not the correct type;
 *   - \c CUEST_STATUS_INVALID_ARGUMENT if \c component is not a valid \c cuestNablaComputeParametersComponent_t value;
 *   - \c CUEST_STATUS_EXCEPTION or \c CUEST_STATUS_UNKNOWN_ERROR otherwise.
 */
CUEST_API
cuestStatus_t cuestNablaCompute(
    cuestHandle_t handle,
    const cuestOEIntPlan_t plan,
    const cuestNablaComputeParameters_t parameters,
    cuestWorkspace_t* temporaryWorkspace,
    cuestNablaComputeParametersComponent_t component,
    double* outMatrix);

/**
 * @brief Query the temporary workspace required (in bytes) for nabla matrix calculation.
 * @ingroup Nabla
 * @since v0.2.0
 *
 * This function computes the workspace requirements for a requested nabla calculation. Fill the 
 * provided workspace descriptor with host and device buffer sizes required. The \c outMatrix pointer may be NULL.
 *
 * @param[in]  handle                            cuEST handle. Must not be NULL.
 * @param[in]  plan                              One-electron integral computation plan (opaque handle). Must not be NULL.
 * @param[in]  parameters                        Compute parameters (\c cuestNablaComputeParameters_t). Must not be NULL
 * @param[out] temporaryWorkspaceDescriptor      Output descriptor for temporary workspace sizes. Must not be NULL.
 * @param[in]  component                         Enum (\c cuestNablaComputeParametersComponent_t) defining the nabla operator (i.e. \f$\nabla_x\f$, \f$\nabla_y\f$, or \f$\nabla_z\f$).
 * @param      outMatrix                         User matrix buffer (may be NULL during the workspace query).
 *
 * @return
 *   - \c CUEST_STATUS_SUCCESS on success;
 *   - \c CUEST_STATUS_INVALID_HANDLE if the cuEST handle is NULL;
 *   - \c CUEST_STATUS_NULL_POINTER if any required pointer is NULL;
 *   - \c CUEST_STATUS_INVALID_TYPE if opaque handles are not the correct type;
 *   - \c CUEST_STATUS_INVALID_ARGUMENT if \c component is not a valid \c cuestNablaComputeParametersComponent_t value;
 *   - \c CUEST_STATUS_EXCEPTION or \c CUEST_STATUS_UNKNOWN_ERROR otherwise.
 */
CUEST_API
cuestStatus_t cuestNablaComputeWorkspaceQuery(
    cuestHandle_t handle,
    const cuestOEIntPlan_t plan,
    const cuestNablaComputeParameters_t parameters,
    cuestWorkspaceDescriptor_t* temporaryWorkspaceDescriptor,
    cuestNablaComputeParametersComponent_t component,
    double* outMatrix);

#ifdef __cplusplus
}
#endif

#endif /* NABLA_INTEGRAL_COMPUTE_API_H */
