/*
 * Copyright (c) 2022, Shenzhen CVA Innovation CO.,LTD
 * All rights reserved.
 *
 * Shenzhen CVA Innovation CO.,LTD (CVA chip) is supplying this file for use
 * exclusively with CVA's microcontroller products. This file can be freely
 * distributed within development tools that are supporting such microcontroller
 * products.
 *
 * THIS SOFTWARE IS PROVIDED "AS IS".  NO WARRANTIES, WHETHER EXPRESS, IMPLIED
 * OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE APPLY TO THIS SOFTWARE.
 * CVA SHALL NOT, IN ANY CIRCUMSTANCES, BE LIABLE FOR SPECIAL, INCIDENTAL,
 * OR CONSEQUENTIAL DAMAGES, FOR ANY REASON WHATSOEVER.
 */

#ifndef _GRADIENT_H_
#define _GRADIENT_H_

/*! \brief Contains public interface to various functions related
 *         to the 1st order linear curve with GRADIENT
 */

/*******************************************************************************
 * the includes
 ******************************************************************************/

#include <stdint.h>
#include "common/iqmath/iqmath.h"

#ifdef __cplusplus
extern "C" {
#endif

/*******************************************************************************
 * the defines
 ******************************************************************************/

/*******************************************************************************
 * the typedefs
 ******************************************************************************/

/*! \brief  Declaration of Gradient Class
 *
 */
typedef struct _GradientType_
{
    _iq target;   /*!< Input: target input */
    _iq upStep;   /*!< Parameter: up step of ramp */
    _iq downStep; /*!< Parameter: down step of ramp */
    _iq output;   /*!< Output: output value */

} GradientType;

/*******************************************************************************
 * the globals
 ******************************************************************************/

/*******************************************************************************
 * the function prototypes
 ******************************************************************************/

/*! \brief Initialize the Gradient instance
 *
 * This function initializes the Gradient instance
 *
 * \param[in] obj : pointer to Gradient instance
 * \param[in] upStep : step when going up
 * \param[in] downStep : step when going down
 */
static inline void Gradient_Init(GradientType *obj, _iq upStep, _iq downStep)
{
    obj->target   = 0;
    obj->output   = 0;
    obj->upStep   = upStep;
    obj->downStep = downStep;
}

/*! \brief Calculates the output
 *
 * This function calculates the output
 *
 * \param[in] obj : pointer to Gradient instance
 */
static inline void Gradient_Calc(GradientType *obj)
{
    _iq upStep   = _IQabs(obj->upStep);   /* step must be a positive value */
    _iq downStep = _IQabs(obj->downStep); /* step must be a positive value */

    if(obj->target > obj->output)
    {
        if((obj->target - obj->output) > upStep)
        {
            obj->output += upStep;
        }
        else
        {
            obj->output = obj->target; /* less than one step needed, just jump to the target */
        }
    }
    else if(obj->target < obj->output)
    {
        if((obj->output - obj->target) > downStep)
        {
            obj->output -= downStep;
        }
        else
        {
            obj->output = obj->target; /* less than one step needed, just jump to the target */
        }
    }
}

/*! \brief Calculate the output using the external reference
 *
 * This function calculates the output using the external reference,
 * instead of the internal output
 *
 * \param[in] obj : pointer to Gradient instance
 * \param[in] pOutput : pointer to external output
 */
static inline void Gradient_CalcExternal(GradientType *obj, _iq *pOutput)
{
    _iq upStep   = _IQabs(obj->upStep);   /* step must be a positive value */
    _iq downStep = _IQabs(obj->downStep); /* step must be a positive value */

    if(obj->target > (*pOutput))
    {
        if((obj->target - (*pOutput)) > upStep)
        {
            (*pOutput) += upStep;
        }
        else
        {
            (*pOutput) = obj->target; /* less than one step needed, just jump to the target */
        }
    }
    else if(obj->target < (*pOutput))
    {
        if(((*pOutput) - obj->target) > downStep)
        {
            (*pOutput) -= downStep;
        }
        else
        {
            (*pOutput) = obj->target; /* less than one step needed, just jump to the target */
        }
    }

    obj->output = *pOutput; /* We don't use the obj->output normally in this function, just be safe */
}

#ifdef __cplusplus
}
#endif /* extern "C" */

#endif /* _GRADIENT_H_ */