/* Copyright 2018 Espressif Systems (Shanghai) PTE LTD
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef _ESP_MB_MASTER_INTERFACE_H
#define _ESP_MB_MASTER_INTERFACE_H

#include <stdint.h>                 // for standard int types definition
#include <stddef.h>                 // for NULL and std defines
#include "soc/soc.h"                // for BITN definitions
#include "esp_modbus_common.h"      // for common types

#ifdef __cplusplus
extern "C" {
#endif

/*!
 * \brief Modbus descriptor table parameter type defines.
 */
typedef enum {
    PARAM_TYPE_U8 = 0x00,                   /*!< Unsigned 8 */
    PARAM_TYPE_U16 = 0x01,                  /*!< Unsigned 16 */
    PARAM_TYPE_U32 = 0x02,                  /*!< Unsigned 32 */
    PARAM_TYPE_FLOAT = 0x03,                /*!< Float type */
    PARAM_TYPE_ASCII = 0x04                 /*!< ASCII type */
} mb_descr_type_t;

/*!
 * \brief Modbus descriptor table parameter size in bytes.
 */
typedef enum {
    PARAM_SIZE_U8 = 0x01,                   /*!< Unsigned 8 */
    PARAM_SIZE_U16 = 0x02,                  /*!< Unsigned 16 */
    PARAM_SIZE_U32 = 0x04,                  /*!< Unsigned 32 */
    PARAM_SIZE_FLOAT = 0x04,                /*!< Float size */
    PARAM_SIZE_ASCII = 0x08,                /*!< ASCII size */
    PARAM_SIZE_ASCII24 = 0x18,              /*!< ASCII24 size */
    PARAM_MAX_SIZE
} mb_descr_size_t;

/*!
 * \brief Modbus parameter options for description table
 */
typedef union {
    struct {
        int opt1;                         /*!< Parameter option1 */
        int opt2;                         /*!< Parameter option2 */
        int opt3;                         /*!< Parameter option3 */
    };
    struct {
        int min;                          /*!< Parameter minimum value */
        int max;                          /*!< Parameter maximum value */
        int step;                         /*!< Step of parameter change tracking */
    };
} mb_parameter_opt_t;

/**
 * @brief Permissions for the characteristics
 */
typedef enum {
    PAR_PERMS_READ               = 1 << BIT0,                                   /**< the characteristic of the device are readable */
    PAR_PERMS_WRITE              = 1 << BIT1,                                   /**< the characteristic of the device are writable*/
    PAR_PERMS_TRIGGER            = 1 << BIT2,                                   /**< the characteristic of the device are triggerable */
    PAR_PERMS_READ_WRITE         = PAR_PERMS_READ | PAR_PERMS_WRITE,            /**< the characteristic of the device are readable & writable */
    PAR_PERMS_READ_TRIGGER       = PAR_PERMS_READ | PAR_PERMS_TRIGGER,          /**< the characteristic of the device are readable & triggerable */
    PAR_PERMS_WRITE_TRIGGER      = PAR_PERMS_WRITE | PAR_PERMS_TRIGGER,         /**< the characteristic of the device are writable & triggerable */
    PAR_PERMS_READ_WRITE_TRIGGER = PAR_PERMS_READ_WRITE | PAR_PERMS_TRIGGER,    /**< the characteristic of the device are readable & writable & triggerable */
} mb_param_perms_t;

/**
 * @brief Characteristics descriptor type is used to describe characteristic and
 * link it with Modbus parameters that reflect its data.
 */
typedef struct {
    uint16_t            cid;                /*!< Characteristic cid */
    const char*         param_key;          /*!< The key (name) of the parameter */
    const char*         param_units;        /*!< The physical units of the parameter */
    uint8_t             mb_slave_addr;      /*!< Slave address of device in the Modbus segment */
    mb_param_type_t     mb_param_type;      /*!< Type of modbus parameter */
    uint16_t            mb_reg_start;       /*!< This is the Modbus register address. This is the 0 based value. */
    uint16_t            mb_size;            /*!< Size of mb parameter in registers */
    uint16_t            param_offset;       /*!< Parameter name (OFFSET in the parameter structure) */
    mb_descr_type_t     param_type;         /*!< Float, U8, U16, U32, ASCII, etc. */
    mb_descr_size_t     param_size;         /*!< Number of bytes in the parameter. */
    mb_parameter_opt_t  param_opts;         /*!< Parameter options used to check limits and etc. */
    mb_param_perms_t    access;             /*!< Access permissions based on mode */
} mb_parameter_descriptor_t;

/**
 * @brief Modbus register request type structure
 */
typedef struct {
    uint8_t slave_addr;             /*!< Modbus slave address */
    uint8_t command;                /*!< Modbus command to send */
    uint16_t reg_start;             /*!< Modbus start register */
    uint16_t reg_size;              /*!< Modbus number of registers */
} mb_param_request_t;

/**
 * @brief Initialize Modbus controller and stack for TCP port
 *
 * @param[out] handler handler(pointer) to master data structure
 * @return
 *     - ESP_OK                 Success
 *     - ESP_ERR_NO_MEM         Parameter error
 *     - ESP_ERR_NOT_SUPPORTED  Port type not supported
 *     - ESP_ERR_INVALID_STATE  Initialization failure
 */
esp_err_t mbc_master_init_tcp(void** handler);

/**
 * @brief Initialize Modbus Master controller and stack for Serial port
 *
 * @param[out] handler handler(pointer) to master data structure
 * @param[in] port_type type of stack
 * @return
 *     - ESP_OK                 Success
 *     - ESP_ERR_NO_MEM         Parameter error
 *     - ESP_ERR_NOT_SUPPORTED  Port type not supported
 *     - ESP_ERR_INVALID_STATE  Initialization failure
 */
esp_err_t mbc_master_init(mb_port_type_t port_type, void** handler);

/**
 * @brief Initialize Modbus Master controller interface handle
 *
 * @param[in] handler - pointer to master data structure
 */
void mbc_master_init_iface(void* handler);

/**
 * @brief Destroy Modbus controller and stack
 *
 * @return
 *     - ESP_OK   Success
 *     - ESP_ERR_INVALID_STATE Parameter error
 */
esp_err_t mbc_master_destroy(void);

/**
 * @brief Start Modbus communication stack
 *
 * @return
 *     - ESP_OK   Success
 *     - ESP_ERR_INVALID_ARG Modbus stack start error
 */
esp_err_t mbc_master_start(void);

/**
 * @brief Set Modbus communication parameters for the controller
 *
 * @param comm_info Communication parameters structure.
 *
 * @return
 *     - ESP_OK Success
 *     - ESP_ERR_INVALID_ARG Incorrect parameter data
 */
esp_err_t mbc_master_setup(void* comm_info);

/***************************** Specific interface functions ********************************************
 * Interface functions below provide basic methods to read/write access to slave devices in Modbus
 * segment as well as API to read specific supported characteristics linked to Modbus parameters
 * of devices in Modbus network.
*******************************************************************************************************/

/**
 * @brief Assign parameter description table for Modbus controller interface.
 *
 * @param[in] descriptor pointer to parameter description table
 * @param num_elements number of elements in the table
 *
 * @return
 *     - esp_err_t ESP_OK - set descriptor successfully
 *     - esp_err_t ESP_ERR_INVALID_ARG - invalid argument in function call
 */
esp_err_t mbc_master_set_descriptor(const mb_parameter_descriptor_t* descriptor, const uint16_t num_elements);

/**
 * @brief Send data request as defined in parameter request, waits response
 *        from slave and returns status of command execution. This function provides standard way
 *        for read/write access to Modbus devices in the network.
 *
 * @param[in] request pointer to request structure of type mb_param_request_t
 * @param[in] data_ptr pointer to data buffer to send or received data (dependent of command field in request)
 *
 * @return
 *     - esp_err_t ESP_OK - request was successful
 *     - esp_err_t ESP_ERR_INVALID_ARG - invalid argument of function
 *     - esp_err_t ESP_ERR_INVALID_RESPONSE - an invalid response from slave
 *     - esp_err_t ESP_ERR_TIMEOUT - operation timeout or no response from slave
 *     - esp_err_t ESP_ERR_NOT_SUPPORTED - the request command is not supported by slave
 *     - esp_err_t ESP_FAIL - slave returned an exception or other failure
 */
esp_err_t mbc_master_send_request(mb_param_request_t* request, void* data_ptr);

/**
 * @brief Get information about supported characteristic defined as cid. Uses parameter description table to get
 *        this information. The function will check if characteristic defined as a cid parameter is supported
 *        and returns its description in param_info. Returns ESP_ERR_NOT_FOUND if characteristic is not supported.
 *
 * @param[in] cid characteristic id
 * @param param_info pointer to pointer of characteristic data.
 *
 * @return
 *     - esp_err_t ESP_OK - request was successful and buffer contains the supported characteristic name
 *     - esp_err_t ESP_ERR_INVALID_ARG - invalid argument of function
 *     - esp_err_t ESP_ERR_NOT_FOUND - the characteristic (cid) not found
 *     - esp_err_t ESP_FAIL - unknown error during lookup table processing
*/
esp_err_t mbc_master_get_cid_info(uint16_t cid, const mb_parameter_descriptor_t** param_info);

/**
 * @brief Read parameter from modbus slave device whose name is defined by name and has cid.
 *        The additional data for request is taken from parameter description (lookup) table.
 *
 * @param[in] cid id of the characteristic for parameter
 * @param[in] name pointer into string name (key) of parameter (null terminated)
 * @param[out] value pointer to data buffer of parameter
 * @param[out] type parameter type associated with the name returned from parameter description table.
 *
 * @return
 *     - esp_err_t ESP_OK - request was successful and value buffer contains
 *                          representation of actual parameter data from slave
 *     - esp_err_t ESP_ERR_INVALID_ARG - invalid argument of function or parameter descriptor
 *     - esp_err_t ESP_ERR_INVALID_RESPONSE - an invalid response from slave
 *     - esp_err_t ESP_ERR_INVALID_STATE - invalid state during data processing or allocation failure
 *     - esp_err_t ESP_ERR_TIMEOUT - operation timed out and no response from slave
 *     - esp_err_t ESP_ERR_NOT_SUPPORTED - the request command is not supported by slave
 *     - esp_err_t ESP_ERR_NOT_FOUND - the parameter is not found in the parameter description table
 *     - esp_err_t ESP_FAIL - slave returned an exception or other failure
*/
esp_err_t mbc_master_get_parameter(uint16_t cid, char* name, uint8_t* value, uint8_t *type);

/**
 * @brief Set characteristic's value defined as a name and cid parameter.
 *        The additional data for cid parameter request is taken from master parameter lookup table.
 *
 * @param[in] cid id of the characteristic for parameter
 * @param[in] name pointer into string name (key) of parameter (null terminated)
 * @param[out] value pointer to data buffer of parameter (actual representation of json value field in binary form)
 * @param[out] type pointer to parameter type associated with the name returned from parameter lookup table.
 *
 * @return
 *     - esp_err_t ESP_OK - request was successful and value was saved in the slave device registers
 *     - esp_err_t ESP_ERR_INVALID_ARG - invalid argument of function or parameter descriptor
 *     - esp_err_t ESP_ERR_INVALID_RESPONSE - an invalid response from slave during processing of parameter
 *     - esp_err_t ESP_ERR_INVALID_STATE - invalid state during data processing or allocation failure
 *     - esp_err_t ESP_ERR_TIMEOUT - operation timed out and no response from slave
 *     - esp_err_t ESP_ERR_NOT_SUPPORTED - the request command is not supported by slave
 *     - esp_err_t ESP_FAIL - slave returned an exception or other failure
*/
esp_err_t mbc_master_set_parameter(uint16_t cid, char* name, uint8_t* value, uint8_t *type);

#ifdef __cplusplus
}
#endif

#endif // _ESP_MB_MASTER_INTERFACE_H
