#ifndef MODBUSINO_H
#define MODBUSINO_H

#include <stdbool.h>
#include <stdint.h>


typedef enum mbsn_error {
    // Library errors
    MBSN_ERROR_TRANSPORT = -3,
    MBSN_ERROR_TIMEOUT = -2,
    MBSN_ERROR_INVALID_ARGUMENT = -1,
    MBSN_ERROR_NONE = 0,

    // Modbus exceptions
    MBSN_EXCEPTION_ILLEGAL_FUNCTION = 1,
    MBSN_EXCEPTION_ILLEGAL_DATA_ADDRESS = 2,
    MBSN_EXCEPTION_ILLEGAL_DATA_VALUE = 3,
    MBSN_EXCEPTION_SERVER_DEVICE_FAILURE = 4,
} mbsn_error;

#define mbsn_error_is_exception(e) ((e) > 0 && (e) < 5)


typedef uint8_t mbsn_bitfield[250];

#define mbsn_bitfield_read(bf, b) ((bool) ((bf)[(b) / 8] & (0x1 << ((b) % 8))))

#define mbsn_bitfield_write(bf, b, v)                                                                                  \
    (((bf)[(b) / 8]) = ((v) ? (((bf)[(b) / 8]) | (0x1 << ((b) % 8))) : (((bf)[(b) / 8]) & !(0x1 << ((b) % 8)))))


typedef enum mbsn_transport {
    MBSN_TRANSPORT_RTU = 1,
    MBSN_TRANSPORT_TCP = 2,
} mbsn_transport;


typedef struct {
    char* vendor_name;
    char* product_code;
    char* major_minor_revision;
    char* vendor_uri;
    char* product_name;
    char* model_name;
    char* user_application_name;
    char* extended;
} mbsn_device_identification_data_t;


typedef struct {
    mbsn_error (*read_coils)(uint16_t address, uint16_t quantity, mbsn_bitfield coils_out);
    mbsn_error (*read_discrete_inputs)(uint16_t address, uint16_t quantity, mbsn_bitfield inputs_out);
    mbsn_error (*read_holding_registers)(uint16_t address, uint16_t quantity, uint16_t* registers_out);
    mbsn_error (*read_input_registers)(uint16_t address, uint16_t quantity, uint16_t* registers_out);
    mbsn_error (*write_single_coil)(uint16_t address, bool value);
    mbsn_error (*write_single_register)(uint16_t address, uint16_t value);
    mbsn_error (*write_multiple_coils)(uint16_t address, uint16_t quantity, mbsn_bitfield coils);
    mbsn_error (*write_multiple_registers)(uint16_t address, uint16_t quantity, uint16_t* registers);
} mbsn_callbacks;


typedef struct mbsn_t {
    // Private fields
    mbsn_callbacks callbacks;

    int64_t byte_timeout_ms;
    int64_t response_timeout_ms;

    mbsn_transport transport;
    mbsn_error (*transport_read_byte)(uint8_t*);
    mbsn_error (*transport_write_byte)(uint8_t);

    uint8_t address_rtu;
    uint8_t server_dest_address_rtu;
} mbsn_t;


mbsn_error mbsn_client_create(mbsn_t* mbsn, mbsn_transport transport);

mbsn_error mbsn_server_create(mbsn_t* mbsn, mbsn_transport transport, uint8_t address, mbsn_callbacks callbacks);

void mbsn_set_response_timeout(mbsn_t* mbsn, int64_t timeout_ms);

void mbsn_set_byte_timeout(mbsn_t* mbsn, int64_t timeout_ms);

void mbsn_client_set_server_address(mbsn_t* mbsn, uint16_t address);

mbsn_error mbsn_server_poll(mbsn_t* mbsn);

mbsn_error mbsn_read_coils(uint16_t address, uint16_t quantity, uint8_t* coils_out);

mbsn_error mbsn_read_discrete_inputs(uint16_t address, uint16_t quantity, uint8_t* inputs_out);

mbsn_error mbsn_read_holding_registers(uint16_t address, uint16_t quantity, uint16_t* registers_out);

mbsn_error mbsn_read_input_registers(uint16_t address, uint16_t quantity, uint16_t* registers_out);

mbsn_error mbsn_write_single_coil(uint16_t address, uint8_t value);

mbsn_error mbsn_write_single_register(uint16_t address, uint16_t value);

mbsn_error mbsn_write_multiple_coils(uint16_t address, uint16_t quantity, const uint8_t* values);

mbsn_error mbsn_write_multiple_registers(uint16_t address, uint16_t quantity, const uint16_t* values);

const char* mbsn_strerror(int error);


#endif    //MODBUSINO_H