#ifndef MODBUS_DATA_STORE_H
#define MODBUS_DATA_STORE_H

#include <stdint.h>

#ifdef __cplusplus
extern "C" {
#endif

/* Logical PLC word-device spaces.  These values intentionally match the
 * PLSR D/HD/FD device codes, but this module does not depend on PLSR. */
typedef enum
{
    MODBUS_DATA_DEVICE_D = 0,
    MODBUS_DATA_DEVICE_HD,
    MODBUS_DATA_DEVICE_FD
} MODBUS_DATA_DEVICE;

/* Logical PLC bit-device spaces.  Standard Modbus coils expose M; X is
 * written by the input-image producer and HM is available to retained logic.
 * All consumers, including PLSR, read the same packed images here. */
typedef enum
{
    MODBUS_BIT_DEVICE_X = 0,
    MODBUS_BIT_DEVICE_M,
    MODBUS_BIT_DEVICE_HM
} MODBUS_BIT_DEVICE;

#define MODBUS_DATA_D_WORD_COUNT   (10000UL)
#define MODBUS_DATA_HD_WORD_COUNT  (10000UL)
#define MODBUS_DATA_FD_WORD_COUNT  (10000UL)
#define MODBUS_DATA_X_BIT_COUNT    (10000UL)
#define MODBUS_DATA_M_BIT_COUNT    (10000UL)
#define MODBUS_DATA_HM_BIT_COUNT   (10000UL)

uint8_t ModbusDataValidateWords(MODBUS_DATA_DEVICE device,
                                uint32_t firstAddress,
                                uint32_t wordCount);
uint8_t ModbusDataReadWord(MODBUS_DATA_DEVICE device,
                           uint32_t address,
                           uint16_t *value);
uint8_t ModbusDataReadDword(MODBUS_DATA_DEVICE device,
                            uint32_t lowAddress,
                            int32_t *value);
uint8_t ModbusDataWriteWord(MODBUS_DATA_DEVICE device,
                            uint32_t address,
                            uint16_t value);
uint8_t ModbusDataWriteWords(MODBUS_DATA_DEVICE device,
                             uint32_t firstAddress,
                             const uint16_t *values,
                             uint32_t wordCount);

/* Existing function 0x48 uses a sparse linear address space:
 * 0..19999 are normal SRAM and 40000..69998 are CCMRAM. */
uint8_t ModbusDataReadLinear(uint32_t address, uint16_t *value);

/* Even means stable; odd means a multi-register write is in progress. */
uint32_t ModbusDataGetWriteSequence(void);

uint8_t ModbusDataValidateBits(MODBUS_BIT_DEVICE device,
                               uint32_t firstAddress,
                               uint32_t bitCount);
uint8_t ModbusDataReadBit(MODBUS_BIT_DEVICE device,
                          uint32_t address,
                          uint8_t *value);
uint8_t ModbusDataWriteBit(MODBUS_BIT_DEVICE device,
                           uint32_t address,
                           uint8_t value);

#ifdef __cplusplus
}
#endif

#endif /* MODBUS_DATA_STORE_H */