#ifndef MODBUS_RTU_H
#define MODBUS_RTU_H

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

#include "driver/uart.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"

#include "modbus_memory.h"

#ifdef __cplusplus
extern "C" {
#endif

#define MODBUS_RTU_MAX_ADU_LEN   256
#define MODBUS_RTU_MAX_DEVICES   16

typedef struct
{
    uint8_t unit_id;
    modbus_memory_t *mem;
    const char *name;
} modbus_rtu_device_t;

typedef struct
{
    uart_port_t uart_num;
    uint32_t baud_rate;
    uint8_t unit_count;
    modbus_rtu_device_t devices[MODBUS_RTU_MAX_DEVICES];
} modbus_rtu_ctx_t;

void modbus_rtu_init(modbus_rtu_ctx_t *ctx, uart_port_t uart_num, uint32_t baud_rate);

bool modbus_rtu_add_device(modbus_rtu_ctx_t *ctx,
                           uint8_t unit_id,
                           modbus_memory_t *mem,
                           const char *name);

modbus_rtu_device_t *modbus_rtu_find_device(modbus_rtu_ctx_t *ctx, uint8_t unit_id);

int modbus_rtu_read_frame(modbus_rtu_ctx_t *ctx,
                          uint8_t *buf,
                          size_t buf_size,
                          TickType_t first_byte_timeout);

bool modbus_rtu_process_request(modbus_rtu_ctx_t *ctx,
                                const uint8_t *req,
                                size_t req_len,
                                uint8_t *resp,
                                size_t resp_size,
                                size_t *resp_len);

uint16_t modbus_rtu_crc16(const uint8_t *data, size_t len);

#ifdef __cplusplus
}
#endif

#endif /* MODBUS_RTU_H */