#ifndef RS485_BOOT_H
#define RS485_BOOT_H

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

#ifdef __cplusplus
extern "C" {
#endif

#define RS485_BOOT_VERSION          1U
#define RS485_BOOT_MAX_PAYLOAD      512U
#define RS485_BOOT_MAX_FRAME        (8U + RS485_BOOT_MAX_PAYLOAD + 4U)
#define RS485_BOOT_DATA_HEADER_SIZE 8U
#define RS485_BOOT_MAX_BLOCK        (RS485_BOOT_MAX_PAYLOAD - RS485_BOOT_DATA_HEADER_SIZE)

typedef enum {
    RS485_BOOT_IDLE = 0U,
    RS485_BOOT_RECEIVING = 1U,
    RS485_BOOT_READY = 2U,
    RS485_BOOT_FAILED = 3U
} rs485_boot_state_t;

typedef enum {
    RS485_BOOT_OK = 0U,
    RS485_BOOT_INVALID_ARGUMENT = 1U,
    RS485_BOOT_INVALID_LENGTH = 2U,
    RS485_BOOT_BUSY = 5U,
    RS485_BOOT_INTERNAL = 7U,
    RS485_BOOT_UNSUPPORTED = 0x11U
} rs485_boot_result_t;

typedef struct {
    uint32_t app_address;
    uint32_t app_size;
    uint16_t max_block_size;
} rs485_boot_config_t;

typedef struct {
    bool (*transmit)(void *user, const uint8_t *data, uint16_t length);
    bool (*erase)(void *user, uint32_t image_size);
    bool (*write)(void *user, uint32_t offset, const uint8_t *data, uint16_t length);
    bool (*read)(void *user, uint32_t offset, uint8_t *data, uint16_t length);
    bool (*image_valid)(void *user, uint32_t image_size, uint32_t image_crc32);
    void (*reboot)(void *user);
} rs485_boot_port_t;

typedef struct {
    rs485_boot_config_t config;
    rs485_boot_port_t port;
    void *port_user;
    uint8_t parser[RS485_BOOT_MAX_FRAME];
    uint16_t parser_length;
    uint8_t tx[RS485_BOOT_MAX_FRAME];
    uint8_t scratch[32];
    uint32_t image_size;
    uint32_t image_crc32;
    uint32_t next_offset;
    uint32_t crc_errors;
    rs485_boot_state_t state;
} rs485_boot_t;

bool rs485_boot_init(rs485_boot_t *boot, const rs485_boot_config_t *config,
                     const rs485_boot_port_t *port, void *port_user);
void rs485_boot_feed(rs485_boot_t *boot, const uint8_t *data, size_t length);
void rs485_boot_abort(rs485_boot_t *boot);
uint32_t rs485_boot_crc32(const uint8_t *data, size_t length);

#ifdef __cplusplus
}
#endif
#endif