#include "include/cmd_parser.h"

// 定义协议中的常量
#define HEADER_BYTE1 0xEF
#define HEADER_BYTE2 0xEF

// 校验函数：简单求和校验
uint8_t calculate_checksum(const uint8_t *data, uint8_t len)
{
    uint8_t checksum = 0;
    for (uint8_t i = 0; i < len; ++i)
    {
        checksum += data[i];
    }
    return checksum;
}

// 串口指令解析函数
int8_t parse_serial_command(const uint8_t *buffer, uint8_t length)
{
    if (length < 7)
    {
        // 长度不足以包含最小协议帧
        return -1;
    }

    // 检查头部
    if (buffer[0] != HEADER_BYTE1 || buffer[1] != HEADER_BYTE2)
    {
        // 头部不匹配
        return -2;
    }

    // 读取长度
    uint8_t len = buffer[2];

    // 读取地址
    uint8_t addr = buffer[3];

    // 读取指令
    const uint8_t cmd = buffer[4];
    // 读取数据
    const uint8_t *data = &buffer[5];

    // 读取校验
    uint8_t received_checksum = buffer[2 + len];

    // 计算校验
    uint8_t calculated_checksum = calculate_checksum(buffer, 2 + len);

    // 校验验证
    if (received_checksum != calculated_checksum)
    {
        // 校验失败
        return -4;
    }
    else
    {
        // printf("check success!\n");
    }

    // 返回指令
    return cmd;
}