#include "data_packet.h"

// CRC16-MODBUS
uint16_t Calculate_CRC16(uint8_t *data, uint16_t len) {
    uint16_t crc = 0xFFFF;
    for (uint16_t i = 0; i < len; i++) {
        crc ^= data[i];
        for (uint8_t j = 0; j < 8; j++) {
            if (crc & 0x0001) {
                crc = (crc >> 1) ^ 0xA001;
            } else {
                crc = crc >> 1;
            }
        }
    }
    return crc;
}

void PackData(DataPacket_t *packet, int32_t adc1, int32_t adc2, int32_t adc3)
{
    // packet->start_byte = PACKET_START_BYTE; // Incorrect assignment
    uint32_t start = PACKET_START_BYTE;
    packet->start_byte[0] = (start >> 24) & 0xFF; // A5
    packet->start_byte[1] = (start >> 16) & 0xFF; // A5
    packet->start_byte[2] = (start >> 8)  & 0xFF; // 5A
    packet->start_byte[3] = (start)       & 0xFF; // 5A
    
    // MCU 原生字节序 (小端)
    packet->adc_data1 = adc1;
    packet->adc_data2 = adc2;
    packet->adc_data3 = adc3;
    
    // 计算校验和 (只计算 ADC 数据部分)
    // uint16_t checksum = Calculate_CRC16((uint8_t*)&packet->adc_data1, sizeof(uint32_t) * 3);
    // packet->checksum = checksum; // 校验和也用小端
    
//    packet->end_byte = PACKET_END_BYTE;
}