#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
校验和调试工具 - 详细分析STM32输出的原始数据帧
"""

import serial
import struct
import time

# 协议常量
FRAME_HEADER = bytes([0xAA, 0x55])
FRAME_FOOTER = bytes([0x0D, 0x0A])
TYPE_GPS = 0x01
TYPE_IMU = 0x02

def calculate_checksum(data):
    """计算16位累加和"""
    return sum(data) & 0xFFFF

def main():
    port = "COM28"
    baudrate = 921600
    
    print(f"打开串口 {port} @ {baudrate}")
    
    try:
        ser = serial.Serial(port, baudrate, timeout=1)
        print("串口已打开，接收数据中...\n")
        
        buffer = bytearray()
        frame_count = 0
        
        while frame_count < 5:  # 只分析前5帧
            if ser.in_waiting > 0:
                data = ser.read(ser.in_waiting)
                buffer.extend(data)
                
                # 查找帧头
                while len(buffer) >= 9:
                    idx = buffer.find(FRAME_HEADER)
                    if idx == -1:
                        buffer.clear()
                        break
                    
                    if idx > 0:
                        buffer = buffer[idx:]
                    
                    # 检查是否有足够的数据解析帧头
                    if len(buffer) < 5:
                        break
                    
                    frame_type = buffer[2]
                    payload_len = struct.unpack('<H', buffer[3:5])[0]
                    expected_len = 2 + 1 + 2 + payload_len + 2 + 2
                    
                    print(f"\n[调试] 发现帧头 @ buffer[{idx}], 类型=0x{frame_type:02X}, 载荷长度={payload_len}, 需要={expected_len}, 可用={len(buffer)}")
                    
                    if len(buffer) < expected_len:
                        print(f"[调试] 数据不足，等待更多数据...")
                        break
                    
                    # 提取完整帧
                    frame = buffer[:expected_len]
                    buffer = buffer[expected_len:]
                    
                    frame_count += 1
                    
                    # 详细分析这一帧
                    print(f"{'='*70}")
                    print(f"帧 #{frame_count} - 类型: 0x{frame_type:02X} ({'GPS' if frame_type == TYPE_GPS else 'IMU' if frame_type == TYPE_IMU else '未知'})")
                    print(f"{'='*70}")
                    
                    # 打印原始十六进制
                    print(f"原始数据 ({len(frame)} 字节):")
                    hex_str = ' '.join(f'{b:02X}' for b in frame)
                    for i in range(0, len(hex_str), 72):
                        print(f"  {hex_str[i:i+72]}")
                    
                    # 解析各个部分
                    print(f"\n帧结构分析:")
                    print(f"  帧头: {frame[:2].hex().upper()} (应为 AA55)")
                    print(f"  类型: 0x{frame[2]:02X}")
                    print(f"  长度: {payload_len} (0x{frame[3]:02X}{frame[4]:02X})")
                    
                    payload = frame[5:5+payload_len]
                    print(f"  载荷: {payload.hex().upper()} ({len(payload)} 字节)")
                    
                    checksum_received = struct.unpack('<H', frame[5+payload_len:5+payload_len+2])[0]
                    print(f"  校验和(接收): 0x{checksum_received:04X}")
                    
                    footer = frame[5+payload_len+2:5+payload_len+4]
                    print(f"  帧尾: {footer.hex().upper()} (应为 0D0A)")
                    
                    # 计算校验和 - 三种方式
                    print(f"\n校验和验证:")
                    
                    # 方式1: Type + Length + Payload (正确方式)
                    checksum_data1 = frame[2:5+payload_len]
                    checksum_calc1 = calculate_checksum(checksum_data1)
                    match1 = "✓" if checksum_calc1 == checksum_received else "✗"
                    print(f"  方式1 (Type+Len+Payload): 0x{checksum_calc1:04X} {match1}")
                    print(f"    计算范围: 字节[2:{5+payload_len}] = {checksum_data1.hex().upper()}")
                    
                    # 方式2: 包含帧头 (错误方式)
                    checksum_data2 = frame[0:5+payload_len]
                    checksum_calc2 = calculate_checksum(checksum_data2)
                    match2 = "✓" if checksum_calc2 == checksum_received else "✗"
                    print(f"  方式2 (含帧头AA55): 0x{checksum_calc2:04X} {match2}")
                    
                    # 方式3: 只有Payload (错误方式)
                    checksum_calc3 = calculate_checksum(payload)
                    match3 = "✓" if checksum_calc3 == checksum_received else "✗"
                    print(f"  方式3 (仅Payload): 0x{checksum_calc3:04X} {match3}")
                    
                    # 计算差值
                    diff = checksum_received - checksum_calc1
                    print(f"\n  差值 (接收 - 方式1): {diff} (0x{diff & 0xFFFF:04X})")
                    
                    print()
                    
                    if frame_count >= 5:
                        break
            
            time.sleep(0.01)
        
        ser.close()
        print("分析完成")
        
    except Exception as e:
        print(f"错误: {e}")
        import traceback
        traceback.print_exc()

if __name__ == "__main__":
    main()