"""
编解码工具模块
支持 HEX / GB2312 / UTF-8 之间的转换
"""

import binascii
import re
from core.constants import EncodeMode


def encode_data(text: str, mode: EncodeMode) -> bytes:
 """
 将输入文本按指定模式编码为字节数据
 :param text: 输入文本
 :param mode: 编码模式
 :return: 编码后的字节数据
 """
 if mode == EncodeMode.HEX:
 return _hex_to_bytes(text)
 elif mode == EncodeMode.GB2312:
 return text.encode('gb2312', errors='replace')
 elif mode == EncodeMode.UTF8:
 return text.encode('utf-8', errors='replace')
 else:
 raise ValueError(f"不支持的编码模式: {mode}")


def decode_data(data: bytes, mode: EncodeMode) -> str:
 """
 将接收到的字节数据按指定模式解码为显示文本
 :param data: 字节数据
 :param mode: 解码模式
 :return: 解码后的显示文本
 """
 if not data:
 return ""

 if mode == EncodeMode.HEX:
 return _bytes_to_hex(data)
 elif mode == EncodeMode.GB2312:
 try:
 return data.decode('gb2312', errors='replace')
 except Exception:
 return data.decode('gb2312', errors='replace')
 elif mode == EncodeMode.UTF8:
 try:
 return data.decode('utf-8', errors='replace')
 except Exception:
 return data.decode('utf-8', errors='replace')
 else:
 raise ValueError(f"不支持的解码模式: {mode}")


def _hex_to_bytes(hex_str: str) -> bytes:
 """
 将十六进制字符串转为字节,支持空格/逗号/无分隔符
 例如: "01 02 AB" / "01,02,AB" / "0102AB"
 """
 # 去除空格、逗号、0x前缀等
 cleaned = re.sub(r'[,\s]', '', hex_str)
 # 去除 0x 前缀
 cleaned = re.sub(r'0x', '', cleaned, flags=re.IGNORECASE)

 if not cleaned:
 raise ValueError("HEX 字符串为空")

 if len(cleaned) % 2 != 0:
 raise ValueError(f"HEX 字符长度必须为偶数: {cleaned}")

 try:
 return binascii.unhexlify(cleaned)
 except binascii.Error as e:
 raise ValueError(f"HEX 解析错误: {e}")


def _bytes_to_hex(data: bytes) -> str:
 """将字节数据转为空格分隔的大写十六进制字符串"""
 return ' '.join(f'{b:02X}' for b in data)


def validate_hex_string(hex_str: str) -> tuple:
 """
 校验 HEX 字符串是否合法
 :return: (is_valid, error_msg)
 """
 if not hex_str.strip():
 return False, "输入为空"

 cleaned = re.sub(r'[,\s]', '', hex_str)
 cleaned = re.sub(r'0x', '', cleaned, flags=re.IGNORECASE)

 if not cleaned:
 return False, "输入为空"

 if len(cleaned) % 2 != 0:
 return False, "HEX 字符长度必须为偶数(每个字节由两个十六进制字符表示)"

 if not re.match(r'^[0-9A-Fa-f]+$', cleaned):
 return False, "包含非法字符,只允许 0-9, A-F"

 return True, ""