# -*- coding: utf-8 -*-
# !/usr/bin/env python

import random
import string
import struct
import time

def get_random_str(num, seq=string.ascii_letters):
    ret_list = []
    for i in range(1, num + 1):
        ret_list.append("".join(random.sample(seq, 1)))

    return "".join(ret_list)

def make_six_bytes_session_id():
    # 至少可以用到2050
    ts = long(time.time() * 100000)
    ts = ts + long(get_random_str(2, seq = string.digits))
    return fill_2_hexByte(hex(ts), 12)

def hexbyte_2_bin(hexCode):
    binTemp = bin(int(hexCode, 16))
    needNum = 8 - len(binTemp) + 2
    c = '00000000'
    result = c[0:needNum] + binTemp[2::]
    return result


def decimal_2_hexByte(decimalCode):
    hexTemp = hex(decimalCode)
    c = '00'
    needNum = 2 - len(hexTemp) + 2
    result = c[0:needNum] + hexTemp[2::]
    return result


def fill_2_hexByte(hexCode, num = 4, reverse = False):
    hexCode = hexCode.replace('L', '')
    tList = ['0' for _ in range(num)]
    c = ''.join(tList)
    needNum = len(c) + 2 - len(hexCode)
    if needNum <= 0:
        return hexCode[2::].upper()
    result = c[0:needNum] + hexCode[2::]

    if reverse:
        return reverse_hex(result).upper()
    return result.upper()


def pack_float(value, reverse = False):
    """
    将浮点数转换为16进制转换的 float
    :param value: 浮点数
    :param reverse: 小端 （True）或者 大端
    :return:
    """
    sign = ">f" if not reverse else "<f"
    return struct.pack(sign, value).encode("hex")


def asc_to_string(ascString):
    result = ''
    for ii in range(len(ascString) / 2):
        char = int(ascString[ii * 2:ii * 2 + 2], 16)
        if char == 0:
            break
        result += chr(char)
    return result


def unpack_float(value, reverse = False):
    """
    解析16进制浮点数
    :param value:  16进制浮点数
    :param reverse:小端 （True）或者 大端
    :return:
    """
    sign = ">f" if not reverse else "<f"
    return struct.unpack(sign, value.decode("hex"))[0]


def reverse_hex(hexNum):
    newHexNum = ""
    while hexNum:
        newHexNum += hexNum[-2:]
        hexNum = hexNum[: -2]

    return newHexNum


def calc_crc(data):
    checkSum = 0
    for ii in range(len(data) / 2):
        hexByte = int(data[2 * ii:2 * ii + 2], 16)
        checkSum = checkSum ^ hexByte

    checkSum = fill_2_hexByte(hex(checkSum), 1)
    return str(checkSum)