#!/usr/bin/env python3
# -*- coding: utf-8 -*-

import json
import time
import urllib
import hmac
import hashlib

# 1.AK/SK、host、method、URL绝对路径、querystring
# AK = 'ALTAKHxKxmjjm7Z19TpUxPAinY'
# SK = '5db9420661a549ee84440284ad07c229'

AK = 'ALTAKPk92fX9cgGDax83yNL8mP'
SK = '9b16b8efd4dc463d8bbd5462db1db8a5'

# 2.x-bce-date
x_bce_date = time.gmtime()
x_bce_date = time.strftime('%Y-%m-%dT%H:%M:%SZ', x_bce_date)

async def get_auth_header(method: str, url: str, header: dict, query={}, get_res=False):
    # 解析uri
    url_parse = urllib.parse.urlparse(url)
    uri = url_parse.path
    url_query = url_parse.query

    # 获取query
    if url_query:
        query = dict(urllib.parse.parse_qsl(url_query))

    # 4.认证字符串前缀
    authStringPrefix = "bce-auth-v1" + "/" + AK + "/" + x_bce_date + "/" +"1800"

    # windows下为urllib.parse.quote，Linux下为urllib.quote
    # 5.生成CanonicalRequest
    # 5.1生成CanonicalURI
    CanonicalURI = urllib.parse.quote(uri)

    # 如果您调用的接口的query比较复杂的话，需要做额外处理
    # 5.2生成CanonicalQueryString
    # CanonicalQueryString = query
    result = ['%s=%s' % (k, urllib.parse.quote(str(v))) for k, v in query.items() if k.lower != 'authorization']
    result.sort()
    CanonicalQueryString = '&'.join(result)

    # 5.3生成CanonicalHeaders
    result = []
    signedHeaders_list = []
    for key,value in header.items():
        tempStr = str(urllib.parse.quote(key.lower(),safe="")) + ":" + str(urllib.parse.quote(value,safe=""))
        signedHeaders_list.append(str(urllib.parse.quote(key.lower(),safe="")))
        result.append(tempStr)
    result.sort()
    signedHeaders = ';'.join(sorted(signedHeaders_list))
    CanonicalHeaders = "\n".join(result)

    # 5.4拼接得到CanonicalRequest
    CanonicalRequest = method + "\n" + CanonicalURI + "\n" + CanonicalQueryString +"\n" + CanonicalHeaders

    # 6.生成signingKey
    signingKey = hmac.new(SK.encode('utf-8'), authStringPrefix.encode('utf-8'), hashlib.sha256)

    # 7.生成Signature
    Signature = hmac.new((signingKey.hexdigest()).encode('utf-8'), CanonicalRequest.encode('utf-8'), hashlib.sha256)

    # 8.生成Authorization并放到header里
    header['Authorization'] = authStringPrefix + "/" + signedHeaders + "/" + Signature.hexdigest()

    if get_res:
        # 异步请求链接 返回结果
        async with aiohttp_client.request(
                        method=method,
                        url=url,
                        headers=header,
                        allow_redirects=True,
                        json=query) as res:
            return res
    else:
        return header