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

"""
 * Copyright 2015 Alibaba Group Holding Limited
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
"""

import base64
import hashlib
import hmac
import requests
import time
import uuid

from urllib import parse
from ali_speech._logging import _log


class AccessToken:
    @staticmethod
    def _encode_text(text):
        encoded_text = parse.quote_plus(text)
        return encoded_text.replace('+', '%20').replace('*', '%2A').replace('%7E', '~')

    @staticmethod
    def _encode_dict(dic):
        keys = dic.keys()
        dic_sorted = [(key, dic[key]) for key in sorted(keys)]
        encoded_text = parse.urlencode(dic_sorted)
        return encoded_text.replace('+', '%20').replace('*', '%2A').replace('%7E', '~')

    @staticmethod
    def create_token(access_key_id, access_key_secret):
        parameters = {'AccessKeyId': access_key_id,
                      'Action': 'CreateToken',
                      'Format': 'JSON',
                      'RegionId': 'cn-shanghai',
                      'SignatureMethod': 'HMAC-SHA1',
                      'SignatureNonce': str(uuid.uuid1()),
                      'SignatureVersion': '1.0',
                      'Timestamp': time.strftime("%Y-%m-%dT%H:%M:%SZ", time.gmtime()),
                      'Version': '2019-02-28'}
        # 构造规范化的请求字符串
        query_string = AccessToken._encode_dict(parameters)
        _log.debug('规范化的请求字符串: %s' % query_string)
        # 构造待签名字符串
        string_to_sign = 'GET' + '&' + AccessToken._encode_text('/') + '&' + AccessToken._encode_text(query_string)
        _log.debug('待签名的字符串: %s' % string_to_sign)
        # 计算签名
        secreted_string = hmac.new(bytes(access_key_secret + '&', encoding='utf-8'),
                                   bytes(string_to_sign, encoding='utf-8'),
                                   hashlib.sha1).digest()
        signature = base64.b64encode(secreted_string)
        _log.debug('签名: %s' % signature)
        # 进行URL编码
        signature = AccessToken._encode_text(signature)
        _log.debug('URL编码后的签名: %s' % signature)
        # 调用服务
        full_url = 'http://nls-meta.cn-shanghai.aliyuncs.com/?Signature=%s&%s' % (signature, query_string)
        _log.debug('url: %s' % full_url)
        # 提交HTTP GET请求
        response = requests.get(full_url)
        if response.ok:
            root_obj = response.json()
            key = 'Token'
            if key in root_obj:
                token = root_obj[key]['Id']
                expire_time = root_obj[key]['ExpireTime']
                return token, expire_time

        _log.error(response.text)
        return None, None