# -*- coding: UTF-8 -*-
import hashlib
import hmac
import string
import datetime
import requests
import json
import time

AUTHORIZATION = "authorization"
BCE_PREFIX = "x-bce-"
DEFAULT_ENCODING = 'UTF-8'


# 保存AK/SK的类
class BceCredentials(object):
    def __init__(self, access_key_id, secret_access_key):
        self.access_key_id = access_key_id
        self.secret_access_key = secret_access_key


# 根据RFC 3986，除了：
#   1.大小写英文字符
#   2.阿拉伯数字
#   3.点'.'、波浪线'~'、减号'-'以及下划线'_'
# 以外都要编码
RESERVED_CHAR_SET = set(string.ascii_letters + string.digits + '.~-_')


def get_normalized_char(i):
    char = chr(i)
    if char in RESERVED_CHAR_SET:
        return char
    else:
        return '%%%02X' % i


NORMALIZED_CHAR_LIST = [get_normalized_char(i) for i in range(256)]


# 正规化字符串
def normalize_string(in_str, encoding_slash=True):
    if in_str is None:
        return ''

    # 如果输入是unicode，则先使用UTF8编码之后再编码
    in_str = in_str.encode(DEFAULT_ENCODING) if isinstance(
        in_str, unicode) else str(in_str)

    # 在生成规范URI时。不需要对斜杠'/'进行编码，其他情况下都需要
    if encoding_slash:
        def encode_f(c): return NORMALIZED_CHAR_LIST[ord(c)]
    else:
        # 仅仅在生成规范URI时。不需要对斜杠'/'进行编码
        def encode_f(c): return NORMALIZED_CHAR_LIST[ord(c)] if c != '/' else c

    # 按照RFC 3986进行编码
    return ''.join([encode_f(ch) for ch in in_str])


# 生成规范时间戳
def get_canonical_time(timestamp=0):
    # 不使用任何参数调用的时候返回当前时间
    if timestamp == 0:
        utctime = datetime.datetime.utcnow()
    else:
        utctime = datetime.datetime.utcfromtimestamp(timestamp)

    # 时间戳格式：[year]-[month]-[day]T[hour]:[minute]:[second]Z
    return "%04d-%02d-%02dT%02d:%02d:%02dZ" % (
        utctime.year, utctime.month, utctime.day,
        utctime.hour, utctime.minute, utctime.second)


# 生成规范URI
def get_canonical_uri(path):
    # 规范化URI的格式为：/{bucket}/{object}，并且要对除了斜杠"/"之外的所有字符编码
    return normalize_string(path, False)


# 生成规范query string
def get_canonical_querystring(params):
    if params is None:
        return ''

    # 除了authorization之外，所有的query string全部加入编码
    result = ['%s=%s' % (k, normalize_string(v)) for k, v in params.items() if
        k.lower != AUTHORIZATION]

    # 按字典序排序
    result.sort()

    # 使用&符号连接所有字符串并返回
    return '&'.join(result)


# 生成规范header
def get_canonical_headers(headers, headers_to_sign=None):
    headers = headers or {}

    # 没有指定header_to_sign的情况下，默认使用：
    #   1.host
    #   2.content-md5
    #   3.content-length
    #   4.content-type
    #   5.所有以x-bce-开头的header项
    # 生成规范header
    if headers_to_sign is None or len(headers_to_sign) == 0:
        headers_to_sign = {"host", "content-md5",
                           "content-length", "content-type"}

    # 对于header中的key，去掉前后的空白之后需要转化为小写
    # 对于header中的value，转化为str之后去掉前后的空白
    def f((key, value)): return (key.strip().lower(), str(value).strip())

    result = []
    for k, v in map(f, headers.iteritems()):
        # 无论何种情况，以x-bce-开头的header项都需要被添加到规范header中
        if k.startswith(BCE_PREFIX) or k in headers_to_sign:
            result.append("%s:%s" % (normalize_string(k), normalize_string(v)))

    # 按照字典序排序
    result.sort()

    # 使用\n符号连接所有字符串并返回
    return '\n'.join(result)


# 签名主算法
def sign(credentials, http_method, path, headers, params,
        timestamp=0, expiration_in_seconds=18000, headers_to_sign=None):
    headers = headers or {}
    params = params or {}

    # 1.生成sign key
    # 1.1.生成auth-string，格式为：bce-auth-v1/{accessKeyId}/{timestamp}/{expirationPeriodInSeconds}
    sign_key_info = 'bce-auth-v1/%s/%s/%d' % (
        credentials.access_key_id,
        get_canonical_time(timestamp),
        expiration_in_seconds)
    # 1.2.使用auth-string加上SK，用SHA-256生成sign key
    sign_key = hmac.new(
        credentials.secret_access_key,
        sign_key_info,
        hashlib.sha256).hexdigest()

    # 2.生成规范化uri
    canonical_uri = get_canonical_uri(path)

    # 3.生成规范化query string
    canonical_querystring = get_canonical_querystring(params)

    # 4.生成规范化header
    canonical_headers = get_canonical_headers(headers, headers_to_sign)

    # 5.使用'\n'将HTTP METHOD和2、3、4中的结果连接起来，成为一个大字符串
    string_to_sign = '\n'.join(
        [http_method, canonical_uri, canonical_querystring, canonical_headers])

    # 6.使用5中生成的签名串和1中生成的sign key，用SHA-256算法生成签名结果
    sign_result = hmac.new(sign_key, string_to_sign,
                           hashlib.sha256).hexdigest()

    # 7.拼接最终签名结果串
    if headers_to_sign:
        # 指定header to sign
        result = '%s/%s/%s' % (sign_key_info,
                               ';'.join(headers_to_sign), sign_result)
    else:
        # 不指定header to sign情况下的默认签名结果串，但百度智能云API的唯一要求是Host域必须被编码，所以此处需要至少添加上host
        result = '%s/host/%s' % (sign_key_info, sign_result) #官网demo需要改的地方
    return result


if __name__ == "__main__":
    # 填写AK SK
    credentials = BceCredentials(
          "ak", "sk") # 填写ak、sk
    # API接口的请求方法
    http_method = "POST"
    # 接口请求路径
    path = "/haoma-cloud/openapi/phone-tag/1.0"
    # 接口请求的header头
    headers = {
        "host": "pnvs.baidubce.com",
        "content-type": "application/json; charset=utf-8",
        "x-bce-date": datetime.datetime.now().strftime("%Y-%m-%dT%H:%M:%SZ"),
    }
    # 接口请求参数
    params = {
    }
    # 接口请求的body数据
    body = {
        "phone": "",
        "appkey": "开通服务时颁发的appkey"
    }
    # 设置参与鉴权编码的header，即headers_to_sign,至少包含host，百度智能云API的唯一要求是Host域必须被编码
    headers_to_sign = {
        "host",
        "x-bce-date",
    }
    # 设置到期时间，默认1800s
    expiration_in_seconds = 18000
    # 设置参与鉴权的时间戳
    timestamp = int(time.time())
    # 生成鉴权字符串
    result = sign(credentials, http_method, path, headers, params, timestamp, expiration_in_seconds,
                  headers_to_sign)
    print result
    # 使用request进行请求接口
    request = {
        'method': http_method,
        'uri': path,
        'headers': headers,
        'params': params
    }
    # headers字典中需要加上鉴权字符串authorization的请求头
    headers['authorization'] = result
    print headers

    # 拼接接口的url地址
    url = 'http://%s%s' % (headers['host'],
                            request['uri'])

    # 发起请求
    response = requests.request(
        request["method"], url, headers=headers, data=json.dumps(body))
    # 打印请求结果
    print 'url: ', response.url
    print 'status: ', response.status_code
    print 'headers: ', response.headers
    print 'response: ', response.text