from __future__ import print_function
import base64
import requests
import os
import json
import time
import sys

from .client import Spotify

"""
Borrowed from Spotipy
"""
"""
The MIT License (MIT)

Copyright (c) 2014 Paul Lamere

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
"""

# Workaround to support both python 2 & 3
try:
    import urllib.request, urllib.error
    import urllib.parse as urllibparse
except ImportError:
    import urllib as urllibparse



class SpotifyOauthError(Exception):
    pass


class SpotifyClientCredentials(object):
    OAUTH_TOKEN_URL = 'https://accounts.spotify.com/api/token'

    def __init__(self, client_id=None, client_secret=None, proxies=None):
        """
        You can either provid a client_id and client_secret to the
        constructor or set SPOTIPY_CLIENT_ID and SPOTIPY_CLIENT_SECRET
        environment variables
        """
        if not client_id:
            client_id = os.getenv('SPOTIPY_CLIENT_ID')

        if not client_secret:
            client_secret = os.getenv('SPOTIPY_CLIENT_SECRET')

        if not client_id:
            raise SpotifyOauthError('No client id')

        if not client_secret:
            raise SpotifyOauthError('No client secret')

        self.client_id = client_id
        self.client_secret = client_secret
        self.token_info = None
        self.proxies = proxies

    def get_access_token(self):
        """
        If a valid access token is in memory, returns it
        Else feches a new token and returns it
        """
        if self.token_info and not self._is_token_expired(self.token_info):
            return self.token_info['access_token']

        token_info = self._request_access_token()
        token_info = self._add_custom_values_to_token_info(token_info)
        self.token_info = token_info
        return self.token_info['access_token']

    def _request_access_token(self):
        """Gets client credentials access token """
        payload = { 'grant_type': 'client_credentials'}

        if sys.version_info[0] >= 3: # Python 3
            auth_header = base64.b64encode(str(self.client_id + ':' + self.client_secret).encode())
            headers = {'Authorization': 'Basic %s' % auth_header.decode()}
        else: # Python 2
            auth_header = base64.b64encode(self.client_id + ':' + self.client_secret)
            headers = {'Authorization': 'Basic %s' % auth_header}

        response = requests.post(self.OAUTH_TOKEN_URL, data=payload,
            headers=headers, verify=True, proxies=self.proxies)
        if response.status_code is not 200:
            raise SpotifyOauthError(response.reason)
        token_info = response.json()
        return token_info

    def _is_token_expired(self, token_info):
        now = int(time.time())
        return token_info['expires_at'] - now < 60

    def _add_custom_values_to_token_info(self, token_info):
        """
        Store some values that aren't directly provided by a Web API
        response.
        """
        token_info['expires_at'] = int(time.time()) + token_info['expires_in']
        return token_info


class SpotifyOAuth(object):
    '''
    Implements Authorization Code Flow for Spotify's OAuth implementation.
    '''

    OAUTH_AUTHORIZE_URL = 'https://accounts.spotify.com/authorize'
    OAUTH_TOKEN_URL = 'https://accounts.spotify.com/api/token'

    def __init__(self, client_id, client_secret, redirect_uri,
            state=None, scope=None, cache_path=None, proxies=None):
        '''
            Creates a SpotifyOAuth object

            Parameters:
                 - client_id - the client id of your app
                 - client_secret - the client secret of your app
                 - redirect_uri - the redirect URI of your app
                 - state - security state
                 - scope - the desired scope of the request
                 - cache_path - path to location to save tokens
        '''

        self.client_id = client_id
        self.client_secret = client_secret
        self.redirect_uri = redirect_uri
        self.state=state
        self.cache_path = cache_path
        self.scope=self._normalize_scope(scope)
        self.proxies = proxies

    def get_cached_token(self):
        ''' Gets a cached auth token
        '''
        token_info = None
        if self.cache_path:
            try:
                f = open(self.cache_path)
                token_info_string = f.read()
                f.close()
                token_info = json.loads(token_info_string)

                # if scopes don't match, then bail
                if 'scope' not in token_info or not self._is_scope_subset(self.scope, token_info['scope']):
                    return None

                if self._is_token_expired(token_info):
                    token_info = self.refresh_access_token(token_info['refresh_token'])

            except IOError:
                pass
        return token_info

    def _save_token_info(self, token_info):
        if self.cache_path:
            try:
                f = open(self.cache_path, 'w')
                f.write(json.dumps(token_info))
                f.close()
            except IOError:
                self._warn("couldn't write token cache to " + self.cache_path)
                pass

    def _is_scope_subset(self, needle_scope, haystack_scope):
        needle_scope = set(needle_scope.split())
        haystack_scope = set(haystack_scope.split())

        return needle_scope <= haystack_scope

    def _is_token_expired(self, token_info):
        now = int(time.time())
        return token_info['expires_at'] < now

    def get_authorize_url(self):
        """ Gets the URL to use to authorize this app
        """
        payload = {'client_id': self.client_id,
                   'response_type': 'code',
                   'redirect_uri': self.redirect_uri}
        if self.scope:
            payload['scope'] = self.scope
        if self.state:
            payload['state'] = self.state

        urlparams = urllibparse.urlencode(payload)

        return "%s?%s" % (self.OAUTH_AUTHORIZE_URL, urlparams)

    def parse_response_code(self, url):
        """ Parse the response code in the given response url

            Parameters:
                - url - the response url
        """

        try:
            return url.split("?code=")[1].split("&")[0]
        except IndexError:
            return None

    def get_access_token(self, code):
        """ Gets the access token for the app given the code

            Parameters:
                - code - the response code
        """

        payload = {'redirect_uri': self.redirect_uri,
                   'code': code,
                   'grant_type': 'authorization_code'}
        if self.scope:
            payload['scope'] = self.scope
        if self.state:
            payload['state'] = self.state

        if sys.version_info[0] >= 3: # Python 3
            auth_header = base64.b64encode(str(self.client_id + ':' + self.client_secret).encode())
            headers = {'Authorization': 'Basic %s' % auth_header.decode()}
        else: # Python 2
            auth_header = base64.b64encode(self.client_id + ':' + self.client_secret)
            headers = {'Authorization': 'Basic %s' % auth_header}

        response = requests.post(self.OAUTH_TOKEN_URL, data=payload,
            headers=headers, verify=True, proxies=self.proxies)
        if response.status_code is not 200:
            raise SpotifyOauthError(response.reason)
        token_info = response.json()
        token_info = self._add_custom_values_to_token_info(token_info)
        self._save_token_info(token_info)
        return token_info

    def _normalize_scope(self, scope):
        if scope:
            scopes = scope.split()
            scopes.sort()
            return ' '.join(scopes)
        else:
            return None

    def refresh_access_token(self, refresh_token):
        payload = { 'refresh_token': refresh_token,
                   'grant_type': 'refresh_token'}

        if sys.version_info[0] >= 3: # Python 3
            auth_header = base64.b64encode(str(self.client_id + ':' + self.client_secret).encode())
            headers = {'Authorization': 'Basic %s' % auth_header.decode()}
        else: # Python 2
            auth_header = base64.b64encode(self.client_id + ':' + self.client_secret)
            headers = {'Authorization': 'Basic %s' % auth_header}

        response = requests.post(self.OAUTH_TOKEN_URL, data=payload,
            headers=headers, proxies=self.proxies)
        if response.status_code != 200:
            if False:  # debugging code
                print('headers', headers)
                print('request', response.url)
            self._warn("couldn't refresh token: code:%d reason:%s" \
                % (response.status_code, response.reason))
            return None
        token_info = response.json()
        token_info = self._add_custom_values_to_token_info(token_info)
        if not 'refresh_token' in token_info:
            token_info['refresh_token'] = refresh_token
        self._save_token_info(token_info)
        return token_info

    def _add_custom_values_to_token_info(self, token_info):
        '''
        Store some values that aren't directly provided by a Web API
        response.
        '''
        token_info['expires_at'] = int(time.time()) + token_info['expires_in']
        token_info['scope'] = self.scope
        return token_info

    def _warn(self, msg):
        print('warning:' + msg, file=sys.stderr)


def from_env_token():
    auth = SpotifyOAuth(os.environ['SPOTIFY_CLIENT_ID'],
                        os.environ['SPOTIFY_CLIENT_SECRET'],
                        os.environ['SPOTIFY_REDIRECT_URI'])
    token = auth.refresh_access_token(os.environ['SPOTIFY_REFRESH_TOKEN'])
    return Spotify(access_token=token)        
