#!/usr/bin/env python3
import sys
import requests
import xdg.BaseDirectory

api_url = 'https://api.twitch.tv/helix'
id_url = 'https://id.twitch.tv/oauth2/token'
api_key = 'cotxsalhlctv8z572f7fant4b0sc3u'
api_secret = 'gaofxvult280l3sbz8n6btvk5fdswp'
api_file = xdg.BaseDirectory.xdg_cache_home + "/twitch/api"


def get_api_token():
    """
    get api token from twitch
    :return: json object with access_token attribute
    """
    data = {
        "client_id": api_key,
        "client_secret": api_secret,
        "grant_type": "client_credentials"
    }
    r = requests.post(id_url, data=data)
    if not r.ok:
        sys.stderr.write("api error def get_api_token: api request not valid")
        return False

    return r.json()['access_token']


def download_api(access_token, to_send):
    """
    print streamers selected who are online
    :param access_token: access_token from .cache/twitch/api
    :param to_send: url with streamers
    :return: print list of streamers who are online
    """
    headers = {
        "Client-ID": api_key,
        "Authorization": "Bearer " + access_token
    }
    r = requests.get(to_send, headers=headers)

    if not r.ok:
        sys.stderr.write("download_api err: trying to refresh access_token")
        f = open(api_file, "w")
        f.write(get_api_token()['access_token'])
        f.close()
        return False

    for entry in r.json()['data']:
        print(entry['user_login'])

def main():
    """
    :param streamer_name: streamer names, can be empty.

    if streamer name is none then we want to see everyone who is online currently
    if streamer name is defined then append parameters
     to send and call download api with access_token and to_send
    """
    try:
        # try to create file and write access_token
        f = open(api_file, "x")
        json_response = get_api_token()
        f.write(json_response)
        access_token = json_response
        f.close()
    except FileExistsError:
        # if file does exist then read the file and assign the access_token
        f = open(api_file, "r")
        access_token = f.read()
        f.close()

    # puts each word piped in into array
    streamers = sys.stdin.read().rsplit()

    # make the url to send
    tosend = api_url + "/streams?"
    for streamer in streamers:
        tosend += "user_login=" + streamer + "&"

    return download_api(access_token, tosend)


main()