/******************************************************************************\
* Copyright 2019 SAS Institute Inc.
*
* 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
*
* https://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.
*
* Author: Vatslav Orlov
*
* Output: Authentication Token
*
* All code included in this section must be submitted in a 
* Viya 3.4 (or later) environment 
\******************************************************************************/

import requests #the only library actually required -  to send requests
import datetime #not required. Only here because of the optional logging I have included when testing

#######################################################
# Function creates a logfile on the system in order
# to have a reference to what was the app name,
# tokens, and secret
#######################################################   
def createLogFile():
    startTime = datetime.datetime.now()
    admRec = open("AdminRecords_" +str(startTime.year) + str(startTime.month) + str(startTime.day)+str(startTime.hour)+"_"+str(startTime.minute)+".txt", "x")
    return admRec

#######################################################
# Function that prompts the user for the hostname
# in the demo environment this is example.com
#######################################################       
def getHostName():
    h_name_yn = input("The default hostname is: 'example.com'. Change? [Y/N]")
    if h_name_yn == "Y":
        hostname= str(input("Input hostname:"))
    else:
        hostname = "example.com"
    #admRec.write("The hostname has been set to: "  +str(hostname)+ "\n") 
    return hostname

#######################################################
# Function that prompts the user to create an App name
#######################################################   
def getAppName():
    appName = input("Provide application name:")
    #admRec.write("The App Name is: "  +str(appName)+ " \n")
    return appName

#######################################################
# Prompts the user for the secret
# In this case the the person who is performing the
# registration creates the secret to their linking
#######################################################       
def promptUserForSecret():
    secret = input("Enter the secret phrase (you come up with one):")
    #admRec.write("The secret is: "  +str(secret)+ " \n")    
    return secret
    
#######################################################
# Retrieve the Consul Token that is residing on the 
# primary Viya Node
#######################################################   
def getConsulToken():
    with open('/opt/sas/viya/config/etc/SASSecurityCertificateFramework/tokens/consul/default/client.token', 'r') as file:
        data = file.read()
        
        if len(data) == 36:
            print("The consul Token is: [" + str(data)+"]")
            #admRec.write("The consul Token is: [" + str(data)+"] \n")
            return str(data)
        else:
            print("Consul Token returned is: [" + str(data) + "] however it is not 36 characters, program will now exit")

#######################################################
# This function uses the Consul Token in order to 
# make a reqest to get a registartion OAuth token
# for a given appName that the user provides
#######################################################   
def registrationOauthTokenReuqest(appName, consulToken):
    print("Attempting to get a registration Oauth token")
    url = "http://" +str(hostname)+ "/SASLogon/oauth/clients/consul?callback=false&serviceId="+ str(appName)
    headers = {"X-Consul-Token":str(consulToken)}
    r = requests.post(url, headers=headers, timeout=30)
    
    print(r)
    if r.status_code == 200:
        print(r.json())
        print("-------ACCESS TOKEN: " + str(r.json()['access_token']))
        #admRec.write("The access token is: " + str(r.json()['access_token']) + "\n")
        return r.json()['access_token']
    else:
        print("Could not get registration oauth token")

####################################################################
# This is where the actual registration happens
# User provides the appName, a secret of their choice,
# registration OAuth token and a validity (12 hrs by default)
# 
# Admin would give python developer the name of the app and secret
# after running this function
####################################################################
def registerNewClient(appName, secret, authToken, validity=43199):
    print("Attempting to register")
    #admRec.write("Attempting to register \n")
    url = "https://" + str(hostname) + "/SASLogon/oauth/clients"
    
    headers = {"Content-Type":"application/json",
               "Authorization": "Bearer " + str(authToken)}
               
    data = {"client_id":str(appName),
            "client_secret":str(secret),
            "scope": "openid",
            "authorized_grant_types":"password",
            "access_token_validity":validity
            }
    r = requests.post(url,headers=headers, json=data, timeout=30, verify=False)
    print(r)
    if r.status_code == 201:
      print("Register success")
      #admRec.write("Register - success \n")
      print(r.json())

#######################################################
# MAIN
# Space where all the functions are called
#######################################################     
try:
  #admRec = createLogFile() #create the log file
  appName = getAppName() # ask for app name
  hostname = getHostName() #ask for host name
  consulToken = getConsulToken() #get the consul token
  access_token = registrationOauthTokenReuqest(appName, consulToken) #get registration OAuth Token
  secret = promptUserForSecret() # prompt for secret
  registerNewClient(appName, secret, access_token, validity=43199) #register the app using the Oauth token
  #admRec.close() #close the log file
  
  print("Application Name: [" + str(appName) + "] Secret [" + str(secret) + "] - this is the info the python developer will need")
except Exception as e:
  #admRec.close() #if encounter any errors, close the log file before exiting.
  print(str(e))