import requests
import base64
import json
client_id = 'fakeclient_id'
client_secret = 'fakeclient_secret'
redirect_url = 'callbackurl here'
b64_id_secret = base64.b64encode(bytes(client_id + ':' + client_secret, 'utf-8')).decode('utf-8')

def XeroTenants(access_token):
	connections_url = 'https://api.xero.com/connections'
	response = requests.get(connections_url,
						   headers = {
							   'Authorization': 'Bearer ' + access_token,
							   'Content-Type': 'application/json'
						   })
	json_response = response.json()

	
	for tenants in json_response:
		json_dict = tenants
		return json_dict['tenantId']

def XeroRefreshToken(refresh_token):
	token_refresh_url = 'https://identity.xero.com/connect/token'
	response = requests.post(token_refresh_url,
							headers = {
								'Authorization' : 'Basic ' + b64_id_secret,
								'Content-Type': 'application/x-www-form-urlencoded'
							},
							data = {
								'grant_type' : 'refresh_token',
								'refresh_token' : refresh_token
							})
	json_response = response.json()
	
	new_refresh_token = json_response['refresh_token']
	rt_file = open('refresh_token.txt', 'w')
	rt_file.write(new_refresh_token)
	rt_file.close()
	
	return [json_response['access_token'], json_response['refresh_token']]
	
def find(InvoiceNumber):
		old_refresh_token = open('refresh_token.txt', 'r').read()
		new_tokens = XeroRefreshToken(old_refresh_token)
		xero_tenant_id = XeroTenants(new_tokens[0])
		
		get_url = "https://api.xero.com/api.xro/2.0/Invoices/INV-" + InvoiceNumber 
		response = requests.get(get_url,
							headers = {
								'Authorization': 'Bearer ' + new_tokens[0],
								'Xero-tenant-id': xero_tenant_id,
								'Accept': 'application/json',
								'Content-Type': 'application/json'
							})
		resp = response.json()
		#resp["Invoices"]0['AmountDue']
		print(resp["Invoices"][0]['AmountDue'])	  


find("0228")