import logging
import json
import requests
import xmltodict

from lxml import etree
from django.conf import settings

from core import ShippingContainer


logger = logging.getLogger(__name__)


class USPSApiError(Exception):
    pass


class USPSApi:
    BASE_URL = 'https://secure.shippingapis.com/ShippingAPI.dll?API='
    urls = {
        'validate': 'Verify&XML={xml}',
        'rate': 'RateV4&XML={xml}'
    }

    def __init__(self,  api_user_id, test=False):
        self.api_user_id = api_user_id
        self.test = test

    def get_url(self, action, xml):
        return self.BASE_URL + self.urls[action].format(
            **{'test': 'Certify' if self.test else '', 'xml': xml}
        )

    def send_request(self, action, xml):
        # The USPS developer guide says "ISO-8859-1 encoding is the expected character set for the request."
        # (see https://www.usps.com/business/web-tools-apis/general-api-developer-guide.htm)
        xml = etree.tostring(xml, encoding='iso-8859-1', pretty_print=self.test).decode()
        url = self.get_url(action, xml)
        xml_response = requests.get(url).content
        response = json.loads(json.dumps(xmltodict.parse(xml_response)))
        if 'Error' in response:
            raise USPSApiError(response['Error']['Description'])
        return response

    def validate_address(self, *args, **kwargs):
        return AddressValidate(self, *args, **kwargs)

    def get_rate(self, *args, **kwargs):
        return Rate(self, *args, **kwargs)



class AddressValidate:
    def __init__(self, usps, address):
        xml = etree.Element('AddressValidateRequest', {'USERID': usps.api_user_id})
        _address = etree.SubElement(xml, 'Address', {'ID': '0'})
        address.add_to_xml(_address, prefix='', validate=True)

        self.result = usps.send_request('validate', xml)


class Rate:
    def __init__(self, usps, request, **kwargs):
        xml = etree.Element('RateV4Request', {'USERID': usps.api_user_id})
        etree.SubElement(xml, 'Revision').text = '2'
        package = etree.SubElement(xml, 'Package', {'ID': '0'})
        etree.SubElement(package, 'Service').text = request['service']
        etree.SubElement(package, 'ZipOrigination').text = request['zip_origination']
        etree.SubElement(package, 'ZipDestination').text = request['zip_destination']
        etree.SubElement(package, 'Pounds').text = request['pounds']
        etree.SubElement(package, 'Ounces').text = request['ounces']
        etree.SubElement(package, 'Container').text = request['container']
        etree.SubElement(package, 'Width').text = request['width']
        etree.SubElement(package, 'Length').text = request['length']
        etree.SubElement(package, 'Height').text = request['height']
        etree.SubElement(package, 'Girth').text = request['girth']
        etree.SubElement(package, 'Machinable').text = request['machinable']

        self.result = usps.send_request('rate', xml)