# -*- coding: utf-8 -*-
##############################################################################
#
#    Copyright (c) 2009 CamptoCamp. All rights reserved.
#    @author Nicolas Bessi
#
#    Abstract class to fetch rates from European Central Bank
#
#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU Affero General Public License as
#    published by the Free Software Foundation, either version 3 of the
#    License, or (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU Affero General Public License for more details.
#
#    You should have received a copy of the GNU Affero General Public License
#    along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
##############################################################################
from .currency_getter_interface import Currency_getter_interface

from datetime import datetime
from openerp.tools import DEFAULT_SERVER_DATE_FORMAT

import logging
_logger = logging.getLogger(__name__)


class ECB_getter(Currency_getter_interface):
    """Implementation of Currency_getter_factory interface
    for ECB service
    """

    def rate_retrieve(self, dom, ns, curr):
        """Parse a dom node to retrieve-
        currencies data

        """
        res = {}
        xpath_curr_rate = ("/gesmes:Envelope/def:Cube/def:Cube/"
                           "def:Cube[@currency='%s']/@rate") % (curr.upper())
        res['rate_currency'] = float(
            dom.xpath(xpath_curr_rate, namespaces=ns)[0]
        )
        return res

    def get_updated_currency(self, currency_array, main_currency,
                             max_delta_days):
        """implementation of abstract method of Curreny_getter_interface"""
        url = 'http://www.ecb.europa.eu/stats/eurofxref/eurofxref-daily.xml'
        # Important : as explained on the ECB web site, the currencies are
        # at the beginning of the afternoon ; so, until 3 p.m. Paris time
        # the currency rates are the ones of trading day N-1
        # http://www.ecb.europa.eu/stats/exchange/eurofxref/html/index.en.html

        # We do not want to update the main currency
        if main_currency in currency_array:
            currency_array.remove(main_currency)
        # Move to new XML lib cf Launchpad bug #645263
        from lxml import etree
        _logger.debug("ECB currency rate service : connecting...")
        rawfile = self.get_url(url)
        dom = etree.fromstring(rawfile)
        _logger.debug("ECB sent a valid XML file")
        ecb_ns = {
            'gesmes': 'http://www.gesmes.org/xml/2002-08-01',
            'def': 'http://www.ecb.int/vocabulary/2002-08-01/eurofxref'
        }
        rate_date = dom.xpath('/gesmes:Envelope/def:Cube/def:Cube/@time',
                              namespaces=ecb_ns)[0]
        rate_date_datetime = datetime.strptime(rate_date,
                                               DEFAULT_SERVER_DATE_FORMAT)
        self.check_rate_date(rate_date_datetime, max_delta_days)
        # We dynamically update supported currencies
        self.supported_currency_array = dom.xpath(
            "/gesmes:Envelope/def:Cube/def:Cube/def:Cube/@currency",
            namespaces=ecb_ns
        )
        self.supported_currency_array.append('EUR')
        _logger.debug("Supported currencies = %s " %
                      self.supported_currency_array)
        self.validate_cur(main_currency)
        if main_currency != 'EUR':
            main_curr_data = self.rate_retrieve(dom, ecb_ns, main_currency)
        for curr in currency_array:
            self.validate_cur(curr)
            if curr == 'EUR':
                rate = 1 / main_curr_data['rate_currency']
            else:
                curr_data = self.rate_retrieve(dom, ecb_ns, curr)
                if main_currency == 'EUR':
                    rate = curr_data['rate_currency']
                else:
                    rate = (curr_data['rate_currency'] /
                            main_curr_data['rate_currency'])
            self.updated_currency[curr] = rate
            _logger.debug(
                "Rate retrieved : 1 %s = %s %s" % (main_currency, rate, curr)
            )
        return self.updated_currency, self.log_info