# 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
#
#      http://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.

from __future__ import division

import datetime

from django.utils import timezone
from django.utils.translation import ugettext_lazy as _

from horizon import forms
from horizon import messages


class BaseBilling(object):

    def __init__(self, request, project_id=None):
        self.project_id = project_id or request.user.tenant_id
        self.request = request
        self.billing_list = []

    @property
    def today(self):
        return timezone.now()

    @staticmethod
    def get_start(year, month, day):
        start = datetime.datetime(year, month, day, 0, 0, 0)
        return timezone.make_aware(start, timezone.utc)

    @staticmethod
    def get_end(year, month, day):
        end = datetime.datetime(year, month, day, 23, 59, 59)
        return timezone.make_aware(end, timezone.utc)

    def get_date_range(self):
        if not hasattr(self, "start") or not hasattr(self, "end"):
            args_start = (self.today.year, self.today.month, 1)
            args_end = (self.today.year, self.today.month, self.today.day)
            form = self.get_form()
            if form.is_valid():
                start = form.cleaned_data['start']
                end = form.cleaned_data['end']
                args_start = (start.year,
                              start.month,
                              start.day)
                args_end = (end.year,
                            end.month,
                            end.day)
            elif form.is_bound:
                messages.error(self.request,
                               _("Invalid date format: "
                                 "Using today as default."))
        self.start = self.get_start(*args_start)
        self.end = self.get_end(*args_end)
        return self.start, self.end

    def init_form(self):
        today = datetime.date.today()
        self.start = datetime.date(day=1, month=today.month, year=today.year)
        self.end = today

        return self.start, self.end

    def get_form(self):
        if not hasattr(self, 'form'):
            req = self.request
            start = req.GET.get('start', req.session.get('billing_start'))
            end = req.GET.get('end', req.session.get('billing_end'))
            if start and end:
                # bound form
                self.form = forms.DateForm({'start': start, 'end': end})
            else:
                # non-bound form
                init = self.init_form()
                start = init[0].isoformat()
                end = init[1].isoformat()
                self.form = forms.DateForm(initial={'start': start,
                                                    'end': end})
            req.session['billing_start'] = start
            req.session['billing_end'] = end
        return self.form

    def get_billing_list(self, start, end):
        return []

    def csv_link(self):
        form = self.get_form()
        data = {}
        if hasattr(form, "cleaned_data"):
            data = form.cleaned_data
        if not ('start' in data and 'end' in data):
            data = {"start": self.today.date(), "end": self.today.date()}
        return "?start=%s&end=%s&format=csv" % (data['start'],
                                                data['end'])