# -*- coding: utf-8 -*-

from django.utils.translation import ugettext_lazy as _
from django.shortcuts import get_object_or_404

from rest_framework.permissions import IsAuthenticated
from rest_framework.decorators import detail_route
from rest_framework.response import Response

from greenmine.base import filters
from greenmine.base import exceptions as exc
from greenmine.base.api import ModelCrudViewSet
from greenmine.base.notifications.api import NotificationSenderMixin

from . import serializers
from . import models
from . import permissions

import datetime


class MilestoneViewSet(NotificationSenderMixin, ModelCrudViewSet):
    queryset = models.Milestone.objects.all().order_by("-estimated_start")
    serializer_class = serializers.MilestoneSerializer
    permission_classes = (IsAuthenticated, permissions.MilestonePermission)
    filter_backends = (filters.IsProjectMemberFilterBackend,)
    filter_fields = ("project",)
    create_notification_template = "create_milestone_notification"
    update_notification_template = "update_milestone_notification"
    destroy_notification_template = "destroy_milestone_notification"

    def pre_conditions_on_save(self, obj):
        super().pre_conditions_on_save(obj)

        if (obj.project.owner != self.request.user and
                obj.project.memberships.filter(user=self.request.user).count() == 0):
            raise exc.PreconditionError("You must not add a new milestone to this project.")

    def pre_save(self, obj):
        if not obj.id:
            obj.owner = self.request.user

        super().pre_save(obj)

    @detail_route(methods=['get'])
    def stats(self, request, pk=None):
        milestone = get_object_or_404(models.Milestone, pk=pk)
        total_points = milestone.total_points
        milestone_stats = {
            'name': milestone.name,
            'estimated_start': milestone.estimated_start,
            'estimated_finish': milestone.estimated_finish,
            'total_points': total_points,
            'completed_points': milestone.closed_points.values(),
            'total_userstories': milestone.user_stories.count(),
            'completed_userstories': len([us for us in milestone.user_stories.all() if us.is_closed]),
            'total_tasks': milestone.tasks.all().count(),
            'completed_tasks': milestone.tasks.all().filter(status__is_closed=True).count(),
            'days': []
        }
        current_date = milestone.estimated_start
        sumTotalPoints = sum(total_points.values())
        optimal_points = sumTotalPoints
        milestone_days = (milestone.estimated_finish - milestone.estimated_start).days
        optimal_points_per_day = sumTotalPoints / (milestone_days + 1) if milestone_days else 0
        while current_date <= (milestone.estimated_finish + datetime.timedelta(days=1)):
            milestone_stats['days'].append({
                'day': current_date,
                'name': current_date.day,
                'open_points':  sumTotalPoints - sum(milestone.closed_points_by_date(current_date).values()),
                'optimal_points': optimal_points,
            })
            current_date = current_date + datetime.timedelta(days=1)
            optimal_points -= optimal_points_per_day

        return Response(milestone_stats)