import json

from django.db import transaction
from django.shortcuts import get_object_or_404

from api.serializers.event import EventSerializer
from api.views.base import BaseView
from web.models.category import Category
from web.models.event_category import EventCategory
from web.models.event import Event
from web.models.tag import Tag
from web.models.event_tag import EventTag


class EventView(BaseView):
    SERIALIZER = EventSerializer

    def get(self, request, event_id):
        event = get_object_or_404(Event, pk=event_id, active=True)
        return self._build_response(event)

    @transaction.atomic
    def post(self, request):
        data = json.loads(request.body)
        event = Event(
            name=data.get('name'),
            description=data.get('description'),
            url=data.get('url'),
            address=data.get('address'),
            status=data.get('status'),
            price=data.get('price'),
            require_rsvp=data.get('require_rsvp'),
            start_time=data.get('start_time'),
            end_time=data.get('end_time'),
            rain_date=data.get('rain_date'),
            email=data.get('email'),
            phone_number=data.get('phone_number'),
        )

        event.save()

        categories = data.get('categories', [])
        self._create_event_categories(categories, event)

        tag_names = data.get('tags', [])
        self._create_event_tags(tag_names, event)

        return self._build_response(event)

    def _create_event_categories(self, categories, event):
        event_categories = []
        for category_id in categories:
            category = get_object_or_404(Category, pk=category_id)
            event_category = EventCategory(
                event=event,
                category=category
            )

            event_categories.append(event_category)
        EventCategory.objects.bulk_create(event_categories)

    def _create_event_tags(self, tag_names, event):
        event_tags = []
        for tag_name in tag_names:
            tag, created = Tag.objects.get_or_create(name=tag_name)

            event_tag = EventTag(
                tag=tag,
                event=event
            )

            event_tags.append(event_tag)
        EventTag.objects.bulk_create(event_tags)

    @transaction.atomic
    def put(self, request, event_id):
        data = json.loads(request.body)

        event = get_object_or_404(Event, pk=event_id)

        event.name = data.get('name', event.name)
        event.description = data.get('description', event.description)
        event.url = data.get('url', event.url)
        event.address = data.get('address', event.address)
        event.status = data.get('status', event.status)
        event.price = data.get('price', event.price)
        event.require_rsvp = data.get('require_rsvp', event.require_rsvp)
        event.start_time = data.get('start_time', event.start_time)
        event.end_time = data.get('end_time', event.end_time)
        event.rain_date = data.get('rain_date', event.rain_date)
        event.email = data.get('email', event.email)
        event.phone_number = data.get('phone_number', event.phone_number)

        categories = data.get('categories', [])
        self._update_event_categories(categories, event)

        tag_names = data.get('tags', [])
        self._update_event_tags(tag_names, event)

        event.save()
        self._build_response(event)

    def _update_event_categories(self, categories, event):
        if categories:
            current_event_categories = EventCategory.objects.filter(event=event).filter(active=True).all()
            current_event_category_map = {ec.category.id: ec for ec in current_event_categories}

            for current_event_category in current_event_categories:
                if current_event_category.category.id not in categories:
                    current_event_category.active = False
                    current_event_category.save()

            new_event_categories = []
            for category_id in categories:
                category = get_object_or_404(Category, pk=category_id)
                if category not in current_event_category_map:
                    event_category = EventCategory(
                        category=category,
                        event=event
                    )

                    new_event_categories.append(event_category)

        if new_event_categories:
            EventCategory.objects.bulk_create(new_event_categories)

    def _update_event_tags(self, tag_names, event):
        if tag_names:
            current_event_tags = EventTag.objects.filter(event=event).filter(active=True).all()
            current_event_tag_names = [x.name for x in current_event_tags]

            for current_event_tag in current_event_tags:
                if current_event_tag.tag.name not in tag_names:
                    current_event_tag.active = False
                    current_event_tag.save()

            new_event_tags = []
            for tag_name in tag_names:
                if tag_name not in current_event_tag_names:
                    tag, created = Tag.objects.get_or_create(name=tag_name)

                    event_tag = EventTag(
                        tag=tag,
                        event=event
                    )

                    new_event_tags.append(event_tag)

            if new_event_tags:
                EventTag.objects.bulk_create(new_event_tags)

    def delete(self, request, event_id):
        event = get_object_or_404(Event, pk=event_id)
        event.active = False
        event.save()
        return self._build_response(event)