import re
from boards.mdx_neboard import get_parser

from boards.models import Post, GlobalId
from boards.models.post import REGEX_NOTIFICATION
from boards.models.post import REGEX_REPLY, REGEX_GLOBAL_REPLY
from boards.models.user import Notification
from django.db.models.signals import post_save, pre_save, pre_delete, \
    post_delete
from django.dispatch import receiver
from django.utils import timezone


@receiver(post_save, sender=Post)
def connect_replies(instance, **kwargs):
    for reply_number in re.finditer(REGEX_REPLY, instance.get_raw_text()):
        post_id = reply_number.group(1)

        try:
            referenced_post = Post.objects.get(id=post_id)

            if not referenced_post.referenced_posts.filter(id=instance.id).exists():
                referenced_post.referenced_posts.add(instance)
                referenced_post.last_edit_time = instance.pub_time
                referenced_post.build_refmap()
                referenced_post.save(update_fields=['refmap', 'last_edit_time'])
        except Post.ObjectDoesNotExist:
            pass


@receiver(post_save, sender=Post)
def connect_global_replies(instance, **kwargs):
    for reply_number in re.finditer(REGEX_GLOBAL_REPLY, instance.get_raw_text()):
        key_type = reply_number.group(1)
        key = reply_number.group(2)
        local_id = reply_number.group(3)

        try:
            global_id = GlobalId.objects.get(key_type=key_type, key=key,
                    local_id=local_id)
            referenced_post = Post.objects.get(global_id=global_id)
            referenced_post.referenced_posts.add(instance)
            referenced_post.last_edit_time = instance.pub_time
            referenced_post.build_refmap()
            referenced_post.save(update_fields=['refmap', 'last_edit_time'])
        except (GlobalId.DoesNotExist, Post.DoesNotExist):
            pass


@receiver(post_save, sender=Post)
def connect_notifications(instance, **kwargs):
    for reply_number in re.finditer(REGEX_NOTIFICATION, instance.get_raw_text()):
        user_name = reply_number.group(1).lower()
        Notification.objects.get_or_create(name=user_name, post=instance)


@receiver(pre_save, sender=Post)
def preparse_text(instance, **kwargs):
    instance._text_rendered = get_parser().parse(instance.get_raw_text())


@receiver(pre_delete, sender=Post)
def delete_images(instance, **kwargs):
    for image in instance.images.all():
        image_refs_count = image.post_images.count()
        if image_refs_count == 1:
            image.delete()


@receiver(pre_delete, sender=Post)
def delete_attachments(instance, **kwargs):
    for attachment in instance.attachments.all():
        attachment_refs_count = attachment.attachment_posts.count()
        if attachment_refs_count == 1:
            attachment.delete()


@receiver(post_delete, sender=Post)
def update_thread_on_delete(instance, **kwargs):
    thread = instance.get_thread()
    thread.last_edit_time = timezone.now()
    thread.save()


@receiver(post_delete, sender=Post)
def delete_global_id(instance, **kwargs):
    if instance.global_id and instance.global_id.id:
        instance.global_id.delete()