# coding: utf-8
from __future__ import unicode_literals

from django.db import models
from django.db.models.signals import m2m_changed


class Host(models.Model):
     name = models.CharField(max_length=20)
     isdelete = models.BooleanField(default=False)

     def __unicode__(self):
          return self.name


class Project(models.Model):
     name = models.CharField(max_length=20)
     host = models.ManyToManyField(Host)
     isdelete = models.BooleanField(default=False)

     def __unicode__(self):
          return self.name


class Instance(models.Model):
     name = models.CharField(max_length=20)
     project = models.ForeignKey(Project)
     host = models.ManyToManyField(Host)
     isdelete = models.BooleanField(default=False)

     def __unicode__(self):
          return self.name


def instance_m2m_change(**kwargs):
     instance = kwargs.pop('instance', None)
     host = kwargs.pop('model', None)
     host_id = kwargs.pop('pk_set', None)
     action = kwargs.pop('action', None)
     if action == 'post_add':
          if host_id:
               for i in host_id:
                    host_obj = host.objects.get(id=i)
                    instance.project.host.add(host_obj)
     if action == 'post_remove':
          if host_id:
               for i in host_id:
                    host_obj = host.objects.get(id=i)
                    still_has_instance = instance.project.instance_set.filter(host=host_obj)
                    if not still_has_instance:
                         instance.project.host.remove(host_obj)
                         host_obj = host.objects.get(id=i)
                         still_has_instance = instance.project.instance_set.filter(host=host_obj)


class InstanceModule(models.Model):
     name = models.CharField(max_length=20)
     instance = models.ForeignKey(Instance)
     host = models.ManyToManyField(Host)
     isdelete = models.BooleanField(default=False)

     def __unicode__(self):
          return self.name


def instancemodule_m2m_change(**kwargs):
     instance = kwargs.pop('instance', None)
     host = kwargs.pop('model', None)
     host_id = kwargs.pop('pk_set', None)
     action = kwargs.pop('action', None)
     if action == 'post_add':
          if host_id:
               for i in host_id:
                    host_obj = host.objects.get(id=i)
                    instance.instance.host.add(host_obj)
     if action == 'post_remove':
          if host_id:
               for i in host_id:
                    host_obj = host.objects.get(id=i)
                    still_has_instance = instance.instance.instancemodule_set.filter(host=host_obj)
                    if not still_has_instance:
                         instance.instance.host.remove(host_obj)

m2m_changed.connect(instance_m2m_change, sender=Instance.host.through)
m2m_changed.connect(instancemodule_m2m_change, sender=InstanceModule.host.through)