from django.conf import settings
from django.db import models, transaction
from django.contrib.auth.models import BaseUserManager, AbstractBaseUser
from django.utils import timezone
from django.core.exceptions import SuspiciousOperation, ValidationError
from desecapi import pdns, mixins
import datetime
from django.core.validators import MinValueValidator


class MyUserManager(BaseUserManager):
    def create_user(self, email, password=None, registration_remote_ip=None, captcha_required=False):
        """
        Creates and saves a User with the given email, date of
        birth and password.
        """
        if not email:
            raise ValueError('Users must have an email address')

        user = self.model(
            email=self.normalize_email(email),
            registration_remote_ip=registration_remote_ip,
            captcha_required=captcha_required,
        )

        user.set_password(password)
        user.save(using=self._db)
        return user

    def create_superuser(self, email, password):
        """
        Creates and saves a superuser with the given email, date of
        birth and password.
        """
        user = self.create_user(email,
                                password=password
        )
        user.is_admin = True
        user.save(using=self._db)
        return user


class User(AbstractBaseUser):
    email = models.EmailField(
        verbose_name='email address',
        max_length=191,
        unique=True,
    )
    is_active = models.BooleanField(default=True)
    is_admin = models.BooleanField(default=False)
    registration_remote_ip = models.CharField(max_length=1024, blank=True)
    captcha_required = models.BooleanField(default=False)
    created = models.DateTimeField(auto_now_add=True)
    limit_domains = models.IntegerField(default=settings.LIMIT_USER_DOMAIN_COUNT_DEFAULT,null=True,blank=True)
    dyn = models.BooleanField(default=True)

    objects = MyUserManager()

    USERNAME_FIELD = 'email'
    REQUIRED_FIELDS = []

    def get_full_name(self):
        return self.email

    def get_short_name(self):
        return self.email

    def __str__(self):
        return self.email

    def has_perm(self, perm, obj=None):
        "Does the user have a specific permission?"
        # Simplest possible answer: Yes, always
        return True

    def has_module_perms(self, app_label):
        "Does the user have permissions to view the app `app_label`?"
        # Simplest possible answer: Yes, always
        return True

    @property
    def is_staff(self):
        "Is the user a member of staff?"
        # Simplest possible answer: All admins are staff
        return self.is_admin

    def unlock(self):
        self.captcha_required = False
        for domain in self.domains.all():
            domain.pdns_resync()
        self.save()


class Domain(models.Model, mixins.SetterMixin):
    created = models.DateTimeField(auto_now_add=True)
    updated = models.DateTimeField(null=True)
    name = models.CharField(max_length=191, unique=True)
    arecord = models.GenericIPAddressField(protocol='IPv4', blank=False, null=True)
    aaaarecord = models.GenericIPAddressField(protocol='IPv6', blank=False, null=True)
    owner = models.ForeignKey(settings.AUTH_USER_MODEL, related_name='domains')
    acme_challenge = models.CharField(max_length=255, blank=True)
    _dirtyName = False
    _dirtyRecords = False

    def setter_name(self, val):
        if val != self.name:
            self._dirtyName = True

        return val

    def setter_arecord(self, val):
        if val != self.arecord:
            self._dirtyRecords = True

        return val

    def setter_aaaarecord(self, val):
        if val != self.aaaarecord:
            self._dirtyRecords = True

        return val

    def setter_acme_challenge(self, val):
        if val != self.acme_challenge:
            self._dirtyRecords = True

        return val

    def clean(self):
        if self._dirtyName:
            raise ValidationError('You must not change the domain name')

    @property
    def pdns_id(self):
        if '/' in self.name or '?' in self.name:
            raise SuspiciousOperation('Invalid hostname ' + self.name)

        # Transform to be valid pdns API identifiers (:id in their docs).  The
        # '/' case here is just a safety measure (this case should never occur due
        # to the above check).
        # See also pdns code, apiZoneNameToId() in ws-api.cc
        name = self.name.translate(str.maketrans({'/': '=2F', '_': '=5F'}))

        if not name.endswith('.'):
            name += '.'

        return name

    def pdns_resync(self):
        """
        Make sure that pdns gets the latest information about this domain/zone.
        Re-Syncing is relatively expensive and should not happen routinely.
        """

        # Create zone if needed
        if not pdns.zone_exists(self):
            pdns.create_zone(self)

        # update zone to latest information
        pdns.set_dyn_records(self)

    def pdns_sync(self, new_domain):
        """
        Command pdns updates as indicated by the local changes.
        """

        if self.owner.captcha_required:
            # suspend all updates
            return

        # if this zone is new, create it and set dirty flag if necessary
        if new_domain:
            pdns.create_zone(self)
            self._dirtyRecords = bool(self.arecord) or bool(self.aaaarecord) or bool(self.acme_challenge)

        # make changes if necessary
        if self._dirtyRecords:
            pdns.set_dyn_records(self)

        self._dirtyRecords = False

    def sync_from_pdns(self):
        with transaction.atomic():
            RRset.objects.filter(domain=self).delete()
            rrsets = pdns.get_rrsets(self)
            rrsets = [rrset for rrset in rrsets if rrset.type != 'SOA']
            RRset.objects.bulk_create(rrsets)

    @transaction.atomic
    def delete(self, *args, **kwargs):
        super(Domain, self).delete(*args, **kwargs)

        pdns.delete_zone(self)
        if self.name.endswith('.dedyn.io'):
            pdns.set_rrset_in_parent(self, 'DS', '')
            pdns.set_rrset_in_parent(self, 'NS', '')

    @transaction.atomic
    def save(self, *args, **kwargs):
        # Record here if this is a new domain (self.pk is only None until we call super.save())
        new_domain = self.pk is None

        self.updated = timezone.now()
        self.clean()
        super(Domain, self).save(*args, **kwargs)

        self.pdns_sync(new_domain)

    class Meta:
        ordering = ('created',)


def get_default_value_created():
    return timezone.now()


def get_default_value_due():
    return timezone.now() + datetime.timedelta(days=7)


def get_default_value_mref():
    return "ONDON" + str((timezone.now() - timezone.datetime(1970,1,1,tzinfo=timezone.utc)).total_seconds())


class Donation(models.Model):

    created = models.DateTimeField(default=get_default_value_created)
    name = models.CharField(max_length=255)
    iban = models.CharField(max_length=34)
    bic = models.CharField(max_length=11)
    amount = models.DecimalField(max_digits=8,decimal_places=2)
    message = models.CharField(max_length=255, blank=True)
    due = models.DateTimeField(default=get_default_value_due)
    mref = models.CharField(max_length=32,default=get_default_value_mref)
    email = models.EmailField(max_length=255, blank=True)


    def save(self, *args, **kwargs):
        self.iban = self.iban[:6] + "xxx" # do NOT save account details
        super(Donation, self).save(*args, **kwargs) # Call the "real" save() method.


    class Meta:
        ordering = ('created',)


def validate_upper(value):
    if value != value.upper():
        raise ValidationError('Invalid value (not uppercase): %(value)s',
                              code='invalid',
                              params={'value': value})


class RRset(models.Model, mixins.SetterMixin):
    created = models.DateTimeField(auto_now_add=True)
    updated = models.DateTimeField(null=True)
    domain = models.ForeignKey(Domain, on_delete=models.CASCADE, related_name='rrsets')
    subname = models.CharField(max_length=178, blank=True)
    type = models.CharField(max_length=10, validators=[validate_upper])
    records = models.CharField(max_length=64000, blank=True)
    ttl = models.PositiveIntegerField(validators=[MinValueValidator(1)])
    _dirty = False


    class Meta:
        unique_together = (("domain","subname","type"),)

    def __init__(self, *args, **kwargs):
        self._dirties = set()
        super().__init__(*args, **kwargs)

    def setter_domain(self, val):
        if val != self.domain:
            self._dirties.add('domain')

        return val

    def setter_subname(self, val):
        # On PUT, RRsetSerializer sends None, denoting the unchanged value
        if val is None:
            return self.subname

        if val != self.subname:
            self._dirties.add('subname')

        return val

    def setter_type(self, val):
        if val != self.type:
            self._dirties.add('type')

        return val

    def setter_records(self, val):
        if val != self.records:
            self._dirty = True

        return val

    def setter_ttl(self, val):
        if val != self.ttl:
            self._dirty = True

        return val

    def clean(self):
        errors = {}
        for field in self._dirties:
            errors[field] = ValidationError(
                'You cannot change the `%s` field.' % field)

        if errors:
            raise ValidationError(errors)

    @property
    def name(self):
        return '.'.join(filter(None, [self.subname, self.domain.name])) + '.'

    def update_pdns(self):
        pdns.set_rrset(self)
        pdns.notify_zone(self.domain)

    @transaction.atomic
    def delete(self, *args, **kwargs):
        # Reset records so that our pdns update later will cause deletion
        self.records = '[]'
        super().delete(*args, **kwargs)

        self.update_pdns()

    @transaction.atomic
    def save(self, *args, **kwargs):
        new = self.pk is None
        self.updated = timezone.now()
        self.full_clean()
        super().save(*args, **kwargs)

        if self._dirty or new:
            self.update_pdns()