from django.db import models
from django.dispatch import receiver

from misago.core import serializer
from misago.core.signals import secret_key_changed

from . import hydrators


class SettingsGroupsManager(models.Manager):
    def ordered_alphabetically(self):
        from django.utils.translation import ugettext as _

        groups_dict = {}

        for group in self.all():
            groups_dict[_(group.name)] = group

        ordered_groups = []
        for key in groups_dict.keys():
            ordered_groups.append(groups_dict[key])
        return ordered_groups


class SettingsGroup(models.Model):
    key = models.CharField(max_length=255, unique=True)
    name = models.CharField(max_length=255)
    description = models.TextField(null=True, blank=True)

    objects = SettingsGroupsManager()


class SettingsManager(models.Manager):
    def change_setting(self, setting, dry_value=None, wet_value=None):
        if dry_value:
            return self.filter(setting=setting).update(dry_value=dry_value)
        elif wet_value:
            try:
                setting = self.get(setting=setting)
                setting.value = wet_value
                setting.save(update_fields=['dry_value'])
            except Setting.DoesNotExist:
                return 0


class Setting(models.Model):
    group = models.ForeignKey(SettingsGroup)
    setting = models.CharField(max_length=255, unique=True)
    name = models.CharField(max_length=255)
    description = models.TextField(null=True, blank=True)
    legend = models.CharField(max_length=255, null=True, blank=True)
    order = models.IntegerField(default=0, db_index=True)
    dry_value = models.TextField(null=True, blank=True)
    default_value = models.TextField(null=True, blank=True)
    python_type = models.CharField(max_length=255, default='string')
    is_public = models.BooleanField(default=False)
    is_lazy = models.BooleanField(default=False)
    form_field = models.CharField(max_length=255, default='text')
    pickled_field_extra = models.TextField(null=True, blank=True)

    objects = SettingsManager()

    @property
    def value(self):
        if not self.dry_value and self.default_value:
            return hydrators.hydrate_value(self.python_type,
                                           self.default_value)
        else:
            return hydrators.hydrate_value(self.python_type,
                                           self.dry_value)

    @value.setter
    def value(self, new_value):
        if new_value is not None:
            self.dry_value = hydrators.dehydrate_value(self.python_type,
                                                       new_value)
        else:
            self.dry_value = None
        return self.value

    @property
    def has_custom_value(self):
        return self.dry_value and self.dry_value != self.default_value

    @property
    def field_extra(self):
        if self.pickled_field_extra:
            return serializer.loads(self.pickled_field_extra)
        else:
            return {}

    @field_extra.setter
    def field_extra(self, new_extra):
        if new_extra:
            self.pickled_field_extra = serializer.dumps(new_extra)


"""
Signal handlers
"""
@receiver(secret_key_changed)
def update_settings_pickles(sender, **kwargs):
    for setting in Setting.objects.iterator():
        if setting.pickled_field_extra:
            setting.pickled_field_extra = serializer.regenerate_checksum(
                setting.pickled_field_extra)
            setting.save(update_fields=['pickled_field_extra'])