# -*- coding: utf-8 -*-
from datetime import timedelta
from decimal import Decimal

from django import forms
from django.core.exceptions import ValidationError
from django.db import models

from djconfig import config
from djconfig.forms import ConfigForm

from .models import Account


class KFetConfig(object):
    """kfet app configuration.

    Enhance isolation with backend used to store config.
    Usable after DjConfig middleware was called.

    """
    prefix = 'kfet_'

    def __getattr__(self, key):
        if key == 'subvention_cof':
            # Allows accessing to the reduction as a subvention
            # Other reason: backward compatibility
            reduction_mult = 1 - self.reduction_cof / 100
            return (1 / reduction_mult - 1) * 100
        return getattr(config, self._get_dj_key(key))

    def list(self):
        """Get list of kfet app configuration.

        Returns:
            (key, value) for each configuration entry as list.

        """
        return [(field.label, getattr(config, name), )
                for name, field in KFetConfigForm.base_fields.items()]

    def _get_dj_key(self, key):
        return '{}{}'.format(self.prefix, key)

    def set(self, **kwargs):
        """Update configuration value(s).

        Args:
            **kwargs: Keyword arguments. Keys must be in kfet config.
                Config entries are updated to given values.

        """
        # get old config
        new_cfg = KFetConfigForm().initial
        # update to new config
        for key, value in kwargs.items():
            dj_key = self._get_dj_key(key)
            if isinstance(value, models.Model):
                new_cfg[dj_key] = value.pk
            else:
                new_cfg[dj_key] = value
        # save new config
        cfg_form = KFetConfigForm(new_cfg)
        if cfg_form.is_valid():
            cfg_form.save()
        else:
            raise ValidationError(
                'Invalid values in kfet_config.set: %(fields)s',
                params={'fields': list(cfg_form.errors)})


kfet_config = KFetConfig()


class KFetConfigForm(ConfigForm):

    kfet_reduction_cof = forms.DecimalField(
        label='Réduction COF', initial=Decimal('20'),
        max_digits=6, decimal_places=2,
        help_text="Réduction, à donner en pourcentage, appliquée lors d'un "
                  "achat par un-e membre du COF sur le montant en euros.",
    )
    kfet_addcost_amount = forms.DecimalField(
        label='Montant de la majoration (en €)', initial=Decimal('0'),
        required=False,
        max_digits=6, decimal_places=2,
    )
    kfet_addcost_for = forms.ModelChoiceField(
        label='Destinataire de la majoration', initial=None, required=False,
        help_text='Laissez vide pour désactiver la majoration.',
        queryset=(Account.objects
                  .select_related('cofprofile', 'cofprofile__user')
                  .all()),
    )
    kfet_overdraft_duration = forms.DurationField(
        label='Durée du découvert autorisé par défaut',
        initial=timedelta(days=1),
    )
    kfet_overdraft_amount = forms.DecimalField(
        label='Montant du découvert autorisé par défaut (en €)',
        initial=Decimal('20'),
        max_digits=6, decimal_places=2,
    )
    kfet_cancel_duration = forms.DurationField(
        label='Durée pour annuler une commande sans mot de passe',
        initial=timedelta(minutes=5),
    )