"""
Transaction Modles
"""
from django.core.exceptions import ValidationError
from django.db import models
from django.utils.translation import ugettext_lazy as _
from django.contrib.auth import get_user_model

User = get_user_model()

def validate_type(value):
    """Validate type value"""
    if value not in ('inflow', 'outflow'):
        raise ValidationError(
            _('%(value)s is not an even number'),
            params={'value': value},
        )


class Transaction(models.Model):
    """
    Transaction core model
    """
    user = models.ForeignKey(User,related_name='transactions', on_delete=models.CASCADE)
    reference = models.CharField(_('Transaction reference'), max_length=8, unique=True,
                                 help_text=_('Unique value'))
    account = models.CharField(_('Account'), max_length=8, help_text=_('Account Number'))
    type = models.CharField(_('Type'), max_length=8,
                            choices=(('inflow', 'inflow'), ('outflow', 'outflow')),
                            validators=[validate_type],
                            help_text=_('Choice "outflow" or "inflow"'))
    amount = models.FloatField(_('Amount'), max_length=255,
                               help_text=_('''Only negative numbers for "outflow" and
                                           positive numbers for "inflow"'''))

    category = models.CharField(_('Category'), max_length=255, help_text=_('Category Name'))
    date = models.DateField('Date',help_text=_('Transaction date. YYYY-MM-DD format.'))