# lingo - payment and billing system
# Copyright (C) 2022  Entr'ouvert
#
# This program is free software: you can redistribute it and/or modify it
# under the terms of the GNU Affero General Public License as published
# by the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

import copy

from django.contrib.auth.models import Group
from django.contrib.postgres.fields import JSONField
from django.db import models
from django.utils.formats import date_format
from django.utils.text import slugify
from django.utils.translation import gettext_lazy as _

from lingo.utils.misc import generate_slug


class RegieImportError(Exception):
    pass


class Regie(models.Model):
    label = models.CharField(_('Label'), max_length=150)
    slug = models.SlugField(_('Identifier'), max_length=160, unique=True)
    description = models.TextField(
        _('Description'), null=True, blank=True, help_text=_('Optional regie description.')
    )
    cashier_role = models.ForeignKey(
        Group,
        blank=True,
        null=True,
        default=None,
        related_name='+',
        verbose_name=_('Cashier Role'),
        on_delete=models.SET_NULL,
    )

    class Meta:
        ordering = ['label']

    def __str__(self):
        return self.label

    def save(self, *args, **kwargs):
        if not self.slug:
            self.slug = generate_slug(self)
        super().save(*args, **kwargs)

    @property
    def base_slug(self):
        return slugify(self.label)

    def export_json(self):
        return {
            'label': self.label,
            'slug': self.slug,
            'description': self.description,
            'permissions': {
                'cashier': self.cashier_role.name if self.cashier_role else None,
            },
        }

    @classmethod
    def import_json(cls, data):
        data = copy.deepcopy(data)
        permissions = data.pop('permissions') or {}
        role_name = permissions.get('cashier')
        if role_name:
            try:
                data['cashier_role'] = Group.objects.get(name=role_name)
            except Group.DoesNotExists:
                raise RegieImportError('Missing role: %s' % role_name)
            except Group.MultipleObjectsReturned:
                raise RegieImportError('Multiple role exist with the name: %s' % role_name)

        regie, created = cls.objects.update_or_create(slug=data['slug'], defaults=data)
        return created, regie


class Campaign(models.Model):
    date_start = models.DateField(_('Start date'))
    date_end = models.DateField(_('End date'))
    date_issue = models.DateField(_('Issue date'))

    def __str__(self):
        return _('From %(start)s to %(end)s') % {
            'start': date_format(self.date_start, 'd/m/Y'),
            'end': date_format(self.date_end, 'd/m/Y'),
        }


class Pool(models.Model):
    campaign = models.ForeignKey(Campaign, on_delete=models.PROTECT)
    draft = models.BooleanField(default=True)
    created_at = models.DateTimeField(auto_now_add=True)


class AbstractInvoice(models.Model):
    label = models.CharField(_('Label'), max_length=300)
    total_amount = models.DecimalField(max_digits=9, decimal_places=2, default=0)
    date_issue = models.DateField(_('Issue date'))
    regie = models.ForeignKey(Regie, on_delete=models.PROTECT)
    payer = models.CharField(_('Payer'), max_length=300)

    pool = models.ForeignKey(Pool, on_delete=models.PROTECT)

    class Meta:
        abstract = True


class DraftInvoice(AbstractInvoice):
    pass


class Invoice(AbstractInvoice):
    pass


class AbstractInvoiceLine(models.Model):
    slug = models.SlugField(max_length=250)
    label = models.CharField(max_length=260)
    quantity = models.FloatField()
    unit_amount = models.DecimalField(max_digits=9, decimal_places=2)
    total_amount = models.DecimalField(max_digits=9, decimal_places=2)

    user_external_id = models.CharField(max_length=250)
    payer_external_id = models.CharField(max_length=250)
    event = JSONField(default=dict)
    pricing_data = JSONField(default=dict)
    status = models.CharField(
        max_length=10,
        choices=[
            ('success', _('Success')),
            ('error', _('Error')),
        ],
    )

    pool = models.ForeignKey(Pool, on_delete=models.PROTECT)

    class Meta:
        abstract = True


class DraftInvoiceLine(AbstractInvoiceLine):
    invoice = models.ForeignKey(DraftInvoice, on_delete=models.PROTECT, null=True, related_name='lines')


class InvoiceLine(AbstractInvoiceLine):
    invoice = models.ForeignKey(Invoice, on_delete=models.PROTECT, null=True, related_name='lines')