from django.db import models
from apps.core.models import BaseModel


# Create your models here.

class ReferenceProduct(BaseModel):
    """ Reference product - like: rice """

    name = models.CharField(max_length=250, default='empty')  # noqa
    type_choices = (
        ('F', 'Free'),  # free product
        ('G', 'Governmental')  # government product
    )
    type = models.CharField(max_length=3, choices=type_choices)
    img = models.CharField(max_length=100, default='empty')

    def __str__(self):
        return f'name: {self.name} - type: {self.type}'

    def save(self, *args, **kwargs):
        super(ReferenceProduct, self).save(*args, **kwargs)


class Product(BaseModel):
    """ Child of reference product - like: brown rice """
    name = models.CharField(max_length=250, default='empty')  # noqa
    type_choices = (
        ('F', 'Free'),  # free product
        ('G', 'Governmental')  #
    )
    type = models.CharField(max_length=3, choices=type_choices)
    img = models.CharField(max_length=100, default='empty')
    reference = models.ForeignKey(
        ReferenceProduct,
        on_delete=models.CASCADE,
        related_name='reference_product',
        null=True
    )

    def __str__(self):
        return f'name: {self.name} - type: {self.type}'

    def save(self, *args, **kwargs):
        super(Product, self).save(*args, **kwargs)


class Attribute(BaseModel):
    """
    every reference product have multiple attributes
    """
    reference_product = models.ForeignKey(
        ReferenceProduct,
        on_delete=models.CASCADE,
        related_name='reference_attribute',
        null=True
    )
    name = models.CharField(max_length=100, default='empty')
    type = models.CharField(
        max_length=255,
        default='empty',
        help_text='type of attribute like: calculate product by kilogram'
    )

    def __str__(self):
        return f'{self.reference_product.name} - {self.name}'

    def save(self, *args, **kwargs):
        return super(Attribute, self).save(*args, **kwargs)


class AttributeValue(BaseModel):
    """
    every child product should have attribute value for
    reference product attribute
    """
    product = models.ForeignKey(
        Product,
        on_delete=models.CASCADE,
        related_name='product_attribute_value',
        null=True
    )
    attribute = models.ForeignKey(
        Attribute,
        on_delete=models.CASCADE,
        related_name='attribute_value'
    )
    value = models.IntegerField(default=0)

    def __str__(self):
        return f'{self.product.name} - {self.attribute.name} - {self.value}'

    def save(self, *args, **kwargs):
        return super(AttributeValue, self).save(*args, **kwargs)


class SaleUnit(BaseModel):
    product = models.ForeignKey(
        ReferenceProduct,
        on_delete=models.CASCADE,
        related_name='sale_unit',
        null=True
    )
    unit = models.CharField(max_length=255, null=True)
    variation_coefficient = models.CharField(max_length=255, null=True)
    required = models.BooleanField(default=False)

    def __str__(self):
        return f'{self.product} - {self.unit} - {self.variation_coefficient}'