import sqlalchemy as sa

from sqlalchemy_utils.observer import observes
from tests import TestCase


class TestObservesForManyToManyToManyToMany(TestCase):
    dns = 'postgres://postgres@localhost/sqlalchemy_utils_test'

    def create_models(self):
        catalog_category = sa.Table(
            'catalog_category',
            self.Base.metadata,
            sa.Column('catalog_id', sa.Integer, sa.ForeignKey('catalog.id')),
            sa.Column('category_id', sa.Integer, sa.ForeignKey('category.id'))
        )

        category_subcategory = sa.Table(
            'category_subcategory',
            self.Base.metadata,
            sa.Column(
                'category_id',
                sa.Integer,
                sa.ForeignKey('category.id')
            ),
            sa.Column(
                'subcategory_id',
                sa.Integer,
                sa.ForeignKey('sub_category.id')
            )
        )

        subcategory_product = sa.Table(
            'subcategory_product',
            self.Base.metadata,
            sa.Column(
                'subcategory_id',
                sa.Integer,
                sa.ForeignKey('sub_category.id')
            ),
            sa.Column(
                'product_id',
                sa.Integer,
                sa.ForeignKey('product.id')
            )
        )

        class Catalog(self.Base):
            __tablename__ = 'catalog'
            id = sa.Column(sa.Integer, primary_key=True)
            product_count = sa.Column(sa.Integer, default=0)

            @observes('categories.sub_categories.products')
            def product_observer(self, products):
                self.product_count = len(products)

            categories = sa.orm.relationship(
                'Category',
                backref='catalogs',
                secondary=catalog_category
            )

        class Category(self.Base):
            __tablename__ = 'category'
            id = sa.Column(sa.Integer, primary_key=True)

            sub_categories = sa.orm.relationship(
                'SubCategory',
                backref='categories',
                secondary=category_subcategory
            )

        class SubCategory(self.Base):
            __tablename__ = 'sub_category'
            id = sa.Column(sa.Integer, primary_key=True)
            products = sa.orm.relationship(
                'Product',
                backref='sub_categories',
                secondary=subcategory_product
            )

        class Product(self.Base):
            __tablename__ = 'product'
            id = sa.Column(sa.Integer, primary_key=True)
            price = sa.Column(sa.Numeric)

        self.Catalog = Catalog
        self.Category = Category
        self.SubCategory = SubCategory
        self.Product = Product

    def create_catalog(self):
        sub_category = self.SubCategory(products=[self.Product()])
        category = self.Category(sub_categories=[sub_category])
        catalog = self.Catalog(categories=[category])
        self.session.add(catalog)
        self.session.flush()
        return catalog

    def test_simple_insert(self):
        catalog = self.create_catalog()
        assert catalog.product_count == 1

    def test_add_leaf_object(self):
        catalog = self.create_catalog()
        product = self.Product()
        catalog.categories[0].sub_categories[0].products.append(product)
        self.session.flush()
        assert catalog.product_count == 2

    def test_remove_leaf_object(self):
        catalog = self.create_catalog()
        product = self.Product()
        catalog.categories[0].sub_categories[0].products.append(product)
        self.session.flush()
        self.session.delete(product)
        self.session.flush()
        assert catalog.product_count == 1

    def test_delete_intermediate_object(self):
        catalog = self.create_catalog()
        self.session.delete(catalog.categories[0].sub_categories[0])
        self.session.commit()
        assert catalog.product_count == 0

    def test_gathered_objects_are_distinct(self):
        catalog = self.Catalog()
        category = self.Category(catalogs=[catalog])
        product = self.Product()
        category.sub_categories.append(
            self.SubCategory(products=[product])
        )
        self.session.add(
            self.SubCategory(categories=[category], products=[product])
        )
        self.session.commit()
        assert catalog.product_count == 1