"""Model and functions to work with product data."""

from oto import response
from sqlalchemy import BigInteger
from sqlalchemy import Column
from sqlalchemy import Enum
from sqlalchemy import String
from sqlalchemy import UniqueConstraint
from sqlalchemy.dialects import mysql

from availability.connectors import sql
from availability.constants import error
from availability.constants import field_const
from availability.constants import models
from availability.models import error_handlers


class Product(sql.BaseModel):
    """Class representing the product table."""

    __tablename__ = models.PRODUCT_TABLE
    __table_args__ = (
        UniqueConstraint(
            'provider', 'itunes_vendor_id',
            name='unique_itunes_id_within_provider'),)

    # product_id matches the value from art_relations.releases.release_id
    product_id = Column(
        mysql.INTEGER(unsigned=True), primary_key=True, autoincrement=False)
    orchard_product_id = Column(BigInteger, unique=True, nullable=False)
    upc = Column(String(14), index=True, nullable=False)
    itunes_vendor_id = Column(String(25), nullable=True)
    provider = Column(Enum(*models.PROVIDERS_ENUM), default=models.ORCHARD)

    def as_dict(self):
        """Return dictionary representation of the product data.

        Returns:
            dict: Product fields.
        """
        return {
            field_const.PRODUCT_ID: self.product_id,
            field_const.ORCHARD_PRODUCT_ID: self.orchard_product_id,
            field_const.UPC: self.upc,
            field_const.ITUNES_VENDOR_ID: self.itunes_vendor_id,
            field_const.PROVIDER: self.provider,
        }


@error_handlers.sqlalchemy_error_handler
@error_handlers.integrity_error_handler(
    error_code=error.ERROR_CODE_MODEL_VALIDATION)
def create_product(
        product_id, orchard_product_id, upc, itunes_vendor_id=None,
        provider=models.ORCHARD):
    """Create a new record in the product table.

    Args:
        product_id (int): Product PK.
        orchard_product_id (int): The Orchard's unique product ID.
        upc (str): The Universal Product Code.
        itunes_vendor_id (str): Vendor-specific product ID in iTunes.
        provider (str): One of models.PROVIDERS_ENUM.

    Returns:
        response.Response: Product.as_dict() or error in message attribute.
    """
    product = get_product_by_id(product_id)
    if product:
        return product
    product = Product(
        product_id=product_id, orchard_product_id=orchard_product_id,
        upc=upc, itunes_vendor_id=itunes_vendor_id, provider=provider)
    if not itunes_vendor_id:
        product.itunes_vendor_id = upc
    with sql.session_scope() as session:
        session.add(product)
    return response.Response(product.as_dict())


@error_handlers.sqlalchemy_error_handler
def get_product_by_id(product_id):
    """Get product data from db by product id.

    Args:
        product_id (int): Product PK.
    Returns:
        response.Response: Product.as_dict() or error in message attribute.
    """
    with sql.session_scope() as session:
        product = session.query(Product).filter_by(
            product_id=product_id).first()
        if not product:
            return response.create_not_found_response(
                error.ERROR_MESSAGE_RELEASE_NOT_FOUND)
        return response.Response(product.as_dict())