"""Exchange rate model."""

from abacus_common_logic.connectors.database import db
from abacus_common_logic.models.base import BaseModel
from sqlalchemy import Index
from sqlalchemy.orm import backref


class ExchangeRate(BaseModel):
    """Exchange rate model."""

    __tablename__ = 'exchange_rate'
    exchange_rate_id = db.Column(db.Integer, primary_key=True)
    statement_period_id = db.Column(
        db.Integer,
        db.ForeignKey('statement_period.statement_period_id'),
        nullable=False,
    )
    statement_period = db.relationship(
        'StatementPeriod',
        lazy='joined',
        backref=backref('exchange_rates', cascade='all, delete-orphan'),
    )
    from_currency_code = db.Column(db.String(3), nullable=False)
    to_currency_code = db.Column(db.String(3), nullable=False)
    rate = db.Column(db.Numeric(30, 19), nullable=False)
    __table_args__ = (
        Index(
            'uq_statement_period_id_from_currency_code_to_currency_code',
            'statement_period_id',
            'from_currency_code',
            'to_currency_code',
            unique=True,
        ),
        Index(
            'ix_statement_period_id_from_currency_code_to_currency_code_rat',
            'statement_period_id',
            'from_currency_code',
            'to_currency_code',
            'rate',
            unique=False,
        ),
    )