from datetime import datetime
from typing import Optional, TYPE_CHECKING
from sqlalchemy import Boolean, DateTime, ForeignKey, Index, Integer, Text
from sqlalchemy.orm import Mapped, mapped_column, relationship
from sqlalchemy.sql import func
from src.apps.base.models.base import Base

if TYPE_CHECKING:
    from src.apps.merchants.models.merchant import Merchant
    from src.apps.pricing_control.models.pricing_template import PricingTemplate


class MerchantPricingAssignment(Base):
    __tablename__ = "merchant_pricing_assignments"
    __table_args__ = (
        Index("ix_merchant_pricing_assignments_merchant_active", "merchant_id", "is_active"),
    )

    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
    merchant_id: Mapped[int] = mapped_column(
        Integer, ForeignKey("merchants.id"), nullable=False, index=True
    )
    template_id: Mapped[int] = mapped_column(
        Integer, ForeignKey("pricing_templates.id"), nullable=False, index=True
    )
    effective_date: Mapped[datetime] = mapped_column(DateTime(timezone=True), nullable=False)
    is_active: Mapped[bool] = mapped_column(Boolean, nullable=False, default=True)
    assigned_by_user_id: Mapped[Optional[int]] = mapped_column(
        Integer, ForeignKey("users.id"), nullable=True
    )
    notes: Mapped[Optional[str]] = mapped_column(Text, nullable=True)
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), server_default=func.now(), nullable=False
    )
    updated_at: Mapped[Optional[datetime]] = mapped_column(
        DateTime(timezone=True), nullable=True, onupdate=func.now()
    )
    deleted_at: Mapped[Optional[datetime]] = mapped_column(DateTime(timezone=True), nullable=True)

    merchant: Mapped["Merchant"] = relationship("Merchant")
    template: Mapped["PricingTemplate"] = relationship(
        "PricingTemplate", back_populates="assignments"
    )