import ulid
from sqlalchemy import Column, String, Numeric, DateTime, Integer, ForeignKey, Text, Index
from sqlalchemy.sql import func
from sqlalchemy.orm import relationship
from app.core.database.db_session import Base

class Order(Base):
    __tablename__ = "orders"

    order_id = Column(String(26), primary_key=True, default=lambda: str(ulid.new()))
    order_no = Column(String(50), unique=True, nullable=False, index=True)
    customer_id = Column(String(26), ForeignKey("ecom_customers.customer_id", ondelete="SET NULL"), nullable=True, index=True)
    
    total_amount = Column(Numeric(10, 2), nullable=False)
    discount_amount = Column(Numeric(10, 2), default=0.00)
    tax_amount = Column(Numeric(10, 2), default=0.00)
    shipping_cost = Column(Numeric(10, 2), default=0.00)
    final_amount = Column(Numeric(10, 2), nullable=False)
    
    status = Column(String(50), default="ORDER_CREATED", index=True) # ORDER_CREATED, PAYMENT_PENDING, ORDER_CONFIRMED, PROCESSING, PACKED, SHIPPED, DELIVERED, CANCELLED
    payment_status = Column(String(50), default="PAYMENT_PENDING", index=True) # PAYMENT_PENDING, PAYMENT_CAPTURED, PAYMENT_FAILED, REFUNDED
    fulfillment_status = Column(String(50), default="UNFULFILLED")
    
    shipping_address_json = Column(Text, nullable=True)
    billing_address_json = Column(Text, nullable=True)
    tracking_number = Column(String(100), nullable=True)
    courier_name = Column(String(100), nullable=True)
    
    created_at = Column(DateTime, server_default=func.now(), index=True)
    updated_at = Column(DateTime, server_default=func.now(), onupdate=func.now())

    __table_args__ = (
        Index('idx_orders_customer_created', 'customer_id', 'created_at'),
        Index('idx_orders_status_created', 'status', 'created_at'),
    )

    customer = relationship("EcomCustomer", back_populates="orders")
    items = relationship("OrderItem", back_populates="order", cascade="all, delete-orphan")
    history = relationship("OrderStatusHistory", back_populates="order", cascade="all, delete-orphan")

class OrderItem(Base):
    __tablename__ = "order_items"

    item_id = Column(String(26), primary_key=True, default=lambda: str(ulid.new()))
    order_id = Column(String(26), ForeignKey("orders.order_id", ondelete="CASCADE"), nullable=False, index=True)
    product_id = Column(String(26), nullable=False)
    variant_id = Column(String(26), nullable=False, index=True)
    product_name = Column(String(255), nullable=False)
    sku = Column(String(100), nullable=False)
    unit_price = Column(Numeric(10, 2), nullable=False)
    quantity = Column(Integer, nullable=False)
    total_price = Column(Numeric(10, 2), nullable=False)

    order = relationship("Order", back_populates="items")

class OrderStatusHistory(Base):
    __tablename__ = "order_status_history"

    history_id = Column(String(26), primary_key=True, default=lambda: str(ulid.new()))
    order_id = Column(String(26), ForeignKey("orders.order_id", ondelete="CASCADE"), nullable=False, index=True)
    previous_status = Column(String(50), nullable=True)
    new_status = Column(String(50), nullable=False)
    changed_by = Column(String(100), default="SYSTEM")
    reason = Column(String(255), nullable=True)
    created_at = Column(DateTime, server_default=func.now())

    order = relationship("Order", back_populates="history")