from datetime import datetime, timezone
from sqlalchemy import Column, Integer, String, Float, ForeignKey, DateTime, Text
from sqlalchemy.orm import relationship
from .database import Base


class Category(Base):
    __tablename__ = "categories"

    id = Column(Integer, primary_key=True, index=True)
    name = Column(String, unique=True, nullable=False)
    created_at = Column(DateTime, default=lambda: datetime.now(timezone.utc))

    piggy_banks = relationship("PiggyBank", back_populates="category")


class PiggyBank(Base):
    __tablename__ = "piggy_banks"

    id = Column(Integer, primary_key=True, index=True)
    name = Column(String, nullable=False)
    target_amount = Column(Float, nullable=False)
    current_amount = Column(Float, default=0.0, nullable=False)
    currency = Column(String, default="USD", nullable=False)
    category_id = Column(Integer, ForeignKey("categories.id"), nullable=True)
    created_at = Column(DateTime, default=lambda: datetime.now(timezone.utc))
    updated_at = Column(DateTime, default=lambda: datetime.now(timezone.utc), onupdate=lambda: datetime.now(timezone.utc))

    category = relationship("Category", back_populates="piggy_banks")
    transactions = relationship("Transaction", back_populates="piggy_bank", cascade="all, delete-orphan")


class Transaction(Base):
    __tablename__ = "transactions"

    id = Column(Integer, primary_key=True, index=True)
    piggy_bank_id = Column(Integer, ForeignKey("piggy_banks.id"), nullable=False)
    amount = Column(Float, nullable=False)
    description = Column(Text, nullable=True)
    created_at = Column(DateTime, default=lambda: datetime.now(timezone.utc))

    piggy_bank = relationship("PiggyBank", back_populates="transactions")