from sqlalchemy import Column, Integer, String, Text, Boolean, Float, DateTime, ForeignKey, Date
from sqlalchemy.orm import relationship
from app.database import Base
from app.utils.datetime import utcnow


class FinancialAccount(Base):
    """财务账户模型"""
    __tablename__ = "financial_accounts"

    id = Column(Integer, primary_key=True, index=True)
    name = Column(String(100), nullable=False)
    account_type = Column(String(20), nullable=False, default="savings")  # savings / debt
    balance = Column(Float, default=0.0)
    icon = Column(String(50), default="wallet")
    color = Column(String(20), default="#FFB7C5")
    sort_order = Column(Integer, default=0)
    is_active = Column(Boolean, default=True)
    description = Column(Text, nullable=True)
    created_at = Column(DateTime, default=utcnow)
    updated_at = Column(DateTime, default=utcnow, onupdate=utcnow)

    # 关联关系
    history_records = relationship("AccountHistory", back_populates="account", cascade="all, delete-orphan")
    debt_installments = relationship("DebtInstallment", back_populates="account", cascade="all, delete-orphan")


class AccountHistory(Base):
    """余额变更历史"""
    __tablename__ = "account_history"

    id = Column(Integer, primary_key=True, index=True)
    account_id = Column(Integer, ForeignKey("financial_accounts.id"), nullable=False)
    change_amount = Column(Float, nullable=False)
    balance_before = Column(Float, nullable=False)
    balance_after = Column(Float, nullable=False)
    note = Column(String(200), nullable=True)
    created_at = Column(DateTime, default=utcnow)

    # 关联关系
    account = relationship("FinancialAccount", back_populates="history_records")


class DebtInstallment(Base):
    """分期还款计划"""
    __tablename__ = "debt_installments"

    id = Column(Integer, primary_key=True, index=True)
    account_id = Column(Integer, ForeignKey("financial_accounts.id"), nullable=False)
    total_amount = Column(Float, nullable=False)
    total_periods = Column(Integer, nullable=False)
    current_period = Column(Integer, nullable=False, default=1)  # 1-based, 指向下一期待还
    payment_day = Column(Integer, nullable=False)  # 每月还款日 1-31
    payment_amount = Column(Float, nullable=False)
    start_date = Column(Date, nullable=False)
    is_completed = Column(Boolean, default=False)
    created_at = Column(DateTime, default=utcnow)
    updated_at = Column(DateTime, default=utcnow, onupdate=utcnow)

    # 关联关系
    account = relationship("FinancialAccount", back_populates="debt_installments")