from __future__ import annotations

from datetime import datetime, timezone

from sqlalchemy import Boolean, DateTime, ForeignKey, Integer, String, Text, UniqueConstraint
from sqlalchemy.orm import Mapped, mapped_column

from app.core.db.common import CommonBase


class AccountingNature(CommonBase):
    """Firm-scoped canonical accounting nature used by the intelligence engine.

    Phase 4 intentionally stores accounting meaning separately from any client's
    Tally ledger name.  Later mapping/learning phases can link a nature code to
    client-specific ledgers without changing this taxonomy.
    """

    __tablename__ = "accounting_natures"
    __table_args__ = (
        UniqueConstraint("tenant_id", "code", name="uq_accounting_natures_tenant_code"),
    )

    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
    tenant_id: Mapped[int] = mapped_column(ForeignKey("tenants.id", ondelete="CASCADE"), nullable=False, index=True)
    code: Mapped[str] = mapped_column(String(80), nullable=False, index=True)
    name: Mapped[str] = mapped_column(String(160), nullable=False, index=True)
    parent_code: Mapped[str | None] = mapped_column(String(80), nullable=True, index=True)
    classification_group: Mapped[str] = mapped_column(String(40), nullable=False, index=True)
    capital_revenue: Mapped[str] = mapped_column(String(20), nullable=False, default="revenue", index=True)
    description: Mapped[str | None] = mapped_column(Text, nullable=True)
    sort_order: Mapped[int] = mapped_column(Integer, nullable=False, default=100)
    is_posting_nature: Mapped[bool] = mapped_column(Boolean, nullable=False, default=True, index=True)
    is_active: Mapped[bool] = mapped_column(Boolean, nullable=False, default=True, index=True)
    is_system_defined: Mapped[bool] = mapped_column(Boolean, nullable=False, default=True)
    created_by_user_id: Mapped[int | None] = mapped_column(ForeignKey("users.id", ondelete="SET NULL"), nullable=True)
    updated_by_user_id: Mapped[int | None] = mapped_column(ForeignKey("users.id", ondelete="SET NULL"), nullable=True)
    created_at_utc: Mapped[datetime] = mapped_column(DateTime(timezone=True), default=lambda: datetime.now(timezone.utc), nullable=False)
    updated_at_utc: Mapped[datetime] = mapped_column(DateTime(timezone=True), default=lambda: datetime.now(timezone.utc), onupdate=lambda: datetime.now(timezone.utc), nullable=False)