from __future__ import annotations

from datetime import date, datetime

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

from app.core.db.common import CommonBase


class AccountingTDSRule(CommonBase):
    __tablename__ = "accounting_tds_rules"
    __table_args__ = (
        UniqueConstraint("tenant_id", "rule_code", "effective_from", name="uq_accounting_tds_rule_version"),
    )

    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
    tenant_id: Mapped[int] = mapped_column(ForeignKey("tenants.id", ondelete="CASCADE"), index=True)
    rule_code: Mapped[str] = mapped_column(String(80), nullable=False)
    name: Mapped[str] = mapped_column(String(200), nullable=False)
    statutory_reference: Mapped[str] = mapped_column(String(160), default="Income-tax Act, 2025 - section 393(1)")
    legacy_section: Mapped[str | None] = mapped_column(String(40), nullable=True)
    nature_keywords: Mapped[str] = mapped_column(Text, default="")
    effective_from: Mapped[date] = mapped_column(Date, nullable=False)
    effective_to: Mapped[date | None] = mapped_column(Date, nullable=True)
    threshold_mode: Mapped[str] = mapped_column(String(30), default="ANNUAL")
    single_threshold: Mapped[float] = mapped_column(Float, default=0.0)
    aggregate_threshold: Mapped[float] = mapped_column(Float, default=0.0)
    rate_individual_huf: Mapped[float] = mapped_column(Float, default=0.0)
    rate_other: Mapped[float] = mapped_column(Float, default=0.0)
    no_pan_rate: Mapped[float] = mapped_column(Float, default=20.0)
    deduct_on_excess_only: Mapped[bool] = mapped_column(Boolean, default=False)
    applies_to_purchases: Mapped[bool] = mapped_column(Boolean, default=False)
    applies_to_expenses: Mapped[bool] = mapped_column(Boolean, default=True)
    is_active: Mapped[bool] = mapped_column(Boolean, default=True)
    is_system_default: Mapped[bool] = mapped_column(Boolean, default=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, default=datetime.utcnow)
    updated_at_utc: Mapped[datetime] = mapped_column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)


class AccountingTDSPostingInstruction(CommonBase):
    __tablename__ = "accounting_tds_posting_instructions"

    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
    tenant_id: Mapped[int] = mapped_column(ForeignKey("tenants.id", ondelete="CASCADE"), index=True)
    client_id: Mapped[int] = mapped_column(ForeignKey("clients.id", ondelete="CASCADE"), index=True)
    rule_id: Mapped[int | None] = mapped_column(ForeignKey("accounting_tds_rules.id", ondelete="SET NULL"), nullable=True)
    company_guid: Mapped[str | None] = mapped_column(String(255), nullable=True)
    company_name: Mapped[str | None] = mapped_column(String(255), nullable=True)
    source_voucher_number: Mapped[str | None] = mapped_column(String(120), nullable=True)
    source_voucher_date: Mapped[date | None] = mapped_column(Date, nullable=True)
    party_ledger: Mapped[str] = mapped_column(String(255), nullable=False)
    tds_ledger: Mapped[str] = mapped_column(String(255), nullable=False, default="TDS Payable")
    taxable_base: Mapped[float] = mapped_column(Float, default=0.0)
    expected_tds: Mapped[float] = mapped_column(Float, default=0.0)
    actual_tds: Mapped[float] = mapped_column(Float, default=0.0)
    liability_amount: Mapped[float] = mapped_column(Float, default=0.0)
    statutory_reference: Mapped[str | None] = mapped_column(String(160), nullable=True)
    narration: Mapped[str | None] = mapped_column(Text, nullable=True)
    erp_reference: Mapped[str | None] = mapped_column(String(80), nullable=True, unique=True)
    status: Mapped[str] = mapped_column(String(30), default="prepared", index=True)
    tally_voucher_id: Mapped[str | None] = mapped_column(String(120), nullable=True)
    prepared_by_user_id: Mapped[int | None] = mapped_column(ForeignKey("users.id", ondelete="SET NULL"), nullable=True)
    approved_by_user_id: Mapped[int | None] = mapped_column(ForeignKey("users.id", ondelete="SET NULL"), nullable=True)
    posted_by_user_id: Mapped[int | None] = mapped_column(ForeignKey("users.id", ondelete="SET NULL"), nullable=True)
    prepared_at_utc: Mapped[datetime] = mapped_column(DateTime, default=datetime.utcnow)
    approved_at_utc: Mapped[datetime | None] = mapped_column(DateTime, nullable=True)
    posted_at_utc: Mapped[datetime | None] = mapped_column(DateTime, nullable=True)