import uuid
from datetime import date, datetime
from decimal import Decimal
from sqlalchemy import String, Boolean, Date, DateTime, Text, Numeric, Integer, UniqueConstraint, Index, ForeignKey
from sqlalchemy.orm import Mapped, mapped_column, relationship
from sqlalchemy.dialects.postgresql import UUID
from app.database import Base
from typing import TYPE_CHECKING
if TYPE_CHECKING:
    from app.domains.tenants.models import Tenant


class PricingTier(Base):
    __tablename__ = "pricing_tiers"

    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
    category_key: Mapped[str] = mapped_column(String(100), nullable=False)
    quality_level: Mapped[str] = mapped_column(String(50), nullable=False, default="Normal")
    price_per_item: Mapped[Decimal] = mapped_column(Numeric(10, 2), nullable=False)
    description: Mapped[str | None] = mapped_column(Text, nullable=True)
    is_active: Mapped[bool] = mapped_column(Boolean, default=True, nullable=False)
    tenant_id: Mapped[uuid.UUID | None] = mapped_column(
        UUID(as_uuid=True), ForeignKey("tenants.id"), nullable=True, index=True
    )
    created_at: Mapped[datetime] = mapped_column(DateTime, default=datetime.utcnow, nullable=False)
    updated_at: Mapped[datetime] = mapped_column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow, nullable=False)

    output_types: Mapped[list["OutputType"]] = relationship("OutputType", back_populates="pricing_tier")

    __table_args__ = (
        UniqueConstraint("category_key", "quality_level", name="uq_pricing_tier"),
        Index("ix_pricing_tiers_category_key", "category_key"),
    )


class Invoice(Base):
    __tablename__ = "invoices"

    id: Mapped[uuid.UUID] = mapped_column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
    tenant_id: Mapped[uuid.UUID | None] = mapped_column(UUID(as_uuid=True), ForeignKey("tenants.id"), nullable=True, index=True)
    invoice_number: Mapped[str] = mapped_column(String(20), nullable=False, unique=True)
    status: Mapped[str] = mapped_column(String(20), nullable=False, default="draft")
    issued_at: Mapped[date | None] = mapped_column(Date, nullable=True)
    due_at: Mapped[date | None] = mapped_column(Date, nullable=True)
    total_net: Mapped[Decimal | None] = mapped_column(Numeric(12, 2), nullable=True)
    total_vat: Mapped[Decimal | None] = mapped_column(Numeric(12, 2), nullable=True)
    vat_rate: Mapped[Decimal] = mapped_column(Numeric(5, 4), nullable=False, default=Decimal("0.19"))
    currency: Mapped[str] = mapped_column(String(3), nullable=False, default="EUR")
    notes: Mapped[str | None] = mapped_column(Text, nullable=True)
    pdf_key: Mapped[str | None] = mapped_column(Text, nullable=True)
    created_at: Mapped[datetime] = mapped_column(DateTime, default=datetime.utcnow, nullable=False)
    updated_at: Mapped[datetime] = mapped_column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow, nullable=False)

    lines: Mapped[list["InvoiceLine"]] = relationship("InvoiceLine", back_populates="invoice", cascade="all, delete-orphan")


class InvoiceLine(Base):
    __tablename__ = "invoice_lines"

    id: Mapped[uuid.UUID] = mapped_column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
    invoice_id: Mapped[uuid.UUID] = mapped_column(UUID(as_uuid=True), ForeignKey("invoices.id", ondelete="CASCADE"), nullable=False)
    order_line_id: Mapped[uuid.UUID | None] = mapped_column(UUID(as_uuid=True), ForeignKey("order_lines.id", ondelete="SET NULL"), nullable=True)
    description: Mapped[str] = mapped_column(Text, nullable=False)
    quantity: Mapped[int] = mapped_column(Integer, nullable=False, default=1)
    unit_price: Mapped[Decimal | None] = mapped_column(Numeric(10, 2), nullable=True)
    total: Mapped[Decimal | None] = mapped_column(Numeric(10, 2), nullable=True)

    invoice: Mapped["Invoice"] = relationship("Invoice", back_populates="lines")