import uuid
from datetime import date, datetime, timezone
from decimal import Decimal

from sqlalchemy import CheckConstraint, Date, DateTime, ForeignKey, Numeric, String, Text, UniqueConstraint
from sqlalchemy.dialects.postgresql import UUID
from sqlalchemy.orm import Mapped, mapped_column

from app.db.base import Base


class Quote(Base):
    __tablename__ = "quotes"
    __table_args__ = (
        UniqueConstraint("business_id", "quote_number", name="uq_quote_business_number"),
        CheckConstraint("subtotal >= 0 AND discount >= 0 AND tax >= 0 AND total >= 0", name="ck_quote_nonnegative"),
    )
    id: Mapped[uuid.UUID] = mapped_column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
    business_id: Mapped[uuid.UUID] = mapped_column(UUID(as_uuid=True), ForeignKey("businesses.id", ondelete="CASCADE"), nullable=False, index=True)
    branch_id: Mapped[uuid.UUID | None] = mapped_column(UUID(as_uuid=True), ForeignKey("branches.id", ondelete="RESTRICT"), index=True)
    customer_id: Mapped[uuid.UUID] = mapped_column(UUID(as_uuid=True), ForeignKey("customers.id", ondelete="RESTRICT"), nullable=False, index=True)
    quote_number: Mapped[str] = mapped_column(String(100), nullable=False)
    status: Mapped[str] = mapped_column(String(20), nullable=False, default="DRAFT")
    issue_date: Mapped[date] = mapped_column(Date, nullable=False, default=date.today)
    expiry_date: Mapped[date | None] = mapped_column(Date, nullable=True)
    subtotal: Mapped[Decimal] = mapped_column(Numeric(14, 2), nullable=False)
    discount: Mapped[Decimal] = mapped_column(Numeric(14, 2), nullable=False)
    tax: Mapped[Decimal] = mapped_column(Numeric(14, 2), nullable=False)
    total: Mapped[Decimal] = mapped_column(Numeric(14, 2), nullable=False)
    notes: Mapped[str | None] = mapped_column(Text, nullable=True)
    created_by: Mapped[uuid.UUID] = mapped_column(UUID(as_uuid=True), ForeignKey("users.id", ondelete="RESTRICT"), nullable=False)
    converted_invoice_id: Mapped[uuid.UUID | None] = mapped_column(UUID(as_uuid=True), ForeignKey("invoices.id", ondelete="RESTRICT"), unique=True)
    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), default=lambda: datetime.now(timezone.utc), nullable=False)
    updated_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), default=lambda: datetime.now(timezone.utc), onupdate=lambda: datetime.now(timezone.utc), nullable=False)


class QuoteItem(Base):
    __tablename__ = "quote_items"
    __table_args__ = (CheckConstraint("quantity > 0 AND unit_price >= 0 AND discount >= 0 AND line_total >= 0", name="ck_quote_item_amounts"),)
    id: Mapped[uuid.UUID] = mapped_column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
    quote_id: Mapped[uuid.UUID] = mapped_column(UUID(as_uuid=True), ForeignKey("quotes.id", ondelete="RESTRICT"), nullable=False, index=True)
    product_id: Mapped[uuid.UUID | None] = mapped_column(UUID(as_uuid=True), ForeignKey("products.id", ondelete="RESTRICT"))
    variant_id: Mapped[uuid.UUID | None] = mapped_column(UUID(as_uuid=True), ForeignKey("product_variants.id", ondelete="RESTRICT"))
    description: Mapped[str] = mapped_column(String(500), nullable=False)
    quantity: Mapped[Decimal] = mapped_column(Numeric(14, 4), nullable=False)
    unit_price: Mapped[Decimal] = mapped_column(Numeric(14, 2), nullable=False)
    discount: Mapped[Decimal] = mapped_column(Numeric(14, 2), nullable=False)
    line_total: Mapped[Decimal] = mapped_column(Numeric(14, 2), nullable=False)