"""
合同域 ORM 模型
映射: erp_contracts / erp_contract_items / erp_contract_attachments
"""

from __future__ import annotations

import uuid
from datetime import date, datetime

from sqlalchemy import (
    Boolean,
    Date,
    DateTime,
    ForeignKey,
    Numeric,
    String,
    Text,
    func,
)
from sqlalchemy.dialects.postgresql import UUID
from sqlalchemy.orm import Mapped, mapped_column, relationship

from app.models.base import Base


# ── 付款条件枚举 ─────────────────────────────────────────
PAYMENT_TERMS = [
    "预付全款订货",
    "预付30%订货，到货前付清",
    "预付50%订货，到货前付清",
    "货到付全款",
    "开具发票后30天内付款",
    "开具发票45天付款",
    "开具发票60天付款",
    "开具发票90天付款",
]

# ── 运费条款枚举 ─────────────────────────────────────────
SHIPPING_TERMS = [
    "买方自提",
    "卖方免费送达天津指定地点",
    "卖方免费送达指定地点",
    "物流发货，运费买方承担",
]


class ErpContract(Base):
    """合同主表 —— B2B 交易防线核心"""
    __tablename__ = "erp_contracts"

    id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True), primary_key=True, default=uuid.uuid4
    )
    contract_no: Mapped[str] = mapped_column(String(30), unique=True, nullable=False)
    buyer_customer_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True), ForeignKey("crm_customers.id"), nullable=False,
        comment="买方（CRM 客户）"
    )
    seller_company_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True), ForeignKey("sys_companies.id"), nullable=False,
        comment="卖方（当前操作公司）"
    )
    company_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True), ForeignKey("sys_companies.id"), nullable=False, index=True,
        comment="多租户隔离"
    )
    total_amount_excl_tax: Mapped[float] = mapped_column(Numeric(14, 2), default=0)
    total_amount_incl_tax: Mapped[float] = mapped_column(Numeric(14, 2), default=0)
    total_amount_cn: Mapped[str | None] = mapped_column(
        String(100), nullable=True, comment="大写合计金额"
    )
    payment_terms: Mapped[str] = mapped_column(
        String(50), nullable=False, default="货到付全款"
    )
    shipping_terms: Mapped[str] = mapped_column(
        String(50), nullable=False, default="买方自提"
    )
    status: Mapped[str] = mapped_column(
        String(20), nullable=False, default="draft",
        comment="draft→active→completed→cancelled"
    )
    is_signed: Mapped[bool] = mapped_column(Boolean, default=False)
    signed_file_url: Mapped[str | None] = mapped_column(String(500), nullable=True)
    linked_order_id: Mapped[uuid.UUID | None] = mapped_column(
        UUID(as_uuid=True), ForeignKey("erp_orders.id"), nullable=True,
        comment="一键推单后回填"
    )
    salesperson_id: Mapped[uuid.UUID | None] = mapped_column(
        UUID(as_uuid=True), ForeignKey("sys_users.id"), nullable=True
    )
    sign_date: Mapped[date | None] = mapped_column(Date, nullable=True)
    remark: Mapped[str | None] = mapped_column(Text, nullable=True)
    delivery_terms: Mapped[str | None] = mapped_column(
        String(200), nullable=True, comment="货期（手动输入）"
    )
    created_at: Mapped[datetime] = mapped_column(DateTime, server_default=func.now())
    updated_at: Mapped[datetime] = mapped_column(
        DateTime, server_default=func.now(), onupdate=func.now()
    )
    is_deleted: Mapped[bool] = mapped_column(Boolean, default=False)

    # 关系
    buyer_customer: Mapped["CrmCustomer"] = relationship(  # noqa: F821
        "CrmCustomer", lazy="selectin"
    )
    seller_company: Mapped["SysCompany"] = relationship(  # noqa: F821
        "SysCompany", foreign_keys=[seller_company_id], lazy="selectin"
    )
    salesperson: Mapped["SysUser | None"] = relationship("SysUser", foreign_keys=[salesperson_id], lazy="selectin")  # noqa: F821
    linked_order: Mapped["ErpOrder | None"] = relationship("ErpOrder", foreign_keys=[linked_order_id], lazy="selectin")  # noqa: F821
    items: Mapped[list["ErpContractItem"]] = relationship(
        "ErpContractItem", back_populates="contract", lazy="selectin"
    )
    attachments: Mapped[list["ErpContractAttachment"]] = relationship(
        "ErpContractAttachment", back_populates="contract", lazy="selectin"
    )


class ErpContractItem(Base):
    """合同明细行"""
    __tablename__ = "erp_contract_items"

    id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True), primary_key=True, default=uuid.uuid4
    )
    contract_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True), ForeignKey("erp_contracts.id"), nullable=False
    )
    sku_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True), ForeignKey("erp_product_skus.id"), nullable=False
    )
    qty: Mapped[float] = mapped_column(Numeric(12, 2), nullable=False)
    unit_price: Mapped[float] = mapped_column(Numeric(12, 2), nullable=False)
    sub_total: Mapped[float] = mapped_column(Numeric(14, 2), nullable=False)
    created_at: Mapped[datetime] = mapped_column(DateTime, server_default=func.now())
    updated_at: Mapped[datetime] = mapped_column(
        DateTime, server_default=func.now(), onupdate=func.now()
    )
    is_deleted: Mapped[bool] = mapped_column(Boolean, default=False)

    # 关系
    contract: Mapped[ErpContract] = relationship("ErpContract", back_populates="items")
    sku: Mapped["ProductSku"] = relationship("ProductSku", lazy="selectin")  # noqa: F821


class ErpContractAttachment(Base):
    """合同附件（双签盖章版等）"""
    __tablename__ = "erp_contract_attachments"

    id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True), primary_key=True, default=uuid.uuid4
    )
    contract_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True), ForeignKey("erp_contracts.id"), nullable=False
    )
    file_name: Mapped[str] = mapped_column(String(200), nullable=False)
    file_url: Mapped[str] = mapped_column(String(500), nullable=False)
    file_type: Mapped[str] = mapped_column(
        String(30), nullable=False, default="signed_copy",
        comment="signed_copy / supplement / other"
    )
    uploader_id: Mapped[uuid.UUID | None] = mapped_column(
        UUID(as_uuid=True), ForeignKey("sys_users.id"), nullable=True
    )
    created_at: Mapped[datetime] = mapped_column(DateTime, server_default=func.now())
    is_deleted: Mapped[bool] = mapped_column(Boolean, default=False)

    # 关系
    contract: Mapped[ErpContract] = relationship("ErpContract", back_populates="attachments")
    uploader: Mapped["SysUser | None"] = relationship("SysUser", lazy="selectin")  # noqa: F821