"""
ERP 供应链域 Pydantic V2 Schemas
分类树 / 产品 SKU / 库存流水
"""

from __future__ import annotations

import uuid
from datetime import datetime

from pydantic import BaseModel, Field


# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
# 分类树
# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
class CategoryNode(BaseModel):
    """递归树节点，适配前端 el-tree"""
    id: uuid.UUID
    parent_id: uuid.UUID | None = None
    name: str
    sort_order: int = 0
    children: list[CategoryNode] = Field(default_factory=list)

    model_config = {"from_attributes": True}


class CategoryCreate(BaseModel):
    name: str = Field(..., min_length=1, max_length=100)
    parent_id: uuid.UUID | None = None
    sort_order: int = Field(default=0)


class CategoryUpdate(BaseModel):
    name: str | None = Field(default=None, min_length=1, max_length=100)
    parent_id: uuid.UUID | None = None
    sort_order: int | None = None


# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
# 产品 SKU
# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
class SkuCreate(BaseModel):
    sku_code: str = Field(..., min_length=1, max_length=50, examples=["SKU-LUB-001"])
    name: str = Field(..., min_length=1, max_length=200, examples=["昆仑天润 KR9"])
    category_id: uuid.UUID | None = None
    spec: str | None = Field(default=None, max_length=100, examples=["200L/桶"])
    standard_price: float = Field(default=0, ge=0)
    stock_qty: float = Field(default=0, ge=0, description="初始库存（仅创建时可设，后续只能通过流水变更）")
    warning_threshold: float = Field(default=0, ge=0)
    unit: str = Field(default="桶", max_length=20)
    status: int = Field(default=1, ge=0, le=1)


class SkuUpdate(BaseModel):
    """
    ⚠️ 架构师红线：不包含 stock_qty 字段！
    库存只能通过 InventoryFlow 事务接口变更。
    """
    name: str | None = Field(default=None, min_length=1, max_length=200)
    category_id: uuid.UUID | None = None
    spec: str | None = Field(default=None, max_length=100)
    standard_price: float | None = Field(default=None, ge=0)
    warning_threshold: float | None = Field(default=None, ge=0)
    unit: str | None = Field(default=None, max_length=20)
    status: int | None = Field(default=None, ge=0, le=1)


class SkuResponse(BaseModel):
    id: uuid.UUID
    sku_code: str
    name: str
    category_id: uuid.UUID | None = None
    category_name: str | None = None
    spec: str | None = None
    standard_price: float = 0
    stock_qty: float = 0
    warning_threshold: float = 0
    unit: str = "桶"
    status: int = 1
    created_at: datetime
    updated_at: datetime

    model_config = {"from_attributes": True}


class SkuListResponse(BaseModel):
    total: int
    items: list[SkuResponse]
    page: int
    size: int


# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
# 库存流水
# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
class InventoryFlowCreate(BaseModel):
    """库存变更请求"""
    sku_id: uuid.UUID = Field(..., description="产品 SKU ID")
    change_qty: float = Field(..., description="变更数量，正=入库 负=出库")
    reason: str = Field(
        ..., max_length=50,
        description="变动原因: purchase/shipment/loss/adjust",
        examples=["purchase"],
    )
    remark: str | None = Field(default=None, description="备注")
    purchase_unit_price: float = Field(default=0, ge=0, description="采购单价（仅入库时有意义）")
    is_special_zero_cost: bool = Field(default=False, description="特殊零元入库标识，不参与 MWA 计算")


class InventoryFlowResponse(BaseModel):
    id: uuid.UUID
    sku_id: uuid.UUID
    sku_code: str | None = None
    sku_name: str | None = None
    change_qty: float
    reason: str
    remark: str | None = None
    operator_id: uuid.UUID | None = None
    operator_name: str | None = None
    created_at: datetime

    model_config = {"from_attributes": True}