"""
库存管理路由模块

提供库存信息的查询功能，包括：
- 库存列表查询（支持分页、仓库筛选、产品筛选、低库存筛选）
- 显示产品库存数量、锁定数量、可用数量等信息

路由前缀: /api/inventory
"""
from fastapi import APIRouter, Depends, Query, HTTPException
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy import select
from typing import Optional, List

from database.database import get_db_session
from services.auth_service import get_current_active_user
from models.database import User, Product, Warehouse, Inventory
from .schemas import InventoryResponse, InventoryCreate, InventoryUpdate

router = APIRouter(prefix="/inventory", tags=["库存管理"])


@router.get("", response_model=List[InventoryResponse])
async def list_inventory(
    warehouse_id: Optional[int] = None,
    product_id: Optional[int] = None,
    low_stock: bool = False,
    skip: int = Query(0, ge=0),
    limit: int = Query(20, ge=1, le=100),
    db_session: AsyncSession = Depends(get_db_session),
    current_user: User = Depends(get_current_active_user)
):
    query = (
        select(Inventory, Product, Warehouse)
        .join(Product, Inventory.product_id == Product.id)
        .join(Warehouse, Inventory.warehouse_id == Warehouse.id)
        .where(Product.is_active == True)
        .where(Product.item_type == "material")
        .where(Warehouse.is_active == True)
    )
    
    if warehouse_id:
        query = query.where(Inventory.warehouse_id == warehouse_id)
    if product_id:
        query = query.where(Inventory.product_id == product_id)
    if low_stock:
        query = query.where(Inventory.quantity <= Product.min_stock)
    
    query = query.offset(skip).limit(limit)
    result = await db_session.execute(query)
    
    inventory_list = []
    for inv, product, warehouse in result.all():
        inventory_list.append(InventoryResponse(
            id=inv.id,
            product_id=inv.product_id,
            product_name=product.name,
            product_sku=product.sku,
            warehouse_id=inv.warehouse_id,
            warehouse_name=warehouse.name,
            quantity=inv.quantity,
            locked_quantity=inv.locked_quantity,
            available_quantity=inv.available_quantity
        ))
    
    return inventory_list


@router.post("", response_model=InventoryResponse, status_code=201)
async def create_inventory(
    payload: InventoryCreate,
    db_session: AsyncSession = Depends(get_db_session),
    current_user: User = Depends(get_current_active_user)
):
    if payload.quantity < 0 or payload.locked_quantity < 0:
        raise HTTPException(status_code=400, detail="库存数量不能为负数")
    if payload.locked_quantity > payload.quantity:
        raise HTTPException(status_code=400, detail="锁定数量不能大于库存数量")

    product_result = await db_session.execute(
        select(Product).where(Product.id == payload.product_id, Product.is_active == True)
    )
    product = product_result.scalar_one_or_none()
    if not product:
        raise HTTPException(status_code=404, detail="物料不存在")
    if product.item_type != "material":
        raise HTTPException(status_code=400, detail="库存仅支持物料")

    warehouse_result = await db_session.execute(
        select(Warehouse).where(Warehouse.id == payload.warehouse_id, Warehouse.is_active == True)
    )
    warehouse = warehouse_result.scalar_one_or_none()
    if not warehouse:
        raise HTTPException(status_code=404, detail="仓库不存在")

    exists_result = await db_session.execute(
        select(Inventory).where(
            Inventory.product_id == payload.product_id,
            Inventory.warehouse_id == payload.warehouse_id
        )
    )
    if exists_result.scalar_one_or_none():
        raise HTTPException(status_code=400, detail="该仓库已存在该物料库存记录")

    inventory = Inventory(
        product_id=payload.product_id,
        warehouse_id=payload.warehouse_id,
        quantity=payload.quantity,
        locked_quantity=payload.locked_quantity,
        batch_number=payload.batch_number,
        location=payload.location
    )
    db_session.add(inventory)
    await db_session.commit()
    await db_session.refresh(inventory)

    return InventoryResponse(
        id=inventory.id,
        product_id=product.id,
        product_name=product.name,
        product_sku=product.sku,
        warehouse_id=warehouse.id,
        warehouse_name=warehouse.name,
        quantity=inventory.quantity,
        locked_quantity=inventory.locked_quantity,
        available_quantity=inventory.available_quantity
    )


@router.put("/{inventory_id}", response_model=InventoryResponse)
async def update_inventory(
    inventory_id: int,
    payload: InventoryUpdate,
    db_session: AsyncSession = Depends(get_db_session),
    current_user: User = Depends(get_current_active_user)
):
    result = await db_session.execute(
        select(Inventory, Product, Warehouse)
        .join(Product, Inventory.product_id == Product.id)
        .join(Warehouse, Inventory.warehouse_id == Warehouse.id)
        .where(Inventory.id == inventory_id)
        .where(Product.item_type == "material")
    )
    row = result.first()
    if not row:
        raise HTTPException(status_code=404, detail="库存记录不存在")
    inventory, product, warehouse = row

    if payload.quantity is not None:
        if payload.quantity < 0:
            raise HTTPException(status_code=400, detail="库存数量不能为负数")
        inventory.quantity = payload.quantity
    if payload.locked_quantity is not None:
        if payload.locked_quantity < 0:
            raise HTTPException(status_code=400, detail="锁定数量不能为负数")
        inventory.locked_quantity = payload.locked_quantity
    if inventory.locked_quantity > inventory.quantity:
        raise HTTPException(status_code=400, detail="锁定数量不能大于库存数量")

    if payload.batch_number is not None:
        inventory.batch_number = payload.batch_number
    if payload.location is not None:
        inventory.location = payload.location

    await db_session.commit()
    await db_session.refresh(inventory)
    return InventoryResponse(
        id=inventory.id,
        product_id=product.id,
        product_name=product.name,
        product_sku=product.sku,
        warehouse_id=warehouse.id,
        warehouse_name=warehouse.name,
        quantity=inventory.quantity,
        locked_quantity=inventory.locked_quantity,
        available_quantity=inventory.available_quantity
    )


@router.delete("/{inventory_id}")
async def delete_inventory(
    inventory_id: int,
    db_session: AsyncSession = Depends(get_db_session),
    current_user: User = Depends(get_current_active_user)
):
    result = await db_session.execute(select(Inventory).where(Inventory.id == inventory_id))
    inventory = result.scalar_one_or_none()
    if not inventory:
        raise HTTPException(status_code=404, detail="库存记录不存在")
    await db_session.delete(inventory)
    await db_session.commit()
    return {"message": "库存记录已删除"}