import uuid
from datetime import datetime
from sqlalchemy import or_
from app.extensions import db
from app.models.outbound import TransOutbound

# 引入所有库存模型以进行查询
from app.models.inbound.buy import StockBuy
from app.models.inbound.semi import StockSemi
from app.models.inbound.product import StockProduct
# ★★★ [关键] 引入基础信息表，用于手动补全名称
from app.models.base import MaterialBase


class OutboundService:

    @staticmethod
    def generate_outbound_no():
        """生成出库单号: OUT-yyyyMMdd-随机码"""
        date_str = datetime.now().strftime('%Y%m%d')
        short_uuid = uuid.uuid4().hex[:6].upper()
        return f"OUT-{date_str}-{short_uuid}"

    @staticmethod
    def get_stock_by_barcode(barcode):
        """
        [核心逻辑] 根据扫码内容查找对应的库存物品
        查找顺序: 成品 (StockProduct) -> 半成品 (StockSemi) -> 采购件 (StockBuy)
        匹配逻辑: 匹配 barcode 字段 OR sku 字段
        """
        if not barcode:
            return None

        clean_code = barcode.strip()

        # --- 1. 查找成品表 (StockProduct) ---
        prod = StockProduct.query.filter(
            or_(StockProduct.barcode == clean_code, StockProduct.sku == clean_code)
        ).first()
        if prod:
            return OutboundService._format_scan_result(prod, 'stock_product')

        # --- 2. 查找半成品表 (StockSemi) ---
        semi = StockSemi.query.filter(
            or_(StockSemi.barcode == clean_code, StockSemi.sku == clean_code)
        ).first()
        if semi:
            return OutboundService._format_scan_result(semi, 'stock_semi')

        # --- 3. 查找采购件表 (StockBuy) ---
        buy = StockBuy.query.filter(
            or_(StockBuy.barcode == clean_code, StockBuy.sku == clean_code)
        ).first()
        if buy:
            return OutboundService._format_scan_result(buy, 'stock_buy')

        return None

    @staticmethod
    def _format_scan_result(item, table_name):
        """
        [核心修复] 格式化返回数据，确保名称和规格一定能取到
        """
        base_name = ""
        base_spec = ""

        # -------------------------------------------------------
        # 修复逻辑：强制获取基础信息
        # -------------------------------------------------------

        # 步骤 1: 尝试通过 ORM 关联获取 (如果有定义 relationship)
        if hasattr(item, 'base') and item.base:
            base_name = item.base.name
            base_spec = item.base.spec_model

        # 步骤 2: [关键] 如果步骤1失败，但有 base_id，则手动查询 MaterialBase 表
        # 这能解决“扫码有库存但显示未知物品”的问题
        if not base_name and hasattr(item, 'base_id') and item.base_id:
            try:
                # 手动查基础表
                base_info = MaterialBase.query.get(item.base_id)
                if base_info:
                    base_name = base_info.name
                    base_spec = base_info.spec_model
            except Exception as e:
                print(f"基础信息查询失败: {e}")

        # 步骤 3: 兜底逻辑，某些旧表可能直接存了 material_name 字段
        if not base_name and hasattr(item, 'material_name'):
            base_name = item.material_name

        stock_qty = float(item.stock_quantity) if item.stock_quantity else 0
        avail_qty = float(item.available_quantity) if item.available_quantity else 0

        return {
            'id': item.id,
            'sku': item.sku,
            'name': base_name or "未知物品",  # 此时应该能正确显示名称了
            'spec_model': base_spec or "",  # 此时应该能正确显示规格了
            'source_table': table_name,  # 标记来源表
            'stock_quantity': stock_qty,  # 当前库存
            'available_quantity': avail_qty,  # 可用库存
            'batch_number': getattr(item, 'batch_number', ''),
            'warehouse_location': getattr(item, 'warehouse_location', ''),
            'barcode': getattr(item, 'barcode', '')
        }

    @staticmethod
    def create_outbound(data, operator_name='System'):
        """
        [核心逻辑] 执行出库：扣减对应表的库存 + 创建记录
        """
        source_table = data.get('source_table')
        stock_id = data.get('stock_id')
        quantity = float(data.get('quantity', 0))

        if quantity <= 0:
            raise ValueError("出库数量必须大于0")

        # 1. 动态映射表模型
        model_map = {
            'stock_buy': StockBuy,
            'stock_semi': StockSemi,
            'stock_product': StockProduct
        }

        ModelClass = model_map.get(source_table)
        if not ModelClass:
            raise ValueError(f"无效的数据来源表: {source_table}")

        # 2. 锁定并查询库存 (使用 with_for_update 防止并发超卖)
        stock_item = ModelClass.query.with_for_update().get(stock_id)
        if not stock_item:
            raise ValueError("库存记录不存在或已被删除")

        # 3. 校验库存充足
        current_avail = float(stock_item.available_quantity)
        if current_avail < quantity:
            raise ValueError(f"库存不足！当前可用: {current_avail}, 请求出库: {quantity}")

        try:
            # 4. 扣减库存
            stock_item.stock_quantity = float(stock_item.stock_quantity) - quantity
            stock_item.available_quantity = float(stock_item.available_quantity) - quantity

            # 5. 创建出库记录
            new_outbound = TransOutbound(
                outbound_no=OutboundService.generate_outbound_no(),
                sku=data.get('sku'),
                source_table=source_table,
                stock_id=stock_id,
                barcode=data.get('barcode'),
                outbound_type=data.get('outbound_type', 'SALES'),
                quantity=quantity,
                consumer_name=data.get('consumer_name'),
                signature_path=data.get('signature_path'),  # 存储签名的 URL
                operator_name=operator_name,
                remark=data.get('remark')
            )

            db.session.add(new_outbound)
            db.session.commit()

            return new_outbound

        except Exception as e:
            db.session.rollback()
            raise e

    @staticmethod
    def get_list(page=1, per_page=10, keyword=None, start_date=None, end_date=None):
        """查询出库历史记录"""
        query = TransOutbound.query.order_by(TransOutbound.outbound_time.desc())

        if keyword:
            query = query.filter(or_(
                TransOutbound.outbound_no.ilike(f'%{keyword}%'),
                TransOutbound.consumer_name.ilike(f'%{keyword}%'),
                TransOutbound.sku.ilike(f'%{keyword}%')
            ))

        if start_date and end_date:
            query = query.filter(TransOutbound.outbound_time.between(start_date, end_date))

        pagination = query.paginate(page=page, per_page=per_page, error_out=False)

        return {
            'items': [item.to_dict() for item in pagination.items],
            'total': pagination.total,
            'pages': pagination.pages,
            'current_page': page
        }