from app.extensions import db
from app.models.material import MaterialBase
from app.models.stock import StockBuy  # 需要引入库存表做删除时的依赖检查
from sqlalchemy import or_
import traceback


class MaterialBaseService:
    @staticmethod
    def get_list(page, limit, filters=None):
        """
        获取基础信息列表
        :param page: 页码
        :param limit: 每页条数
        :param filters: 筛选条件字典 {keyword, category, type, isEnabled}
        """
        try:
            query = MaterialBase.query

            if filters:
                # 1. 关键词模糊搜索 (名称 或 规格型号)
                if filters.get('keyword'):
                    kw = f"%{filters['keyword']}%"
                    query = query.filter(or_(
                        MaterialBase.name.like(kw),
                        MaterialBase.spec_model.like(kw)
                    ))

                # 2. 精确筛选
                if filters.get('category'):
                    query = query.filter_by(category=filters['category'])

                if filters.get('type'):
                    query = query.filter_by(material_type=filters['type'])

                if filters.get('isEnabled') is not None:
                    # 前端传 1/0，转为 Boolean
                    is_active = bool(int(filters['isEnabled']))
                    query = query.filter_by(is_enabled=is_active)

            # 按 ID 倒序排列
            pagination = query.order_by(MaterialBase.id.desc()).paginate(page=page, per_page=limit, error_out=False)

            items = [item.to_dict() for item in pagination.items]
            return {"total": pagination.total, "items": items}

        except Exception as e:
            print(f"查询基础信息列表失败: {e}")
            # 生产环境建议记录日志
            return {"total": 0, "items": []}

    @staticmethod
    def create_material(data):
        """新增基础信息"""
        try:
            # 0. 基础校验
            if not data.get('name') or not data.get('spec'):
                raise ValueError("名称和规格型号不能为空")

            # 1. 查重 (名称+规格型号 唯一)
            exist = MaterialBase.query.filter_by(
                name=data['name'],
                spec_model=data['spec']
            ).first()
            if exist:
                raise ValueError(f"已存在相同名称和规格的数据 (ID: {exist.id})")

            # 2. 创建对象 (注意前端驼峰 -> 后端下划线映射)
            new_material = MaterialBase(
                name=data['name'],
                spec_model=data['spec'],  # 映射
                category=data.get('category'),
                material_type=data.get('type'),  # 映射
                unit=data.get('unit'),
                visibility_level=data.get('visibilityLevel'),  # 映射
                manual_link=data.get('generalManual'),  # 映射
                product_image=data.get('generalImage'),  # 映射
                is_enabled=True if data.get('isEnabled', 1) == 1 else False
            )

            db.session.add(new_material)
            db.session.commit()
            return new_material

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

    @staticmethod
    def update_material(m_id, data):
        """修改基础信息"""
        try:
            material = MaterialBase.query.get(m_id)
            if not material:
                raise ValueError("数据不存在")

            # 更新字段 (仅更新传入的字段)
            if 'name' in data: material.name = data['name']
            if 'spec' in data: material.spec_model = data['spec']
            if 'category' in data: material.category = data['category']
            if 'type' in data: material.material_type = data['type']
            if 'unit' in data: material.unit = data['unit']
            if 'visibilityLevel' in data: material.visibility_level = data['visibilityLevel']
            if 'generalManual' in data: material.manual_link = data['generalManual']
            if 'generalImage' in data: material.product_image = data['generalImage']

            if 'isEnabled' in data:
                material.is_enabled = bool(int(data['isEnabled']))

            db.session.commit()
            return material

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

    @staticmethod
    def delete_material(m_id):
        """删除基础信息 (带依赖检查)"""
        try:
            material = MaterialBase.query.get(m_id)
            if not material:
                raise ValueError("数据不存在")

            # 1. 依赖检查：如果该基础信息已经在库存表(StockBuy)中使用，禁止物理删除
            # 这里假设 StockBuy 表有一个外键或字段指向 MaterialBase (e.g., base_id)
            usage_count = StockBuy.query.filter_by(base_id=m_id).count()
            if usage_count > 0:
                raise ValueError(f"无法删除：该基础信息已被 {usage_count} 条库存记录引用，请先清理库存或仅禁用此条目。")

            # 2. 执行删除
            db.session.delete(material)
            db.session.commit()
            return True

        except Exception as e:
            db.session.rollback()
            print(f"删除基础信息失败: {e}")
            raise e