from app import db
from app.models.inbound.service import StockService
from app.models.base import MaterialBase
from datetime import datetime, timedelta
import re


class ServiceService:
    """服务权益库存业务逻辑"""

    SKU_PREFIX = 'SRV'
    SKU_DATE_FORMAT = '%Y%m%d'
    SKU_SUFFIX_LEN = 4

    @classmethod
    def _generate_sku(cls):
        """生成唯一SKU，格式 SRV-YYYYMMDD-XXXX"""
        today_str = datetime.now().strftime(cls.SKU_DATE_FORMAT)
        prefix = f'{cls.SKU_PREFIX}-{today_str}-'
        # 查找今天已有的最大后缀
        max_sku = db.session.query(db.func.max(StockService.sku)).filter(
            StockService.sku.like(f'{prefix}%')
        ).scalar()
        if not max_sku:
            suffix_num = 1
        else:
            # 提取后缀数字
            suffix_part = max_sku.replace(prefix, '')
            match = re.match(r'^(\d+)', suffix_part)
            suffix_num = int(match.group(1)) if match else 0
            suffix_num += 1
        # 格式化为4位数字，左侧补零
        suffix = str(suffix_num).zfill(cls.SKU_SUFFIX_LEN)
        return f'{prefix}{suffix}'

    @classmethod
    def search_base_material(cls, keyword):
        """搜索基础物料，供前端远程选择"""
        try:
            query = MaterialBase.query.filter(MaterialBase.is_enabled == True)
            if keyword:
                query = query.filter(
                    db.or_(
                        MaterialBase.name.ilike(f'%{keyword}%'),
                        MaterialBase.spec_model.ilike(f'%{keyword}%'),
                    )
                )
            query = query.order_by(MaterialBase.id.desc()).limit(20)
            results = []
            for item in query.all():
                results.append({
                    'id': item.id,
                    'name': item.name,
                    'spec': item.spec_model,
                    'category': item.category,
                    'unit': item.unit,
                    'type': item.material_type,
                })
            return results
        except Exception as e:
            import traceback
            traceback.print_exc()
            return []

    @classmethod
    def create_service(cls, data):
        """创建服务权益记录"""
        # 检查基础物料是否存在
        base = MaterialBase.query.get(data.get('base_id'))
        if not base:
            raise ValueError('基础物料不存在')
        # 生成SKU
        sku = cls._generate_sku()
        service = StockService(
            base_id=data['base_id'],
            sku=sku,
            sale_price=data['sale_price'],
            provider_name=data['provider_name'],
            description=data.get('description', '')
        )
        db.session.add(service)
        db.session.commit()
        return service

    @classmethod
    def get_service(cls, service_id):
        """获取单个服务权益"""
        service = StockService.query.filter_by(id=service_id, is_deleted=False).first()
        if not service:
            raise ValueError('服务权益记录不存在')
        return service

    @classmethod
    def update_service(cls, service_id, data):
        """更新服务权益记录"""
        service = cls.get_service(service_id)
        # 不允许修改 base_id 和 sku（业务上不允许变更基础物料）
        if 'sale_price' in data:
            service.sale_price = data['sale_price']
        if 'provider_name' in data:
            service.provider_name = data['provider_name']
        if 'description' in data:
            service.description = data.get('description', '')
        service.updated_at = datetime.now()
        db.session.commit()
        return service

    @classmethod
    def delete_service(cls, service_id):
        """软删除服务权益"""
        service = cls.get_service(service_id)
        service.is_deleted = True
        service.updated_at = datetime.now()
        db.session.commit()
        return True

    @classmethod
    def get_service_list(cls, page=1, per_page=20, keyword=None,
                         start_date=None, end_date=None, provider_name=None):
        """分页查询服务权益列表"""
        query = StockService.query.filter_by(is_deleted=False)
        # 关键词搜索：可搜索 SKU 或 关联物料名称
        if keyword:
            # 子查询查找物料名称匹配的 base_id
            subquery = MaterialBase.query.filter(
                MaterialBase.name.ilike(f'%{keyword}%')
            ).subquery()
            query = query.filter(
                db.or_(
                    StockService.sku.ilike(f'%{keyword}%'),
                    StockService.base_id.in_([row.id for row in db.session.query(subquery.c.id)])
                )
            )
        if start_date:
            start = datetime.strptime(start_date, '%Y-%m-%d')
            query = query.filter(StockService.created_at >= start)
        if end_date:
            end = datetime.strptime(end_date, '%Y-%m-%d')
            # 包含当天
            end = end + timedelta(days=1) - timedelta(seconds=1)
            query = query.filter(StockService.created_at <= end)
        if provider_name:
            query = query.filter(StockService.provider_name.ilike(f'%{provider_name}%'))
        # 总数
        total = query.count()
        # 分页
        items = query.order_by(StockService.created_at.desc())\
                     .offset((page - 1) * per_page)\
                     .limit(per_page).all()
        return {
            'items': [item.to_dict() for item in items],
            'total': total,
            'page': page,
            'per_page': per_page
        }