# inventory-backend/app/services/inbound/repair_service.py
from app.extensions import db
from app.models.transaction import TransRepair
from app.models.base import MaterialBase
from datetime import datetime, timezone
import random
import string


class RepairInboundService:

    @staticmethod
    def _generate_repair_no():
        """
        生成唯一的维修单号
        格式: REP-YYYYMMDD-XXXX (X为随机大写字母或数字)
        防重复策略: 
        1. 先尝试生成4位随机序列
        2. 检查数据库中是否存在该单号
        3. 如果冲突，重试最多10次
        4. 如果10次都冲突，加入时间戳毫秒数确保唯一
        """
        for _ in range(10):
            date_str = datetime.now().strftime('%Y%m%d')
            random_str = ''.join(random.choices(string.ascii_uppercase + string.digits, k=4))
            repair_no = f"REP-{date_str}-{random_str}"
            
            # 检查是否已存在
            exists = TransRepair.query.filter_by(repair_no=repair_no).first()
            if not exists:
                return repair_no
        
        # 兜底策略：使用时间戳毫秒
        timestamp = int(datetime.now().timestamp() * 1000) % 100000
        date_str = datetime.now().strftime('%Y%m%d')
        return f"REP-{date_str}-{timestamp:05d}"

    @staticmethod
    def get_list(params):
        """
        获取维修单列表
        支持按 repair_no, sku, material_name, serial_number, repair_status 模糊查询
        实现分页
        """
        page = params.get('page', 1)
        page_size = params.get('page_size', 20)
        
        query = TransRepair.query
        
        # 模糊查询条件
        if params.get('repair_no'):
            query = query.filter(TransRepair.repair_no.ilike(f"%{params['repair_no']}%"))
        if params.get('sku'):
            query = query.filter(TransRepair.sku.ilike(f"%{params['sku']}%"))
        if params.get('serial_number'):
            query = query.filter(TransRepair.serial_number.ilike(f"%{params['serial_number']}%"))
        if params.get('repair_status'):
            query = query.filter(TransRepair.repair_status == params['repair_status'])
        
        # 关联 MaterialBase 查询物料名称
        if params.get('material_name'):
            query = query.join(MaterialBase, TransRepair.base_id == MaterialBase.id).filter(
                MaterialBase.name.ilike(f"%{params['material_name']}%")
            )
        
        # 按创建时间倒序
        query = query.order_by(db.desc(TransRepair.id))
        
        # 分页
        pagination = query.paginate(page=page, per_page=page_size, error_out=False)
        
        items = []
        for item in pagination.items:
            item_dict = item.to_dict()
            # 如果有 base_id，尝试获取物料名称
            if item.base_id:
                base = MaterialBase.query.get(item.base_id)
                if base:
                    item_dict['material_name'] = base.name
                    item_dict['company_name'] = base.company_name
            items.append(item_dict)
        
        return {
            'list': items,
            'total': pagination.total,
            'page': page,
            'page_size': page_size
        }

    @staticmethod
    def create(data):
        """
        新增维修单
        核心要求:
        1. 生成以 REP- 打头的自增维修单号
        2. 支持自动获取传入的 base_id 获取基础物料名称
        """
        # 生成维修单号
        repair_no = RepairInboundService._generate_repair_no()
        
        # 获取物料信息
        material_name = None
        company_name = None
        sku = data.get('sku')
        if data.get('base_id'):
            base = MaterialBase.query.get(data['base_id'])
            if base:
                material_name = base.name
                company_name = base.company_name
                if not sku:
                    sku = base.code
        
        repair = TransRepair(
            repair_no=repair_no,
            base_id=data.get('base_id'),
            sku=sku or data.get('sku'),
            serial_number=data.get('serial_number'),
            arrival_date=data.get('arrival_date'),
            repair_status=data.get('repair_status', '待检测'),
            fault_description=data.get('fault_description'),
            expected_repair_time=data.get('expected_repair_time'),
            repair_result=data.get('repair_result'),
            repair_manager=data.get('repair_manager'),
            shipping_date=data.get('shipping_date'),
            related_contract_id=data.get('related_contract_id'),
            cost_price=data.get('cost_price'),
            sale_price=data.get('sale_price'),
            company_id=data.get('company_id'),
            source_table=data.get('source_table'),
            stock_id=data.get('stock_id'),
            is_self_made=data.get('is_self_made', False),
            related_product_id=data.get('related_product_id'),
        )
        
        db.session.add(repair)
        db.session.commit()
        
        result = repair.to_dict()
        result['material_name'] = material_name
        result['company_name'] = company_name
        return result

    @staticmethod
    def update(id, data):
        """
        更新维修单
        """
        repair = TransRepair.query.get(id)
        if not repair:
            return None
        
        # 可更新字段
        updatable_fields = [
            'base_id', 'sku', 'serial_number', 'arrival_date', 'repair_status',
            'fault_description', 'expected_repair_time', 'repair_result',
            'repair_manager', 'shipping_date', 'related_contract_id',
            'cost_price', 'sale_price', 'company_id'
        ]
        
        for field in updatable_fields:
            if field in data:
                setattr(repair, field, data[field])
        
        db.session.commit()
        return repair.to_dict()

    @staticmethod
    def update_status(id, status, repair_log=None):
        """
        专门用于更新维修状态和追加维修日志
        """
        repair = TransRepair.query.get(id)
        if not repair:
            return None
        
        repair.repair_status = status
        
        # 追加维修日志
        if repair_log:
            if repair.repair_result:
                repair.repair_result = repair.repair_result + '\n' + f"[{datetime.now().strftime('%Y-%m-%d %H:%M:%S')}] {repair_log}"
            else:
                repair.repair_result = f"[{datetime.now().strftime('%Y-%m-%d %H:%M:%S')}] {repair_log}"
        
        db.session.commit()
        return repair.to_dict()

    @staticmethod
    def delete(id):
        """
        删除维修单
        """
        repair = TransRepair.query.get(id)
        if not repair:
            return False
        
        db.session.delete(repair)
        db.session.commit()
        return True

    @staticmethod
    def get_by_id(id):
        """
        根据ID获取维修单详情
        """
        repair = TransRepair.query.get(id)
        if not repair:
            return None
        
        item_dict = repair.to_dict()
        if repair.base_id:
            base = MaterialBase.query.get(repair.base_id)
            if base:
                item_dict['material_name'] = base.name
                item_dict['company_name'] = base.company_name
        return item_dict