refactor(api): 重构数据库访问为SQLAlchemy绑定的session

- 统一移除手动创建的数据库session，统一使用models模块中的db.session
- 修正项目创建接口，增加开始和结束日期的格式验证与处理
- 更新导入项目接口，使用枚举类型校验项目类型并优化异常处理
- 更新统计接口，避免多次查询假期数据，优化日期字符串处理
- 删除回滚前多余的session关闭调用，改为使用db.session.rollback()
- app.py中重构数据库初始化：统一配置SQLAlchemy，动态创建数据库路径和表
- 项目模型新增开始日期和结束日期字段支持
- 添加导入批次历史记录模型支持
- 优化工具函数中日期类型提示，移除无用导入
- 更新requirements.txt依赖版本回退，确保兼容性
- 前端菜单添加导入历史导航入口，实现页面访问路由绑定

backend/api/statistics.py

@@ -1,35 +1,25 @@
 from flask import Blueprint, request, jsonify
-from sqlalchemy.orm import sessionmaker
-from sqlalchemy import create_engine, and_
-from backend.models.models import TimeRecord, Project, CutoffPeriod
-from backend.models.utils import *
+from sqlalchemy import and_
+from models.models import db, TimeRecord, Project, CutoffPeriod, Holiday
+from models.utils import *
 from datetime import datetime, date, timedelta
 from collections import defaultdict
 
 statistics_bp = Blueprint('statistics', __name__)
 
-def get_db_session():
-    """获取数据库会话"""
-    engine = create_engine('sqlite:///data/timetrack.db')
-    Session = sessionmaker(bind=engine)
-    return Session()
-
 @statistics_bp.route('/api/statistics/weekly', methods=['GET'])
 def get_weekly_statistics():
     """获取周统计数据"""
     try:
-        session = get_db_session()
-        
         # 获取查询参数
         period_id = request.args.get('period_id')
-        start_date = request.args.get('start_date')
-        end_date = request.args.get('end_date')
+        start_date_str = request.args.get('start_date')
+        end_date_str = request.args.get('end_date')
         
         # 如果指定了周期ID，使用周期的日期范围
         if period_id:
-            period = session.query(CutoffPeriod).get(int(period_id))
+            period = db.session.query(CutoffPeriod).get(int(period_id))
             if not period:
-                session.close()
                 return jsonify({'success': False, 'error': '周期不存在'}), 404
             
             start_date = period.start_date
@@ -38,12 +28,11 @@ def get_weekly_statistics():
             period_info = period.to_dict()
         else:
             # 使用指定的日期范围
-            if not start_date or not end_date:
-                session.close()
+            if not start_date_str or not end_date_str:
                 return jsonify({'success': False, 'error': '请提供开始日期和结束日期'}), 400
             
-            start_date = datetime.strptime(start_date, '%Y-%m-%d').date()
-            end_date = datetime.strptime(end_date, '%Y-%m-%d').date()
+            start_date = datetime.strptime(start_date_str, '%Y-%m-%d').date()
+            end_date = datetime.strptime(end_date_str, '%Y-%m-%d').date()
             target_hours = 40  # 默认目标工时
             period_info = {
                 'period_name': f"{start_date.strftime('%m月%d日')}-{end_date.strftime('%m月%d日')}",
@@ -53,7 +42,7 @@ def get_weekly_statistics():
             }
         
         # 查询该时间范围内的所有工时记录
-        records = session.query(TimeRecord).filter(
+        records = db.session.query(TimeRecord).filter(
             and_(TimeRecord.date >= start_date, TimeRecord.date <= end_date)
         ).order_by(TimeRecord.date).all()
         
@@ -68,6 +57,9 @@ def get_weekly_statistics():
                 record_dict[record.date] = []
             record_dict[record.date].append(record)
         
+        # 获取时间范围内的所有假期定义，避免在循环中重复查询
+        holidays_in_range = db.session.query(Holiday).all()
+
         # 生成每日汇总
         while current_date <= end_date:
             day_records = record_dict.get(current_date, [])
@@ -104,8 +96,7 @@ def get_weekly_statistics():
                 }
             else:
                 # 如果没有记录，生成默认记录
-                holidays = session.query(Holiday).all()
-                holiday_info = is_holiday(current_date, holidays)
+                holiday_info = is_holiday(current_date, holidays_in_range)
                 
                 daily_record = {
                     'date': current_date.isoformat(),
@@ -183,7 +174,6 @@ def get_weekly_statistics():
             'completion_rate': round((workday_total + holiday_total) / target_hours * 100, 1) if target_hours > 0 else 0
         }
         
-        session.close()
         return jsonify({'success': True, 'data': result})
     
     except Exception as e:
@@ -193,14 +183,9 @@ def get_weekly_statistics():
 def get_cutoff_periods():
     """获取Cut-Off周期列表"""
     try:
-        session = get_db_session()
-        
-        periods = session.query(CutoffPeriod).order_by(CutoffPeriod.start_date.desc()).all()
+        periods = db.session.query(CutoffPeriod).order_by(CutoffPeriod.start_date.desc()).all()
         result = [period.to_dict() for period in periods]
-        
-        session.close()
         return jsonify({'success': True, 'data': result})
-    
     except Exception as e:
         return jsonify({'success': False, 'error': str(e)}), 500
 
@@ -209,7 +194,6 @@ def create_cutoff_period():
     """创建Cut-Off周期"""
     try:
         data = request.json
-        session = get_db_session()
         
         # 验证必填字段
         if not all(key in data for key in ['period_name', 'start_date', 'end_date']):
@@ -235,33 +219,29 @@ def create_cutoff_period():
             month=start_date.month
         )
         
-        session.add(period)
-        session.commit()
+        db.session.add(period)
+        db.session.commit()
         
         result = period.to_dict()
-        session.close()
-        
         return jsonify({'success': True, 'data': result})
     
     except Exception as e:
+        db.session.rollback()
         return jsonify({'success': False, 'error': str(e)}), 500
 
 @statistics_bp.route('/api/statistics/periods/<int:period_id>', methods=['DELETE'])
 def delete_cutoff_period(period_id):
     """删除Cut-Off周期"""
     try:
-        session = get_db_session()
-        
-        period = session.query(CutoffPeriod).get(period_id)
+        period = db.session.query(CutoffPeriod).get(period_id)
         if not period:
-            session.close()
             return jsonify({'success': False, 'error': '周期不存在'}), 404
         
-        session.delete(period)
-        session.commit()
-        session.close()
+        db.session.delete(period)
+        db.session.commit()
         
         return jsonify({'success': True, 'message': '周期已删除'})
     
     except Exception as e:
+        db.session.rollback()
         return jsonify({'success': False, 'error': str(e)}), 500