import json
import os
from datetime import datetime

class Student:
    def __init__(self, student_id, name, class_name, total_score=0):
        self.student_id = student_id
        self.name = name
        self.class_name = class_name
        self.total_score = total_score
    
    def to_dict(self):
        return {
            'student_id': self.student_id,
            'name': self.name,
            'class_name': self.class_name,
            'total_score': self.total_score
        }

class RollCallRecord:
    def __init__(self, record_id, student_id, student_name, call_time, score_change=0):
        self.record_id = record_id
        self.student_id = student_id
        self.student_name = student_name
        self.call_time = call_time
        self.score_change = score_change
    
    def to_dict(self):
        return {
            'record_id': self.record_id,
            'student_id': self.student_id,
            'student_name': self.student_name,
            'call_time': self.call_time,
            'score_change': self.score_change
        }

class Database:
    def __init__(self):
        self.students_file = 'data/students.json'
        self.records_file = 'data/records.json'
        self._ensure_data_directory()
        self._initialize_data()
    
    def _ensure_data_directory(self):
        os.makedirs('data', exist_ok=True)
    
    def _initialize_data(self):
        # 初始化示例数据
        if not os.path.exists(self.students_file):
            sample_students = [
                Student("2024001", "张三", "软工K班").to_dict(),
                Student("2024002", "李四", "软工K班").to_dict(),
                Student("2024003", "王五", "软工K班").to_dict(),
                Student("2024004", "赵六", "软工K班").to_dict(),
                Student("2024005", "钱七", "软工K班").to_dict()
            ]
            self._save_json(self.students_file, sample_students)
        
        if not os.path.exists(self.records_file):
            self._save_json(self.records_file, [])
    
    def _load_json(self, filename):
        try:
            with open(filename, 'r', encoding='utf-8') as f:
                return json.load(f)
        except:
            return []
    
    def _save_json(self, filename, data):
        with open(filename, 'w', encoding='utf-8') as f:
            json.dump(data, f, ensure_ascii=False, indent=2)
    
    def get_all_students(self):
        data = self._load_json(self.students_file)
        return [Student(**item) for item in data]
    
    def get_students_by_class(self, class_name):
        students = self.get_all_students()
        return [s for s in students if s.class_name == class_name]
    
    def update_student_score(self, student_id, score_delta):
        students = self.get_all_students()
        for student in students:
            if student.student_id == student_id:
                student.total_score += score_delta
                break
        
        # 保存更新
        self._save_json(self.students_file, [s.to_dict() for s in students])
        return True
    
    def add_roll_call_record(self, student_id, student_name, score_change=0):
        records = self._load_json(self.records_file)
        new_record = RollCallRecord(
            record_id=len(records) + 1,
            student_id=student_id,
            student_name=student_name,
            call_time=datetime.now().strftime("%Y-%m-%d %H:%M:%S"),
            score_change=score_change
        )
        records.append(new_record.to_dict())
        self._save_json(self.records_file, records)
        return new_record
    
    def get_recent_records(self, limit=10):
        records = self._load_json(self.records_file)
        return records[-limit:][::-1]  # 返回最新的记录