from flask import Flask, request, jsonify, redirect, url_for, render_template, session, make_response, flash
from flask_mail import Mail, Message
from flask_bcrypt import Bcrypt
import mysql.connector
import boto3
from botocore.client import Config
import os
import logging
import random
import pandas as pd
from dotenv import load_dotenv
from flask import send_file
import io
from functools import wraps
import tempfile
import shutil
import zipfile
import time
from urllib.parse import quote

load_dotenv()
bcrypt = Bcrypt()

# 配置 AWS S3
aws_access_key_id = os.getenv('AWS_ACCESS_KEY_ID')
aws_secret_access_key = os.getenv('AWS_SECRET_ACCESS_KEY')
region_name = os.getenv('AWS_REGION')
bucket_name = os.getenv('S3_BUCKET_NAME')
s3_client = boto3.client(
    's3',
    aws_access_key_id=aws_access_key_id,
    aws_secret_access_key=aws_secret_access_key,
    region_name=region_name,
    config=Config(signature_version='s3v4')
)

# 下载相关
def download_and_zip_files(bucket_name, folder_key):
    """下载文件并进行支持 ZIP64 的压缩打包"""
    temp_dir = tempfile.mkdtemp()  # 创建一个临时目录
    zip_file_path = os.path.join(temp_dir, 'homework.zip')

    try:
        # 列出文件
        file_keys = list_files_in_folder(bucket_name, folder_key)

        if not file_keys:
            logging.error(f"No files found in folder: {folder_key}")
            return None

        # 下载文件
        for file_key in file_keys:
            file_name = os.path.basename(file_key)
            file_download_path = os.path.join(temp_dir, file_name)

            # 下载文件
            logging.info(f"Downloading {file_key} to {file_download_path}")
            s3_client.download_file(bucket_name, file_key, file_download_path)
        
        # ZIP 压缩过程
        with zipfile.ZipFile(zip_file_path, 'w', zipfile.ZIP_DEFLATED, allowZip64=True) as zipf:
            for root, _, files in os.walk(temp_dir):
                for file in files:
                    file_path = os.path.join(root, file)

                    # 排除自身的 ZIP 文件，防止自我压缩
                    if file == os.path.basename(zip_file_path):
                        logging.info(f"Skipping self zip file: {file}")
                        continue
                    
                    # 打包其它文件
                    arcname = os.path.relpath(file_path, start=temp_dir)
                    logging.info(f"Adding {file} to archive as {arcname}")
                    zipf.write(file_path, arcname=arcname)

        logging.info(f"Zip file created at {zip_file_path}")
        return zip_file_path  # 返回 ZIP 文件路径

    except Exception as e:
        logging.error(f"Error during download or zip operation: {e}")
        return None


def upload_zip_to_s3(zip_file_path, bucket_name, object_key):
    """上传压缩包文件到S3"""
    try:
        s3_client.upload_file(zip_file_path, bucket_name, object_key)
    except ClientError as e:
        logging.error(f"Error uploading zip to S3: {e}")
        return None

    return generate_presigned_download_url(bucket_name, object_key)

# 列出文件
def list_files_in_folder(bucket_name, folder_key):
    try:
        response = s3_client.list_objects_v2(Bucket=bucket_name, Prefix=folder_key)
        if 'Contents' not in response:
            logging.error(f"No contents found in S3 folder {folder_key}")
            return []
        
        files = [obj['Key'] for obj in response['Contents'] if obj['Key'] != folder_key]
        logging.info(f"Files in folder {folder_key}: {files}")
        return files
    
    except ClientError as e:
        logging.error(f"Error listing files in folder {folder_key}: {e}")
        return []

# 数据库连接函数
def get_db_connection():
    return mysql.connector.connect(
        host=os.getenv('MYSQL_HOST'),
        user=os.getenv('MYSQL_USER'),
        password=os.getenv('MYSQL_PASSWORD'),
        database=os.getenv('MYSQL_DB')
    )

# 验证学生身份
def validate_student(student_id, password, bcrypt):
    conn = get_db_connection()
    cursor = conn.cursor(dictionary=True)
    cursor.execute('SELECT * FROM students WHERE id = %s', (student_id,))
    student = cursor.fetchone()
    cursor.close()
    conn.close()
    if student and bcrypt.check_password_hash(student['password'], password):
        return student
    return None

# 验证管理员身份
def validate_admin(username, password):
    conn = get_db_connection()
    cursor = conn.cursor(dictionary=True)
    cursor.execute('SELECT * FROM administrators WHERE username = %s', (username,))
    admin = cursor.fetchone()
    cursor.close()
    conn.close()

    if admin and bcrypt.check_password_hash(admin['password'], password):
        return admin
    return None

# 验证教师身份
def validate_teacher(email, password, bcrypt):
    conn = get_db_connection()  # 或者其他方法来获取数据库连接
    cursor = conn.cursor(dictionary=True)
    cursor.execute('SELECT * FROM teachers WHERE email = %s', (email,))
    teacher = cursor.fetchone()
    cursor.close()
    conn.close()

    if teacher and bcrypt.check_password_hash(teacher['password'], password):
        return teacher
    return None

def fetch_all_departments():
    conn = get_db_connection()
    cursor = conn.cursor(dictionary=True)
    cursor.execute('SELECT * FROM departments')
    departments = cursor.fetchall()
    cursor.close()
    conn.close()
    return departments

def fetch_all_grades():
    conn = get_db_connection()
    cursor = conn.cursor(dictionary=True)
    cursor.execute('SELECT * FROM grades')
    grades = cursor.fetchall()
    cursor.close()
    conn.close()
    return grades

def fetch_all_classes():
    conn = get_db_connection()
    cursor = conn.cursor(dictionary=True)
    cursor.execute('SELECT * FROM classes')
    classes = cursor.fetchall()
    cursor.close()
    conn.close()
    return classes

def fetch_all_teachers():
    conn = get_db_connection()
    cursor = conn.cursor(dictionary=True)
    cursor.execute('SELECT * FROM teachers')
    teachers = cursor.fetchall()
    cursor.close()
    conn.close()
    return teachers

def fetch_teacher_classes(teacher_id):
    conn = get_db_connection()
    cursor = conn.cursor(dictionary=True)

    # 假设每个教师和班级的关联存储在一个中间表 `class_teacher` 中
    cursor.execute('''
        SELECT c.id, c.name FROM classes c
        JOIN class_teacher ct ON c.id = ct.class_id
        WHERE ct.teacher_id = %s
    ''', (teacher_id,))

    classes = cursor.fetchall()

    cursor.close()
    conn.close()
    return classes

def fetch_class_assignments(class_id):
    conn = get_db_connection()
    cursor = conn.cursor(dictionary=True)
    pivot_query = '''
        SELECT * FROM assignments
        WHERE class_id = %s
    '''
    cursor.execute(pivot_query, (class_id,))
    assignments = cursor.fetchall()
    cursor.close()
    conn.close()
    return assignments


def fetch_class_students(class_id):
    conn = get_db_connection()
    cursor = conn.cursor(dictionary=True)

    # 查询属于给定class_id的所有学生
    cursor.execute('''
        SELECT * FROM students
        WHERE class_id = %s
    ''', (class_id,))

    students = cursor.fetchall()

    cursor.close()
    conn.close()
    return students


# 添加到提交历史表
def add_to_submission_history(student_id, assignment_id, filename):
    conn = get_db_connection()
    cursor = conn.cursor()
    cursor.execute(
        'INSERT INTO submission_history (student_id, assignment_id, filename, submit_date) VALUES (%s, %s, %s, NOW())',
        (student_id, assignment_id, filename)
    )
    conn.commit()
    cursor.close()
    conn.close()

# 添加或更新作业提交记录
def add_or_update_submission(student_id, assignment_id, filename, code_verified=False):
    add_to_submission_history(student_id, assignment_id, filename)  # 保留历史记录

    conn = get_db_connection()
    cursor = conn.cursor()
    if code_verified:
        cursor.execute(
            'UPDATE submissions SET submit_date = NOW(), filename = %s WHERE student_id = %s AND assignment_id = %s',
            (filename, student_id, assignment_id))
    else:
        cursor.execute(
            'INSERT INTO submissions (student_id, assignment_id, filename, submit_date) VALUES (%s, %s, %s, NOW())',
            (student_id, assignment_id, filename))
    conn.commit()
    cursor.close()
    conn.close()

# 生成预签名URL
def generate_presigned_url(object_key, content_type, expiration=3600):
    try:
        url = s3_client.generate_presigned_url(
            'put_object',
            Params={'Bucket': bucket_name, 'Key': object_key, 'ContentType': content_type},
            ExpiresIn=expiration
        )
        return url
    except Exception as e:
        logging.error(f"Failed to generate presigned URL: {str(e)}")
        return None

# 添加管理员路由
def add_admin_routes(app, mail, bcrypt):
    # 管理员登录装饰器
    def admin_required(f):
        @wraps(f)
        def decorated_function(*args, **kwargs):
            if 'admin_id' not in session:
                return redirect(url_for('admin_login'))
            return f(*args, **kwargs)
        return decorated_function

    @app.route('/admin/add_department', methods=['POST'])
    @admin_required
    def add_department():
        name = request.form['name']
        conn = get_db_connection()
        cursor = conn.cursor()
        cursor.execute('INSERT INTO departments (name) VALUES (%s)', (name,))
        conn.commit()
        cursor.close()
        conn.close()
        flash('Department added successfully', 'success')
        return redirect(url_for('admin_panel'))

    @app.route('/admin/add_grade', methods=['POST'])
    @admin_required
    def add_grade():
        year = request.form['year']
        conn = get_db_connection()
        cursor = conn.cursor()
        cursor.execute('INSERT INTO grades (year) VALUES (%s)', (year,))
        conn.commit()
        cursor.close()
        conn.close()
        flash('Grade added successfully', 'success')
        return redirect(url_for('admin_panel'))

    @app.route('/admin/add_class', methods=['POST'])
    @admin_required
    def add_class():
        name = request.form['name']
        department_id = request.form['department_id']
        grade_id = request.form['grade_id']
        conn = get_db_connection()
        cursor = conn.cursor()
        cursor.execute('INSERT INTO classes (name, department_id, grade_id) VALUES (%s, %s, %s)',
                       (name, department_id, grade_id))
        conn.commit()
        cursor.close()
        conn.close()
        flash('Class added successfully', 'success')
        return redirect(url_for('admin_panel'))

    @app.route('/admin/add_teacher', methods=['POST'])
    @admin_required
    def add_teacher():
        name = request.form['name']
        email = request.form['email']
        password = bcrypt.generate_password_hash(request.form['password']).decode('utf-8')
        conn = get_db_connection()
        cursor = conn.cursor()
        cursor.execute('INSERT INTO teachers (name, email, password) VALUES (%s, %s, %s)',
                       (name, email, password))
        conn.commit()
        cursor.close()
        conn.close()
        flash('Teacher added successfully', 'success')
        return redirect(url_for('admin_panel'))

    @app.route('/admin/add_administrator', methods=['POST'])
    @admin_required
    def add_administrator():
        username = request.form['username']
        password = bcrypt.generate_password_hash(request.form['password']).decode('utf-8')
        teacher_id = request.form['teacher_id']
        conn = get_db_connection()
        cursor = conn.cursor()
        cursor.execute('INSERT INTO administrators (username, password, teacher_id) VALUES (%s, %s, %s)',
                       (username, password, teacher_id))
        conn.commit()
        cursor.close()
        conn.close()
        flash('Administrator added successfully', 'success')
        return redirect(url_for('admin_panel'))

    @app.route('/admin/assign_teacher', methods=['POST'])
    @admin_required
    def assign_teacher():
        class_id = request.form['class_id']
        teacher_id = request.form['teacher_id']
        conn = get_db_connection()
        cursor = conn.cursor()
        cursor.execute('INSERT INTO class_teacher (class_id, teacher_id) VALUES (%s, %s)', (class_id, teacher_id))
        conn.commit()
        cursor.close()
        conn.close()
        flash('Teacher assigned to class successfully', 'success')
        return redirect(url_for('admin_panel'))

    @app.route('/admin/login', methods=['GET', 'POST'])
    def admin_login():
        if request.method == 'POST':
            username = request.form['username']
            password = request.form['password']
            admin = validate_admin(username, password)
            if admin:
                session['admin_id'] = admin['id']
                return redirect(url_for('admin_panel'))
            else:
                flash('Invalid credentials', 'error')
        return render_template('admin_login.html')

    @app.route('/admin/logout')
    def admin_logout():
        session.pop('admin_id', None)
        return redirect(url_for('admin_login'))

    @app.route('/admin/panel')
    @admin_required
    def admin_panel():
        # Retrieve necessary data (e.g., departments, grades, classes, etc.)
        departments = fetch_all_departments()
        grades = fetch_all_grades()
        classes = fetch_all_classes()
        teachers = fetch_all_teachers()
        return render_template('admin_panel.html', departments=departments, grades=grades, classes=classes, teachers=teachers)

    @app.route('/admin/add_assignment', methods=['POST'])
    @admin_required
    def admin_add_assignment():
        value = request.form['value']
        name = request.form['name']
        deadline = request.form['deadline']
        conn = get_db_connection()
        cursor = conn.cursor()
        cursor.execute('INSERT INTO assignments (value, name, deadline) VALUES (%s, %s, %s)', (value, name, deadline))
        conn.commit()
        cursor.close()
        conn.close()
        flash('Assignment added successfully', 'success')
        return redirect(url_for('admin_panel'))

    @app.route('/login', methods=['GET', 'POST'])
    def login():
        if request.method == 'POST':
            student_id = request.form.get('student_id')
            password = request.form.get('password')
            student = validate_student(student_id, password, bcrypt)
            if student:
                session['student_id'] = student['id']
                session['student_name'] = student['name']
                return redirect(url_for('serve_index'))
            else:
                return render_template('login.html', error='学号或密码错误')
        return render_template('login.html')

    @app.route('/reset-password', methods=['GET', 'POST'])
    def reset_password():
        if request.method == 'POST':
            student_id = request.form.get('student_id')
            email = request.form.get('email')
            code = request.form.get('code')
            new_password = request.form.get('new_password')
            if code:
                if session.get('reset_code') == code and session.get('reset_student_id') == student_id:
                    conn = get_db_connection()
                    cursor = conn.cursor()
                    hashed_password = bcrypt.generate_password_hash(new_password).decode('utf-8')
                    cursor.execute('UPDATE students SET password = %s WHERE id = %s', (hashed_password, student_id))
                    conn.commit()
                    cursor.close()
                    conn.close()
                    return render_template('login.html', success='密码已成功重置，请使用新密码登录')
                else:
                    return render_template('reset_password.html', error='验证码错误')
            else:
                conn = get_db_connection()
                cursor = conn.cursor(dictionary=True)
                cursor.execute('SELECT * FROM students WHERE id = %s AND email = %s', (student_id, email))
                student = cursor.fetchone()
                cursor.close()
                conn.close()
                if student:
                    reset_code = ''.join(random.choices('0123456789', k=6))
                    session['reset_code'] = reset_code
                    session['reset_student_id'] = student_id
                    try:
                        msg = Message('重置密码验证码', recipients=[email])
                        msg.body = f'您用于重置密码的验证码是: {reset_code}'
                        mail.send(msg)
                        return render_template('reset_password.html',
                                               success='验证码已发送到您的邮箱，请检查并输入验证码')
                    except Exception as e:
                        logging.error(f"Error sending email: {str(e)}")
                        return render_template('reset_password.html', error='发送验证码失败，请稍后再试')
                else:
                    return render_template('reset_password.html', error='学号和邮箱不匹配')
        return render_template('reset_password.html')

    @app.route('/record-submission', methods=['POST'])
    def record_submission():
        data = request.json
        student_id = session.get('student_id')
        student_name = session.get('student_name')
        assignment = data.get('assignment')
        filename = data.get('filename')  # 通过前端传递的文件名获取

        if not student_id or not filename or not assignment:
            return jsonify({'error': '学号、作业和文件名是必要参数'}), 400

        conn = get_db_connection()
        cursor = conn.cursor(dictionary=True)
        cursor.execute('SELECT * FROM submissions WHERE student_id = %s AND assignment_id = %s',
                       (student_id, assignment))
        submission = cursor.fetchone()  # 检查该学生是否已提交过此作业

        cursor.close()
        conn.close()

        if submission:
            session['filename'] = filename  # 保留新文件名以备`validate-code`使用
            return jsonify({'error': '作业已提交过，请输入验证码继续'}), 401  # 提示用户输入验证码以覆盖提交

        # 提取当前上传文件的扩展名
        _, file_extension = os.path.splitext(filename)  # 通过前端传递的文件提取扩展名

        # 生成新的文件名，并确保文件扩展名保持正确
        # 提取学号的最后两位
        student_last_two_digits = student_id[-2:]
        # 使用学号最后两位、学生名、作业名生成文件名
        new_filename = f'{student_last_two_digits}_{student_name}_{assignment}{file_extension}'
        folder_name = f'sure_homework_define_by_qin/{assignment}'
        object_key = f'{folder_name}/{new_filename}'

        # 生成预签名 URL
        url = generate_presigned_url(object_key, 'application/octet-stream')

        if not url:
            logging.error("Failed to generate presigned URL")
            return jsonify({'error': '无法生成预签名 URL'}), 500

        # 保存提交记录
        add_or_update_submission(student_id, assignment, new_filename, code_verified=False)

        return jsonify({'status': 'success', 'upload_url': url})

    @app.route('/generate-code', methods=['POST'])
    def generate_code():
        student_id = session.get('student_id')
        assignment = request.json.get('assignment')

        conn = get_db_connection()
        cursor = conn.cursor(dictionary=True)
        cursor.execute('SELECT email FROM students WHERE id = %s', (student_id,))
        student = cursor.fetchone()
        cursor.close()
        conn.close()

        if not student:
            return jsonify({'error': '学生信息未找到'}), 404

        email = student['email']
        reset_code = ''.join(random.choices('0123456789', k=6))
        session['submission_code'] = reset_code
        session['submission_student_id'] = student_id
        session['submission_assignment'] = assignment

        try:
            msg = Message('提交作业验证码', recipients=[email])
            msg.body = f'您用于提交作业的验证码是: {reset_code}'
            mail.send(msg)
            return jsonify({'status': '验证码已发送到您的邮箱，请检查并输入验证码'})
        except Exception as e:
            logging.error(f"Error sending email: {str(e)}")
            return jsonify({'error': '发送验证码失败，请稍后再试'}), 500

    @app.route('/validate-code', methods=['POST'])
    def validate_code():
        request_data = request.json
        student_id = session.get('student_id')
        assignment = request_data.get('assignment')
        code = request_data.get('code')

        # 验证提交的验证码与 session 中的值是否匹配
        if (code == session.get('submission_code') and
                student_id == session.get('submission_student_id') and
                assignment == session.get('submission_assignment')):

            # 从 session 中获取新文件名
            filename = session.pop('filename', None)

            if not filename:
                return jsonify({'error': 'No file was found in session'}), 400

            # 提取文件扩展名
            _, file_extension = os.path.splitext(filename)  # 获取文件的后缀名

            # 使用学号、学生名、作业名生成文件名（不含后缀）
            # 提取学号的最后两位
            student_last_two_digits = student_id[-2:]
            # 使用学号最后两位、学生名、作业名生成文件名
            new_filename = f'{student_last_two_digits}_{session.get("student_name")}_{assignment}{file_extension}'
            folder_name = f'sure_homework_define_by_qin/{assignment}'

            # 生成对象键前缀（不含扩展名），用于查找已存在的文件
            object_key_prefix = f'{folder_name}/{student_id}_{session.get("student_name")}_{assignment}'

            # 删除已存在的文件（任何扩展名）
            delete_old_files_in_s3(object_key_prefix)

            # 再生成新的对象键（含有扩展名）
            object_key = f'{object_key_prefix}{file_extension}'

            logging.info(f"Generated object_key: {object_key}")

            # 生成预签名 URL
            url = generate_presigned_url(object_key, 'application/octet-stream')

            if not url:
                logging.error("Failed to generate presigned URL")
                return jsonify({'error': 'Failed to generate presigned URL'}), 500

            # 更新数据库记录
            add_or_update_submission(student_id, assignment, new_filename, code_verified=True)

            # 清除 session 中的验证码和作业信息
            session.pop('submission_code', None)
            session.pop('submission_student_id', None)
            session.pop('submission_assignment', None)

            session['validated_assignment'] = assignment
            session['validation_presigned_url'] = url

            return jsonify({'status': '成功', 'upload_url': url})
        else:
            return jsonify({'error': '验证码错误'}), 400

    # 辅助函数：删除 S3 存储桶中具有指定前缀的旧文件（无论扩展名是何）
    def delete_old_files_in_s3(object_key_prefix):
        # 查找存储桶中是否已经存在具有相同前缀（不同后缀）的文件
        response = s3_client.list_objects_v2(Bucket=bucket_name, Prefix=object_key_prefix)

        if 'Contents' in response:
            for obj in response['Contents']:
                s3_client.delete_object(Bucket=bucket_name, Key=obj['Key'])
                logging.info(f"Deleted old file from S3: {obj['Key']}")

    @app.route('/api/submissions')
    def get_submissions():
        try:
            conn = get_db_connection()
            cursor = conn.cursor(dictionary=True)
            cursor.execute("""
                SELECT 
                    sh.submit_date AS 时间, 
                    sh.filename AS 提交的文件, 
                    s.name AS 姓名, 
                    s.id AS 学号, 
                    sh.assignment_id AS 作业
                FROM submission_history sh
                JOIN students s ON sh.student_id = s.id
                ORDER BY sh.submit_date DESC
            """)
            submissions = cursor.fetchall()
            cursor.close()
            conn.close()

            # 格式化日期时间
            for sub in submissions:
                sub['时间'] = sub['时间'].strftime('%Y-%m-%d %H:%M:%S') if sub['时间'] else None

            return jsonify(submissions)
        except Exception as e:
            logging.error(f"Error in get_submissions: {str(e)}", exc_info=True)
            return jsonify({'error': str(e)}), 500

    @app.route('/api/assignment-status')
    def get_assignment_status():
        try:
            conn = get_db_connection()
            cursor = conn.cursor(dictionary=True)
            cursor.execute("""
                SELECT 
                    s.id AS 学号, 
                    s.name AS 姓名,
                    a.assignment_id AS 作业,
                    CASE WHEN sub.id IS NOT NULL THEN '已提交' ELSE '未提交' END AS 提交情况,
                    COALESCE(sub.filename, '') AS 提交的文件
                FROM students s
                CROSS JOIN (SELECT DISTINCT assignment_id FROM submissions) a
                LEFT JOIN submissions sub ON s.id = sub.student_id AND a.assignment_id = sub.assignment_id
                ORDER BY s.id, a.assignment_id
            """)
            status_data = cursor.fetchall()
            cursor.close()
            conn.close()

            return jsonify(status_data)
        except Exception as e:
            logging.error(f"Error in get_assignment_status: {str(e)}", exc_info=True)
            return jsonify({'error': str(e)}), 500

    @app.route('/download-submissions')
    def download_submissions():
        try:
            conn = get_db_connection()
            cursor = conn.cursor(dictionary=True)
            cursor.execute("""
                SELECT 
                    sh.submit_date AS 时间, 
                    sh.filename AS 提交的项目, 
                    s.name AS 姓名, 
                    s.id AS 学号, 
                    sh.assignment_id AS 作业
                FROM submission_history sh
                JOIN students s ON sh.student_id = s.id
                ORDER BY sh.submit_date DESC
            """)
            submissions = cursor.fetchall()
            cursor.close()
            conn.close()

            # 创建 DataFrame
            df = pd.DataFrame(submissions)

            # 格式化日期时间
            df['时间'] = pd.to_datetime(df['时间']).dt.strftime('%Y-%m-%d %H:%M:%S')

            # 确保列的顺序
            df = df[['时间', '提交的项目', '姓名', '学号', '作业']]

            # 创建一个 BytesIO 对象，用于存储 Excel 文件
            output = io.BytesIO()

            # 使用 ExcelWriter 来设置列宽
            with pd.ExcelWriter(output, engine='xlsxwriter') as writer:
                df.to_excel(writer, sheet_name='提交记录', index=False)
                worksheet = writer.sheets['提交记录']

                # 设置列宽
                worksheet.set_column('A:A', 20)  # 时间
                worksheet.set_column('B:B', 30)  # 提交的项目
                worksheet.set_column('C:C', 15)  # 姓名
                worksheet.set_column('D:D', 15)  # 学号
                worksheet.set_column('E:E', 20)  # 作业

            output.seek(0)

            return send_file(
                output,
                as_attachment=True,
                download_name='submissions.xlsx',
                mimetype='application/vnd.openxmlformats-officedocument.spreadsheetml.sheet'
            )
        except Exception as e:
            logging.error(f"Error in download_submissions: {str(e)}", exc_info=True)
            return jsonify({'error': str(e)}), 500

    @app.route('/download-assignment-status')
    def download_assignment_status():
        try:
            conn = get_db_connection()
            cursor = conn.cursor(dictionary=True)
            cursor.execute("""
                SELECT 
                    s.id AS 学号, 
                    s.name AS 姓名, 
                    COALESCE(sub.assignment_id, 'No assignment') AS 作业,
                    CASE WHEN sub.id IS NOT NULL THEN '已提交' ELSE '未提交' END AS 作业提交情况,
                    COALESCE(sub.filename, '') AS 提交的项目,
                    COALESCE(sub.submit_date, '') AS 提交时间
                FROM students s
                LEFT JOIN submissions sub ON s.id = sub.student_id
                ORDER BY s.id, sub.assignment_id
            """)
            status_data = cursor.fetchall()
            cursor.close()
            conn.close()

            df = pd.DataFrame(status_data)

            # 格式化日期时间
            df['提交时间'] = pd.to_datetime(df['提交时间']).dt.strftime('%Y-%m-%d %H:%M:%S')

            # 确保列的顺序
            df = df[['学号', '姓名', '作业', '作业提交情况', '提交的项目', '提交时间']]

            output = io.BytesIO()
            with pd.ExcelWriter(output, engine='xlsxwriter') as writer:
                df.to_excel(writer, sheet_name='作业提交情况', index=False)
                worksheet = writer.sheets['作业提交情况']

                # 设置列宽
                worksheet.set_column('A:A', 15)  # 学号
                worksheet.set_column('B:B', 10)  # 姓名
                worksheet.set_column('C:C', 15)  # 作业
                worksheet.set_column('D:D', 12)  # 作业提交情况
                worksheet.set_column('E:E', 30)  # 提交的项目
                worksheet.set_column('F:F', 20)  # 提交时间

            output.seek(0)

            return send_file(
                output,
                as_attachment=True,
                download_name='assignment_status.xlsx',
                mimetype='application/vnd.openxmlformats-officedocument.spreadsheetml.sheet'
            )
        except Exception as e:
            logging.error(f"Error in download_assignment_status: {str(e)}", exc_info=True)
            return jsonify({'error': str(e)}), 500

    @app.route('/')
    def serve_index():
        if 'student_id' not in session:
            return redirect(url_for('login'))
        conn = get_db_connection()
        cursor = conn.cursor(dictionary=True)
        cursor.execute('SELECT * FROM assignments ORDER BY deadline')
        assignments = cursor.fetchall()
        cursor.close()
        conn.close()
        return render_template('index.html', assignments=assignments)

    @app.route('/logout')
    def logout():
        session.clear()
        return redirect(url_for('login'))

    def _build_cors_preflight_response():
        response = make_response()
        response.headers.add("Access-Control-Allow-Origin", "*")
        response.headers.add("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, OPTIONS")
        response.headers.add("Access-Control-Allow-Headers", "Content-Type")
        return response

# 教师管理路由
def add_teacher_routes(app, mail, bcrypt):
    # 教师登录装饰器
    def teacher_required(f):
        @wraps(f)
        def decorated_function(*args, **kwargs):
            if 'teacher_id' not in session:
                return redirect(url_for('teacher_login'))
            return f(*args, **kwargs)
        return decorated_function

    # Teacher Login Route
    @app.route('/teacher/login', methods=['GET', 'POST'])
    def teacher_login():
        if request.method == 'POST':
            email = request.form['email']
            password = request.form['password']
            teacher = validate_teacher(email, password, bcrypt)
            if teacher:
                session['teacher_id'] = teacher['id']
                return redirect(url_for('teacher_panel'))
            else:
                flash('Invalid credentials', 'error')
        return render_template('teacher_login.html')

    @app.route('/teacher/logout')
    def teacher_logout():
        session.pop('teacher_id', None)
        return redirect(url_for('teacher_login'))

    @app.route('/teacher/panel')
    @teacher_required
    def teacher_panel():
        # Fetch the classes this teacher is responsible for
        teacher_id = session['teacher_id']
        classes = fetch_teacher_classes(teacher_id)
        return render_template('teacher_panel.html', classes=classes)

    @app.route('/teacher/download-assignment/<assignment_value>', methods=['GET'])
    def download_assignment(assignment_value):
        """生成 ZIP 并直接发送给用户"""
        teacher_id = session.get('teacher_id')
        if not teacher_id:
            return redirect(url_for('teacher_login'))

        # 构造 S3 文件夹路径
        folder_key = f"sure_homework_define_by_qin/{assignment_value}/"

        # 下载并压缩作业文件夹
        zip_file_path = download_and_zip_files(os.getenv('S3_BUCKET_NAME'), folder_key)

        if not zip_file_path or not os.path.exists(zip_file_path):
            logging.error(f"Failed to create ZIP file at {zip_file_path}")
            return jsonify({"error": "无法创建 zip 文件"}), 500

        try:
            # 将来自 assignment_value 的文件名进行 URL 编码，以支持中文和特殊字符
            filename = quote(f"{assignment_value}.zip")

            logging.info(f"Sending file: {zip_file_path} as {filename}")
            return send_file(zip_file_path, as_attachment=True, download_name=filename, mimetype='application/zip')
        except Exception as ex:
            logging.error(f"Error sending file: {str(ex)}")
            return jsonify({"error": "Error sending file", "details": str(ex)}), 500
        
    @app.route('/teacher/class/<int:class_id>')
    @teacher_required
    def view_class(class_id):
        # Fetch the assignments and students of the class
        assignments = fetch_class_assignments(class_id)
        students = fetch_class_students(class_id)
        return render_template('class_detail.html', assignments=assignments, students=students, class_id=class_id)

    @app.route('/teacher/class/<int:class_id>/add_assignment', methods=['POST'])
    @teacher_required
    def teacher_add_assignment(class_id):
        # Adding a new assignment to the class
        value = request.form['value']
        name = request.form['name']
        deadline = request.form['deadline']
        conn = get_db_connection()
        cursor = conn.cursor()
        cursor.execute('INSERT INTO assignments (value, name, deadline, class_id) VALUES (%s, %s, %s, %s)', (value, name, deadline, class_id))
        conn.commit()
        cursor.close()
        conn.close()
        flash('Assignment added successfully', 'success')
        return redirect(url_for('view_class', class_id=class_id))

    @app.route('/teacher/edit_assignment/<int:assignment_id>', methods=['POST'])
    def edit_assignment(assignment_id):
        new_deadline = request.json.get('deadline')
        if new_deadline:
            conn = get_db_connection()
            cursor = conn.cursor()
            cursor.execute('UPDATE assignments SET deadline = %s WHERE id = %s', (new_deadline, assignment_id))
            conn.commit()
            cursor.close()
            conn.close()
            return jsonify({'status': 'success'})
        return jsonify({'error': 'Invalid deadline'}), 400

    @app.route('/teacher/delete_assignment/<int:assignment_id>', methods=['DELETE'])
    def delete_assignment(assignment_id):
        conn = get_db_connection()
        cursor = conn.cursor()
        cursor.execute('DELETE FROM assignments WHERE id = %s', (assignment_id,))
        conn.commit()
        cursor.close()
        conn.close()
        return jsonify({'status': 'success'})