import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.util.*;
import java.util.List;
import java.util.regex.Pattern;
import java.io.*;
import java.nio.file.*;

/**
 * MathLearningApp的方法扩展类
 * 包含所有事件处理和工具方法
 */
public class MathLearningAppMethods {
    
    /**
     * 创建样式化按钮
     */
    public static JButton createStyledButton(String text, Color backgroundColor) {
        JButton button = new JButton(text) {
            @Override
            protected void paintComponent(Graphics g) {
                Graphics2D g2 = (Graphics2D) g.create();
                g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
                
                // 创建渐变效果
                GradientPaint gradient = new GradientPaint(0, 0, backgroundColor.brighter(), 
                                                         0, getHeight(), backgroundColor.darker());
                g2.setPaint(gradient);
                g2.fillRoundRect(0, 0, getWidth(), getHeight(), 15, 15);
                
                // 添加内阴影效果
                g2.setColor(new Color(0, 0, 0, 30));
                g2.drawRoundRect(1, 1, getWidth()-3, getHeight()-3, 13, 13);
                
                g2.dispose();
                super.paintComponent(g);
            }
        };
        
        button.setFont(new Font("微软雅黑", Font.BOLD, 14));
        button.setForeground(Color.WHITE);
        button.setFocusPainted(false);
        button.setBorderPainted(false);
        button.setContentAreaFilled(false);
        button.setPreferredSize(new Dimension(130, 40));
        button.setCursor(new Cursor(Cursor.HAND_CURSOR));
        
        // 添加鼠标悬停效果
        button.addMouseListener(new java.awt.event.MouseAdapter() {
            @Override
            public void mouseEntered(java.awt.event.MouseEvent evt) {
                button.setBackground(backgroundColor.brighter());
                button.repaint();
            }
            
            @Override
            public void mouseExited(java.awt.event.MouseEvent evt) {
                button.setBackground(backgroundColor);
                button.repaint();
            }
        });
        
        return button;
    }
    
    /**
     * 创建大型难度选择按钮
     */
    public static JButton createLargeDifficultyButton(String text, Color backgroundColor) {
        JButton button = new JButton(text) {
            @Override
            protected void paintComponent(Graphics g) {
                Graphics2D g2 = (Graphics2D) g.create();
                g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
                
                // 创建渐变效果
                GradientPaint gradient = new GradientPaint(0, 0, backgroundColor.brighter(), 
                                                         0, getHeight(), backgroundColor);
                g2.setPaint(gradient);
                g2.fillRoundRect(0, 0, getWidth(), getHeight(), 20, 20);
                
                // 添加外阴影效果
                g2.setColor(new Color(0, 0, 0, 20));
                g2.fillRoundRect(3, 3, getWidth(), getHeight(), 20, 20);
                
                // 重新绘制按钮
                g2.setPaint(gradient);
                g2.fillRoundRect(0, 0, getWidth()-3, getHeight()-3, 20, 20);
                
                // 添加边框
                g2.setColor(backgroundColor.darker());
                g2.setStroke(new BasicStroke(2));
                g2.drawRoundRect(1, 1, getWidth()-5, getHeight()-5, 18, 18);
                
                g2.dispose();
                super.paintComponent(g);
            }
        };
        
        button.setFont(new Font("微软雅黑", Font.BOLD, 22));
        button.setForeground(new Color(40, 40, 40));
        button.setFocusPainted(false);
        button.setBorderPainted(false);
        button.setContentAreaFilled(false);
        button.setPreferredSize(new Dimension(320, 70));
        button.setCursor(new Cursor(Cursor.HAND_CURSOR));
        
        // 添加鼠标悬停效果
        button.addMouseListener(new java.awt.event.MouseAdapter() {
            @Override
            public void mouseEntered(java.awt.event.MouseEvent evt) {
                button.setForeground(new Color(20, 20, 20));
                button.repaint();
            }
            
            @Override
            public void mouseExited(java.awt.event.MouseEvent evt) {
                button.setForeground(new Color(40, 40, 40));
                button.repaint();
            }
        });
        
        return button;
    }
    
    /**
     * 发送验证码
     */
    public static void sendVerificationCode(ActionEvent e, JTextField emailField, Map<String, RegisteredUser> registeredUsers) {
        String email = emailField.getText().trim();
        
        if (!isValidEmail(email)) {
            JOptionPane.showMessageDialog(null, "请输入有效的邮箱地址！", "错误", JOptionPane.ERROR_MESSAGE);
            return;
        }
        
        // 检查邮箱是否已完成注册（验证码验证成功且设置了密码）
        RegisteredUser existingUser = registeredUsers.get(email);
        if (existingUser != null && existingUser.isVerified() && existingUser.getPassword() != null) {
            JOptionPane.showMessageDialog(null, "该邮箱已注册！", "错误", JOptionPane.ERROR_MESSAGE);
            return;
        }
        
        // 生成6位验证码
        String verificationCode = generateVerificationCode();
        
        // 创建或更新用户对象（仅用于临时存储验证码）
        RegisteredUser user = new RegisteredUser(email, verificationCode);
        registeredUsers.put(email, user);
        
        // 显示发送中的提示
        JOptionPane.showMessageDialog(null, 
            "正在通过QQ邮箱发送验证码到您的邮箱，请稍候...", 
            "发送中", 
            JOptionPane.INFORMATION_MESSAGE);
        
        // 在后台线程发送邮件，避免阻塞UI
        new Thread(() -> {
            boolean success = QQEmailService.sendVerificationCode(email, verificationCode);
            
            // 在EDT线程中显示结果
            javax.swing.SwingUtilities.invokeLater(() -> {
                if (success) {
                    JOptionPane.showMessageDialog(null, 
                        "✅ 验证码已通过QQ邮箱发送！\n" +
                        "📧 请查收邮件并输入6位验证码。\n" +
                        "📱 如果没收到，请检查垃圾邮件文件夹。", 
                        "发送成功", 
                        JOptionPane.INFORMATION_MESSAGE);
                } else {
                    JOptionPane.showMessageDialog(null, 
                        "❌ 验证码发送失败！\n" +
                        "请检查：\n" +
                        "• 接收邮箱地址是否正确\n" +
                        "• QQ邮箱配置是否正确\n" +
                        "• 网络连接是否正常", 
                        "发送失败", 
                        JOptionPane.ERROR_MESSAGE);
                    // 发送失败时移除用户
                    registeredUsers.remove(email);
                }
            });
        }).start();
    }
    
    /**
     * 处理用户注册
     */
    public static boolean handleRegister(JTextField emailField, JTextField verificationCodeField, 
                                       Map<String, RegisteredUser> registeredUsers, CardLayout cardLayout, JPanel mainPanel) {
        String email = emailField.getText().trim();
        String code = verificationCodeField.getText().trim();
        
        if (email.isEmpty() || code.isEmpty()) {
            JOptionPane.showMessageDialog(null, "请填写完整信息！", "错误", JOptionPane.ERROR_MESSAGE);
            return false;
        }
        
        RegisteredUser user = registeredUsers.get(email);
        if (user == null) {
            JOptionPane.showMessageDialog(null, "请先发送验证码！", "错误", JOptionPane.ERROR_MESSAGE);
            return false;
        }
        
        if (!user.verifyCode(code)) {
            JOptionPane.showMessageDialog(null, "验证码错误！", "错误", JOptionPane.ERROR_MESSAGE);
            return false;
        }
        
        user.setVerified(true);
        JOptionPane.showMessageDialog(null, "注册成功！请设置密码。", "成功", JOptionPane.INFORMATION_MESSAGE);
        cardLayout.show(mainPanel, "PASSWORD_SETUP");
        return true;
    }
    
    /**
     * 处理密码设置
     */
    public static boolean handlePasswordSetup(JPasswordField passwordField, JPasswordField confirmPasswordField,
                                            Map<String, RegisteredUser> registeredUsers, CardLayout cardLayout, JPanel mainPanel) {
        String password = new String(passwordField.getPassword());
        String confirmPassword = new String(confirmPasswordField.getPassword());
        
        if (!password.equals(confirmPassword)) {
            JOptionPane.showMessageDialog(null, "两次输入的密码不一致！", "错误", JOptionPane.ERROR_MESSAGE);
            return false;
        }
        
        if (!isValidPassword(password)) {
            JOptionPane.showMessageDialog(null, 
                "密码不符合要求！\n要求：6-10位，必须包含大小写字母和数字", 
                "错误", JOptionPane.ERROR_MESSAGE);
            return false;
        }
        
        // 找到当前注册的用户
        RegisteredUser currentUser = null;
        for (RegisteredUser user : registeredUsers.values()) {
            if (user.isVerified() && user.getPassword() == null) {
                currentUser = user;
                break;
            }
        }
        
        if (currentUser != null) {
            currentUser.setPassword(password);
            saveUserData(registeredUsers);
            JOptionPane.showMessageDialog(null, "密码设置成功！", "成功", JOptionPane.INFORMATION_MESSAGE);
            cardLayout.show(mainPanel, "DIFFICULTY_SELECTION");
            return true;
        }
        
        return false;
    }
    
    /**
     * 处理用户登录
     */
    public static RegisteredUser handleLogin(String email, String password, 
                                           Map<String, RegisteredUser> registeredUsers, 
                                           CardLayout cardLayout, JPanel mainPanel) {
        if (email.isEmpty() || password.isEmpty()) {
            JOptionPane.showMessageDialog(null, "请填写完整信息！", "错误", JOptionPane.ERROR_MESSAGE);
            return null;
        }
        
        RegisteredUser user = registeredUsers.get(email);
        if (user == null || !user.isVerified() || !user.verifyPassword(password)) {
            JOptionPane.showMessageDialog(null, "用户名或密码错误！", "错误", JOptionPane.ERROR_MESSAGE);
            return null;
        }
        
        JOptionPane.showMessageDialog(null, "登录成功！", "成功", JOptionPane.INFORMATION_MESSAGE);
        cardLayout.show(mainPanel, "DIFFICULTY_SELECTION");
        return user;
    }
    
    /**
     * 处理密码修改
     */
    public static boolean handlePasswordChange(String oldPassword, String newPassword, String confirmNewPassword,
                                             RegisteredUser currentUser) {
        if (!currentUser.verifyPassword(oldPassword)) {
            JOptionPane.showMessageDialog(null, "原密码错误！", "错误", JOptionPane.ERROR_MESSAGE);
            return false;
        }
        
        if (!newPassword.equals(confirmNewPassword)) {
            JOptionPane.showMessageDialog(null, "两次输入的新密码不一致！", "错误", JOptionPane.ERROR_MESSAGE);
            return false;
        }
        
        if (!isValidPassword(newPassword)) {
            JOptionPane.showMessageDialog(null, 
                "新密码不符合要求！\n要求：6-10位，必须包含大小写字母和数字", 
                "错误", JOptionPane.ERROR_MESSAGE);
            return false;
        }
        
        currentUser.setPassword(newPassword);
        JOptionPane.showMessageDialog(null, "密码修改成功！", "成功", JOptionPane.INFORMATION_MESSAGE);
        return true;
    }
    
    /**
     * 生成选择题
     */
    public static List<MultipleChoiceQuestion> generateQuestions(String difficulty, int count, MathQuestionGenerator generator) {
        List<MultipleChoiceQuestion> questions = new ArrayList<>();
        Random random = new Random();

        int attempts = 0;
        int maxAttempts = count * 5; // 防止无限循环

        while (questions.size() < count && attempts < maxAttempts) {
            // 生成数学表达式
            MathQuestion mathQuestion = generateSingleQuestion(difficulty, generator);
            String expression = mathQuestion.getExpression();

            // 验证表达式语法
            if (!ExpressionEvaluator.isValidMathExpression(expression)) {
                attempts++;
                continue;
            }

            // 计算正确答案
            double correctAnswer = evaluateExpression(expression);

            // 检查答案是否有效
            if (Double.isNaN(correctAnswer) || Double.isInfinite(correctAnswer)) {
                attempts++;
                continue;
            }

            // 生成选项
            String[] options = new String[4];
            int correctIndex = random.nextInt(4);

            // 设置正确答案
            options[correctIndex] = formatAnswer(correctAnswer);

            // 生成3个错误答案
            String[] wrongAnswers = ExpressionEvaluator.generateWrongAnswers(correctAnswer, 3);
            int wrongIndex = 0;
            for (int j = 0; j < 4; j++) {
                if (j != correctIndex) {
                    options[j] = wrongAnswers[wrongIndex++];
                }
            }

            MultipleChoiceQuestion question = new MultipleChoiceQuestion(
                    "计算：" + expression + " = ?", options, correctIndex);
            questions.add(question);
            attempts = 0; // 重置尝试计数
        }

        return questions;
    }
    
    /**
     * 生成单个数学题目
     */
    private static MathQuestion generateSingleQuestion(String difficulty, MathQuestionGenerator generator) {
        List<MathQuestion> questions = generator.generateQuestions(difficulty, 1);
        return questions.get(0);
    }
    
    /**
     * 计算数学表达式的值
     */
    private static double evaluateExpression(String expression) {
        return ExpressionEvaluator.evaluate(expression);
    }
    
    /**
     * 格式化答案
     */
    private static String formatAnswer(double answer) {
        return ExpressionEvaluator.formatAnswer(answer);
    }
    
    /**
     * 验证邮箱格式
     */
    public static boolean isValidEmail(String email) {
        String emailRegex = "^[a-zA-Z0-9_+&*-]+(?:\\.[a-zA-Z0-9_+&*-]+)*@(?:[a-zA-Z0-9-]+\\.)+[a-zA-Z]{2,7}$";
        Pattern pattern = Pattern.compile(emailRegex);
        return pattern.matcher(email).matches();
    }
    
    /**
     * 验证密码格式
     */
    public static boolean isValidPassword(String password) {
        if (password.length() < 6 || password.length() > 10) {
            return false;
        }
        
        boolean hasUpper = false, hasLower = false, hasDigit = false;
        
        for (char c : password.toCharArray()) {
            if (Character.isUpperCase(c)) hasUpper = true;
            else if (Character.isLowerCase(c)) hasLower = true;
            else if (Character.isDigit(c)) hasDigit = true;
        }
        
        return hasUpper && hasLower && hasDigit;
    }
    
    /**
     * 生成验证码
     */
    public static String generateVerificationCode() {
        Random random = new Random();
        StringBuilder code = new StringBuilder();
        for (int i = 0; i < 6; i++) {
            code.append(random.nextInt(10));
        }
        return code.toString();
    }
    
    /**
     * 保存用户数据
     */
    public static void saveUserData(Map<String, RegisteredUser> users) {
        try {
            Path dataFile = Paths.get("user_data.txt");
            try (BufferedWriter writer = Files.newBufferedWriter(dataFile)) {
                for (RegisteredUser user : users.values()) {
                    if (user.isVerified() && user.getPassword() != null) {
                        writer.write(user.getEmail() + ":" + user.getPassword());
                        writer.newLine();
                    }
                }
            }
        } catch (IOException e) {
            System.err.println("保存用户数据失败: " + e.getMessage());
        }
    }
    
    /**
     * 加载用户数据
     */
    public static void loadUserData(Map<String, RegisteredUser> users) {
        try {
            Path dataFile = Paths.get("user_data.txt");
            if (Files.exists(dataFile)) {
                List<String> lines = Files.readAllLines(dataFile);
                for (String line : lines) {
                    String[] parts = line.split(":");
                    if (parts.length == 2) {
                        RegisteredUser user = new RegisteredUser(parts[0], "");
                        user.setVerified(true);
                        user.setPassword(parts[1]);
                        users.put(parts[0], user);
                    }
                }
            }
        } catch (IOException e) {
            System.err.println("加载用户数据失败: " + e.getMessage());
        }
    }
}