package controller;

import model.User;
import utils.FileUtil;
import utils.ValidationUtil;
import utils.EmailUtil;

public class UserController extends BaseController implements UserService {

    @Override
    public String registerUser(String username, String email) {
        try {
            validateStringLength(username, "用户名", 2, 20);
            validateStringNotEmpty(email, "邮箱");

            if (!ValidationUtil.isValidEmail(email)) {
                return "邮箱格式不正确";
            }

            if (FileUtil.usernameExists(username)) {
                return "用户名已被使用";
            }

            if (FileUtil.emailExists(email)) {
                return "该邮箱已被注册";
            }

            String registrationCode = EmailUtil.generateRegistrationCode();
            User user = new User(username, email, registrationCode);

            boolean sendSuccess = EmailUtil.sendRegistrationCode(email, username, registrationCode);

            if (sendSuccess) {
                FileUtil.saveUser(user);
                logInfo("用户注册成功: " + username);
                return "注册码已发送到您的邮箱，请查收！";
            } else {
                return "邮件发送失败，请检查邮箱地址或稍后重试";
            }
        } catch (IllegalArgumentException e) {
            return e.getMessage();
        } catch (Exception e) {
            logError("用户注册异常: " + e.getMessage());
            return "系统错误，请稍后重试";
        }
    }

    @Override
    public String completeRegistration(String username, String code, String password, String confirmPassword) {
        try {
            validateStringNotEmpty(username, "用户名");
            validateStringNotEmpty(code, "注册码");
            validateStringNotEmpty(password, "密码");
            validateStringNotEmpty(confirmPassword, "确认密码");

            User user = FileUtil.loadUserByUsername(username);
            if (user == null) {
                return "用户不存在或注册码未发送";
            }

            if (!user.getRegistrationCode().equals(code)) {
                return "注册码不正确";
            }

            if (!password.equals(confirmPassword)) {
                return "两次输入的密码不一致";
            }

            if (!ValidationUtil.isValidPassword(password)) {
                return "密码必须为6-10位，且包含大小写字母和数字";
            }

            user.setPassword(password);
            user.setRegistered(true);
            FileUtil.saveUser(user);

            logInfo("用户完成注册: " + username);
            return "注册成功！";
        } catch (Exception e) {
            logError("完成注册异常: " + e.getMessage());
            return "系统错误，请稍后重试";
        }
    }

    @Override
    public User login(String loginId, String password) {
        try {
            validateStringNotEmpty(loginId, "登录ID");
            validateStringNotEmpty(password, "密码");

            User user;
            if (loginId.contains("@")) {
                user = FileUtil.loadUserByEmail(loginId);
            } else {
                user = FileUtil.loadUserByUsername(loginId);
            }

            if (user == null) {
                logInfo("登录失败: 用户不存在 - " + loginId);
                return null;
            }

            if (user.getPassword() == null || !user.getPassword().equals(password)) {
                logInfo("登录失败: 密码错误 - " + loginId);
                return null;
            }

            logInfo("登录成功: " + user.getUsername());
            return user;
        } catch (Exception e) {
            logError("登录异常: " + e.getMessage());
            return null;
        }
    }

    @Override
    public String changePassword(User user, String oldPassword, String newPassword, String confirmPassword) {
        try {
            validateNotNull(user, "用户");
            validateStringNotEmpty(oldPassword, "原密码");
            validateStringNotEmpty(newPassword, "新密码");
            validateStringNotEmpty(confirmPassword, "确认密码");

            if (!user.getPassword().equals(oldPassword)) {
                return "原密码不正确";
            }

            if (!newPassword.equals(confirmPassword)) {
                return "两次输入的新密码不一致";
            }

            if (!ValidationUtil.isValidPassword(newPassword)) {
                return "新密码必须为6-10位，且包含大小写字母和数字";
            }

            user.setPassword(newPassword);
            FileUtil.saveUser(user);

            logInfo("密码修改成功: " + user.getUsername());
            return "密码修改成功";
        } catch (Exception e) {
            logError("修改密码异常: " + e.getMessage());
            return "系统错误，请稍后重试";
        }
    }

    @Override
    public void cleanupUnregisteredUsers() {
        try {
            FileUtil.cleanupUnregisteredUsers();
            logInfo("执行未注册用户清理");
        } catch (Exception e) {
            logError("清理未注册用户异常: " + e.getMessage());
        }
    }
}