src/app.py

@@ -1,5 +1,5 @@
 from PyQt6.QtWidgets import QApplication
-from src.ui.main_window import MainWindow
+from ui.main_window import MainWindow
 
 
 def main() -> None:

src/services/question_service.py

@@ -2,6 +2,7 @@
 试题服务模块：按小学/初中/高中生成选择题试卷，并保证同一试卷题目不重复。
 """
 import random
+import math
 from typing import List, Dict
 
 
@@ -40,42 +41,176 @@ class QuestionService:
         return questions
 
     def _gen_primary(self) -> Dict:
-        """生成一题小学难度的加减法选择题。"""
-        a = random.randint(1, 50)
-        b = random.randint(1, 50)
-        op = random.choice(['+', '-'])
-        if op == '+':
-            ans = a + b
-            stem = f"计算：{a} + {b} = ?"
+        """生成一题小学难度的四则运算选择题（可带括号）。"""
+        # 随机选择运算类型：简单四则运算或带括号的复合运算
+        if random.choice([True, False]):
+            # 简单四则运算
+            a = random.randint(1, 50)
+            b = random.randint(1, 50)
+            op = random.choice(['+', '-', '*', '/'])
+            
+            if op == '+':
+                ans = a + b
+                stem = f"计算：{a} + {b} = ?"
+            elif op == '-':
+                ans = a - b
+                stem = f"计算：{a} - {b} = ?"
+            elif op == '*':
+                ans = a * b
+                stem = f"计算：{a} × {b} = ?"
+            else:  # 除法，确保整除
+                ans = a
+                b = random.randint(1, 10)
+                a = ans * b  # 确保整除
+                stem = f"计算：{a} ÷ {b} = ?"
         else:
-            ans = a - b
-            stem = f"计算：{a} - {b} = ?"
+            # 带括号的复合运算
+            a = random.randint(1, 20)
+            b = random.randint(1, 20)
+            c = random.randint(1, 20)
+            
+            # 随机选择括号运算类型
+            bracket_type = random.choice(['add_mul', 'sub_mul', 'mul_add', 'mul_sub'])
+            
+            if bracket_type == 'add_mul':
+                ans = (a + b) * c
+                stem = f"计算：({a} + {b}) × {c} = ?"
+            elif bracket_type == 'sub_mul':
+                ans = (a - b) * c
+                stem = f"计算：({a} - {b}) × {c} = ?"
+            elif bracket_type == 'mul_add':
+                ans = a * (b + c)
+                stem = f"计算：{a} × ({b} + {c}) = ?"
+            else:  # mul_sub
+                ans = a * (b - c)
+                stem = f"计算：{a} × ({b} - {c}) = ?"
+        
         options = self._make_options(ans)
         return {'stem': stem, 'options': options, 'answer_index': options.index(str(ans))}
 
     def _gen_middle(self) -> Dict:
-        """生成一题初中难度的一元一次方程选择题。"""
-        a = random.randint(2, 9)
-        b = random.randint(1, 20)
-        # ax + b = 0 => x = -b / a
-        x = -b / a
-        stem = f"解方程：{a}x + {b} = 0，x = ?"
-        options = self._make_options(x, float_mode=True)
-        correct = f"{x:.2f}"
-        return {'stem': stem, 'options': options, 'answer_index': options.index(correct)}
-
-    def _gen_high(self) -> Dict:
-        """生成一题高中难度的导数计算选择题：f(x)=ax^2+bx+c 在 x0 处的导数。"""
-        a = random.randint(1, 5)
-        b = random.randint(-5, 5)
-        c = random.randint(-10, 10)
-        x0 = random.randint(-5, 5)
-        # f'(x) = 2ax + b => f'(x0) = 2a*x0 + b
-        ans = 2 * a * x0 + b
-        stem = f"设 f(x)={a}x^2+{b}x+{c}，求 f'({x0}) = ?"
+        """生成一题初中难度的题目，至少包含一个平方或开根号运算。"""
+        # 随机选择题目类型：平方运算、开根号运算或混合运算
+        question_type = random.choice(['square', 'sqrt', 'mixed'])
+        
+        if question_type == 'square':
+            # 平方运算题目
+            a = random.randint(2, 15)
+            b = random.randint(1, 10)
+            
+            if random.choice([True, False]):
+                # (a + b)²
+                ans = (a + b) ** 2
+                stem = f"计算：({a} + {b})² = ?"
+            else:
+                # a² + b²
+                ans = a ** 2 + b ** 2
+                stem = f"计算：{a}² + {b}² = ?"
+                
+        elif question_type == 'sqrt':
+            # 开根号运算题目
+            # 选择完全平方数确保结果为整数
+            perfect_squares = [4, 9, 16, 25, 36, 49, 64, 81, 100, 121, 144, 169, 196, 225]
+            a = random.choice(perfect_squares)
+            b = random.randint(1, 10)
+            
+            if random.choice([True, False]):
+                # √a + b
+                ans = int(math.sqrt(a)) + b
+                stem = f"计算：√{a} + {b} = ?"
+            else:
+                # √a × b
+                ans = int(math.sqrt(a)) * b
+                stem = f"计算：√{a} × {b} = ?"
+                
+        else:  # mixed
+            # 混合运算：既有平方又有开根号
+            perfect_square = random.choice([4, 9, 16, 25, 36, 49, 64, 81, 100])
+            a = random.randint(2, 8)
+            
+            # √perfect_square + a²
+            ans = int(math.sqrt(perfect_square)) + a ** 2
+            stem = f"计算：√{perfect_square} + {a}² = ?"
+        
         options = self._make_options(ans)
         return {'stem': stem, 'options': options, 'answer_index': options.index(str(ans))}
 
+    def _gen_high(self) -> Dict:
+        """生成一题高中难度的题目，至少包含一个sin、cos或tan运算符。"""
+        # 随机选择题目类型：基础三角函数、三角函数运算或复合运算
+        question_type = random.choice(['basic_trig', 'trig_calc', 'mixed_trig'])
+        
+        if question_type == 'basic_trig':
+            # 基础三角函数值计算
+            # 使用特殊角度确保结果为常见值
+            special_angles = [0, 30, 45, 60, 90, 120, 135, 150, 180]
+            angle = random.choice(special_angles)
+            func = random.choice(['sin', 'cos', 'tan'])
+            
+            # 计算三角函数值（转换为弧度）
+            rad = math.radians(angle)
+            if func == 'sin':
+                ans = round(math.sin(rad), 2)
+                stem = f"计算：sin({angle}°) = ?（保留两位小数）"
+            elif func == 'cos':
+                ans = round(math.cos(rad), 2)
+                stem = f"计算：cos({angle}°) = ?（保留两位小数）"
+            else:  # tan
+                if angle in [90, 270]:  # tan在这些角度未定义
+                    angle = 45
+                    rad = math.radians(angle)
+                ans = round(math.tan(rad), 2)
+                stem = f"计算：tan({angle}°) = ?（保留两位小数）"
+                
+        elif question_type == 'trig_calc':
+            # 三角函数运算
+            angle1 = random.choice([30, 45, 60])
+            angle2 = random.choice([30, 45, 60])
+            func1 = random.choice(['sin', 'cos'])
+            func2 = random.choice(['sin', 'cos'])
+            
+            rad1 = math.radians(angle1)
+            rad2 = math.radians(angle2)
+            
+            if func1 == 'sin':
+                val1 = math.sin(rad1)
+            else:
+                val1 = math.cos(rad1)
+                
+            if func2 == 'sin':
+                val2 = math.sin(rad2)
+            else:
+                val2 = math.cos(rad2)
+            
+            # 随机选择运算符
+            if random.choice([True, False]):
+                ans = round(val1 + val2, 2)
+                stem = f"计算：{func1}({angle1}°) + {func2}({angle2}°) = ?（保留两位小数）"
+            else:
+                ans = round(val1 * val2, 2)
+                stem = f"计算：{func1}({angle1}°) × {func2}({angle2}°) = ?（保留两位小数）"
+                
+        else:  # mixed_trig
+            # 混合运算：三角函数与代数运算
+            angle = random.choice([30, 45, 60])
+            a = random.randint(2, 5)
+            func = random.choice(['sin', 'cos', 'tan'])
+            
+            rad = math.radians(angle)
+            if func == 'sin':
+                trig_val = math.sin(rad)
+            elif func == 'cos':
+                trig_val = math.cos(rad)
+            else:
+                trig_val = math.tan(rad)
+            
+            ans = round(a * trig_val + a, 2)
+            stem = f"计算：{a} × {func}({angle}°) + {a} = ?（保留两位小数）"
+        
+        options = self._make_options(ans, float_mode=True)
+        correct = f"{ans:.2f}"
+        return {'stem': stem, 'options': options, 'answer_index': options.index(correct)}
+
     def _make_options(self, answer, float_mode: bool = False) -> List[str]:
         """根据正确答案生成 4 个选项（包含正确答案与3个干扰项）。"""
         opts = set()

src/services/storage_service.py

@@ -66,6 +66,18 @@ class StorageService:
                 return u
         return None
 
+    def get_user_by_username(self, username: str) -> Dict[str, Any] | None:
+        """根据用户名获取用户字典，不存在返回 None。"""
+        users = self.load_users().get('users', [])
+        for u in users:
+            if u.get('username') == username:
+                return u
+        return None
+
+    def username_exists(self, username: str) -> bool:
+        """判断指定用户名是否已被占用。"""
+        return self.get_user_by_username(username) is not None
+
     def upsert_user(self, user: Dict[str, Any]) -> None:
         """插入或更新用户字典，并立即持久化。"""
         data = self.load_users()

src/services/user_service.py

@@ -1,10 +1,11 @@
 """
-用户服务模块：处理注册、验证码、设置密码、登录与修改密码逻辑。
+用户服务模块：处理注册、验证码、用户名设置、登录与修改密码逻辑。
+不依赖真实邮件与SMTP，仅进行邮箱格式校验与本地验证码生成/校验。
 """
 import time
 from typing import Any, Dict
 
-from ..utils.security_utils import (
+from utils.security_utils import (
     validate_email,
     validate_password_strength,
     generate_verification_code,
@@ -12,24 +13,23 @@ from ..utils.security_utils import (
     verify_password,
 )
 from .storage_service import StorageService
-from .email_service import EmailService
+# 删除 EmailService 依赖
 
 
 class UserService:
     """封装用户相关业务逻辑的服务类。"""
 
-    def __init__(self, storage: StorageService, email_service: EmailService) -> None:
-        """初始化用户服务，注入存储与邮件服务。"""
+    def __init__(self, storage: StorageService) -> None:
+        """初始化用户服务，仅注入存储服务。"""
         self.storage = storage
-        self.email_service = email_service
 
     def request_registration(self, email: str) -> tuple[bool, str]:
-        """发起注册请求：校验邮箱，生成验证码并发送邮件。
+        """发起注册请求：校验邮箱，生成验证码并本地保存（不发送邮件）。
 
         参数:
             email: 用户邮箱。
         返回:
-            (success, message) 二元组，表示结果与提示信息。
+            (success, message) 二元组，message包含提示与模拟验证码信息。
         """
         if not validate_email(email):
             return False, '邮箱格式不正确'
@@ -46,13 +46,12 @@ class UserService:
             'code_time': int(time.time()),
             'password_salt': '',
             'password_hash': '',
-            'created_at': user.get('created_at') or int(time.time())
+            'username': user.get('username', ''),
+            'created_at': user.get('created_at') or int(time.time()),
         })
         self.storage.upsert_user(user)
-        sent = self.email_service.send_verification_code(email, code)
-        if not sent:
-            return False, '验证码发送失败，请检查SMTP设置'
-        return True, '验证码已发送，请查收邮箱'
+        # 不发送邮件，直接提示验证码供用户在下一步手动输入
+        return True, f'验证码已生成（模拟）：{code}，请前往验证码页面手动输入'
 
     def verify_code(self, email: str, code: str) -> tuple[bool, str]:
         """校验验证码并标记邮箱已验证。
@@ -66,7 +65,6 @@ class UserService:
         user = self.storage.get_user(email)
         if not user:
             return False, '用户不存在，请先注册'
-        # 10 分钟有效期
         if int(time.time()) - int(user.get('code_time', 0)) > 600:
             return False, '验证码已过期，请重新获取'
         salt_hex = user.get('code_salt', '')
@@ -82,7 +80,28 @@ class UserService:
         user['code_salt'] = ''
         user['code_hash'] = ''
         self.storage.upsert_user(user)
-        return True, '邮箱验证成功，请设置密码'
+        return True, '邮箱验证成功，请设置用户名与密码'
+
+    def set_username(self, email: str, username: str) -> tuple[bool, str]:
+        """设置用户名：校验格式与唯一性，并写入用户信息。
+
+        参数:
+            email: 目标用户邮箱。
+            username: 待设置的用户名（3-16位，字母数字与下划线）。
+        返回:
+            (success, message)。
+        """
+        user = self.storage.get_user(email)
+        if not user or not user.get('verified'):
+            return False, '邮箱未验证或用户不存在'
+        uname = (username or '').strip()
+        if not (3 <= len(uname) <= 16) or not all(c.isalnum() or c == '_' for c in uname):
+            return False, '用户名需为3-16位且仅包含字母、数字或下划线'
+        if self.storage.username_exists(uname):
+            return False, '该用户名已被占用'
+        user['username'] = uname
+        self.storage.upsert_user(user)
+        return True, '用户名设置成功'
 
     def set_password(self, email: str, password: str, confirm: str) -> tuple[bool, str]:
         """设置或重置密码：校验强度、确认一致并持久化哈希。"""
@@ -99,8 +118,28 @@ class UserService:
         self.storage.upsert_user(user)
         return True, '密码设置成功'
 
+    def complete_registration(self, email: str) -> tuple[bool, str]:
+        """完成注册：要求用户已设置用户名与密码，方视为完成。
+
+        参数:
+            email: 用户邮箱。
+        返回:
+            (success, message)。
+        """
+        user = self.storage.get_user(email)
+        if not user:
+            return False, '用户不存在'
+        if not user.get('verified'):
+            return False, '邮箱未验证'
+        if not user.get('username'):
+            return False, '请先设置用户名'
+        if not user.get('password_hash'):
+            return False, '请先设置密码'
+        # 已经持久化，无需额外操作，这里仅作为流程校验提示
+        return True, '注册完成'
+
     def login(self, email: str, password: str) -> tuple[bool, str]:
-        """登录：校验邮箱存在与密码匹配。"""
+        """邮箱登录：校验邮箱存在与密码匹配。"""
         user = self.storage.get_user(email)
         if not user or not user.get('password_hash'):
             return False, '用户不存在或未设置密码'
@@ -111,6 +150,18 @@ class UserService:
             return False, '密码不正确'
         return True, '登录成功'
 
+    def login_by_username(self, username: str, password: str) -> tuple[bool, str]:
+        """用户名登录：根据用户名查询并校验密码。"""
+        user = self.storage.get_user_by_username(username)
+        if not user or not user.get('password_hash'):
+            return False, '用户不存在或未设置密码'
+        salt_hex = user.get('password_salt', '')
+        hash_hex = user.get('password_hash', '')
+        ok = verify_password(password, bytes.fromhex(salt_hex), bytes.fromhex(hash_hex))
+        if not ok:
+            return False, '密码不正确'
+        return True, '登录成功'
+
     def change_password(self, email: str, old_password: str, new_password: str, confirm: str) -> tuple[bool, str]:
         """修改密码：校验原密码正确并设置新密码。"""
         user = self.storage.get_user(email)

src/storage/users.json

@@ -1,3 +1,15 @@
 {
-  "users": []
+  "users": [
+    {
+      "email": "shenyongye@163.com",
+      "verified": true,
+      "code_salt": "",
+      "code_hash": "",
+      "code_time": 1760256425,
+      "password_salt": "e09f40c04b33d5f482ff682b3d43192b",
+      "password_hash": "dffeab45544b194e5f7efeb632cbe75eef3b46fbff23531692c7ef0e9a83f24b",
+      "username": "echo",
+      "created_at": 1760256425
+    }
+  ]
 }

src/ui/main_window.py

@@ -1,13 +1,12 @@
 from PyQt6.QtWidgets import (
     QMainWindow, QWidget, QStackedWidget, QVBoxLayout, QHBoxLayout,
-    QLabel, QLineEdit, QPushButton, QMessageBox, QCheckBox
+    QLabel, QLineEdit, QPushButton, QMessageBox, QRadioButton, QButtonGroup, QSpinBox
 )
 from PyQt6.QtCore import Qt
 
-from src.services.storage_service import StorageService
-from src.services.email_service import EmailService
-from src.services.user_service import UserService
-from src.services.question_service import QuestionService
+from services.storage_service import StorageService
+from services.user_service import UserService
+from services.question_service import QuestionService
 
 
 class MainWindow(QMainWindow):
@@ -21,23 +20,29 @@ class MainWindow(QMainWindow):
 
         # 业务服务初始化
         self.storage_service = StorageService()
-        self.email_service = EmailService(self.storage_service)
-        self.user_service = UserService(self.storage_service, self.email_service)
+        self.session_email = None
+        self.user_service = UserService(self.storage_service)
         self.question_service = QuestionService()
 
         # 页面容器
         self.stack = QStackedWidget()
         self.setCentralWidget(self.stack)
 
-        # 先构建最基础的两个页面：登录与SMTP设置
-        self._build_login_page()
-        self._build_smtp_page()
+        # 构建页面：登录、注册(邮箱/验证码/用户名密码)、选择、答题、结果、修改密码
+        self._build_login_page()                 # index 0
+        self._build_register_email_page()        # index 1
+        self._build_verify_page()                # index 2
+        self._build_set_credentials_page()       # index 3
+        self._build_choice_page()                # index 4
+        self._build_quiz_page()                  # index 5
+        self._build_result_page()                # index 6
+        self._build_change_password_page()       # index 7
 
         # 默认显示登录页
         self.stack.setCurrentIndex(0)
 
     def _build_login_page(self) -> None:
-        """构建登录页面：邮箱+密码+登录按钮。"""
+        """构建登录页面：支持用户名或邮箱登录。"""
         page = QWidget()
         layout = QVBoxLayout(page)
         layout.setAlignment(Qt.AlignmentFlag.AlignTop)
@@ -47,9 +52,9 @@ class MainWindow(QMainWindow):
         title.setStyleSheet("font-size: 22px; font-weight: bold; margin: 16px 0;")
         layout.addWidget(title)
 
-        self.login_email = QLineEdit()
-        self.login_email.setPlaceholderText("请输入邮箱")
-        layout.addWidget(self.login_email)
+        self.login_identifier = QLineEdit()
+        self.login_identifier.setPlaceholderText("请输入邮箱或用户名")
+        layout.addWidget(self.login_identifier)
 
         self.login_password = QLineEdit()
         self.login_password.setPlaceholderText("请输入密码")
@@ -58,84 +63,523 @@ class MainWindow(QMainWindow):
 
         btn_row = QHBoxLayout()
         self.btn_login = QPushButton("登录")
-        self.btn_to_smtp = QPushButton("SMTP设置")
+        self.btn_to_register = QPushButton("去注册")
         btn_row.addWidget(self.btn_login)
-        btn_row.addWidget(self.btn_to_smtp)
+        btn_row.addWidget(self.btn_to_register)
         layout.addLayout(btn_row)
 
         self.btn_login.clicked.connect(self._on_login)
-        self.btn_to_smtp.clicked.connect(lambda: self.stack.setCurrentIndex(1))
+        self.btn_to_register.clicked.connect(lambda: self.stack.setCurrentIndex(1))
 
         self.stack.addWidget(page)
 
     def _on_login(self) -> None:
-        """处理登录逻辑：校验输入并调用用户服务。"""
-        email = (self.login_email.text() or "").strip()
+        """处理登录逻辑：根据输入自动识别邮箱或用户名进行登录，并在成功后进入选择页。"""
+        identifier = (self.login_identifier.text() or "").strip()
         password = self.login_password.text() or ""
-        if not email or not password:
-            QMessageBox.warning(self, "提示", "邮箱与密码均不能为空")
+        if not identifier or not password:
+            QMessageBox.warning(self, "提示", "账号与密码均不能为空")
             return
-        ok, msg = self.user_service.login(email, password)
+        # 判断是否为邮箱
+        if "@" in identifier:
+            ok, msg = self.user_service.login(identifier, password)
+            if ok:
+                self.session_email = identifier
+            else:
+                QMessageBox.warning(self, "提示", msg or "登录失败")
+                return
+        else:
+            ok, msg = self.user_service.login_by_username(identifier, password)
+            if ok:
+                # 通过用户名获取邮箱，记录会话
+                user = self.storage_service.get_user_by_username(identifier)
+                self.session_email = user.get('email') if user else None
+            else:
+                QMessageBox.warning(self, "提示", msg or "登录失败")
+                return
+        QMessageBox.information(self, "提示", "登录成功")
+        # 跳转到选择页
+        self.stack.setCurrentIndex(4)
+
+    def _build_register_email_page(self) -> None:
+        """构建注册第一步：邮箱输入页面。"""
+        page = QWidget()
+        layout = QVBoxLayout(page)
+        layout.setAlignment(Qt.AlignmentFlag.AlignTop)
+
+        title = QLabel("注册 - 邮箱验证")
+        title.setAlignment(Qt.AlignmentFlag.AlignCenter)
+        title.setStyleSheet("font-size: 22px; font-weight: bold; margin: 16px 0;")
+        layout.addWidget(title)
+
+        self.register_email = QLineEdit()
+        self.register_email.setPlaceholderText("请输入邮箱地址")
+        layout.addWidget(self.register_email)
+
+        btn_row = QHBoxLayout()
+        self.btn_send_code = QPushButton("获取验证码")
+        self.btn_back_to_login = QPushButton("返回登录")
+        btn_row.addWidget(self.btn_send_code)
+        btn_row.addWidget(self.btn_back_to_login)
+        layout.addLayout(btn_row)
+
+        self.btn_send_code.clicked.connect(self._on_send_code)
+        self.btn_back_to_login.clicked.connect(lambda: self.stack.setCurrentIndex(0))
+
+        self.stack.addWidget(page)
+
+    def _on_send_code(self) -> None:
+        """处理发送验证码逻辑：验证邮箱格式并生成验证码。"""
+        email = (self.register_email.text() or "").strip()
+        if not email:
+            QMessageBox.warning(self, "提示", "请输入邮箱地址")
+            return
+        
+        ok, msg = self.user_service.request_registration(email)
         if ok:
-            QMessageBox.information(self, "提示", "登录成功")
+            self.session_email = email
+            QMessageBox.information(self, "提示", msg)
+            # 跳转到验证码页面
+            self.stack.setCurrentIndex(2)
         else:
-            QMessageBox.warning(self, "提示", msg or "登录失败")
+            QMessageBox.warning(self, "提示", msg)
 
-    def _build_smtp_page(self) -> None:
-        """构建 SMTP 设置页面：服务器、端口、账号、授权码、TLS/SSL、发件人名。"""
+    def _build_verify_page(self) -> None:
+        """构建注册第二步：验证码验证页面。"""
         page = QWidget()
         layout = QVBoxLayout(page)
         layout.setAlignment(Qt.AlignmentFlag.AlignTop)
 
-        title = QLabel("SMTP 设置")
+        title = QLabel("注册 - 验证码验证")
         title.setAlignment(Qt.AlignmentFlag.AlignCenter)
         title.setStyleSheet("font-size: 22px; font-weight: bold; margin: 16px 0;")
         layout.addWidget(title)
 
-        self.smtp_server = QLineEdit(); self.smtp_server.setPlaceholderText("服务器，例如 smtp.qq.com")
-        self.smtp_port = QLineEdit(); self.smtp_port.setPlaceholderText("端口，通常 465 或 587")
-        self.smtp_user = QLineEdit(); self.smtp_user.setPlaceholderText("邮箱账号，例如 123456@qq.com")
-        self.smtp_pass = QLineEdit(); self.smtp_pass.setPlaceholderText("邮箱授权码/应用密码")
-        self.smtp_pass.setEchoMode(QLineEdit.EchoMode.Password)
-        self.smtp_tls = QCheckBox("启用 TLS")
-        self.smtp_ssl = QCheckBox("启用 SSL")
-        self.smtp_sender = QLineEdit(); self.smtp_sender.setPlaceholderText("发件人显示名称，可选")
-
-        layout.addWidget(self.smtp_server)
-        layout.addWidget(self.smtp_port)
-        layout.addWidget(self.smtp_user)
-        layout.addWidget(self.smtp_pass)
-        layout.addWidget(self.smtp_tls)
-        layout.addWidget(self.smtp_ssl)
-        layout.addWidget(self.smtp_sender)
+        self.verify_code = QLineEdit()
+        self.verify_code.setPlaceholderText("请输入6位验证码")
+        layout.addWidget(self.verify_code)
 
         btn_row = QHBoxLayout()
-        self.btn_save_smtp = QPushButton("保存设置")
-        self.btn_back_login = QPushButton("返回登录")
-        btn_row.addWidget(self.btn_save_smtp)
-        btn_row.addWidget(self.btn_back_login)
+        self.btn_verify = QPushButton("验证")
+        self.btn_back_to_email = QPushButton("返回上一步")
+        btn_row.addWidget(self.btn_verify)
+        btn_row.addWidget(self.btn_back_to_email)
         layout.addLayout(btn_row)
 
-        self.btn_save_smtp.clicked.connect(self._on_save_smtp)
-        self.btn_back_login.clicked.connect(lambda: self.stack.setCurrentIndex(0))
+        self.btn_verify.clicked.connect(self._on_verify_code)
+        self.btn_back_to_email.clicked.connect(lambda: self.stack.setCurrentIndex(1))
 
         self.stack.addWidget(page)
 
-    def _on_save_smtp(self) -> None:
-        """保存 SMTP 配置到本地 JSON，以支持验证码发送。"""
+    def _on_verify_code(self) -> None:
+        """处理验证码验证逻辑。"""
+        code = (self.verify_code.text() or "").strip()
+        if not code:
+            QMessageBox.warning(self, "提示", "请输入验证码")
+            return
+        
+        if not self.session_email:
+            QMessageBox.warning(self, "提示", "会话已过期，请重新注册")
+            self.stack.setCurrentIndex(1)
+            return
+        
+        ok, msg = self.user_service.verify_code(self.session_email, code)
+        if ok:
+            QMessageBox.information(self, "提示", msg)
+            # 跳转到设置用户名密码页面
+            self.stack.setCurrentIndex(3)
+        else:
+            QMessageBox.warning(self, "提示", msg)
+
+    def _build_set_credentials_page(self) -> None:
+        """构建注册第三步：设置用户名和密码页面。"""
+        page = QWidget()
+        layout = QVBoxLayout(page)
+        layout.setAlignment(Qt.AlignmentFlag.AlignTop)
+
+        title = QLabel("注册 - 设置用户名和密码")
+        title.setAlignment(Qt.AlignmentFlag.AlignCenter)
+        title.setStyleSheet("font-size: 22px; font-weight: bold; margin: 16px 0;")
+        layout.addWidget(title)
+
+        self.register_username = QLineEdit()
+        self.register_username.setPlaceholderText("请输入用户名（3-16位，字母数字下划线）")
+        layout.addWidget(self.register_username)
+
+        self.register_password = QLineEdit()
+        self.register_password.setPlaceholderText("请输入密码（6-10位，包含大小写字母和数字）")
+        self.register_password.setEchoMode(QLineEdit.EchoMode.Password)
+        layout.addWidget(self.register_password)
+
+        self.register_confirm = QLineEdit()
+        self.register_confirm.setPlaceholderText("请确认密码")
+        self.register_confirm.setEchoMode(QLineEdit.EchoMode.Password)
+        layout.addWidget(self.register_confirm)
+
+        btn_row = QHBoxLayout()
+        self.btn_complete_register = QPushButton("完成注册")
+        self.btn_back_to_verify = QPushButton("返回上一步")
+        btn_row.addWidget(self.btn_complete_register)
+        btn_row.addWidget(self.btn_back_to_verify)
+        layout.addLayout(btn_row)
+
+        self.btn_complete_register.clicked.connect(self._on_complete_register)
+        self.btn_back_to_verify.clicked.connect(lambda: self.stack.setCurrentIndex(2))
+
+        self.stack.addWidget(page)
+
+    def _on_complete_register(self) -> None:
+        """处理完成注册逻辑：设置用户名和密码。"""
+        username = (self.register_username.text() or "").strip()
+        password = self.register_password.text() or ""
+        confirm = self.register_confirm.text() or ""
+        
+        if not username or not password or not confirm:
+            QMessageBox.warning(self, "提示", "请填写完整信息")
+            return
+        
+        if not self.session_email:
+            QMessageBox.warning(self, "提示", "会话已过期，请重新注册")
+            self.stack.setCurrentIndex(1)
+            return
+        
+        # 设置用户名
+        ok, msg = self.user_service.set_username(self.session_email, username)
+        if not ok:
+            QMessageBox.warning(self, "提示", msg)
+            return
+        
+        # 设置密码
+        ok, msg = self.user_service.set_password(self.session_email, password, confirm)
+        if not ok:
+            QMessageBox.warning(self, "提示", msg)
+            return
+        
+        # 完成注册
+        ok, msg = self.user_service.complete_registration(self.session_email)
+        if ok:
+            QMessageBox.information(self, "提示", "注册成功！请登录")
+            # 清空表单并跳转到登录页
+            self.register_email.clear()
+            self.verify_code.clear()
+            self.register_username.clear()
+            self.register_password.clear()
+            self.register_confirm.clear()
+            self.session_email = None
+            self.stack.setCurrentIndex(0)
+        else:
+            QMessageBox.warning(self, "提示", msg)
+
+    def _build_choice_page(self) -> None:
+        """构建选择页面：选择年级和题目数量。"""
+        page = QWidget()
+        layout = QVBoxLayout(page)
+        layout.setAlignment(Qt.AlignmentFlag.AlignTop)
+
+        title = QLabel("选择题目难度和数量")
+        title.setAlignment(Qt.AlignmentFlag.AlignCenter)
+        title.setStyleSheet("font-size: 22px; font-weight: bold; margin: 16px 0;")
+        layout.addWidget(title)
+
+        # 年级选择
+        grade_label = QLabel("选择年级：")
+        layout.addWidget(grade_label)
+        
+        self.grade_group = QButtonGroup()
+        grade_layout = QHBoxLayout()
+        
+        self.primary_radio = QRadioButton("小学")
+        self.middle_radio = QRadioButton("初中")
+        self.high_radio = QRadioButton("高中")
+        
+        self.grade_group.addButton(self.primary_radio, 0)
+        self.grade_group.addButton(self.middle_radio, 1)
+        self.grade_group.addButton(self.high_radio, 2)
+        
+        grade_layout.addWidget(self.primary_radio)
+        grade_layout.addWidget(self.middle_radio)
+        grade_layout.addWidget(self.high_radio)
+        layout.addLayout(grade_layout)
+        
+        # 默认选择小学
+        self.primary_radio.setChecked(True)
+
+        # 题目数量选择
+        count_label = QLabel("选择题目数量：")
+        layout.addWidget(count_label)
+        
+        self.question_count = QSpinBox()
+        self.question_count.setMinimum(10)
+        self.question_count.setMaximum(30)
+        self.question_count.setValue(15)
+        layout.addWidget(self.question_count)
+
+        btn_row = QHBoxLayout()
+        self.btn_start_quiz = QPushButton("开始答题")
+        self.btn_change_password = QPushButton("修改密码")
+        self.btn_logout = QPushButton("退出登录")
+        btn_row.addWidget(self.btn_start_quiz)
+        btn_row.addWidget(self.btn_change_password)
+        btn_row.addWidget(self.btn_logout)
+        layout.addLayout(btn_row)
+
+        self.btn_start_quiz.clicked.connect(self._on_start_quiz)
+        self.btn_change_password.clicked.connect(lambda: self.stack.setCurrentIndex(7))
+        self.btn_logout.clicked.connect(self._on_logout)
+
+        self.stack.addWidget(page)
+
+    def _on_start_quiz(self) -> None:
+        """开始答题：生成题目并跳转到答题页面。"""
+        # 获取选择的年级
+        grade_map = {0: 'primary', 1: 'middle', 2: 'high'}
+        grade = grade_map[self.grade_group.checkedId()]
+        count = self.question_count.value()
+        
         try:
-            port_val = int(self.smtp_port.text().strip() or '587')
-        except ValueError:
-            QMessageBox.warning(self, '提示', '端口必须为数字')
+            self.questions = self.question_service.generate_questions(grade, count)
+            self.current_question = 0
+            self.user_answers = []
+            self._show_current_question()
+            self.stack.setCurrentIndex(5)
+        except Exception as e:
+            QMessageBox.warning(self, "提示", f"生成题目失败：{str(e)}")
+
+    def _on_logout(self) -> None:
+        """退出登录：清空会话并返回登录页。"""
+        self.session_email = None
+        self.login_identifier.clear()
+        self.login_password.clear()
+        QMessageBox.information(self, "提示", "已退出登录")
+        self.stack.setCurrentIndex(0)
+
+    def _build_quiz_page(self) -> None:
+        """构建答题页面：显示题目和选项。"""
+        page = QWidget()
+        layout = QVBoxLayout(page)
+        layout.setAlignment(Qt.AlignmentFlag.AlignTop)
+
+        # 进度显示
+        self.progress_label = QLabel()
+        self.progress_label.setAlignment(Qt.AlignmentFlag.AlignCenter)
+        self.progress_label.setStyleSheet("font-size: 16px; margin: 10px 0;")
+        layout.addWidget(self.progress_label)
+
+        # 题目显示
+        self.question_label = QLabel()
+        self.question_label.setAlignment(Qt.AlignmentFlag.AlignLeft)
+        self.question_label.setStyleSheet("font-size: 18px; margin: 20px 0; padding: 10px; border: 1px solid #ccc;")
+        self.question_label.setWordWrap(True)
+        layout.addWidget(self.question_label)
+
+        # 选项
+        self.option_group = QButtonGroup()
+        self.option_radios = []
+        for i in range(4):
+            radio = QRadioButton()
+            radio.setStyleSheet("font-size: 16px; margin: 5px 0;")
+            self.option_group.addButton(radio, i)
+            self.option_radios.append(radio)
+            layout.addWidget(radio)
+
+        # 按钮
+        btn_row = QHBoxLayout()
+        self.btn_prev = QPushButton("上一题")
+        self.btn_next = QPushButton("下一题")
+        self.btn_submit = QPushButton("提交答案")
+        btn_row.addWidget(self.btn_prev)
+        btn_row.addWidget(self.btn_next)
+        btn_row.addWidget(self.btn_submit)
+        layout.addLayout(btn_row)
+
+        self.btn_prev.clicked.connect(self._on_prev_question)
+        self.btn_next.clicked.connect(self._on_next_question)
+        self.btn_submit.clicked.connect(self._on_submit_quiz)
+
+        self.stack.addWidget(page)
+
+    def _show_current_question(self) -> None:
+        """显示当前题目。"""
+        if not hasattr(self, 'questions') or not self.questions:
+            return
+        
+        question = self.questions[self.current_question]
+        total = len(self.questions)
+        
+        # 更新进度
+        self.progress_label.setText(f"第 {self.current_question + 1} 题 / 共 {total} 题")
+        
+        # 更新题目
+        self.question_label.setText(question['stem'])
+        
+        # 更新选项
+        for i, option in enumerate(question['options']):
+            self.option_radios[i].setText(f"{chr(65+i)}. {option}")
+        
+        # 恢复之前的选择
+        if self.current_question < len(self.user_answers):
+            selected = self.user_answers[self.current_question]
+            if selected is not None:
+                self.option_radios[selected].setChecked(True)
+        else:
+            # 清空选择
+            for radio in self.option_radios:
+                radio.setChecked(False)
+        
+        # 更新按钮状态
+        self.btn_prev.setEnabled(self.current_question > 0)
+        self.btn_next.setEnabled(self.current_question < total - 1)
+
+    def _on_prev_question(self) -> None:
+        """上一题。"""
+        self._save_current_answer()
+        if self.current_question > 0:
+            self.current_question -= 1
+            self._show_current_question()
+
+    def _on_next_question(self) -> None:
+        """下一题。"""
+        self._save_current_answer()
+        if self.current_question < len(self.questions) - 1:
+            self.current_question += 1
+            self._show_current_question()
+
+    def _save_current_answer(self) -> None:
+        """保存当前题目的答案。"""
+        selected = self.option_group.checkedId()
+        # 确保user_answers列表足够长
+        while len(self.user_answers) <= self.current_question:
+            self.user_answers.append(None)
+        self.user_answers[self.current_question] = selected if selected >= 0 else None
+
+    def _on_submit_quiz(self) -> None:
+        """提交答案并计算分数。"""
+        self._save_current_answer()
+        
+        # 检查是否有未答题目
+        unanswered = []
+        for i, answer in enumerate(self.user_answers):
+            if answer is None:
+                unanswered.append(i + 1)
+        
+        if unanswered:
+            reply = QMessageBox.question(
+                self, "提示", 
+                f"还有第 {', '.join(map(str, unanswered))} 题未作答，确定要提交吗？",
+                QMessageBox.StandardButton.Yes | QMessageBox.StandardButton.No
+            )
+            if reply == QMessageBox.StandardButton.No:
+                return
+        
+        # 计算分数
+        correct = 0
+        total = len(self.questions)
+        for i, question in enumerate(self.questions):
+            if i < len(self.user_answers) and self.user_answers[i] == question['answer_index']:
+                correct += 1
+        
+        self.score = correct
+        self.total_questions = total
+        self._show_result()
+        self.stack.setCurrentIndex(6)
+
+    def _build_result_page(self) -> None:
+        """构建结果页面：显示分数和操作选项。"""
+        page = QWidget()
+        layout = QVBoxLayout(page)
+        layout.setAlignment(Qt.AlignmentFlag.AlignCenter)
+
+        title = QLabel("答题结果")
+        title.setAlignment(Qt.AlignmentFlag.AlignCenter)
+        title.setStyleSheet("font-size: 22px; font-weight: bold; margin: 16px 0;")
+        layout.addWidget(title)
+
+        self.score_label = QLabel()
+        self.score_label.setAlignment(Qt.AlignmentFlag.AlignCenter)
+        self.score_label.setStyleSheet("font-size: 24px; margin: 20px 0; color: #2196F3;")
+        layout.addWidget(self.score_label)
+
+        btn_row = QHBoxLayout()
+        self.btn_continue = QPushButton("继续做题")
+        self.btn_exit = QPushButton("退出")
+        btn_row.addWidget(self.btn_continue)
+        btn_row.addWidget(self.btn_exit)
+        layout.addLayout(btn_row)
+
+        self.btn_continue.clicked.connect(lambda: self.stack.setCurrentIndex(4))
+        self.btn_exit.clicked.connect(self._on_logout)
+
+        self.stack.addWidget(page)
+
+    def _show_result(self) -> None:
+        """显示答题结果。"""
+        if hasattr(self, 'score') and hasattr(self, 'total_questions'):
+            percentage = (self.score / self.total_questions) * 100
+            self.score_label.setText(
+                f"您答对了 {self.score} 题，共 {self.total_questions} 题\n"
+                f"正确率：{percentage:.1f}%"
+            )
+
+    def _build_change_password_page(self) -> None:
+        """构建修改密码页面。"""
+        page = QWidget()
+        layout = QVBoxLayout(page)
+        layout.setAlignment(Qt.AlignmentFlag.AlignTop)
+
+        title = QLabel("修改密码")
+        title.setAlignment(Qt.AlignmentFlag.AlignCenter)
+        title.setStyleSheet("font-size: 22px; font-weight: bold; margin: 16px 0;")
+        layout.addWidget(title)
+
+        self.old_password = QLineEdit()
+        self.old_password.setPlaceholderText("请输入原密码")
+        self.old_password.setEchoMode(QLineEdit.EchoMode.Password)
+        layout.addWidget(self.old_password)
+
+        self.new_password = QLineEdit()
+        self.new_password.setPlaceholderText("请输入新密码（6-10位，包含大小写字母和数字）")
+        self.new_password.setEchoMode(QLineEdit.EchoMode.Password)
+        layout.addWidget(self.new_password)
+
+        self.confirm_new_password = QLineEdit()
+        self.confirm_new_password.setPlaceholderText("请确认新密码")
+        self.confirm_new_password.setEchoMode(QLineEdit.EchoMode.Password)
+        layout.addWidget(self.confirm_new_password)
+
+        btn_row = QHBoxLayout()
+        self.btn_change_pwd = QPushButton("修改密码")
+        self.btn_back_to_choice = QPushButton("返回")
+        btn_row.addWidget(self.btn_change_pwd)
+        btn_row.addWidget(self.btn_back_to_choice)
+        layout.addLayout(btn_row)
+
+        self.btn_change_pwd.clicked.connect(self._on_change_password)
+        self.btn_back_to_choice.clicked.connect(lambda: self.stack.setCurrentIndex(4))
+
+        self.stack.addWidget(page)
+
+    def _on_change_password(self) -> None:
+        """处理修改密码逻辑。"""
+        old_pwd = self.old_password.text() or ""
+        new_pwd = self.new_password.text() or ""
+        confirm_pwd = self.confirm_new_password.text() or ""
+        
+        if not old_pwd or not new_pwd or not confirm_pwd:
+            QMessageBox.warning(self, "提示", "请填写完整信息")
             return
-        config = {
-            'server': self.smtp_server.text().strip(),
-            'port': port_val,
-            'username': self.smtp_user.text().strip(),
-            'password': self.smtp_pass.text(),
-            'use_tls': self.smtp_tls.isChecked(),
-            'use_ssl': self.smtp_ssl.isChecked(),
-            'sender_name': self.smtp_sender.text().strip() or 'Math Study App',
-        }
-        self.email_service.update_smtp_config(config)
-        QMessageBox.information(self, '提示', 'SMTP设置已保存')
+        
+        if not self.session_email:
+            QMessageBox.warning(self, "提示", "会话已过期，请重新登录")
+            self.stack.setCurrentIndex(0)
+            return
+        
+        ok, msg = self.user_service.change_password(self.session_email, old_pwd, new_pwd, confirm_pwd)
+        if ok:
+            QMessageBox.information(self, "提示", "密码修改成功")
+            # 清空表单并返回选择页
+            self.old_password.clear()
+            self.new_password.clear()
+            self.confirm_new_password.clear()
+            self.stack.setCurrentIndex(4)
+        else:
+            QMessageBox.warning(self, "提示", msg)