添加 OIDC 和 OAuth2 服务器的基础结构，包括配置、数据库模型、服务、处理器和路由。新增登录页面模板，支持用户认证和授权流程。

services/auth.go

@@ -0,0 +1,79 @@
+package services
+
+import (
+	"errors"
+	"time"
+
+	"golang.org/x/crypto/bcrypt"
+	"gorm.io/gorm"
+
+	"oidc-oauth2-server/models"
+)
+
+type AuthService struct {
+	db *gorm.DB
+}
+
+func NewAuthService(db *gorm.DB) *AuthService {
+	return &AuthService{db: db}
+}
+
+func (s *AuthService) Authenticate(username, password string) (*models.User, error) {
+	user := &models.User{}
+	if err := s.db.Where("username = ?", username).First(user).Error; err != nil {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			return nil, errors.New("invalid username or password")
+		}
+		return nil, err
+	}
+
+	if err := bcrypt.CompareHashAndPassword([]byte(user.Password), []byte(password)); err != nil {
+		return nil, errors.New("invalid username or password")
+	}
+
+	// 更新最后登录时间
+	user.LastLogin = time.Now()
+	s.db.Save(user)
+
+	return user, nil
+}
+
+func (s *AuthService) CreateUser(username, password, email string) (*models.User, error) {
+	// 检查用户名是否已存在
+	var count int64
+	s.db.Model(&models.User{}).Where("username = ?", username).Count(&count)
+	if count > 0 {
+		return nil, errors.New("username already exists")
+	}
+
+	// 加密密码
+	hashedPassword, err := bcrypt.GenerateFromPassword([]byte(password), bcrypt.DefaultCost)
+	if err != nil {
+		return nil, err
+	}
+
+	user := &models.User{
+		Username: username,
+		Password: string(hashedPassword),
+		Email:    email,
+		IsActive: true,
+	}
+
+	if err := s.db.Create(user).Error; err != nil {
+		return nil, err
+	}
+
+	return user, nil
+}
+
+// GetUserByID 根据用户 ID 获取用户信息
+func (s *AuthService) GetUserByID(id uint, user *models.User) error {
+	result := s.db.First(user, id)
+	if result.Error != nil {
+		if errors.Is(result.Error, gorm.ErrRecordNotFound) {
+			return errors.New("user not found")
+		}
+		return result.Error
+	}
+	return nil
+}