feat(auth): 完成租户用户角色资源核心模块

backend/internal/database/database.go

@@ -0,0 +1,82 @@
+package database
+
+import (
+	"fmt"
+	"log"
+	"smart-customer-service/config"
+	"smart-customer-service/internal/models"
+
+	"gorm.io/driver/mysql"
+	"gorm.io/gorm"
+	"gorm.io/gorm/logger"
+)
+
+var DB *gorm.DB
+
+// Init 初始化数据库连接
+func Init(cfg *config.Config) error {
+	dsn := cfg.GetDSN()
+	
+	// 设置日志级别
+	var logLevel logger.LogLevel
+	if cfg.Server.Mode == "debug" {
+		logLevel = logger.Info
+	} else {
+		logLevel = logger.Warn
+	}
+
+	var err error
+	// 连接 MySQL 数据库
+	DB, err = gorm.Open(mysql.Open(dsn), &gorm.Config{
+		Logger: logger.Default.LogMode(logLevel),
+		DisableForeignKeyConstraintWhenMigrating: true,
+	})
+	
+	if err != nil {
+		return fmt.Errorf("failed to connect to database: %w", err)
+	}
+
+	log.Println("✅ Database connection established")
+	
+	// 自动迁移模型
+	if err := Migrate(cfg); err != nil {
+		return fmt.Errorf("failed to migrate database: %w", err)
+	}
+
+	log.Println("✅ Database migration completed")
+	return nil
+}
+
+// Migrate 执行数据库迁移
+func Migrate(cfg *config.Config) error {
+	// 全局模型
+	if err := DB.AutoMigrate(
+		// 租户体系
+		&models.Tenant{},
+		&models.User{},
+		&models.Role{},
+		&models.Resource{},
+		&models.RoleResource{},
+		&models.UserRole{},
+		
+		// 业务模型
+		&models.Conversation{},
+		&models.Message{},
+		&models.Ticket{},
+		&models.KnowledgeBase{},
+		&models.KnowledgeItem{},
+	); err != nil {
+		return err
+	}
+	
+	return nil
+}
+
+// Close 关闭数据库连接
+func Close() {
+	if DB != nil {
+		db, _ := DB.DB()
+		db.Close()
+		log.Println("✅ Database connection closed")
+	}
+}