feat: Add authentication middleware with JWT validation, RBAC permission checks, and role-based access control

- Add AuthMiddleware with Authorization header parsing, Bearer token extraction, JWT validation, user lookup, and context storage
- Add RequirePermission middleware with user authentication check, database context retrieval, and permission validation
- Add RequireCasbinPermission middleware with user_id context check, Casbin permission validation, and error handling
- Add RequireRole middleware

apps/api-server/internal/middleware/auth.go

@@ -0,0 +1,180 @@
+package middleware
+
+import (
+	"net/http"
+	"slices"
+	"strings"
+
+	"github.com/gin-gonic/gin"
+	"github.com/nutcas3/telecom-platform/apps/api-server/internal/models"
+	"github.com/nutcas3/telecom-platform/apps/api-server/internal/rbac"
+	"github.com/nutcas3/telecom-platform/apps/api-server/internal/services"
+	"gorm.io/gorm"
+)
+
+// AuthMiddleware creates a JWT authentication middleware
+func AuthMiddleware(authService *services.AuthService) gin.HandlerFunc {
+	return func(c *gin.Context) {
+		// Get token from Authorization header
+		authHeader := c.GetHeader("Authorization")
+		if authHeader == "" {
+			c.JSON(http.StatusUnauthorized, gin.H{"error": "Authorization header required"})
+			c.Abort()
+			return
+		}
+
+		// Extract token from "Bearer <token>" format
+		tokenParts := strings.Split(authHeader, " ")
+		if len(tokenParts) != 2 || tokenParts[0] != "Bearer" {
+			c.JSON(http.StatusUnauthorized, gin.H{"error": "Invalid authorization header format"})
+			c.Abort()
+			return
+		}
+
+		token := tokenParts[1]
+
+		// Validate token
+		claims, err := authService.GetJWTService().ValidateToken(token)
+		if err != nil {
+			c.JSON(http.StatusUnauthorized, gin.H{"error": "Invalid token"})
+			c.Abort()
+			return
+		}
+
+		// Get user from database
+		user, err := authService.GetUserByID(claims.UserID)
+		if err != nil {
+			c.JSON(http.StatusUnauthorized, gin.H{"error": "User not found"})
+			c.Abort()
+			return
+		}
+
+		// Store user and claims in context
+		c.Set("user", user)
+		c.Set("user_id", claims.UserID)
+		c.Set("username", claims.Username)
+		c.Set("role", claims.Role)
+
+		c.Next()
+	}
+}
+
+// RequirePermission creates a middleware that checks for specific permissions
+func RequirePermission(resource, action string) gin.HandlerFunc {
+	return func(c *gin.Context) {
+		user, exists := c.Get("user")
+		if !exists {
+			c.JSON(http.StatusUnauthorized, gin.H{"error": "User not authenticated"})
+			c.Abort()
+			return
+		}
+
+		// Get database from context (should be set by the main server)
+		db, exists := c.Get("db")
+		if !exists {
+			c.JSON(http.StatusInternalServerError, gin.H{"error": "Database not available"})
+			c.Abort()
+			return
+		}
+
+		// Check permission
+		if !user.(*models.User).HasPermission(db.(*gorm.DB), resource, action) {
+			c.JSON(http.StatusForbidden, gin.H{"error": "Insufficient permissions"})
+			c.Abort()
+			return
+		}
+
+		c.Next()
+	}
+}
+
+// RequireCasbinPermission creates a middleware that checks for specific permissions using Casbin
+func RequireCasbinPermission(casbinService *rbac.CasbinService, resource, action string) gin.HandlerFunc {
+	return func(c *gin.Context) {
+		userID, exists := c.Get("user_id")
+		if !exists {
+			c.JSON(http.StatusUnauthorized, gin.H{"error": "User not authenticated"})
+			c.Abort()
+			return
+		}
+
+		allowed, err := casbinService.CheckPermission(c.Request.Context(), userID.(uint), resource, action)
+		if err != nil {
+			c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to check permissions"})
+			c.Abort()
+			return
+		}
+
+		if !allowed {
+			c.JSON(http.StatusForbidden, gin.H{"error": "Insufficient permissions"})
+			c.Abort()
+			return
+		}
+
+		c.Next()
+	}
+}
+
+// RequireRole creates a middleware that checks for specific roles (legacy, use RequireCasbinPermission for new features)
+func RequireRole(allowedRoles ...string) gin.HandlerFunc {
+	return func(c *gin.Context) {
+		role, exists := c.Get("role")
+		if !exists {
+			c.JSON(http.StatusUnauthorized, gin.H{"error": "User not authenticated"})
+			c.Abort()
+			return
+		}
+
+		userRole := role.(string)
+		if slices.Contains(allowedRoles, userRole) {
+			c.Next()
+			return
+		}
+
+		c.JSON(http.StatusForbidden, gin.H{"error": "Insufficient role permissions"})
+		c.Abort()
+	}
+}
+
+// OptionalAuthMiddleware creates an optional authentication middleware
+func OptionalAuthMiddleware(authService *services.AuthService) gin.HandlerFunc {
+	return func(c *gin.Context) {
+		// Get token from Authorization header
+		authHeader := c.GetHeader("Authorization")
+		if authHeader == "" {
+			c.Next()
+			return
+		}
+
+		// Extract token from "Bearer <token>" format
+		tokenParts := strings.Split(authHeader, " ")
+		if len(tokenParts) != 2 || tokenParts[0] != "Bearer" {
+			c.Next()
+			return
+		}
+
+		token := tokenParts[1]
+
+		// Validate token
+		claims, err := authService.GetJWTService().ValidateToken(token)
+		if err != nil {
+			c.Next()
+			return
+		}
+
+		// Get user from database
+		user, err := authService.GetUserByID(claims.UserID)
+		if err != nil {
+			c.Next()
+			return
+		}
+
+		// Store user and claims in context
+		c.Set("user", user)
+		c.Set("user_id", claims.UserID)
+		c.Set("username", claims.Username)
+		c.Set("role", claims.Role)
+
+		c.Next()
+	}
+}