Refactor and improve code consistency across multiple files

- Enhanced SQL queries in `session.go` and `share.go` for clarity and consistency.
- Updated comments for better understanding and maintenance.
- Ensured consistent error handling and return statements across various methods.

backend/internal/handlers/auth.go

@@ -64,10 +64,10 @@ func (h *AuthHandler) GoogleLogin(c *gin.Context) {
 // GoogleCallback handles Google OAuth callback
 func (h *AuthHandler) GoogleCallback(c *gin.Context) {
 	oauthState, err := c.Cookie("oauthstate")
-    if err != nil || c.Query("state") != oauthState {
-        c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid oauth state"})
-        return
-    }
+	if err != nil || c.Query("state") != oauthState {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid oauth state"})
+		return
+	}
 	log.Println("Google callback state:", c.Query("state"))
 	// Exchange code for token
 	token, err := h.googleConfig.Exchange(c.Request.Context(), c.Query("code"))
@@ -94,11 +94,11 @@ func (h *AuthHandler) GoogleCallback(c *gin.Context) {
 		Name    string `json:"name"`
 		Picture string `json:"picture"`
 	}
-	
+
 	if err := json.Unmarshal(data, &userInfo); err != nil {
-    log.Printf("Failed to parse Google response: %v | Data: %s", err, string(data))
-    c.JSON(http.StatusInternalServerError, gin.H{"error": "Invalid Google response"})
-    return
+		log.Printf("Failed to parse Google response: %v | Data: %s", err, string(data))
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Invalid Google response"})
+		return
 	}
 	log.Println("Google user info:", userInfo)
 	// Upsert user in database
@@ -118,10 +118,10 @@ func (h *AuthHandler) GoogleCallback(c *gin.Context) {
 	// Create session and JWT
 	jwt, err := h.createSessionAndJWT(c, user)
 	if err != nil {
-		fmt.Printf("❌ DATABASE ERROR: %v\n", err) 
-        c.JSON(http.StatusInternalServerError, gin.H{
-            "error": fmt.Sprintf("CreateSession Error: %v", err), 
-        })
+		fmt.Printf("❌ DATABASE ERROR: %v\n", err)
+		c.JSON(http.StatusInternalServerError, gin.H{
+			"error": fmt.Sprintf("CreateSession Error: %v", err),
+		})
 		return
 	}
 
@@ -140,10 +140,10 @@ func (h *AuthHandler) GithubLogin(c *gin.Context) {
 // GithubCallback handles GitHub OAuth callback
 func (h *AuthHandler) GithubCallback(c *gin.Context) {
 	oauthState, err := c.Cookie("oauthstate")
-    if err != nil || c.Query("state") != oauthState {
-        c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid oauth state"})
-        return
-    }
+	if err != nil || c.Query("state") != oauthState {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid oauth state"})
+		return
+	}
 	log.Println("Github callback state:", c.Query("state"))
 	code := c.Query("code")
 	if code == "" {
@@ -160,7 +160,7 @@ func (h *AuthHandler) GithubCallback(c *gin.Context) {
 
 	// Get user info from GitHub
 	client := h.githubConfig.Client(c.Request.Context(), token)
-	
+
 	// Get user profile
 	resp, err := client.Get("https://api.github.com/user")
 	if err != nil {
@@ -178,10 +178,10 @@ func (h *AuthHandler) GithubCallback(c *gin.Context) {
 		AvatarURL string `json:"avatar_url"`
 	}
 	if err := json.Unmarshal(data, &userInfo); err != nil {
-    log.Printf("Failed to parse GitHub response: %v | Data: %s", err, string(data))
-    c.JSON(http.StatusInternalServerError, gin.H{"error": "Invalid GitHub response"})
-    return
-}
+		log.Printf("Failed to parse GitHub response: %v | Data: %s", err, string(data))
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Invalid GitHub response"})
+		return
+	}
 
 	// If email is not public, fetch it separately
 	if userInfo.Email == "" {
@@ -315,10 +315,10 @@ func (h *AuthHandler) generateStateOauthCookie(w http.ResponseWriter) string {
 		Name:     "oauthstate",
 		Value:    state,
 		Expires:  time.Now().Add(10 * time.Minute),
-		HttpOnly: true,                   // Prevents JavaScript access (XSS protection)
-		Secure:   h.cfg.SecureCookie,     // true in production, false for localhost
-		SameSite: http.SameSiteLaxMode,   // Allows same-site OAuth redirects
-		Path:     "/",                    // Ensures cookie is sent to all backend paths
+		HttpOnly: true,                 // Prevents JavaScript access (XSS protection)
+		Secure:   h.cfg.SecureCookie,   // true in production, false for localhost
+		SameSite: http.SameSiteLaxMode, // Allows same-site OAuth redirects
+		Path:     "/",                  // Ensures cookie is sent to all backend paths
 	}
 	http.SetCookie(w, &cookie)
 

backend/internal/handlers/document.go

@@ -11,16 +11,15 @@ import (
 	"github.com/google/uuid"
 )
 
-  type DocumentHandler struct {
-  	store *store.PostgresStore
-  }
+type DocumentHandler struct {
+	store *store.PostgresStore
+}
 
-  func NewDocumentHandler(s *store.PostgresStore) *DocumentHandler {
-  	return &DocumentHandler{store: s}
-  }
+func NewDocumentHandler(s *store.PostgresStore) *DocumentHandler {
+	return &DocumentHandler{store: s}
+}
 
-
-  // CreateDocument creates a new document (requires auth)
+// CreateDocument creates a new document (requires auth)
 func (h *DocumentHandler) CreateDocument(c *gin.Context) {
 	userID := auth.GetUserFromContext(c)
 	if userID == nil {
@@ -44,7 +43,7 @@ func (h *DocumentHandler) CreateDocument(c *gin.Context) {
 	c.JSON(http.StatusCreated, doc)
 }
 
-  func (h *DocumentHandler) ListDocuments(c *gin.Context) {
+func (h *DocumentHandler) ListDocuments(c *gin.Context) {
 	userID := auth.GetUserFromContext(c)
 	fmt.Println("Getting userId, which is : ")
 	fmt.Println(userID)
@@ -66,8 +65,7 @@ func (h *DocumentHandler) CreateDocument(c *gin.Context) {
 	})
 }
 
-
-  func (h *DocumentHandler) GetDocument(c *gin.Context) {
+func (h *DocumentHandler) GetDocument(c *gin.Context) {
 	id, err := uuid.Parse(c.Param("id"))
 	if err != nil {
 		respondBadRequest(c, "Invalid document ID format")
@@ -104,8 +102,9 @@ func (h *DocumentHandler) CreateDocument(c *gin.Context) {
 
 	c.JSON(http.StatusOK, doc)
 }
-  // GetDocumentState returns the Yjs state for a document
-  // GetDocumentState retrieves document state (requires view permission)
+
+// GetDocumentState returns the Yjs state for a document
+// GetDocumentState retrieves document state (requires view permission)
 func (h *DocumentHandler) GetDocumentState(c *gin.Context) {
 	id, err := uuid.Parse(c.Param("id"))
 	if err != nil {
@@ -143,7 +142,7 @@ func (h *DocumentHandler) GetDocumentState(c *gin.Context) {
 	c.Data(http.StatusOK, "application/octet-stream", state)
 }
 
-  // UpdateDocumentState updates document state (requires edit permission)
+// UpdateDocumentState updates document state (requires edit permission)
 func (h *DocumentHandler) UpdateDocumentState(c *gin.Context) {
 	id, err := uuid.Parse(c.Param("id"))
 	if err != nil {
@@ -195,7 +194,7 @@ func (h *DocumentHandler) UpdateDocumentState(c *gin.Context) {
 	c.JSON(http.StatusOK, gin.H{"message": "State updated successfully"})
 }
 
-  // DeleteDocument deletes a document (owner only)
+// DeleteDocument deletes a document (owner only)
 func (h *DocumentHandler) DeleteDocument(c *gin.Context) {
 	id, err := uuid.Parse(c.Param("id"))
 	if err != nil {
@@ -237,107 +236,109 @@ func (h *DocumentHandler) DeleteDocument(c *gin.Context) {
 
 // GetDocumentPermission returns the user's permission level for a document
 func (h *DocumentHandler) GetDocumentPermission(c *gin.Context) {
-    documentID, err := uuid.Parse(c.Param("id"))
-    if err != nil {
-        respondBadRequest(c, "Invalid document ID format")
-        return
-    }
+	documentID, err := uuid.Parse(c.Param("id"))
+	if err != nil {
+		respondBadRequest(c, "Invalid document ID format")
+		return
+	}
 
-    // 1. 先检查文档是否存在 (Good practice)
-    _, err = h.store.GetDocument(documentID)
-    if err != nil {
-        respondNotFound(c, "document")
-        return
-    }
+	// 1. 先检查文档是否存在 (Good practice)
+	_, err = h.store.GetDocument(documentID)
+	if err != nil {
+		respondNotFound(c, "document")
+		return
+	}
 
-    userID := auth.GetUserFromContext(c)
-    shareToken := c.Query("share")
+	userID := auth.GetUserFromContext(c)
+	shareToken := c.Query("share")
 
-    // 定义两个临时变量，用来存两边的结果
-    var userPerm string  // 存 document_shares 的结果
-    var tokenPerm string // 存 share_token 的结果
+	// 定义两个临时变量，用来存两边的结果
+	var userPerm string  // 存 document_shares 的结果
+	var tokenPerm string // 存 share_token 的结果
 
-    // ====================================================
-    // 步骤 A: 检查个人权限 (Base Permission)
-    // ====================================================
-    if userID != nil {
-        perm, err := h.store.GetUserPermission(c.Request.Context(), documentID, *userID)
-        if err != nil {
-            respondInternalError(c, "Failed to get user permission", err)
-            return
-        }
-        userPerm = perm 
-        // ⚠️ 注意：如果 perm 是空，这里不报错！继续往下走！
-    }
+	// ====================================================
+	// 步骤 A: 检查个人权限 (Base Permission)
+	// ====================================================
+	if userID != nil {
+		perm, err := h.store.GetUserPermission(c.Request.Context(), documentID, *userID)
+		if err != nil {
+			respondInternalError(c, "Failed to get user permission", err)
+			return
+		}
+		userPerm = perm
+		// ⚠️ 注意：如果 perm 是空，这里不报错！继续往下走！
+	}
 
-    // ====================================================
-    // 步骤 B: 检查 Token 权限 (Upgrade Permission)
-    // ====================================================
-    if shareToken != "" {
-        // 先验证 Token 是否有效
-        valid, err := h.store.ValidateShareToken(c.Request.Context(), documentID, shareToken)
-        if err != nil {
-            respondInternalError(c, "Failed to validate token", err)
-            return
-        }
-        
-        // 只有 Token 有效才去取权限
-        if valid {
-            p, err := h.store.GetShareLinkPermission(c.Request.Context(), documentID)
-            if err != nil {
-                respondInternalError(c, "Failed to get token permission", err)
-                return
-            }
-            tokenPerm = p
-            // 处理数据库老数据的 fallback
-            if tokenPerm == "" { tokenPerm = "view" } 
-        }
-    }
+	// ====================================================
+	// 步骤 B: 检查 Token 权限 (Upgrade Permission)
+	// ====================================================
+	if shareToken != "" {
+		// 先验证 Token 是否有效
+		valid, err := h.store.ValidateShareToken(c.Request.Context(), documentID, shareToken)
+		if err != nil {
+			respondInternalError(c, "Failed to validate token", err)
+			return
+		}
 
-    // ====================================================
-    // 步骤 C: ⚡️ 权限合并与计算 (The Brain)
-    // ====================================================
-    
-    finalPermission := ""
-    role := "viewer" // 默认角色
+		// 只有 Token 有效才去取权限
+		if valid {
+			p, err := h.store.GetShareLinkPermission(c.Request.Context(), documentID)
+			if err != nil {
+				respondInternalError(c, "Failed to get token permission", err)
+				return
+			}
+			tokenPerm = p
+			// 处理数据库老数据的 fallback
+			if tokenPerm == "" {
+				tokenPerm = "view"
+			}
+		}
+	}
 
-    // 1. 如果是 Owner，无敌，直接返回
-    if userPerm == "owner" {
-        finalPermission = "edit"
-        role = "owner"
-        // 直接返回，不用看 Token 了
-        c.JSON(http.StatusOK, models.PermissionResponse{
-            Permission: finalPermission,
-            Role:       role,
-        })
-        return
-    }
+	// ====================================================
+	// 步骤 C: ⚡️ 权限合并与计算 (The Brain)
+	// ====================================================
 
-    // 2. 比较 User 和 Token，取最大值
-    // 逻辑：只要任意一边给了 "edit"，那就是 "edit"
-    if userPerm == "edit" || tokenPerm == "edit" {
-        finalPermission = "edit"
-        role = "editor"
-    } else if userPerm == "view" || tokenPerm == "view" {
-        finalPermission = "view"
-        role = "viewer"
-    }
+	finalPermission := ""
+	role := "viewer" // 默认角色
 
-    // ====================================================
-    // 步骤 D: 最终判决
-    // ====================================================
-    if finalPermission == "" {
-        // 既没个人权限，Token 也不对（或者没 Token）
-        if userID == nil {
-             respondUnauthorized(c, "Authentication required") // 没登录且没Token
-        } else {
-             respondForbidden(c, "You don't have permission") // 登录了但没权限
-        }
-        return
-    }
+	// 1. 如果是 Owner，无敌，直接返回
+	if userPerm == "owner" {
+		finalPermission = "edit"
+		role = "owner"
+		// 直接返回，不用看 Token 了
+		c.JSON(http.StatusOK, models.PermissionResponse{
+			Permission: finalPermission,
+			Role:       role,
+		})
+		return
+	}
 
-    c.JSON(http.StatusOK, models.PermissionResponse{
-        Permission: finalPermission,
-        Role:       role,
-    })
-}
+	// 2. 比较 User 和 Token，取最大值
+	// 逻辑：只要任意一边给了 "edit"，那就是 "edit"
+	if userPerm == "edit" || tokenPerm == "edit" {
+		finalPermission = "edit"
+		role = "editor"
+	} else if userPerm == "view" || tokenPerm == "view" {
+		finalPermission = "view"
+		role = "viewer"
+	}
+
+	// ====================================================
+	// 步骤 D: 最终判决
+	// ====================================================
+	if finalPermission == "" {
+		// 既没个人权限，Token 也不对（或者没 Token）
+		if userID == nil {
+			respondUnauthorized(c, "Authentication required") // 没登录且没Token
+		} else {
+			respondForbidden(c, "You don't have permission") // 登录了但没权限
+		}
+		return
+	}
+
+	c.JSON(http.StatusOK, models.PermissionResponse{
+		Permission: finalPermission,
+		Role:       role,
+	})
+}

backend/internal/handlers/errors.go

@@ -91,5 +91,5 @@ func respondInternalError(c *gin.Context, message string, err error) {
 	respondWithError(c, http.StatusInternalServerError, "internal_error", message)
 }
 func respondInvalidID(c *gin.Context, message string) {
-    respondWithError(c, http.StatusBadRequest, "invalid_id", message)
+	respondWithError(c, http.StatusBadRequest, "invalid_id", message)
 }

backend/internal/handlers/share.go

@@ -153,6 +153,7 @@ func (h *ShareHandler) DeleteShare(c *gin.Context) {
 
 	c.Status(204)
 }
+
 // CreateShareLink generates a public share link
 func (h *ShareHandler) CreateShareLink(c *gin.Context) {
 	documentID, err := uuid.Parse(c.Param("id"))
@@ -290,4 +291,4 @@ func (h *ShareHandler) RevokeShareLink(c *gin.Context) {
 
 	// c.JSON(http.StatusOK, gin.H{"message": "Share link revoked successfully"})
 	c.Status(204)
-}
+}

backend/internal/handlers/share_test.go

@@ -70,7 +70,7 @@ func TestShareHandlerSuite(t *testing.T) {
 
 func (s *ShareHandlerSuite) TestCreateShare_ViewPermission() {
 	body := map[string]interface{}{
-		"user_email":      "bob@test.com",
+		"user_email": "bob@test.com",
 		"permission": "view",
 	}
 
@@ -87,7 +87,7 @@ func (s *ShareHandlerSuite) TestCreateShare_ViewPermission() {
 
 func (s *ShareHandlerSuite) TestCreateShare_EditPermission() {
 	body := map[string]interface{}{
-		"user_email":      "bob@test.com",
+		"user_email": "bob@test.com",
 		"permission": "edit",
 	}
 
@@ -104,7 +104,7 @@ func (s *ShareHandlerSuite) TestCreateShare_EditPermission() {
 
 func (s *ShareHandlerSuite) TestCreateShare_NonOwnerDenied() {
 	body := map[string]interface{}{
-		"user_email":      "charlie@test.com",
+		"user_email": "charlie@test.com",
 		"permission": "view",
 	}
 
@@ -118,7 +118,7 @@ func (s *ShareHandlerSuite) TestCreateShare_NonOwnerDenied() {
 
 func (s *ShareHandlerSuite) TestCreateShare_UserNotFound() {
 	body := map[string]interface{}{
-		"user_email":      "nonexistent@test.com",
+		"user_email": "nonexistent@test.com",
 		"permission": "view",
 	}
 
@@ -131,7 +131,7 @@ func (s *ShareHandlerSuite) TestCreateShare_UserNotFound() {
 
 func (s *ShareHandlerSuite) TestCreateShare_InvalidPermission() {
 	body := map[string]interface{}{
-		"user_email":      "bob@test.com",
+		"user_email": "bob@test.com",
 		"permission": "admin", // Invalid permission
 	}
 
@@ -145,7 +145,7 @@ func (s *ShareHandlerSuite) TestCreateShare_InvalidPermission() {
 func (s *ShareHandlerSuite) TestCreateShare_UpdatesExisting() {
 	// Create initial share with view permission
 	body := map[string]interface{}{
-		"user_email":      "bob@test.com",
+		"user_email": "bob@test.com",
 		"permission": "view",
 	}
 
@@ -169,7 +169,7 @@ func (s *ShareHandlerSuite) TestCreateShare_UpdatesExisting() {
 
 func (s *ShareHandlerSuite) TestCreateShare_Unauthorized() {
 	body := map[string]interface{}{
-		"user_email":      "bob@test.com",
+		"user_email": "bob@test.com",
 		"permission": "view",
 	}
 
@@ -182,7 +182,7 @@ func (s *ShareHandlerSuite) TestCreateShare_Unauthorized() {
 
 func (s *ShareHandlerSuite) TestCreateShare_InvalidDocumentID() {
 	body := map[string]interface{}{
-		"user_email":      "bob@test.com",
+		"user_email": "bob@test.com",
 		"permission": "view",
 	}
 
@@ -206,8 +206,8 @@ func (s *ShareHandlerSuite) TestListShares_OwnerSeesAll() {
 	s.assertSuccessResponse(w, http.StatusOK)
 
 	var response models.ShareListResponse
-s.parseJSONResponse(w, &response)
-shares := response.Shares
+	s.parseJSONResponse(w, &response)
+	shares := response.Shares
 	s.GreaterOrEqual(len(shares), 1, "Should have at least one share")
 }
 
@@ -229,8 +229,8 @@ func (s *ShareHandlerSuite) TestListShares_EmptyList() {
 	s.assertSuccessResponse(w, http.StatusOK)
 
 	var response models.ShareListResponse
-s.parseJSONResponse(w, &response)
-shares := response.Shares
+	s.parseJSONResponse(w, &response)
+	shares := response.Shares
 	s.Equal(0, len(shares), "Should have no shares")
 }
 
@@ -243,8 +243,8 @@ func (s *ShareHandlerSuite) TestListShares_IncludesUserDetails() {
 	s.assertSuccessResponse(w, http.StatusOK)
 
 	var response models.ShareListResponse
-s.parseJSONResponse(w, &response)
-shares := response.Shares
+	s.parseJSONResponse(w, &response)
+	shares := response.Shares
 
 	if len(shares) > 0 {
 		share := shares[0]
@@ -266,7 +266,7 @@ func (s *ShareHandlerSuite) TestListShares_OrderedByCreatedAt() {
 	users := []string{"bob@test.com", "charlie@test.com"}
 	for _, email := range users {
 		body := map[string]interface{}{
-			"user_email":      email,
+			"user_email": email,
 			"permission": "view",
 		}
 		w, httpReq, err := s.makeAuthRequest("POST", fmt.Sprintf("/api/documents/%s/shares", s.testData.AlicePrivateDoc), body, s.testData.AliceID)

backend/internal/handlers/websocket_loadtest.go

@@ -48,10 +48,10 @@ func (wsh *WebSocketHandler) HandleWebSocketLoadTest(c *gin.Context) {
 	clientID := uuid.New().String()
 	client := hub.NewClient(
 		clientID,
-		nil,           // userID - nil for anonymous
-		userName,      // userName
-		nil,           // userAvatar
-		"edit",        // permission - full access for load testing
+		nil,      // userID - nil for anonymous
+		userName, // userName
+		nil,      // userAvatar
+		"edit",   // permission - full access for load testing
 		conn,
 		wsh.hub,
 		roomID,