Add hashtag extraction and management in CreatePost and EditPost logic; improve error handling

app/internal/logic/createpostlogic.go

@@ -43,6 +43,13 @@ func (l *CreatePostLogic) CreatePost(req *types.CreatePostReq) (resp *types.Crea
 		return nil, fmt.Errorf("invalid content format")
 	}
 
+	// Extract all hashtags from content
+	hashtags, err := utils.ExtractHashtagsFromContent(req.Content)
+	if err != nil {
+		l.Errorf("Failed to parse hashtags from content: %v", err)
+		return nil, fmt.Errorf("invalid content format")
+	}
+
 	// Migrate cover image from tmpfiles to files if provided
 	var coverID sql.NullInt64
 	if req.CoverImageKey != "" {
@@ -72,6 +79,36 @@ func (l *CreatePostLogic) CreatePost(req *types.CreatePostReq) (resp *types.Crea
 		return nil, err
 	}
 
+	// Create or get hashtag IDs and link them to the post
+	for _, tagName := range hashtags {
+		var tagID int64
+
+		// Try to get existing hashtag
+		getTagQuery := `SELECT id FROM hashtags WHERE name = $1`
+		err := tx.QueryRowContext(l.ctx, getTagQuery, tagName).Scan(&tagID)
+
+		if err == sql.ErrNoRows {
+			// Hashtag doesn't exist, create it
+			createTagQuery := `INSERT INTO hashtags (name) VALUES ($1) RETURNING id`
+			err = tx.QueryRowContext(l.ctx, createTagQuery, tagName).Scan(&tagID)
+			if err != nil {
+				l.Errorf("Failed to create hashtag %s: %v", tagName, err)
+				continue
+			}
+		} else if err != nil {
+			l.Errorf("Failed to get hashtag %s: %v", tagName, err)
+			continue
+		}
+
+		// Link hashtag to post
+		linkQuery := `INSERT INTO post_hashtags (post_id, hashtag_id) VALUES ($1, $2) ON CONFLICT DO NOTHING`
+		_, err = tx.ExecContext(l.ctx, linkQuery, postID, tagID)
+		if err != nil {
+			l.Errorf("Failed to link hashtag %s to post: %v", tagName, err)
+			// Continue with other hashtags
+		}
+	}
+
 	// Commit transaction
 	if err = tx.Commit(); err != nil {
 		l.Errorf("Failed to commit transaction: %v", err)