import { AddVariable, Variable } from '../models/variables';
import { BaseService } from './base';
/**
 * Service for interacting with TestRail variables.
 * @requires TestRail Enterprise license/subscription
 */
export declare class VariableService extends BaseService {
    /**
     * Returns a list of available variables.
     * @param projectId - The ID of the project from which to retrieve variables
     * @returns List of variables
     * @throws {Error} - If the project ID is invalid or missing (400)
     * @throws {Error} - If authentication fails (401)
     * @throws {Error} - If there are insufficient permissions or not an Enterprise license (403)
     */
    list(projectId: number): Promise<Variable[]>;
    /**
     * Creates a new variable.
     * @param projectId - The ID of the project to which the variable should be added
     * @param variable - The variable to create
     * @returns The created variable
     * @throws {Error} - If the project ID is invalid or missing (400)
     * @throws {Error} - If the variable name is invalid or already exists (400)
     * @throws {Error} - If the number of allowed variables is exceeded (400)
     * @throws {Error} - If authentication fails (401)
     * @throws {Error} - If there are insufficient permissions or not an Enterprise license (403)
     */
    add(projectId: number, variable: AddVariable): Promise<Variable>;
    /**
     * Updates an existing variable.
     * @param variableId - The ID of the variable to update
     * @param variable - The variable fields to update
     * @returns The updated variable
     * @throws {Error} - If the variable ID is invalid or missing (400)
     * @throws {Error} - If the variable name is invalid or already exists (400)
     * @throws {Error} - If authentication fails (401)
     * @throws {Error} - If there are insufficient permissions or not an Enterprise license (403)
     */
    update(variableId: number, variable: AddVariable): Promise<Variable>;
    /**
     * Deletes an existing variable.
     * @param variableId - The ID of the variable to be deleted
     * @throws {Error} - If the variable ID is invalid or missing (400)
     * @throws {Error} - If authentication fails (401)
     * @throws {Error} - If there are insufficient permissions or not an Enterprise license (403)
     */
    delete(variableId: number): Promise<void>;
}