//================================================================
/**
 * @packageDocumentation
 * @module std
 */
//================================================================
import { _Get_root } from "../internal/Global";

/**
 * Get unique identifier.
 *
 * @param obj Target object.
 * @return The identifier number.
 */
export function get_uid(obj: object | null | undefined): number {
    // NO UID EXISTS, THEN ISSUE ONE.
    if (obj instanceof Object) {
        if (obj.hasOwnProperty("__get_m_iUID") === false) {
            const uid: number = ++_Get_root().__s_iUID;
            Object.defineProperty(obj, "__get_m_iUID", {
                value: function (): number {
                    return uid;
                },
            });
        }

        // RETURNS
        return (obj as IObject).__get_m_iUID();
    } else if (obj === undefined) return -1;
    // is null
    else return 0;
}

interface IObject {
    readonly __get_m_iUID: () => number;
}