// noinspection ES6ConvertVarToLetConst
window.combos = (function (module){

    /**
     *
     * @param callBack - the function to debounce
     * @param interval - in ms
     * @param leadingExecution - if true, the execution happens before the interval
     * @returns {(function(): void)|*}
     */
    module.debounce = function (callBack, interval, leadingExecution = false) {

        // the schedule identifier, if it's not null/undefined, a callBack function was scheduled
        let timerId;

        return function () {

            // Does the previous run has schedule a run
            let wasFunctionScheduled = (typeof timerId === 'number');

            // Delete the previous run (if timerId is null, it does nothing)
            clearTimeout(timerId);

            // Capture the environment (this and argument) and wraps the callback function
            let funcToDebounceThis = this, funcToDebounceArgs = arguments;
            let funcToSchedule = function () {

                // Reset/delete the schedule
                clearTimeout(timerId);
                timerId = null;

                // trailing execution happens at the end of the interval
                if (!leadingExecution) {
                    // Call the original function with apply
                    callBack.apply(funcToDebounceThis, funcToDebounceArgs);
                }

            }

            // Schedule a new execution at each execution
            timerId = setTimeout(funcToSchedule, interval);

            // Leading execution
            if (!wasFunctionScheduled && leadingExecution) callBack.apply(funcToDebounceThis, funcToDebounceArgs);

        }

    }

    return module;
}(window.combos || {}));