(function() {

'use strict';
console.log ('—-start—-');
xdx();
console.log ('—-end—-');

/* main
*/
function xdx() {

parseSortAndReplace(document);\\

}
END function xdx() /* get the select that has an id which ends with _id
* for each optgroup in it, for each option it in :
* - create a new option with “city + event” as key and HTML text
* - delete the original option inside the optgroup
* - store it in an array
* - sort the array by the keys
* - add the new option to the select
*
* for later : find a way to delete the optgroup within the select element
*/
function parseSortAndReplace(myDocument) { get select with id like _id

//console.log ('start parseSortAndReplace');\\

let nodesSnapshot = myDocument.evaluate(

  '//select[contains(@id,"_id")]' // warning : ends-with() is not available in XPath 1.0\\

, myDocument, null, XPathResult.ORDERED_NODE_SNAPSHOT_TYPE, null
);
let nbrSelects = nodesSnapshot.snapshotLength;

//console.log ('nbrSelects:'+nbrSelects);

if (1==nbrSelects) {\\
    const mySelect = nodesSnapshot.snapshotItem(0);\\
    const myChildrenCardinal = mySelect.childNodes.length;\\
    //console.log ('mySelect children cardinal: '+myChildrenCardinal);\\
    if (0!=myChildrenCardinal) {

        const myNewEventsList = new Array;\\
        //console.log (myNewEventsList);

        // for each optgroup\\
        //console.log ('Enter foreach optgroup loop');\\
        //for (let i=0; i<myChildrenCardinal ; i++) {\\
        for (let i=0; i<myChildrenCardinal ; i++) { // DEBUG\\
            let myOptGroup = mySelect.childNodes[i];\\
            //console.log('lala '+i);\\
                //console.log (myOptGroup);\\
            if ( (undefined!=myOptGroup) && ('OPTGROUP'==myOptGroup.tagName)) {\\
                let myCategory = myOptGroup.getAttribute('label');\\
                //console.log ('---category:'+myCategory);\\
                let myEventsCardinal = myOptGroup.childNodes.length;\\
                //console.log ('size:'+myEventsCardinal);\\
                // for each option in optgroup\\
                for (let j=0 ; j<myEventsCardinal ; j++) {\\
                    let myEvent = myOptGroup.childNodes[j];\\
                    if ((undefined!=myEvent) && ('OPTION'==myEvent.tagName)) {\\
                        let myValue = myEvent.getAttribute('value');\\
                        let myCity  = myEvent.innerHTML;\\
                        //console.log (myCity + '/' + myCategory + '/'+ myValue );\\
                        // create new OPTION\\
                        let myOption = myDocument.createElement('option');\\
                            myOption.setAttribute ('value',myValue);\\
                            myOption.appendChild  (myDocument.createTextNode(myCity + ': '+ myCategory));\\
                        // store as city / optgroup / value into an array\\
                        let myObject = {\\
                              key   : myCity+'¤'+myCategory\\
                            , htmlOpt: myOption\\
                        };\\
                        //console.log (myObject);\\
                        myNewEventsList.push (myObject);\\
                        // delete the option in the optgroup\\
                        myEvent.parentNode.removeChild (myEvent); // until I find a way to delete the original categories\\
                    }\\
                    // END IF\\
                }\\
                // END FOR myEventsCardinal

                // delete the optgroup\\
                //myOptGroup.parentNode.removeChild(myOptGroup);\\
                //mySelect.childNodes[i].parentNode.removeChild (mySelect.childNodes[i]);\\
            }\\
            // END IF\\
        }\\
        // END FOR myChildrenCardinal\\
        //console.log ('before sort');\\
        //console.log (myNewEventsList);

        // sort the list\\
        myNewEventsList.sort(function(a,b) {\\
            const keyA = a.key.toUpperCase();\\
            const keyB = b.key.toUpperCase();\\
            if        (keyA < keyB) { return  1;\\
            } else if (keyA > keyB) { return -1;\\
            } else                  { return  0;\\
            }\\
            // END IF\\
        });\\
        // END SORT

        //console.log ('after sort');\\
        //console.log (myNewEventsList);\\
        //console.log (myNewEventsList.length);

        // for each item in list, add to select\\
        myNewEventsList.forEach( function(myObject2) {\\
            //console.log (myObject2.htmlOpt);\\
            //mySelect.appendChild(myObject2.htmlOpt);\\
            mySelect.insertBefore(myObject2.htmlOpt,mySelect.firstChild); // until I find a way to delete the original categories in the select\\
        });\\
        // END foreach\\
    }\\
    // END if (0!=myChildrenCardinal)\\
}\\
// END if (1==nbrSelects)\\

}
END function parseSortAndReplace(myDocument) })();