source: main/trunk/greenstone3/web/interfaces/default/js/map-scripts-editor.js@ 33102

// Global autocomplete labels list: one list for all the map editors' shape labels in a page
// We use the global labels hashmap to more efficiently ensure uniqueness of labels in our autocomplete list
var global_autocompleteLabelsList = [];
var global_labels_hashmap = {};

function MapEditor(id) {
    // TODO: investigate const, see https://www.w3schools.com/js/js_const.asp and check it will work on older browsers,
    // https://stackoverflow.com/questions/4271566/how-do-i-know-which-version-of-javascript-im-using
    this.MAX_THICKNESS = 5.0; 
    this.MIN_THICKNESS = 0.0;   
    this.MAX_OPACITY = 100.00; 
    this.MIN_OPACITY = 0.00;

    // WORK-IN-PROGRESS FEATURE: label on Map (to be changed to a label associated with each shape later)
    // Also uncomment import of label-overlay-class.js in document.xsl
    //this.labelOverlay = null;
    
    
    this.id = id;
    this.shiftKeyPressed = false;
    this.beingDragged = false;
    this.allowDeselect = true;
    this.colors = ['#1E90FF', '#FF1493', '#4B0082', '#32CD32', '#FF8C00', '#000000'];
    this.selectedColor;
    this.colorButtons = {};
    this.thicknessValue = 1;
    this.opacityValue = 40;
    this.overlays = [];
    this.selectedShapes = [];
    this.listenersArray = [];
    this.mapsArray = [];
    this.drawingManager;
    this.selectedShape;
    this.savedOverlays = null;
    this.map = null;
    this.counter = 0;
    this.branchNum = 1;
    this.mouseState = "up";
    this.thicknessRangeListener = this.thicknessValue; // ????
    this.resizable = false;
    this.dontResize = false;

    this.shapeOptions = {
        suppressUndo: true,
        fillColor: '#CA4A2F',
        strokeWeight: this.thicknessValue,
        fillOpacity: this.opacityValue / 100,
        editable: true,
        geodesic: false,
        draggable: true,
        description: ""
    };
    this.mapEditorHistory = new MapEditorHistory(this);
}

//draggable checkbox control
MapEditor.prototype.initMapEditorControls = function () {
    var that = this;

    var draggableCB = document.getElementById("draggableCB-"+ this.id);
    draggableCB.addEventListener('change', function () {
        if (this.checked) {
            for (var i = 0; i < that.overlays.length; i++) {
                that.overlays[i].draggable = false;
                that.shapeOptions.draggable = false;
            }
        } else {
            for (var i = 0; i < that.overlays.length; i++) {
                that.overlays[i].draggable = true;
                that.shapeOptions.draggable = true;
            }
        }
    });
    
    
    //Update thickness
    var thicknessSliderOutput = document.getElementById("thicknessRangeVal" + "-" + this.id);
    var thicknessSlider = document.getElementById("thicknessRange" + "-" + this.id);
    var thicknessValue = ((thicknessSlider.value / 20) * 100) / 100;
    thicknessSliderOutput.value = thicknessValue.toFixed(2);

    thicknessSlider.oninput = function () {
        that.shapeSpecsChangeMD();
        var thicknessVal = ((this.value / 20) * 100) / 100;
        thicknessSliderOutput.value = thicknessVal.toFixed(2);
        that.thicknessValue = this.value / 20;
        that.shapeOptions.strokeWeight = that.thicknessValue;
        that.setSelectedThickness(that.thicknessValue);
    }
        
    thicknessSliderOutput.oninput = function () {
        that.shapeSpecsChangeMD(); // TODO: DO WE NEED THIS LINE? (LINE COPIED & PASTED FROM ABOVE)
        if(this.value > that.MAX_THICKNESS) this.value = that.MAX_THICKNESS;
        if(this.value < that.MIN_THICKNESS) this.value = that.MIN_THICKNESS;
        var thicknessVal = this.value * 20;
        thicknessSlider.value = thicknessVal.toFixed(2);
        that.thicknessValue = this.value;
        that.shapeOptions.strokeWeight = that.thicknessValue;
        that.setSelectedThickness(that.thicknessValue);
    }
    //Update opacity
    // TODO: https://stackoverflow.com/questions/469357/html-text-input-allow-only-numeric-input?utm_medium=organic&utm_source=google_rich_qa&utm_campaign=google_rich_qa
    var opacitySlider = document.getElementById("colourOpacity" + "-" + this.id);
    var opacitySliderOutput = document.getElementById("opacityRangeVal" + "-" + this.id);
    
    opacitySlider.oninput = function () {
        that.shapeSpecsChangeMD();
        opacitySliderOutput.value = this.value;
        that.opacityValue = this.value / 100;
        that.shapeOptions.fillOpacity = that.opacityValue;
        that.setSelectedOpacity(that.opacityValue);
    }
    opacitySliderOutput.oninput = function () {
        that.shapeSpecsChangeOnInput();
        if(this.value > that.MAX_OPACITY) this.value = that.MAX_OPACITY;
        if(this.value < that.MIN_OPACITY) this.value = that.MIN_OPACITY;
        opacitySlider.value = this.value;
        that.opacityValue = this.value / 100;
        that.shapeOptions.fillOpacity = that.opacityValue;
        that.setSelectedOpacity(that.opacityValue);
    }
    
    var descriptionInput = document.getElementById("description" + "-" + this.id);
    // don't use oninput, use onchange, because with autocomplete a newly entered or pasted value
    // doesn't always get stored properly when using oninput.
    descriptionInput.onchange = function () {       
        that.shapeSpecsChangeOnInput(); // takes care of history (undo/redo)        
        var description = this.value;
        that.shapeOptions.description = description;        
        that.setSelectedDescription(that.shapeOptions.description);        
    }

    // Also add a COMPLETED description (i.e. when description input box loses focus)
    // to the autocomplete list of descriptions/labels
    descriptionInput.onblur = function () {
        var description = this.value;
        that.addToAutocompleteLabelsList(description);
    }
    
    // TODO: Do we need these listeners, when we already have onInput methods above? Test.
    document.getElementById("color-palette1" + "-" + this.id).addEventListener("mousedown", function() { that.shapeSpecsChangeMD() });
    document.getElementById("thicknessRange" + "-" + this.id).addEventListener("mouseup", function () { that.shapeSpecsChangeMU() });
    document.getElementById("colourOpacity" + "-" + this.id).addEventListener("mouseup", function () { that.shapeSpecsChangeMU() });
    //document.getElementById("description" + "-" + this.id).addEventListener("keypress", function () { that.shapeSpecsChangeOnInput() });

    document.onmousedown = function (ev) {
        that.mouseState = "down";
        //    console.log('Down State you can now start dragging');
        //do not write any code here in this function
    }

    document.onmouseup = function (ev) {
        that.mouseState = "up";
        //    console.log('up state you cannot drag now because you are not holding your mouse')
        //do not write any code here in this function
    }
    
    
    //prompts the user to save the changes before reloading/leaving the page
    window.onbeforeunload = function (e) {
        var currentOverlays = JSON.stringify(ShapesUtil.overlayToJSON(that.overlays));
        var enableMessage = currentOverlays !== that.savedOverlays;
        var message = "Changes are not saved. Are you sure you want to leave?";

        
        // Comment out following section in entirety -- from "e = e || window.event" to end of "if(e)" -- if
        // you don't want to see the popup about changes that haven't been saved yet
        e = e || window.event;
        // For IE and Firefox
        if (e) {
            
            if(enableMessage){
                if(currentOverlays !== "[]") {
                    alert(message);
                    e.returnValue = message;
                    
                    // For Safari
                    return message; 
                }
            }
        }
    }
}

// Ensure only unique labels are added to our autocomplete list
MapEditor.prototype.addToAutocompleteLabelsList = function (newLabel) {

    // We use a hashmap to more efficiently ensure uniqueness of labels in our array
    // https://stackoverflow.com/questions/11040472/how-to-check-if-object-property-exists-with-a-variable-holding-the-property-name
    if (newLabel !== "" && !global_labels_hashmap.hasOwnProperty(newLabel)) { // label is not empty and unique, so
        // add to hashmap now
        global_labels_hashmap[newLabel] = 1;
        // add to autocomplete list and sort alphabetically
        global_autocompleteLabelsList.push(newLabel);
        global_autocompleteLabelsList.sort();
    }
}

MapEditor.prototype.settingThePath = function () {
    var that = this;
    this.listenersArray = []
    this.counter = 0;
    this.branchNum = 1;
    
    for (var i = 0; i < this.selectedShapes.length * 2; i++) {
        for (var j = 1; j < 6; j++) {
            var path = "//*[@id='map-" + this.id + "']/div/div/div[1]/div[3]/div/div[3]/div[" + this.branchNum + "]/div[" + j + "]/div";
            this.listenersArray[this.counter] = this.getElementByXpath(path);
            if (this.listenersArray[this.counter] !== (undefined || null)) {
                this.listenersArray[this.counter].addEventListener("mousemove", function () {
                    that.resizable = true;
                    that.shapeResize();
                });
                this.listenersArray[this.counter].addEventListener("mouseout", function () {
                    if (this.mouseDown) {
                        that.resizable = true;
                        that.shapeResize();
                        
                    }
                });
            }
            this.counter++;
        }
        this.branchNum++;
    }
}

MapEditor.prototype.shapeResize = function () {
    if (this.mouseState == "down") {
        if (this.selectedShapes.length > 0) {
            if (this.resizable) {
                if (this.dontResize == false) {
                    this.mapEditorHistory.historyOverlayPush();
                }

            }
        }
    }
}

MapEditor.prototype.shapeSpecsChangeMD = function () {
    if (this.selectedShapes.length > 0) {
        this.mapEditorHistory.historyOverlayPush();
    }
}

MapEditor.prototype.shapeSpecsChangeMU = function () {
    if (this.selectedShapes.length > 0) {
        this.mapEditorHistory.presentOverlayPush();
    }
}

MapEditor.prototype.shapeSpecsChangeOnInput = function () {
    if (this.selectedShapes.length > 0) {
        this.mapEditorHistory.presentOverlayPush();
    }
}

MapEditor.prototype.makeColorButton = function (color) {
    var that = this;

    var button = document.createElement('span');
    button.className = 'color-buttons1';
    button.style.backgroundColor = color;
    google.maps.event.addDomListener(button, 'click', function () {
        that.selectColor(color);
        that.setSelectedShapeColor(color);
        that.shapeSpecsChangeMU();
    });
    return button;
}

MapEditor.prototype.buildColorPalette = function () {
    var colorPalette = document.getElementById("color-palette1" + "-" + this.id);
    for (var i = 0; i < this.colors.length; ++i) {
        var currColor = this.colors[i];
        var colorButton = this.makeColorButton(currColor);
        colorPalette.appendChild(colorButton);
        this.colorButtons[currColor] = colorButton;
    }
    this.selectColor(this.colors[0]);
};

MapEditor.prototype.selectColor = function (color) {
    this.selectedColor = color;
    for (var i = 0; i < this.colors.length; ++i) {
        var currColor = this.colors[i];
        this.colorButtons[currColor].style.border = currColor == color ? '2px solid #789' : '2px solid #fff';
    }

    // Retrieves the current options from the drawing manager and replaces the
    // stroke or fill color as appropriate.
    var polylineOptions = this.drawingManager.get('polylineOptions');
    polylineOptions.strokeColor = color;
    this.drawingManager.set('polylineOptions', polylineOptions);

    var rectangleOptions = this.drawingManager.get('rectangleOptions');
    rectangleOptions.fillColor = color;
    this.drawingManager.set('rectangleOptions', rectangleOptions);

    var circleOptions = this.drawingManager.get('circleOptions');
    circleOptions.fillColor = color;
    this.drawingManager.set('circleOptions', circleOptions);

    var polygonOptions = this.drawingManager.get('polygonOptions');
    polygonOptions.fillColor = color;
    this.drawingManager.set('polygonOptions', polygonOptions);
}

MapEditor.prototype.initMapEditor = function () {
    var that = this;

    this.map = new google.maps.Map(document.getElementById("map-" + this.id), {
            center: {
                lat: -37.7891,
                lng: 175.3180
            },
            zoom: 14,
            mapId: this.id,
        });
    
    // WORK-IN-PROGRESS FEATURE: label on Map (to be changed to a label associated with each shape later)
    // let's associate a label with the map (for now, later associate labels for each shape)
    //this.labelOverlay = new LabelOverlay(this.map);       
        
    this.mapsArray.push(this.map);
    // Add a style-selector control to the map.
    var styleControl = document.getElementById('style-selector-control' + "-" + this.id);
    this.map.controls[google.maps.ControlPosition.TOP_RIGHT].push(styleControl);

    /* 
    // Set the map's style to the initial value of the selector.
    var styleSelector = document.getElementById('style-selector' + "-" + this.id);
    //console.log(styleSelector);
    //map = google.maps.Map(document.getElementById('map' +"-"+ this.id));
    this.map.setOptions({
        styles: styles[styleSelector.value]

    });

    // Apply new JSON when the user selects a different style.
    styleSelector.addEventListener('change', function () {
        that.map.setOptions({
            styles: styles[styleSelector.value]
        });
    });
    */

    this.drawingManager = new google.maps.drawing.DrawingManager({
            //drawingMode: google.maps.drawing.OverlayType.RECTANGLE,
            drawingControl: true,
            drawingControlOptions: {
                position: google.maps.ControlPosition.TOP_CENTER,
                drawingModes: ['marker', 'circle', 'polygon', 'polyline', 'rectangle']
            },
            markerOptions: {
                draggable: true
            },
            circleOptions: this.shapeOptions,
            polylineOptions: this.shapeOptions,
            polygonOptions: this.shapeOptions,
            rectangleOptions: this.shapeOptions,
        });

    this.drawingManager.setMap(this.map);

    google.maps.event.addListener(this.drawingManager, "drawingmode_changed", function () {
        if (that.shiftKeyPressed != true && that.drawingManager.drawingMode !== null) {
            that.deselectAll();
        }
        that.settingThePath();

    })

    // store reference to added overlay
    google.maps.event.addListener(this.drawingManager, 'overlaycomplete', function (e) {
        that.allowDeselect = true;
        that.mapEditorHistory.historyOverlayPush();
        that.overlays.push(e.overlay); // store reference to added overlay
        var newShape = e.overlay;
        newShape.type = e.type;     
        that.mapEditorHistory.presentOverlayPush();
        
        if (e.type !== google.maps.drawing.OverlayType.MARKER) {
            that.addShapeListeners(newShape, e);
            that.setSelection(newShape, e);
        } else {
            that.addMarkerListeners(newShape, e);
            that.setSelection(newShape, e);
        }   
    });

    //Clears selection if clicked on the map when shift is not presseed
    google.maps.event.addListener(this.map, 'click', function (e) {
        var c = document.body.childNodes;
        if (e.target && e.target.matches("a.classA")) {
            console.log("Anchor element clicked!");
        }
        if (that.shiftKeyPressed == false) {
            that.clearSelection();
            that.selectedShape = null;
        }
    });

    google.maps.event.addListener(this.map, 'mousedown', function (e) {
        that.dontResize = true;
    });

    google.maps.event.addListener(this.map, 'mouseup', function (e) {
        that.dontResize = false;
    });

    //Keyboard shortcuts            
    var mapAndControls = document.getElementById("map-and-controls-" + this.id);
    var thicknessField = document.getElementById ("thicknessRangeVal-" + this.id);
    var opacityField = document.getElementById ("opacityRangeVal-" + this.id);
    var openMapFunction = function() {
        //Sets shift as unpressed
        mapAndControls.addEventListener('keyup', function (event) {     
            if (event.keyCode == '16') {
                that.shiftKeyPressed = false;
            }
        });
        
        mapAndControls.addEventListener('keydown', function (event) { 

            // https://stackoverflow.com/questions/2220196/how-to-decode-character-pressed-from-jquerys-keydowns-event-handler  
            var keyCode = String.fromCharCode(event.which);
            //console.log("Key pressed: " + keyCode);
    
            //disable keyboard shortcut within the number input field
            var activeElement = $(document.activeElement);
            if(activeElement.attr('type') == 'number' || activeElement.attr('type') == 'text'){
                //console.log('number detected')
                return;
            }
            //Sets shift as pressed
            if (event.keyCode == '16') {
                that.shiftKeyPressed = true;
            }
            else if (keyCode == 'Y' && (event.ctrlKey || event.metaKey)) {
                that.mapEditorHistory.redo();
            }
            else if (keyCode == 'Z' && (event.ctrlKey || event.metaKey) ) {
                if (that.shiftKeyPressed == false) {
                that.mapEditorHistory.undo();
                }   
            }
            else if (keyCode == 'A' && (event.ctrlKey || event.metaKey)) {
                event.preventDefault();
                that.drawingManager.setDrawingMode(null);
                that.selectAll();       
            }
            else if (keyCode == 'D' && (event.ctrlKey || event.metaKey)) {
                event.preventDefault();
                that.deselectAll();
            }
            
            else if (keyCode == '0' || keyCode == 'À' || (keyCode == 'G'&& (event.ctrlKey || event.metaKey))) {
                event.preventDefault(); 
                that.drawingManager.setDrawingMode(null);
            } else if (keyCode == '1') {
                that.drawingManager.setDrawingMode('marker');
            } else if (keyCode == '2') {
                that.drawingManager.setDrawingMode('circle');
            } else if (keyCode == '3') {
                that.drawingManager.setDrawingMode('polygon');
            } else if (keyCode == '4') {
                that.drawingManager.setDrawingMode('polyline');
            } else if (keyCode == '5') {
                that.drawingManager.setDrawingMode('rectangle');
            } 
            
            //else if (keyCode == 'S') {
            //  that.saveToArchives();  
            //} 
            else if (keyCode == 'Q') { // for debugging information, press Q (easy to hit key)
                that.printHistory();
            }
            else if (keyCode == '.') {
                that.deleteSelectedShapes();
            }
    //                                  console.log(keyCode);
        });
    };
    
    openMapFunction();

    this.buildColorPalette();
    
    
    var collection = gs.cgiParams.c;
    var site_name = gs.xsltParams.site_name;
    var nodeID = this.id; // documentID, hopefully contains section ID too
    var metaname = gps_metadata_name;
        
    // collection, site, documentID, metadataName, metadataPosition, responseFunction
    gs.functions.getArchivesMetadata(collection, site_name, nodeID, metaname, 0, function(responseText){
            // responseText is of type GSMetadata
            
            // called when data has been retrieved from archives
            var JSONString = responseText.getValue();
            if(JSONString !== "")
            {
                that.LOAD(JSONString, nodeID);
                that.savedOverlays = JSONString;
            }
        }
    ); // responseFunctions are now in the setMeta calls
}

//Deletes a vertex if clicked on it
MapEditor.prototype.vertexAndPolyDel = function (e, newShape) {
    var vertex = e.vertex;
    if (e.vertex !== undefined) {
        if (newShape.type === google.maps.drawing.OverlayType.POLYGON) {
            var path = newShape.getPaths().getAt(e.path);
            path.removeAt(e.vertex);
            if (path.length < 3) {
                newShape.setMap(null);
            }
        }
        if (newShape.type === google.maps.drawing.OverlayType.POLYLINE) {
            var path = newShape.getPath();
            path.removeAt(e.vertex);
            if (path.length < 2) {
                newShape.setMap(null);
            }
        }
    }
}

MapEditor.prototype.addMarkerListeners = function (newShape, e) {
    var that = this;
    //Click event if a marker is created
    google.maps.event.addListener(newShape, 'click', function (e) {
        if(that.shiftKeyPressed){
            
        } else {
            that.mapEditorHistory.historyOverlayPush();
            newShape.setMap(null);
            that.mapEditorHistory.presentOverlayPush();         
        }

    });

    google.maps.event.addListener(newShape, 'dragstart', function (e) {
        that.beingDragged = true;
        that.mapEditorHistory.historyOverlayPush();

    });

    google.maps.event.addListener(newShape, 'dragend', function () {
        that.beingDragged = false;
        that.mapEditorHistory.presentOverlayPush();
        that.allowDeselect = false;
    });
}

MapEditor.prototype.addShapeListeners = function (newShape, e) {
    var that = this;
    // Add an event listener that selects the newly-drawn shape when the user
    // mouses down on it.
    google.maps.event.addListener(newShape, 'click', function (e) {
        that.vertexAndPolyDel(e, newShape);
    });

    google.maps.event.addListener(newShape, 'dragstart', function (e) {
        that.allowDeselect = false;
        that.mapEditorHistory.historyOverlayPush();
    });

    google.maps.event.addListener(newShape, 'dragend', function () {
        that.beingDragged = false;
        that.mapEditorHistory.presentOverlayPush();
        that.settingThePath();

        that.allowDeselect = false;
        that.setSelection(newShape, e);
    });

    //Store information after the event ends
    google.maps.event.addListener(newShape, 'bounds_changed', function (e) {
        if (that.beingDragged == false) {
            that.mapEditorHistory.presentOverlayPush();
        }
    });

    //Add an event listener to select a shape if the mouse hovers over it
    google.maps.event.addListener(newShape, 'mousedown', function (e) {
        if (e.target && e.target.matches("a.classA")) {
            console.log("Anchor element clicked!");
        }
        if (e.vertex !== undefined || e.edge !== undefined) {
            that.mapEditorHistory.historyOverlayPush()
        }
        if (that.drawingManager.drawingMode == null) {
            that.setSelection(newShape, e);
        }
    });

    google.maps.event.addListener(newShape, 'mouseup', function (e) {
        if (e.vertex !== undefined || e.edge !== undefined) {
            that.mapEditorHistory.presentOverlayPush()
        } else {
            //that.setSelection(newShape, e);
        }

    });
}
MapEditor.prototype.clearSelection = function () {
    if (this.selectedShape) {
        if (this.shiftKeyPressed == false) {
            for (var i = 0; i < this.selectedShapes.length; i++) {
                if(this.selectedShapes[i].type !== 'marker') {
                    this.selectedShapes[i].setEditable(false);                      
                }
            }
            this.selectedShapes = [];
        }
        this.selectedShape = null;
    }
}

//Set selection for the selected overlay
MapEditor.prototype.setSelection = function (shape, e) {
    //var that = this;
    if (shape.type !== 'marker') {
        if (this.shiftKeyPressed == false) {
            if (e !== null) {
                if (e.vertex == undefined) {
                    if (e.edge == undefined) {
                        this.clearSelection();
                        shape.setEditable(true);
                    }
                }
            }
        }
        if (this.selectedShapes.includes(shape)) {
            if (e !== null) {
                if (e.vertex == undefined) {
                    if (e.edge == undefined) {
                        this.allowDeselect = true;
                        this.removeFromSelectedShapes(shape);
                    }
                }
            }
        } else {
            this.allowDeselect = false;
            shape.setEditable(true);
            this.selectedShapes.push(shape);
        }

        //Send the values to be updated
        var thi = shape.strokeWeight;
        var opa = shape.fillOpacity;        
        var fCol = shape.fillColor;
        var sCol = shape.strokeColor;
        var description = shape.description;
        this.updateMenuValues(thi, opa, fCol, sCol, description);

    } else if (shape.type == 'marker') {
        this.allowDeselect = false;
        this.selectedShapes.push(shape);
    }
    this.selectedShape = shape;
    this.settingThePath();
}

MapEditor.prototype.removeFromSelectedShapes = function (shape) {
    if (this.selectedShapes.includes(shape)) {
        if (this.allowDeselect) {
            const index = this.selectedShapes.indexOf(shape);
            this.selectedShapes.splice(index, 1);
            shape.setEditable(false);
        }
        this.allowDeselect = true;
    }
}

//Set selected label
MapEditor.prototype.setSelectedDescription = function (label) {
    if (this.selectedShapes.length > 0) {
        for (var i = 0; i < this.selectedShapes.length; i++) {
            this.selectedShapes[i].set('description', label); //SAME: this.selectedShapes[i].description = label;            
        }
    }
}

//Set selected thickness
MapEditor.prototype.setSelectedThickness = function (sWeight) {
    if (this.selectedShapes.length > 0) {
        for (var i = 0; i < this.selectedShapes.length; i++) {
            this.selectedShapes[i].set('strokeWeight', sWeight);
        }
    }
}

//Set selected opacity
MapEditor.prototype.setSelectedOpacity = function (fOpacity) {

    if (this.selectedShapes.length > 0) {
        for (var i = 0; i < this.selectedShapes.length; i++) {
            this.selectedShapes[i].set('fillOpacity', fOpacity);
        }
    }
}

//set selected fill colour
MapEditor.prototype.setSelectedShapeColor = function (color) {
    if (this.selectedShapes.length > 0) {
        for (var i = 0; i < this.selectedShapes.length; i++) {
            this.selectedShapes[i].set('fillColor', color);
            this.selectedShapes[i].set('strokeColor', color);
        }
    }
}

MapEditor.prototype.getElementByXpath = function (path) {
    return document.evaluate(path, document, null, XPathResult.FIRST_ORDERED_NODE_TYPE, null).singleNodeValue;
}

MapEditor.prototype.updateMenuValues = function (thi, opa, fCol, sCol, description) {   
    //Update thickness slider and value on the settings menu
    var thicknessSliderOutput = document.getElementById("thicknessRangeVal" + "-" + this.id);
    // update the thickness innerHTML's value to always have 2 decimal places, https://www.w3schools.com/js/js_number_methods.asp   
    thi = parseFloat(thi); //Ensure the thi is a number
    thicknessSliderOutput.value = thi.toFixed(2); 
    document.getElementById("thicknessRange" + "-" + this.id).value = Math.round((thi * 20) * 100) / 100;

    //Update the opacity slider and value on the settings menu
    var opacitySliderOutput = document.getElementById("opacityRangeVal" + "-" + this.id);
    opacitySliderOutput.value = opa * 100;
    document.getElementById("colourOpacity" + "-" + this.id).value = opa * 100;

    // Show the description in the description field
    var descriptionInput = document.getElementById("description" + "-" + this.id);
    descriptionInput.value = description;

    if (this.drawingManager.drawingMode == null) {
        this.selectColor(fCol);
    }
}
MapEditor.prototype.selectAll = function () {
    this.shiftKeyPressed = true;
    var e = new Object();
    e.vertex = undefined;
    this.selectedShapes = [];
    for (var i = 0; i < this.overlays.length; i++) {
        this.setSelection(this.overlays[i], e);
    }
    this.shiftKeyPressed = false;
}
MapEditor.prototype.deselectAll = function () {
    for (var i = 0; i < this.selectedShapes.length; i++) {
        if (this.selectedShapes[i].type !== google.maps.drawing.OverlayType.MARKER) {
            this.selectedShapes[i].setEditable(false);
        }
        
    }
    this.selectedShapes = [];
}

// event handler for s being pressed *when map editor has the focus*
// For saving and rebuilding, see map_scripts
MapEditor.prototype.saveToArchives = function () {
    var that = this;
    console.log("Save pressed");
    
    var json_overlays = JSON.stringify(ShapesUtil.overlayToJSON(this.overlays));    
    that.savedOverlays = json_overlays; // save the old version to compare with future changes
    var collection = gs.cgiParams.c;
    var site_name = gs.xsltParams.site_name;
    var nodeID = this.id; // documentID, hopefully contains section ID too
    var metaname = "GPS.mapOverlay";
    
    // collection, site, documentID, metadataName, metadataPosition, metadataValue, prevMetadataValue, metamode, responseFunction   
    gs.functions.setArchivesMetadata(collection, site_name, nodeID, metaname, 0, json_overlays, null, "override", function(){
            console.log("SAVED");
        }
    );  
}

// TODO: When finished testing, can remove this debug function that just prints to console
MapEditor.prototype.printHistory = function () {
    console.log("prev", this.mapEditorHistory.prevOverlays);
    console.log("present ", this.mapEditorHistory.presentOverlays);
    console.log("undone ", this.mapEditorHistory.undoneOverlays);
    console.log("@@@@ allShapes: ", this.overlays);
    console.log("@@@@ selectedShapes: ", this.selectedShapes);
}

// to be called after reading back in stored JSON from archives meta
MapEditor.prototype.LOAD = function (json_str, nodeID) {
    this.mapEditorHistory.historyOverlayPush();

    // This seems to convert the map_store object into an array and forces array index access, instead of convenient property access using nodeID   
    //Object.values(gsmap_store)[0]; // Always gets top level section's map-editor, not what we want.
    
    // Get the map editor for the nodeID, as we're asked to load that editor
    var map_editor = gsmap_store["map-"+nodeID];
    
    var new_overlays = ShapesUtil.JSONToOverlays(json_str);
    for (var i=0; i<map_editor.overlays.length; i++) {
        map_editor.overlays[i].setMap(null);
    }
    
    map_editor.overlays = new_overlays;

    for (var i=0; i<map_editor.overlays.length; i++) {
        var shape = map_editor.overlays[i];

        // set up the autocomplete list using saved labels/descriptions
        map_editor.addToAutocompleteLabelsList(shape.description); // now efficiently ensures uniqueness of values using (hash)map
        
        // make the shapes selectable on load:
        if (ShapesUtil.overlayItemIsShape(shape)) {
            map_editor.addShapeListeners(shape, null); // don't have an overlay event!
        } else {
            map_editor.addMarkerListeners(shape, null); // don't have an overlay event!
        }
        shape.setMap(map_editor.map);
    }

    this.mapEditorHistory.presentOverlayPush();
}

MapEditor.prototype.deleteSelectedShapes = function () {
    if(this.selectedShapes.length !== 0) {
        this.mapEditorHistory.historyOverlayPush();
        for (var i = 0; i < this.selectedShapes.length; i++) {
            this.selectedShapes[i].setMap(null);

            if (this.overlays.includes(this.selectedShapes[i])) {
                const index = this.overlays.indexOf(this.selectedShapes[i]);
                this.overlays.splice(index, 1);
//              this.selectedShapes[i].setEditable(false);
            }
        }
        this.selectedShapes = [];
        this.mapEditorHistory.presentOverlayPush();     
    }
}

MapEditor.prototype.draggableState = function () {
    
    var draggableCB = document.querySelector("input[name=draggableCB]");
    draggableCB.addEventListener('change', function () {
        if (this.checked) {
            this.overlays.draggable = false;
        } else {
            this.overlays.draggable = false;
        }
    });
}

MapEditor.prototype.deleteAllShapes = function () {
    if(this.overlays.length !== 0) {
        //console.log("deleteAllShape() this.id = " + this.id);
        this.mapEditorHistory.historyOverlayPush();
        for (var i = 0; i < this.overlays.length; i++) {
            this.overlays[i].setMap(null);
        }
        this.overlays = [];
        this.mapEditorHistory.presentOverlayPush();
    }
}

// Global function that uses jquery to set the autocomplete list's data source to whatever's in our global autocomplete labels array
$(function setupAutocompleteLabelsList() {
    // Overrides the default autocomplete filter function to
    // search only from the beginning of the string
    //resource: https://miroslavpopovic.com/posts/2012/06/jqueryui-autocomplete-filter-words-starting-with-term
    $.ui.autocomplete.filter = function (array, term) {
        var matcher = new RegExp("^" + $.ui.autocomplete.escapeRegex(term), "i");
        return $.grep(array, function (value) {
            return matcher.test(value.label || value.value || value);
        });
    };

    $(".description").autocomplete({
        source: global_autocompleteLabelsList
    });
});