Fix handling of view state and layers in URL hash

lib/www/client/source/src/views/Map.vue

@@ -1299,18 +1299,47 @@ export default {
         const [ view, layers, crosshairs ] = hash.split(":");
 
         if (view) {
-          const rx0 = /[xyzpb][+-]?[0-9]+\.?[0-9]*/g;
-          const rx1 = /([xyzpb])([+-]?[0-9]+\.?[0-9]*)/;
-
           const key = {x: "longitude", y: "latitude", z: "zoom", p: "pitch", b: "bearing"};
+          const entries = view
+            .split(/([xyzpb])/)
+            .filter( v => v.length )
+            .reduce( (acc, cur, idx) =>
+                (idx % 2 ? acc[acc.length-1].push(cur) : acc.push([cur]), acc), []
+            ).map( ([k, v]) => [ key[k], Number(v) ] )
+            .filter( ([k, v]) => k && !isNaN(v) );
+
+          this.viewState = Object.fromEntries(entries);
 
-          this.viewState = Object.fromEntries(view.match(rx0).map(i => i.match(rx1).slice(1, 3)).map(i => {i[0] = key[i[0]]; i[1] = Number(i[1]); return i}));
         }
 
         if (layers) {
-          const l = layers.split(";").filter(i => this.layersAvailable.hasOwnProperty(i));
+          const addLayers = [];
-          if (l.length) {
+          const remLayers = [];
-            this.layerSelection = l;
+          const invLayers = [];
+          const setLayers = [];
+
+          layers
+            .split(";")
+            .map( l => l.match(/([!+-])?(.+)/).slice(1) )
+            .forEach( ([ action, name ]) => {
+              if (this.layersAvailable.hasOwnProperty(name)) {
+                const groupKeys = {"+": addLayers, "-": remLayers, "!": invLayers};
+                const group = groupKeys[action] ?? setLayers;
+                group.push(name);
+              }
+            });
+
+          if (!addLayers.length && !remLayers.length && !invLayers.length && setLayers.length) {
+            // Set layers as per setLayers
+            this.layerSelection = [...setLayers];
+          } else {
+            // Otherwise, ignore setLayers and use the current layerset
+            const layerset = new Set(this.layerSelection);
+            addLayers.forEach( layer => layerset.add(layer) );
+            remLayers.forEach( layer => layerset.delete(layer) );
+            invLayers.forEach( layer =>
+              layerset.has(layer) ? layerset.delete(layer) : layerset.add(layer) );
+            this.layerSelection = [...layerset];
           }
         }