From dbc7fce91d3b93c0634196c3e7feaad5a6566d07 Mon Sep 17 00:00:00 2001
From: Norbert Renner <norbert.renner@gmx.de>
Date: Thu, 28 Mar 2019 11:40:50 +0100
Subject: [PATCH] Persist layer selection with local storage (#146)

---
 js/LayersConfig.js      | 25 +++++++++++++++++++++++++
 js/control/LayersTab.js | 24 ++++++++++++++++++++++++
 2 files changed, 49 insertions(+)

diff --git a/js/LayersConfig.js b/js/LayersConfig.js
index 3826701..a710e29 100644
--- a/js/LayersConfig.js
+++ b/js/LayersConfig.js
@@ -18,6 +18,29 @@ BR.LayersConfig = L.Class.extend({
         this._addLeafletProvidersLayers();
 
         this._customizeLayers();
+
+        this.loadDefaultLayers();
+    },
+
+    loadDefaultLayers: function() {
+        if (BR.Util.localStorageAvailable()) {
+            var item = localStorage.getItem("map/defaultLayers");
+            if (item) {
+                var defaultLayers = JSON.parse(item);
+                this.defaultBaseLayers = defaultLayers.baseLayers;
+                this.defaultOverlays = defaultLayers.overlays;
+            }
+        }
+    },
+
+    storeDefaultLayers: function (baseLayers, overlays) {
+        if (BR.Util.localStorageAvailable()) {
+            var defaultLayers = {
+                baseLayers: baseLayers,
+                overlays: overlays
+            };
+            localStorage.setItem("map/defaultLayers", JSON.stringify(defaultLayers));
+        }
     },
 
     _addLeafletProvidersLayers: function () {
@@ -230,6 +253,8 @@ BR.LayersConfig = L.Class.extend({
         }
         layer.getAttribution = getAttribution;
 
+        layer.id = props.id;
+
         return layer;
     }
 });
diff --git a/js/control/LayersTab.js b/js/control/LayersTab.js
index be03d33..3f42c01 100644
--- a/js/control/LayersTab.js
+++ b/js/control/LayersTab.js
@@ -118,6 +118,8 @@ BR.LayersTab = L.Control.Layers.extend({
             } else {
                 this.addBaseLayer(layer, name);
             }
+
+            this.storeDefaultLayers();
         };
 
         var onUncheckNode = function (e, data) {
@@ -132,6 +134,8 @@ BR.LayersTab = L.Control.Layers.extend({
                     this.addFirstLayer();
                 }
             }
+
+            this.storeDefaultLayers();
         };
 
         $('#optional-layers-tree')
@@ -263,6 +267,26 @@ BR.LayersTab = L.Control.Layers.extend({
         return data;
     },
 
+    storeDefaultLayers: function () {
+        var baseLayers = [];
+        var overlays = [];
+
+        for (var i = 0; i < this._layers.length; i++) {
+            var obj = this._layers[i];
+            // id set in LayersConfig.createLayer
+            var id = obj.layer.id;
+            if (id) {
+                if (obj.overlay) {
+                    overlays.push(id);
+                } else {
+                    baseLayers.push(id);
+                }
+            }
+        }
+
+        this.layersConfig.storeDefaultLayers(baseLayers, overlays);
+    },
+
     addFirstLayer: function () {
         for (var i = 0; i < this._layers.length; i++) {
             var obj = this._layers[i];