Use map location form latitude, longitude and zoom when valid

When using an editable map is better to load marker latitude, longitude and
map zoom from form fields so we can show the marker at latest position defined
by user when the page was restored from browser history.

To reproduce this behavior:
0. Undo this commit
1. Go to new proposal page
2. Place the proposal map marker
3. Go away to any other page
4. Restore new proposal page from browser history.

At this point you should not see the recently placed marker.

The same thing happens when editing a proposal.

app/assets/javascripts/map.js

@@ -20,18 +20,36 @@
       App.Map.maps = [];
     },
     initializeMap: function(element) {
-      var addMarkerInvestments, clearFormfields, createMarker, editable, getPopupContent, latitudeInputSelector, longitudeInputSelector, map, mapAttribution, mapCenterLatLng, mapCenterLatitude, mapCenterLongitude, mapTilesProvider, marker, markerIcon, markerLatitude, markerLongitude, moveOrPlaceMarker, openMarkerPopup, removeMarker, removeMarkerSelector, updateFormfields, zoom, zoomInputSelector;
+      var addMarkerInvestments, clearFormfields, createMarker, editable, formCoordinates, getPopupContent,
+        latitudeInputSelector, longitudeInputSelector, map, mapAttribution, mapCenterLatLng,
+        mapCenterLatitude, mapCenterLongitude, mapTilesProvider, marker, markerIcon, markerLatitude,
+        markerLongitude, moveOrPlaceMarker, openMarkerPopup, removeMarker, removeMarkerSelector,
+        updateFormfields, zoom, zoomInputSelector;
       App.Map.cleanInvestmentCoordinates(element);
       mapCenterLatitude = $(element).data("map-center-latitude");
       mapCenterLongitude = $(element).data("map-center-longitude");
-      markerLatitude = $(element).data("marker-latitude");
-      markerLongitude = $(element).data("marker-longitude");
-      zoom = $(element).data("map-zoom");
       mapTilesProvider = $(element).data("map-tiles-provider");
       mapAttribution = $(element).data("map-tiles-provider-attribution");
       latitudeInputSelector = $(element).data("latitude-input-selector");
       longitudeInputSelector = $(element).data("longitude-input-selector");
       zoomInputSelector = $(element).data("zoom-input-selector");
+      formCoordinates = {
+        lat: $(latitudeInputSelector).val(),
+        long: $(longitudeInputSelector).val(),
+        zoom: $(zoomInputSelector).val()
+      };
+      if (App.Map.validCoordinates(formCoordinates)) {
+        markerLatitude = formCoordinates.lat;
+        markerLongitude = formCoordinates.long;
+      } else {
+        markerLatitude = $(element).data("marker-latitude");
+        markerLongitude = $(element).data("marker-longitude");
+      }
+      if (App.Map.validZoom(formCoordinates.zoom)) {
+        zoom = formCoordinates.zoom;
+      } else {
+        zoom = $(element).data("map-zoom");
+      }
       removeMarkerSelector = $(element).data("marker-remove-selector");
       addMarkerInvestments = $(element).data("marker-investments-coordinates");
       editable = $(element).data("marker-editable");
@@ -134,6 +152,9 @@
         $(element).attr("data-marker-investments-coordinates", clean_markers);
       }
     },
+    validZoom: function(zoom) {
+      return App.Map.isNumeric(zoom);
+    },
     validCoordinates: function(coordinates) {
       return App.Map.isNumeric(coordinates.lat) && App.Map.isNumeric(coordinates.long);
     },

spec/shared/system/mappable.rb

@@ -100,6 +100,40 @@ shared_examples "mappable" do |mappable_factory_name, mappable_association_name,
           expect(page).to have_css(".leaflet-map-pane", count: 1)
         end
       end
+
+      scenario "keeps marker and zoom defined by the user", :js do
+        do_login_for user
+        visit send(mappable_new_path, arguments)
+
+        within ".map_location" do
+          expect(page).not_to have_css(".map-icon")
+        end
+        expect(page.execute_script("return App.Map.maps[0].getZoom();")).to eq(10)
+
+        map_zoom_in
+        find("#new_map_location").click
+
+        within ".map_location" do
+          expect(page).to have_css(".map-icon")
+        end
+
+        if management
+          click_link "Select user"
+
+          expect(page).to have_content "User management"
+        else
+          click_link "Help"
+
+          expect(page).to have_content "CONSUL is a platform for citizen participation"
+        end
+
+        go_back
+
+        within ".map_location" do
+          expect(page).to have_css(".map-icon")
+          expect(page.execute_script("return App.Map.maps[0].getZoom();")).to eq(11)
+        end
+      end
     end
 
     scenario "Skip map", :js do
@@ -293,3 +327,11 @@ def set_arguments(arguments, mappable, mappable_path_arguments)
     arguments.merge!("#{argument_name}": mappable.send(path_to_value))
   end
 end
+
+def map_zoom_in
+  initial_zoom = page.execute_script("return App.Map.maps[0].getZoom();")
+  find(".leaflet-control-zoom-in").click
+  until page.execute_script("return App.Map.maps[0].getZoom() === #{initial_zoom + 1};") do
+    sleep 0.01
+  end
+end