ui/widget/frontlightwidget: Add 'Configure' button

For devices with natural light (KA1, H2O2), add new button 'Configure'
at the bottom which will open the naturallightwidget, which will be
placed at the top. The frontlightwidget will be moved to the bottom,
and both have permanent focus. This way, you can change the parameters
and immediately test them by changing the frontlight level and
warmth. On the KA1, both widgets will easily fit, but on smaller
devices it may be that they overlap.

Since the frontlightwidget will keep focus, we disable the 'Configure'
button when the naturallightwidget opens. We also remove its 'Close'
button and disable 'onTapCloseFL', so that the frontlightwidget cannot
be closed while the naturallightwidget is displayed.

frontend/ui/widget/frontlightwidget.lua

@@ -11,6 +11,7 @@ local HorizontalGroup = require("ui/widget/horizontalgroup")
 local HorizontalSpan = require("ui/widget/horizontalspan")
 local InputContainer = require("ui/widget/container/inputcontainer")
 local LineWidget = require("ui/widget/linewidget")
+local NaturalLight = require("ui/widget/naturallightwidget")
 local OverlapGroup = require("ui/widget/overlapgroup")
 local Size = require("ui/size")
 local TextBoxWidget = require("ui/widget/textboxwidget")
@@ -27,6 +28,8 @@ local FrontLightWidget = InputContainer:new{
     title_face = Font:getFace("x_smalltfont"),
     width = nil,
     height = nil,
+    -- This should stay active during natural light configuration
+    is_always_active = true,
 }
 
 function FrontLightWidget:init()
@@ -243,8 +246,21 @@ function FrontLightWidget:setProgress(num, step, num_warmth)
     table.insert(vertical_group,button_group_down)
     table.insert(vertical_group,padding_span)
     if self.natural_light then
-        -- If the device supports natural light, add the widgets for 'warmth'.
+        -- If the device supports natural light, add the widgets for 'warmth'
+        -- and a 'Configure' button
         self:addWarmthWidgets(num_warmth, step, vertical_group)
+        self.configure_button =  Button:new{
+            text = _("Configure"),
+            margin = Size.margin.small,
+            radius = 0,
+            width = self.screen_width * 0.20,
+            enabled = not self.nl_configure_open,
+            show_parent = self,
+            callback = function()
+                UIManager:show(NaturalLight:new{fl_widget = self})
+            end,
+        }
+        table.insert(vertical_group, self.configure_button)
     end
     table.insert(self.fl_container, vertical_group)
     -- Reset container height to what it actually contains
@@ -455,8 +471,11 @@ function FrontLightWidget:onAnyKeyPressed()
 end
 
 function FrontLightWidget:onTapCloseFL(arg, ges_ev)
-    if ges_ev.pos:notIntersectWith(self.light_frame.dimen) then
-        self:onClose()
+    -- Do not close when natural light configuration is open
+    if not self.nl_configure_open then
+        if ges_ev.pos:notIntersectWith(self.light_frame.dimen) then
+            self:onClose()
+        end
     end
     return true
 end
@@ -466,4 +485,26 @@ function FrontLightWidget:onClose()
     return true
 end
 
+-- This is called when natural light configuration is shown
+function FrontLightWidget:naturalLightConfigOpen()
+    -- Remove the close button
+    table.remove(self.light_bar)
+    -- Disable the 'configure' button
+    self.configure_button:disable()
+    self.nl_configure_open = true
+    -- Move to the bottom to make place for the new widget
+    self[1].align="bottom"
+    UIManager:setDirty("all", "ui")
+end
+
+function FrontLightWidget:naturalLightConfigClose()
+    table.insert(self.light_bar,
+                 CloseButton:new{window = self,
+                                 padding_top = Size.margin.title})
+    self.configure_button:enable()
+    self.nl_configure_open = false
+    self[1].align="center"
+    UIManager:setDirty("all", "ui")
+end
+
 return FrontLightWidget