[fractal] fractal-gtk: Reduce margins when leaflet is folded

[Daniel Garcia Moreno <danigm src gnome org>]

commit f96d72654ac5ad43e070ad38f980ac2979c155ff
Author: Christopher Davis <brainblasted disroot org>
Date:   Fri Apr 19 02:52:18 2019 -0400

    fractal-gtk: Reduce margins when leaflet is folded
    
    Our current margins are a little too big for a mobile screen.
    So, we reduce them to 6px when we detect that the app is
    folded with HdyLeaflet.
    
    Closes https://gitlab.gnome.org/GNOME/fractal/issues/480

 fractal-gtk/res/app.css    | 12 ++++++++++++
 fractal-gtk/src/app/mod.rs | 34 ++++++++++++++++++++++++++++++++++
 2 files changed, 46 insertions(+)
---
diff --git a/fractal-gtk/res/app.css b/fractal-gtk/res/app.css
index b968a482..470a9492 100644
--- a/fractal-gtk/res/app.css
+++ b/fractal-gtk/res/app.css
@@ -327,3 +327,15 @@ button.forgot-password {
 .error-label {
   color: @error_color;
 }
+
+box.folded-history
+  > overlay
+  > scrolledwindow
+  > viewport
+  > box
+  > hdycolumn
+  > box
+  > list {
+  padding-left: 6px;
+  padding-right: 6px;
+}
diff --git a/fractal-gtk/src/app/mod.rs b/fractal-gtk/src/app/mod.rs
index 0d91fdb4..47dfd04a 100644
--- a/fractal-gtk/src/app/mod.rs
+++ b/fractal-gtk/src/app/mod.rs
@@ -2,6 +2,7 @@ use gettextrs::{bindtextdomain, setlocale, textdomain, LocaleCategory};
 use gio::prelude::*;
 use gtk;
 use gtk::prelude::*;
+use libhandy::prelude::*;
 use std::cell::RefCell;
 use std::ops;
 use std::rc::{Rc, Weak};
@@ -126,6 +127,39 @@ impl App {
             window.get_style_context().map(|c| c.add_class("devel"));
         }
 
+        let leaflet = ui
+            .builder
+            .get_object::<libhandy::Leaflet>("chat_state_leaflet")
+            .expect("Can't find chat_state_leaflet in ui file.");
+        let container = ui
+            .builder
+            .get_object::<gtk::Box>("history_container")
+            .expect("Can't find history_container in ui file.");
+
+        if let libhandy::Fold::Folded = leaflet.get_fold() {
+            container
+                .get_style_context()
+                .unwrap()
+                .add_class("folded-history");
+        }
+
+        let weak_container = container.downgrade();
+        leaflet.connect_property_fold_notify(move |leaflet| {
+            let container = upgrade_weak!(weak_container);
+
+            match leaflet.get_fold() {
+                libhandy::Fold::Folded => container
+                    .get_style_context()
+                    .unwrap()
+                    .add_class("folded-history"),
+                libhandy::Fold::Unfolded => container
+                    .get_style_context()
+                    .unwrap()
+                    .remove_class("folded-history"),
+                _ => (),
+            }
+        });
+
         let stack = ui
             .builder
             .get_object::<gtk::Stack>("main_content_stack")