Refresh animation during blockchain loading

res/icons/icons.qrc

 <RCC>
   <qresource prefix="icons">
+    <file alias="loader">loader.gif</file>
     <file alias="guest_icon">noun_178537_cc.svg</file>
     <file alias="menu_icon">noun_100552_cc.svg</file>
     <file alias="leave_icon">noun_155520_cc.svg</file>

src/sakia/app.py

@@ -52,6 +52,8 @@ class Application(QObject):
     sources_refreshed = pyqtSignal()
     new_blocks_handled = pyqtSignal()
     view_in_wot = pyqtSignal(Identity)
+    refresh_started = pyqtSignal()
+    refresh_finished = pyqtSignal()
 
     qapp = attr.ib()
     loop = attr.ib()

src/sakia/gui/main_window/controller.py

@@ -87,6 +87,8 @@ class MainWindowController(QObject):
             main_window.view.showMaximized()
         else:
             main_window.view.show()
+        app.refresh_started.connect(main_window.status_bar.start_loading)
+        app.refresh_finished.connect(main_window.status_bar.stop_loading)
         main_window.model.load_plugins(main_window)
         main_window.refresh(app.currency)
         return main_window

src/sakia/gui/main_window/status_bar/controller.py

@@ -14,8 +14,8 @@ class StatusBarController(QObject):
         """
         Constructor of the navigation component
 
-        :param sakia.gui.status_bar.view.StatusBarView view: the presentation
-        :param sakia.core.status_bar.model.StatusBarModel model: the model
+        :param sakia.gui.main_window.status_bar.view.StatusBarView view: the presentation
+        :param sakia.gui.main_window.status_bar.model.StatusBarModel model: the model
         """
         super().__init__()
         self.view = view
@@ -53,6 +53,12 @@ class StatusBarController(QObject):
         timer.timeout.connect(self.update_time)
         timer.start(1000)
 
+    def start_loading(self):
+        self.view.start_loading()
+
+    def stop_loading(self):
+        self.view.stop_loading()
+
     def new_blocks_handled(self):
         current_block = self.model.current_block()
         current_time = self.model.current_time()

src/sakia/gui/main_window/status_bar/view.py

 from PyQt5.QtWidgets import QStatusBar
-from PyQt5.QtWidgets import QLabel, QComboBox
-from PyQt5.QtCore import Qt
+from PyQt5.QtWidgets import QLabel, QComboBox, QSpacerItem, QSizePolicy
+from PyQt5.QtGui import QMovie
+from PyQt5.QtCore import Qt, QSize
 
 
 class StatusBarView(QStatusBar):
@@ -10,7 +11,6 @@ class StatusBarView(QStatusBar):
 
     def __init__(self, parent):
         super().__init__(parent)
-        self.label_icon = QLabel("", parent)
 
         self.status_label = QLabel("", parent)
         self.status_label.setTextFormat(Qt.RichText)
@@ -18,8 +18,20 @@ class StatusBarView(QStatusBar):
         self.label_time = QLabel("", parent)
 
         self.combo_referential = QComboBox(parent)
-
-        self.addPermanentWidget(self.label_icon, 1)
+        self.movie_loader = QMovie(":/icons/loader")
+        self.label_loading = QLabel(parent)
+        self.label_loading.setMovie(self.movie_loader)
+        self.label_loading.setMaximumHeight(self.height())
+        self.movie_loader.setScaledSize(QSize(16, 16))
+        self.movie_loader.start()
+        self.movie_loader.setPaused(True)
+        self.addPermanentWidget(self.label_loading)
         self.addPermanentWidget(self.status_label, 2)
         self.addPermanentWidget(self.label_time)
         self.addPermanentWidget(self.combo_referential)
+
+    def start_loading(self):
+        self.movie_loader.setPaused(False)
+
+    def stop_loading(self):
+        self.movie_loader.setPaused(True)

src/sakia/services/blockchain.py

@@ -60,6 +60,7 @@ class BlockchainService(QObject):
         if self._blockchain_processor.initialized(self.currency) and not self._update_lock:
             try:
                 self._update_lock = True
+                self.app.refresh_started.emit()
                 block_numbers = await self.new_blocks(network_blockstamp)
                 while block_numbers:
                     start = self.current_buid().number
@@ -92,6 +93,7 @@ class BlockchainService(QObject):
             except (NoPeerAvailable, DuniterError) as e:
                 self._logger.debug(str(e))
             finally:
+                self.app.refresh_finished.emit()
                 self._update_lock = False
 
     def current_buid(self):