Fix consistent back buttons

Now you can go all the way back, from any where via backbuttons.

main.py

@@ -45,7 +45,8 @@ class Cast(wx.Frame):
                 channels=[YouTube.YouTube('UCu6mSoMNzHQiBIOCkHUa2Aw')])
         ]
         self.m_selected_channel = None
-        self.show_splash(None)
+        self.m_selected_provider_index = None
+        self.show_provider_list(None)
 
     def get_chromecasts(self) -> None:
         """
@@ -55,7 +56,7 @@ class Cast(wx.Frame):
         """
         self.m_chromecasts, self.m_browser = pychromecast.get_chromecasts()
 
-    def show_splash(self, _) -> None:
+    def show_provider_list(self, _) -> None:
         self.m_sizer.Clear(delete_windows=True)
         self.m_sizer = wx.BoxSizer(wx.VERTICAL)
         provider_index = 0
@@ -75,9 +76,14 @@ class Cast(wx.Frame):
         self.m_panel.Layout()
 
     def show_channel_list(self, _, provider_index) -> None:
+        self.m_selected_provider_index = provider_index
+        self.m_selected_provider = self.m_providers[provider_index]
         self.m_sizer.Clear(delete_windows=True)
         self.m_sizer = wx.BoxSizer(wx.VERTICAL)
-        self.m_selected_provider = self.m_providers[provider_index]
+        backbtn = wx.Button(self.m_panel, -1, label="Go back", size=(480, 40))
+        backbtn.Bind(wx.EVT_BUTTON, lambda event: self.show_provider_list(event))
+        self.m_sizer.Add(backbtn, wx.ALIGN_CENTER_VERTICAL)
+        self.m_sizer.AddSpacer(10)
         channel_index = 0
         for channel in self.m_selected_provider.get_channels():
             bitmap = channel.get_logo_as_bitmap()
@@ -113,7 +119,7 @@ class Cast(wx.Frame):
                     wx.GetApp().Yield()
 
         backbtn = wx.Button(self.m_panel, -1, label="Go back", size=(480, 40))
-        backbtn.Bind(wx.EVT_BUTTON, lambda event: self.show_splash(event))
+        backbtn.Bind(wx.EVT_BUTTON, lambda event: self.show_channel_list(event, self.m_selected_provider_index))
         self.m_sizer.Add(backbtn, wx.ALIGN_CENTER_VERTICAL)
         self.m_sizer.AddSpacer(10)
         for item in channel.get_items():
@@ -171,7 +177,8 @@ class Cast(wx.Frame):
             chromecast_button = wx.Button(self.m_panel, -1, "Cast")
             chromecast_button.Bind(
                 wx.EVT_BUTTON,
-                lambda event, muri=uri: self.select_chromecast(event, muri))
+                lambda event, muri=uri, index=provider_index: self.
+                select_chromecast(event, muri, index))
             self.m_sizer.Add(chromecast_button, (2, 2))
 
         if self.m_selected_chromecast:
@@ -191,7 +198,7 @@ class Cast(wx.Frame):
         self.m_panel.Layout()
         self.m_panel.ScrollChildIntoView(self.m_control)
 
-    def select_chromecast(self, _, uri):
+    def select_chromecast(self, _, uri, provider_index):
         self.m_sizer.Clear(delete_windows=True)
         self.m_sizer = wx.BoxSizer(wx.VERTICAL)
 
@@ -202,16 +209,16 @@ class Cast(wx.Frame):
                             label=friendly_name,
                             size=(480, 40))
             btn.Bind(wx.EVT_BUTTON,
-                     lambda event, chromecast=cast, muri=uri: self.
+                     lambda event, chromecast=cast, muri=uri, index=provider_index: self.
-                     set_chromecast(event, chromecast, muri))
+                     set_chromecast(event, chromecast, muri, index))
             self.m_sizer.Add(btn, wx.ALIGN_CENTER_VERTICAL)
         self.m_panel.SetSizer(self.m_sizer)
         self.m_sizer.Fit(self)
         self.m_panel.Layout()
 
-    def set_chromecast(self, event, chromecast, uri):
+    def set_chromecast(self, event, chromecast, uri, provider_index):
         self.m_selected_chromecast = chromecast
-        self.show_player(event, uri)
+        self.show_player(event, uri, provider_index)
 
     def cast(self, event, uri):
         mimetype = 'video/mp4'