Merge ~pieq/bugit/+git/qabro:modal-error-window into bugit:master

[Pierre Equoy]

See commit message for more info.

To test (on Ubuntu classic):

1. Run `snapcraft` from this branch to build a `qabro_0.13dev_amd64.snap` file
2. Install the snap:
    sudo snap install qabro_0.13dev_amd64.snap --devmode
3. Run `qabro`
4. Try to generate an error (for instance, leave the "Title" field blank and press `Alt+Enter` to try to submit the report)

→ You should see a modal error dialog popping up in red, with a 'OK' button to dismiss it (you can also press Esc key).

[Nara Huang (narahuang)]

Tested, the new error window is great, LGTM.

review: Approve

[Maciej Kisielewski (kissiel)]

The code looks good too. +1

review: Approve

diff --git a/qabro/__init__.py b/qabro/__init__.py
index dee80a3..ce717ad 100644
--- a/qabro/__init__.py
+++ b/qabro/__init__.py
@@ -67,9 +67,8 @@ def start_ui(assignee='', project='', tags=''):
         try:
             result = ba.file_bug()
         except Exception as exc:
-            ui.message.set_text([('error', "Error: "), str(exc)])
             logging.error(exc)
-            ui.run()
+            ui.show_error_dialog(message=str(exc))
             ba.update(ui.report())
         else:
             print(result)
diff --git a/qabro/ui.py b/qabro/ui.py
index 059d39e..1a78c20 100644
--- a/qabro/ui.py
+++ b/qabro/ui.py
@@ -80,12 +80,10 @@ class ReportScreen:
         importance_list = urwid.LineBox(urwid.Pile(self._importance), 'Importance')
         self.bug_features_list = urwid.LineBox(urwid.Pile(self._bug_features), 'Impacted Feature(s)')
         self.bug_vendors_list = urwid.LineBox(urwid.Pile(self._bug_vendors), 'Impacted Vendor(s)')
-        self.message = urwid.Text('')
         self.footer = urwid.AttrMap(urwid.Text(self.footer_text), 'foot')
         self.bug_tags_lists = urwid.Columns([self.bug_features_list,
                                              self.bug_vendors_list])
-        self.pile = urwid.Pile([self.message,
-                                self._title,
+        self.pile = urwid.Pile([self._title,
                                 self._description,
                                 self._project,
                                 self._series,
@@ -94,7 +92,13 @@ class ReportScreen:
                                 self._assignee,
                                 self._tags,
                                 self.bug_tags_lists])
-        self.view = urwid.Frame(urwid.Filler(self.pile, 'top'), footer=self.footer)
+        self.main_view = urwid.Frame(urwid.Filler(self.pile, 'top'), footer=self.footer)
+        self.error_text = urwid.Text("")
+        self.ok_button = urwid.Padding(urwid.Button("OK", on_press=self.close_dialog), align="center", width=6)
+        self.error_dialog = urwid.AttrMap(urwid.LineBox(urwid.Pile([self.error_text, self.ok_button]), "Error"),
+                                          "error")
+        self.error_view = urwid.Overlay(self.error_dialog, self.main_view, align="center", width=("relative", 50),
+                                        valign="middle", height="pack")
 
     def set_tag(self, cb, cb_state, user_data):
         tags = user_data[cb.label]
@@ -113,16 +117,24 @@ class ReportScreen:
         dedup_tags = OrderedDict.fromkeys(current_tags)
         self._tags.base_widget.edit_text = " ".join(dedup_tags)
 
+    def show_error_dialog(self, message):
+        self.error_text.set_text(message)
+        self.loop.widget = self.error_view
+        self.loop.run()
+
+    def close_dialog(self, button=None):
+        self.loop.widget = self.main_view
+
     def run(self):
         """Run the urwid MainLoop."""
-        self.loop = urwid.MainLoop(self.view,
+        self.loop = urwid.MainLoop(self.main_view,
                                    self.palette,
                                    handle_mouse=False,
                                    unhandled_input=self.unhandled_input)
         self.loop.run()
 
     def unhandled_input(self, key):
-        if self.loop.widget == self.view:
+        if self.loop.widget == self.main_view:
             if key == 'esc':
                 sys.exit(0)
             if key == 'meta enter':
@@ -131,6 +143,10 @@ class ReportScreen:
                 self.loop.process_input(['down' for _ in range(5)])
             if key == 'page up':
                 self.loop.process_input(['up' for _ in range(5)])
+        else:  # We are showing the error dialog
+            if key == 'esc':
+                self.close_dialog()
+                return True
 
     def report(self):
         tags = self._tags.base_widget.text