boxes/views: Initial focus set to search-box in EmojiPickerView.

The PanelSearcBox has been refactored to add a static caption for
search. The EmojiPickerView is also updated to set the initial
focus to the search-box(header) instead of emoji list(body). Some
UI improvements have also been added, including popup_contrasts
as used in other PopUp's.

Tests amended.

Author: zee-bit

tests/ui_tools/test_popups.py

@@ -773,7 +773,7 @@ def test_update_emoji_list(self, mocker, emoji_names, search_string,
         emojis_display_name = [
             emoji.emoji_name for emoji in self.emojis_display]
         assert emojis_display_name == assert_list
-        assert self.emoji_picker_view.get_focus() == 'body'
+        assert self.emoji_picker_view.get_focus() == 'header'
 
     @pytest.mark.parametrize('key', keys_for_command('SEARCH_EMOJIS'))
     def test_keypress_search_emoji(self, key, mocker, widget_size):
@@ -790,7 +790,7 @@ def test_keypress_exit_called(self, key, mocker, widget_size,
         if allow_update:
             assert self.controller.exit_popup.called
         else:
-            assert self.emoji_picker_view.get_focus() == 'body'
+            assert self.emoji_picker_view.get_focus() == 'header'
 
     def test_keypress_navigation(self, mocker, widget_size,
                                  navigation_key_expected_key_pair):

zulipterminal/ui_tools/boxes.py

@@ -1564,14 +1564,18 @@ class PanelSearchBox(urwid.Edit):
     """
 
     def __init__(self, panel_view: Any, search_command: str,
-                 update_function: Callable[..., None]) -> None:
+                 update_function: Callable[..., None],
+                 fixed_search_caption: bool=False) -> None:
         self.panel_view = panel_view
         self.search_command = search_command
         self.search_text = (
             f"Search [{', '.join(keys_for_command(search_command))}]: "
         )
         urwid.connect_signal(self, 'change', update_function)
-        super().__init__(caption='', edit_text=self.search_text)
+        if not fixed_search_caption:
+            super().__init__(caption='', edit_text=self.search_text)
+        else:
+            super().__init__(caption=self.search_text, edit_text='')
 
     def reset_search_text(self) -> None:
         self.set_caption('')

zulipterminal/ui_tools/views.py

@@ -1473,16 +1473,18 @@ def __init__(self, controller: Any, title: str, emoji_names: List[str],
         self.emoji_buttons = self.generate_emoji_buttons(emoji_names)
         self.emoji_search = PanelSearchBox(self,
                                            'SEARCH_EMOJIS',
-                                           self.update_emoji_list)
+                                           self.update_emoji_list,
+                                           fixed_search_caption=True)
         self.view.emoji_search = self.emoji_search
         search_box = urwid.LineBox(
             self.emoji_search, tlcorner='─', tline='', lline='',
             trcorner='─', blcorner='─', rline='',
             bline='─', brcorner='─'
             )
-        self.allow_update_emoji_list = True
         super().__init__(controller, self.emoji_buttons, 'ADD_REACTION',
                          self.width, title, header=[search_box])
+        self.set_focus('header')
+        self.allow_update_emoji_list = False
 
     @asynch
     def update_emoji_list(self, search_box: Any=None,
@@ -1512,15 +1514,20 @@ def update_emoji_list(self, search_box: Any=None,
 
     def generate_emoji_buttons(self, emoji_names: List[str]
                                ) -> List[EmojiButton]:
-        return [EmojiButton(self.controller, self.width, emoji_name,
-                            self.message)
-                for emoji_name in emoji_names]
+        emoji_buttons = []
+        for index, emoji_name in enumerate(emoji_names):
+            emoji_buttons.append(urwid.AttrWrap(EmojiButton(
+                self.controller, self.width, emoji_name, self.message
+            ), None if index % 2 else 'popup_contrast'))
+        return emoji_buttons
 
     def keypress(self, size: urwid_Size, key: str) -> str:
         if (is_command_key('SEARCH_EMOJIS', key)
                 and self.allow_update_emoji_list):
             self.allow_update_emoji_list = False
             self.emoji_search.set_edit_text('')
+            self.emoji_search.set_caption(
+                f"Search [{', '.join(keys_for_command('SEARCH_EMOJIS'))}]: ")
             self.set_focus('header')
             return key
         elif (is_command_key('GO_BACK', key)