views/buttons: Add mouse_event support to EmojiPicker view.

This commit adds support for handling mouse_events from the emoji
picker view, so that users can toggle reactions and scroll the view
using their mouse.

The mouse_event looks for left-click for toggling message reactions
and up/down scroll to scroll through the list of emoji's from the
picker. The commit is kept at the last since having mouse support is
one of our least priorities for now, and providing basic functions
bug-free should always come first.

Tests added.

Author: zee-bit

tests/ui_tools/test_popups.py

@@ -1361,6 +1361,20 @@ def test_update_emoji_list(self, emoji_units, search_string, assert_list):
         assert emojis_display_name == assert_list
         assert self.emoji_picker_view.get_focus() == "header"
 
+    @pytest.mark.parametrize(
+        "event, button, keypress",
+        [
+            ("mouse press", 4, "up"),
+            ("mouse press", 5, "down"),
+        ],
+    )
+    def test_mouse_event(self, mocker, widget_size, event, button, keypress):
+        emoji_picker = self.emoji_picker_view
+        mocker.patch.object(emoji_picker, "keypress")
+        size = widget_size(emoji_picker)
+        emoji_picker.mouse_event(size, event, button, 0, 0, mocker.Mock())
+        emoji_picker.keypress.assert_called_once_with(size, keypress)
+
     @pytest.mark.parametrize("key", keys_for_command("SEARCH_EMOJIS"))
     def test_keypress_search_emoji(self, key, widget_size):
         size = widget_size(self.emoji_picker_view)

zulipterminal/ui_tools/buttons.py

@@ -360,6 +360,15 @@ def get_update_widget_text(self, user_reacted: bool) -> str:
         reacted_check_mark = CHECK_MARK if user_reacted else ""
         return f" {reacted_check_mark} {count_text} "
 
+    def mouse_event(
+        self, size: urwid_Size, event: str, button: int, col: int, row: int, focus: int
+    ) -> bool:
+        if event == "mouse press":
+            if button == 1:
+                self.keypress(size, primary_key_for_command("ENTER"))
+                return True
+        return super().mouse_event(size, event, button, col, row, focus)
+
     def update_emoji_button(self) -> None:
         self.toggle_selection(self.emoji_code, self.emoji_name)
         is_reaction_added = self._has_user_reacted_to_msg() != self.is_selected(

zulipterminal/ui_tools/views.py

@@ -2034,6 +2034,21 @@ def generate_emoji_buttons(
         )
         return sorted_emoji_buttons
 
+    def mouse_event(
+        self, size: urwid_Size, event: str, button: int, col: int, row: int, focus: int
+    ) -> bool:
+        if event == "mouse press":
+            if button == 1 and self.controller.is_in_editor_mode():
+                super().keypress(size, "enter")
+                return True
+            if button == 4:
+                self.keypress(size, "up")
+                return True
+            elif button == 5:
+                self.keypress(size, "down")
+                return True
+        return super().mouse_event(size, event, button, col, row, focus)
+
     def keypress(self, size: urwid_Size, key: str) -> str:
         if (
             is_command_key("SEARCH_EMOJIS", key)