view: Fix focus before and after search.

This commit corrects what the code for focus_index_before_search was
intended to do. The focus index was still being updated even in the
search results.

This is fixed by adding a boolean `in_search_mode` which does not
call `get_focus` untill the search is over. Slight reordering was
done in `__init__` to fit the boolean in an ideal place w.r.t.
readability.

Fixes zulip#975

Author: Rohitth007

zulipterminal/ui_tools/views.py

@@ -285,13 +285,17 @@ def __init__(self) -> None:
 class StreamsView(urwid.Frame):
     def __init__(self, streams_btn_list: List[Any], view: Any) -> None:
         self.view = view
-        self.log = urwid.SimpleFocusListWalker(streams_btn_list)
+        # Create Stream List Box
         self.streams_btn_list = streams_btn_list
-        self.focus_index_before_search = 0
+        self.log = urwid.SimpleFocusListWalker(streams_btn_list)
         list_box = urwid.ListBox(self.log)
+        # Create Stream Search Box
         self.stream_search_box = PanelSearchBox(
             self, "SEARCH_STREAMS", self.update_streams
         )
+        self.focus_index_before_search = 0
+        self.in_search_mode = False
+        # Create Stream View Frame
         super().__init__(
             list_box,
             header=urwid.LineBox(
@@ -364,6 +368,7 @@ def mouse_event(
 
     def keypress(self, size: urwid_Size, key: str) -> Optional[str]:
         if is_command_key("SEARCH_STREAMS", key):
+            self.in_search_mode = True
             self.set_focus("header")
             return key
         elif is_command_key("GO_BACK", key):
@@ -373,9 +378,11 @@ def keypress(self, size: urwid_Size, key: str) -> Optional[str]:
             self.set_focus("body")
             self.log.set_focus(self.focus_index_before_search)
             self.view.controller.update_screen()
+            self.in_search_mode = False
             return key
         return_value = super().keypress(size, key)
-        _, self.focus_index_before_search = self.log.get_focus()
+        if not self.in_search_mode:
+            _, self.focus_index_before_search = self.log.get_focus()
         return return_value
 
 
@@ -384,17 +391,21 @@ def __init__(
         self, topics_btn_list: List[Any], view: Any, stream_button: Any
     ) -> None:
         self.view = view
-        self.log = urwid.SimpleFocusListWalker(topics_btn_list)
-        self.topics_btn_list = topics_btn_list
         self.stream_button = stream_button
-        self.focus_index_before_search = 0
+        # Create Topic List Box
+        self.topics_btn_list = topics_btn_list
+        self.log = urwid.SimpleFocusListWalker(topics_btn_list)
         self.list_box = urwid.ListBox(self.log)
+        # Create Topic Search Box
         self.topic_search_box = PanelSearchBox(
             self, "SEARCH_TOPICS", self.update_topics
         )
+        self.focus_index_before_search = 0
+        self.in_search_mode = False
         self.header_list = urwid.Pile(
             [self.stream_button, urwid.Divider("─"), self.topic_search_box]
         )
+        # Create Topic View Frame
         super().__init__(
             self.list_box,
             header=urwid.LineBox(
@@ -476,6 +487,7 @@ def keypress(self, size: urwid_Size, key: str) -> Optional[str]:
             self.view.show_left_panel(visible=False)
             self.view.body.focus_col = 1
         if is_command_key("SEARCH_TOPICS", key):
+            self.in_search_mode = True
             self.set_focus("header")
             self.header_list.set_focus(2)
             return key
@@ -486,9 +498,11 @@ def keypress(self, size: urwid_Size, key: str) -> Optional[str]:
             self.set_focus("body")
             self.log.set_focus(self.focus_index_before_search)
             self.view.controller.update_screen()
+            self.in_search_mode = False
             return key
         return_value = super().keypress(size, key)
-        _, self.focus_index_before_search = self.log.get_focus()
+        if not self.in_search_mode:
+            _, self.focus_index_before_search = self.log.get_focus()
         return return_value