Fix multi-select word movement for snake_case and add Ctrl+scroll zoom

- Implement snake_case-aware word movement treating underscores as part of words
- Fix selection edge detection to only move word markers when caret is at appropriate boundary
- Add INSERT state guards to line_up/down commands to prevent movement in non-insert modes
- Add Ctrl+scroll zoom in/out functionality for text size

src/core/widgets/code/command_system/commands/line_down.py

@@ -8,6 +8,7 @@ gi.require_version('GtkSource', '4')
 from gi.repository import GtkSource
 
 # Application imports
+from libs.dto.states import SourceViewStates
 
 
 
@@ -17,4 +18,6 @@ def execute(
     **kwargs
 ):
     logger.debug("Command: Line Down")
+    if not view.state == SourceViewStates.INSERT: return
+
     view.emit("move-lines", True)

src/core/widgets/code/command_system/commands/line_up.py

@@ -8,6 +8,7 @@ gi.require_version('GtkSource', '4')
 from gi.repository import GtkSource
 
 # Application imports
+from libs.dto.states import SourceViewStates
 
 
 
@@ -17,4 +18,6 @@ def execute(
     **kwargs
 ):
     logger.debug("Command: Line Up")
+    if not view.state == SourceViewStates.INSERT: return
+
     view.emit("move-lines", False)

src/core/widgets/code/controllers/views/marker_manager.py

@@ -56,10 +56,28 @@ class MarkerManager(MarkSupportMixin):
                 continue
 
             if has_selection:
+                caret_itr     = buffer.get_iter_at_mark(end_mark)
+                start_itr     = buffer.get_iter_at_mark(start_mark)
+                is_left_edge  = caret_itr.compare(start_itr) <= 0
+                is_right_edge = not is_left_edge
+                can_move      = (
+                    (is_forward and is_right_edge) or
+                    (not is_forward and is_left_edge)
+                )
+
                 self.collapse_selection(buffer, mark_hash, start_mark, end_mark, is_forward)
+                if mode == "word":
+                    if not can_move: continue
+
+                    itr = caret_itr
+                    self._move_iter(buffer, itr, mode, is_forward)
+                    buffer.move_mark(start_mark, itr)
+                    buffer.move_mark(end_mark, itr)
+
                 continue
 
-            # No selection — move both anchor and caret together
+
+            # No selection - move both anchor and caret together
             self._move_iter(buffer, end_itr, mode, is_forward)
 
             buffer.move_mark(start_mark, end_itr)
@@ -81,17 +99,50 @@ class MarkerManager(MarkSupportMixin):
             left  = end_itr
             right = start_itr
 
-        # If moving forward → collapse to right edge
+        # If moving forward -> collapse to right edge
         collapse_itr = right if is_forward else left
 
         buffer.move_mark(start_mark, collapse_itr)
         buffer.move_mark(end_mark, collapse_itr)
 
+    def move_word_snake_case(self, itr: Gtk.TextIter, count: int):
+        def is_word(ch):
+            return ch and (ch.isalnum() or ch == "_")
+
+        def step(fwd):
+            return itr.forward_cursor_position() if fwd else itr.backward_cursor_position()
+
+        def peek(fwd):
+            if fwd: return itr.get_char()
+            tmp = itr.copy()
+            return tmp.backward_cursor_position() and tmp.get_char()
+
+        def walk(fwd, cond):
+            while True:
+                ch = peek(fwd)
+                if not cond(ch): break
+                if not step(fwd): return False
+
+            return True
+
+        fwd = count > 0
+
+        for _ in range(abs(count)):
+            ch = itr.get_char() if fwd else peek(False)
+
+            if is_word(ch):
+                # inside word
+                if not walk(fwd, is_word): return
+            else:
+                # in separators -> skip them, then the word
+                if not walk(fwd, lambda c: not is_word(c)): return
+                if not walk(fwd, is_word): return
+
     def _move_iter(self, buffer, itr_, mode: str, is_forward: bool):
         if mode == "char":
             itr_.forward_char() if is_forward else itr_.backward_char()
         elif mode == "word":
-            itr_.forward_word_end() if is_forward else itr_.backward_word_start()
+            self.move_word_snake_case(itr_, 1 if is_forward else -1)
         elif mode == "line":
             line   = itr_.get_line()
             offset = itr_.get_line_offset()

src/core/widgets/code/controllers/views/signal_mapper.py

@@ -57,6 +57,7 @@ class SourceViewSignalMapper:
             "key-release-event":    self._key_release_event,
             "button-press-event":   self._button_press_event,
             "button-release-event": self._button_release_event,
+            "scroll-event":         self._scroll_event,
             "populate-popup":       self._populate_popup
         }
 
@@ -81,5 +82,8 @@ class SourceViewSignalMapper:
     def _button_release_event(self, source_view: SourceView, eve):
         return self.state_manager.handle_button_release_event(source_view, eve)
 
-    def _populate_popup(self, source_view, menu):
+    def _scroll_event(self, source_view: SourceView, eve):
+        return self.state_manager.handle_scroll_event(source_view, eve)
+
+    def _populate_popup(self, source_view: SourceView, menu):
         return self.state_manager.handle_populate_popup(source_view, menu, self.emit)

src/core/widgets/code/controllers/views/state_manager.py

@@ -53,8 +53,15 @@ class SourceViewStateManager:
     def handle_button_release_event(self, source_view, eve):
         return self.states[source_view.state].button_release_event(source_view, eve)
 
+    def handle_scroll_event(self, source_view, eve):
+        return self.states[source_view.state].scroll_event(
+            source_view, eve, self.key_mapper
+        )
+
     def handle_populate_popup(self, source_view, menu, emit):
-        return self.states[source_view.state].populate_popup(source_view, menu, emit)
+        return self.states[source_view.state].populate_popup(
+            source_view, menu, emit
+        )
 
     def _handle_multi_insert_toggle(self, source_view, eve):
         is_control = self.key_mapper.is_control(eve)

src/core/widgets/code/controllers/views/states/source_view_base_state.py

@@ -1,6 +1,9 @@
 # Python imports
 
 # Lib imports
+import gi
+gi.require_version('Gdk', '3.0')
+from gi.repository import Gdk
 
 # Application imports
 from libs.event_factory import Event_Factory, Code_Event_Types
@@ -79,6 +82,29 @@ class SourceViewsBaseState:
 
         return True if not response else response
 
+    def scroll_event(self, source_view, eve, key_mapper):
+        is_control = key_mapper.is_control(eve)
+
+        if not is_control: return
+
+        if eve.direction == Gdk.ScrollDirection.SMOOTH:
+            has_deltas, dx, dy = eve.get_scroll_deltas()
+            if not has_deltas: return False
+
+            if dy < 0:
+                source_view.command.exec("zoom_in")
+            elif dy > 0:
+                source_view.command.exec("zoom_out")
+
+            return True
+
+        if eve.direction == Gdk.ScrollDirection.UP:
+            source_view.command.exec("zoom_in")
+        elif eve.direction == Gdk.ScrollDirection.DOWN:
+            source_view.command.exec("zoom_out")
+
+        return True
+
     def populate_popup(self, source_view, menu, emit):
         buffer = source_view.get_buffer()
         event  = Event_Factory.create_event(

src/core/widgets/code/controllers/views/states/source_view_multi_insert_state.py

@@ -61,7 +61,6 @@ class SourceViewsMultiInsertState(SourceViewsBaseState):
         self.marker_manager.apply_to_marks(buffer, replace_word)
         return True
 
-
     def move_cursor(self, source_view, step, count, is_selection, emit):
         is_forward = count > 0
         buffer     = source_view.get_buffer()
@@ -78,6 +77,8 @@ class SourceViewsMultiInsertState(SourceViewsBaseState):
 
         self._signal_cursor_moved(source_view, emit)
 
+        return False
+
     def key_press_event(self, source_view, event, key_mapper):
         char = key_mapper.get_raw_keyname(event).upper()
         self.is_control = key_mapper.is_control(event)

src/core/widgets/code/mixins/mark_support_mixin.py

@@ -106,7 +106,6 @@ class MarkSupportMixin:
             name = f"multi-insert-end-{hash}",
             left_gravity = False
         )
-#            left_gravity = True
 
         buffer.add_mark(start_mark, target_iter)
         buffer.add_mark(end_mark, target_iter)