Refactor cell marking, add undo, update keybindings

CellWidget::set_selected and set_marked now return &mut Self for method
chaining. Added BoardState::undo_marked_cell to remove the last marked
cell and restore focus. Backspace triggers undo, Delete clears marking.

src/app/keybindings/keybindings.rs

@@ -29,14 +29,16 @@ pub enum Action {
     ScrollLeft,
     /// Scroll right without moving the cursor.
     ScrollRight,
-    /// Select the current item.
+    /// Toggle selecting cell.
     Space,
+    /// Unmark last selected cell.
+    Backspace,
+    /// Cancel marking cell.
+    Delete,
     /// Submit or confirm the current choice.
     Enter,
     /// Return to the main menu or previous screen.
     Esc,
-    /// Delete the character before the cursor.
-    Backspace,
     /// Zoom the view in.
     ZoomIn,
     /// Zoom the view out.
@@ -199,15 +201,33 @@ pub static KEYBINDINGS: &[KeyBinding] = &[
         symbol: "Space",
         description: "Marking cells",
     },
-    // KeyBinding {
-    //     action: Action::Enter,
-    //     code: KeyCode::Enter,
-    //     kind: KeyEventKind::Press,
-    //     modifiers: KeyModifiers::NONE,
-    //     group: Group::Select,
-    //     symbol: "Enter",
-    //     description: "Submit",
-    // },
+    KeyBinding {
+        action: Action::Backspace,
+        code: KeyCode::Backspace,
+        kind: KeyEventKind::Press,
+        modifiers: KeyModifiers::NONE,
+        group: Group::Select,
+        symbol: "Backspace",
+        description: "Unmark cell",
+    },
+    KeyBinding {
+        action: Action::Delete,
+        code: KeyCode::Delete,
+        kind: KeyEventKind::Press,
+        modifiers: KeyModifiers::NONE,
+        group: Group::Select,
+        symbol: "Delete",
+        description: "Cancel marking",
+    },
+    KeyBinding {
+        action: Action::Enter,
+        code: KeyCode::Enter,
+        kind: KeyEventKind::Press,
+        modifiers: KeyModifiers::NONE,
+        group: Group::Select,
+        symbol: "Enter",
+        description: "Submit",
+    },
     KeyBinding {
         action: Action::Esc,
         code: KeyCode::Esc,
@@ -217,15 +237,6 @@ pub static KEYBINDINGS: &[KeyBinding] = &[
         symbol: "Esc",
         description: "Main menu",
     },
-    KeyBinding {
-        action: Action::Backspace,
-        code: KeyCode::Backspace,
-        kind: KeyEventKind::Press,
-        modifiers: KeyModifiers::NONE,
-        group: Group::Select,
-        symbol: "Backspace",
-        description: "Cancel marking",
-    },
     KeyBinding {
         action: Action::ZoomIn,
         code: KeyCode::Char(','),

src/app/keybindings/skirmish.rs

@@ -84,7 +84,8 @@ pub fn skirmish_keybindings(app: &mut App, key_event: &KeyEvent) {
                 ZoomLevel::ZoomedOut => {}
             },
             Action::Space => board.toggle_marking(),
-            Action::Backspace => {
+            Action::Backspace => board.undo_marked_cell(),
+            Action::Delete => {
                 board.marking_cells = false;
                 board.clear_marked_cells()
             }

src/app/states/skirmish_states/board.rs

@@ -116,16 +116,35 @@ impl BoardState {
         }
     }
 
-    pub fn set_marked_cell(&mut self, new_cell: (usize, usize), old_cell: (usize, usize)) {
+    pub fn set_marked_cell(&mut self, new_cell: (usize, usize)) {
         let cell: &mut CellWidget = self.get_mut_cell(new_cell.0, new_cell.1);
 
-        if cell.get_marked() && old_cell != new_cell {
-            self.get_mut_cell(old_cell.0, old_cell.1).set_marked(false);
-            self.marked_cells.pop();
-        } else {
+        if !cell.get_marked() {
             cell.set_marked(true);
-            self.marked_cells.push((new_cell.0, new_cell.1));
         }
+
+        self.marked_cells.push((new_cell.0, new_cell.1));
+    }
+
+    pub fn undo_marked_cell(&mut self) {
+        if self.marked_cells.len() < 2 {
+            return;
+        }
+
+        let old: (usize, usize) = self.marked_cells[self.marked_cells.len() - 1];
+        let new: (usize, usize) = self.marked_cells[self.marked_cells.len() - 2];
+        let old_is_unique: bool = self.marked_cells.iter().filter(|x| **x == old).count() == 1;
+
+        let old_cell: &mut CellWidget = self.get_mut_cell(old.0, old.1).set_selected(false);
+        if old_is_unique {
+            old_cell.set_marked(false);
+        }
+
+        self.get_mut_cell(new.0, new.1).set_selected(true);
+
+        self.marked_cells.pop();
+
+        self.focused_cell.set_focused_cell(new);
     }
 
     pub fn start_marking_cells(&mut self) {
@@ -226,7 +245,7 @@ impl BoardState {
         self.get_mut_cell(new_cell.0, new_cell.1).set_selected(true);
 
         if self.marking_cells {
-            self.set_marked_cell(new_cell, old_cell);
+            self.set_marked_cell(new_cell);
         }
     }
 }

src/app/states/skirmish_states/focused_cell.rs

@@ -49,4 +49,9 @@ impl FocusedCell {
 
         (self.row, self.col)
     }
+
+    pub fn set_focused_cell(&mut self, cell: (usize, usize)) {
+        self.row = cell.0.max(0).min(self.max_row - 1);
+        self.col = cell.1.max(0).min(self.max_col - 1);
+    }
 }

src/app/views/skirmish.rs

@@ -27,6 +27,7 @@ const ACTIONS: &[Action] = &[
     Action::VolumeDown,
     Action::Space,
     Action::Backspace,
+    Action::Delete,
     Action::Mute,
     Action::Quit,
     Action::Quit2,

src/app/widgets/cell.rs

@@ -48,8 +48,9 @@ impl CellWidget {
         }
     }
 
-    pub fn set_selected(&mut self, selected: bool) {
+    pub fn set_selected(&mut self, selected: bool) -> &mut Self {
         self.selected = selected;
+        self
     }
 
     pub fn set_zoom_level(&mut self, zoom_level: ZoomLevel) {
@@ -64,8 +65,9 @@ impl CellWidget {
         self.marked
     }
 
-    pub fn set_marked(&mut self, marked: bool) {
-        self.marked = marked
+    pub fn set_marked(&mut self, marked: bool) -> &mut Self {
+        self.marked = marked;
+        self
     }
 
     fn col_to_letters(&self) -> String {
@@ -90,8 +92,9 @@ impl CellWidget {
 
     fn fg_color(&self) -> Color {
         match self.tag {
-            _ if self.marked => Color::LightMagenta,
-            _ if self.selected => Color::LightYellow,
+            _ if self.marked && self.selected => Color::Magenta,
+            _ if self.marked && !self.selected => Color::LightMagenta,
+            _ if self.selected && !self.marked => Color::LightYellow,
             CellTag::Base(Players::Player) if !self.selected => Color::LightBlue,
             CellTag::Base(Players::Enemy) if !self.selected => Color::LightRed,
             CellTag::Tunel if !self.selected => Color::Gray,