refactor(ui): improve panel focus cycling logic

Refactored `CyclePanelFocus` to follow a consistent
`Formula -> Category -> View` order.

Focus now correctly wraps around and handles non-panel modes.

Add regression tests for improved cycling logic.

Co-Authored-By: fiddlerwoaroof/git-smart-commit (unsloth/gemma-4-26B-A4B-it-GGUF:UD-Q5_K_XL)

src/command/cmd/panel.rs

@@ -80,6 +80,7 @@ mod tests {
         );
     }
 
+    /// From a non-panel mode (Normal), cycling goes to the first open panel.
     #[test]
     fn cycle_panel_focus_with_multiple_panels() {
         let m = two_cat_model();
@@ -97,8 +98,106 @@ mod tests {
         assert_eq!(effects.len(), 1);
         let dbg = effects_debug(&effects);
         assert!(
-            dbg.contains("FormulaPanel") || dbg.contains("CategoryPanel"),
-            "Expected panel focus, got: {dbg}"
+            dbg.contains("FormulaPanel"),
+            "Expected first open panel (FormulaPanel) from Normal mode, got: {dbg}"
+        );
+    }
+
+    /// Bug improvise-dqn: CyclePanelFocus always picked the first open panel,
+    /// ignoring the currently focused panel. With formula + category open and
+    /// focus on the formula panel, cycling must move to the category panel.
+    #[test]
+    fn cycle_panel_focus_advances_from_formula_to_category() {
+        let m = two_cat_model();
+        let layout = make_layout(&m);
+        let reg = make_registry();
+        let mut ctx = make_ctx(&m, &layout, &reg);
+        ctx.formula_panel_open = true;
+        ctx.category_panel_open = true;
+        ctx.mode = &AppMode::FormulaPanel;
+        let cmd = CyclePanelFocus {
+            formula_open: true,
+            category_open: true,
+            view_open: false,
+        };
+        let effects = cmd.execute(&ctx);
+        assert_eq!(effects.len(), 1);
+        let dbg = effects_debug(&effects);
+        assert!(
+            dbg.contains("CategoryPanel"),
+            "Expected CategoryPanel after FormulaPanel, got: {dbg}"
+        );
+    }
+
+    /// Bug improvise-dqn: with category + view open and focus on the category
+    /// panel, cycling must advance to the view panel (not stay on category).
+    #[test]
+    fn cycle_panel_focus_advances_from_category_to_view() {
+        let m = two_cat_model();
+        let layout = make_layout(&m);
+        let reg = make_registry();
+        let mut ctx = make_ctx(&m, &layout, &reg);
+        ctx.category_panel_open = true;
+        ctx.view_panel_open = true;
+        ctx.mode = &AppMode::CategoryPanel;
+        let cmd = CyclePanelFocus {
+            formula_open: false,
+            category_open: true,
+            view_open: true,
+        };
+        let effects = cmd.execute(&ctx);
+        assert_eq!(effects.len(), 1);
+        let dbg = effects_debug(&effects);
+        assert!(
+            dbg.contains("ViewPanel"),
+            "Expected ViewPanel after CategoryPanel, got: {dbg}"
+        );
+    }
+
+    /// From the last open panel, cycling wraps back to the first open one.
+    #[test]
+    fn cycle_panel_focus_wraps_from_view_to_formula() {
+        let m = two_cat_model();
+        let layout = make_layout(&m);
+        let reg = make_registry();
+        let mut ctx = make_ctx(&m, &layout, &reg);
+        ctx.formula_panel_open = true;
+        ctx.view_panel_open = true;
+        ctx.mode = &AppMode::ViewPanel;
+        let cmd = CyclePanelFocus {
+            formula_open: true,
+            category_open: false,
+            view_open: true,
+        };
+        let effects = cmd.execute(&ctx);
+        assert_eq!(effects.len(), 1);
+        let dbg = effects_debug(&effects);
+        assert!(
+            dbg.contains("FormulaPanel"),
+            "Expected wrap to FormulaPanel from ViewPanel, got: {dbg}"
+        );
+    }
+
+    /// With exactly one panel open and focus already on it, cycling stays
+    /// there (self-transition back to the same panel mode).
+    #[test]
+    fn cycle_panel_focus_single_panel_stays_put() {
+        let m = two_cat_model();
+        let layout = make_layout(&m);
+        let reg = make_registry();
+        let mut ctx = make_ctx(&m, &layout, &reg);
+        ctx.category_panel_open = true;
+        ctx.mode = &AppMode::CategoryPanel;
+        let cmd = CyclePanelFocus {
+            formula_open: false,
+            category_open: true,
+            view_open: false,
+        };
+        let effects = cmd.execute(&ctx);
+        let dbg = effects_debug(&effects);
+        assert!(
+            effects.is_empty() || dbg.contains("CategoryPanel"),
+            "Expected no-op or self-transition to CategoryPanel, got: {dbg}"
         );
     }
 
@@ -289,7 +388,11 @@ impl Cmd for TogglePanelVisibility {
     }
 }
 
-/// Tab through open panels, entering the first open panel's mode.
+/// Tab through open panels in order Formula → Category → View, wrapping.
+/// The starting point is the panel currently focused (`ctx.mode`); from a
+/// non-panel mode (e.g. Normal) focus goes to the first open panel. With a
+/// single open panel this self-transitions back to it; with none open it is
+/// a no-op.
 #[derive(Debug)]
 pub struct CyclePanelFocus {
     pub formula_open: bool,
@@ -300,16 +403,25 @@ impl Cmd for CyclePanelFocus {
     fn name(&self) -> &'static str {
         "cycle-panel-focus"
     }
-    fn execute(&self, _ctx: &CmdContext) -> Vec<Box<dyn Effect>> {
-        if self.formula_open {
-            vec![effect::change_mode(AppMode::FormulaPanel)]
-        } else if self.category_open {
-            vec![effect::change_mode(AppMode::CategoryPanel)]
-        } else if self.view_open {
-            vec![effect::change_mode(AppMode::ViewPanel)]
-        } else {
-            vec![]
-        }
+    fn execute(&self, ctx: &CmdContext) -> Vec<Box<dyn Effect>> {
+        let order = [
+            (self.formula_open, AppMode::FormulaPanel),
+            (self.category_open, AppMode::CategoryPanel),
+            (self.view_open, AppMode::ViewPanel),
+        ];
+        // Index of the first candidate: the panel after the focused one,
+        // or the first panel when invoked from a non-panel mode.
+        let start = match ctx.mode {
+            AppMode::FormulaPanel => 1,
+            AppMode::CategoryPanel => 2,
+            AppMode::ViewPanel => 3,
+            _ => 0,
+        };
+        (0..order.len())
+            .map(|i| &order[(start + i) % order.len()])
+            .find(|(open, _)| *open)
+            .map(|(_, mode)| vec![effect::change_mode(mode.clone())])
+            .unwrap_or_default()
     }
 }