Add stacked panes

modules/home/terminal/wezterm.nix

@@ -152,7 +152,7 @@
   modes = {
     locked = {
       fg = color.base03;
-      hint = "⌥󱁐:󰌌  ⌥hl:󰿵  ⌥1-9:󰓩  ⌥n:󰤻  ⌥w:󰅙  ^ud:󱕷";
+      hint = "⌥󱁐:󰌌  ⌥hl:󰹳  ^ud:󰹹  ⌥1-9:󰓩  ⌥n:󰤻  ⌥s:󱇳  ⌥w:󰅙  ⌥t:󰓩  ⌥p:󱃔";
     };
     normal = {
       fg = color.base0D;
@@ -207,6 +207,39 @@ in {
           end)
         end
 
+        -- tab_is_zoomed: true if any pane in the current tab is zoomed.
+        -- Used by move_vertical to decide whether to carry zoom forward.
+        local function tab_is_zoomed(pane)
+          for _, info in ipairs(pane:tab():panes_with_info()) do
+            if info.is_zoomed then return true end
+          end
+          return false
+        end
+
+        -- move_vertical: move focus Up/Down.
+        -- If any pane in the tab is currently zoomed (zoom-mode is "on" for this
+        -- tab), zoom the destination pane too — stacked-panel behaviour.
+        -- Otherwise just move focus plainly.
+        local function move_vertical(direction)
+          return wezterm.action_callback(function(window, pane)
+            local neighbour = pane:tab():get_pane_direction(direction)
+            if neighbour == nil then return end
+            if tab_is_zoomed(pane) then
+              -- unzoom_on_switch_pane unzooms the current pane when we move;
+              -- then SetPaneZoomState(true) zooms the newly active pane.
+              window:perform_action(
+                act.Multiple({
+                  act.ActivatePaneDirection(direction),
+                  act.SetPaneZoomState(true),
+                }),
+                pane
+              )
+            else
+              window:perform_action(act.ActivatePaneDirection(direction), pane)
+            end
+          end)
+        end
+
         -- ─── Status bar ────────────────────────────────────────────────────────────
 
         -- Per-mode accent colour and hint text, generated from Nix/stylix palette
@@ -251,6 +284,51 @@ in {
           return tab.active_pane.title
         end)
 
+        -- format-tab-title: show "rank/total title" when the active tab is in
+        -- stacked (zoom) mode; otherwise show plain " title ".
+        -- Returning a cell table gives us explicit padding and colours;
+        -- returning a plain string loses the retro tab bar's built-in spacing.
+        local tab_bg_active   = "${color.base0D}"
+        local tab_fg_active   = "${color.base00}"
+        local tab_bg_inactive = "${color.base01}"
+        local tab_fg_inactive = "${color.base03}"
+
+        wezterm.on("format-tab-title", function(tab, _tabs, panes, _config, _hover, _max_width)
+          local title = (tab.tab_title and tab.tab_title ~= "") and tab.tab_title or tab.active_pane.title
+          local bg = tab.is_active and tab_bg_active or tab_bg_inactive
+          local fg = tab.is_active and tab_fg_active or tab_fg_inactive
+
+          -- Only compute stack position for the active tab.
+          -- The `panes` event parameter only contains the active pane snapshot
+          -- and lacks `top`, so we use wezterm.mux.get_tab():panes_with_info()
+          -- which returns full PaneInformation including top/is_zoomed/is_active.
+          if tab.is_active then
+            local mux_tab = wezterm.mux.get_tab(tab.tab_id)
+            if mux_tab then
+              local infos = mux_tab:panes_with_info()
+              table.sort(infos, function(a, b) return a.top < b.top end)
+
+              local any_zoomed = false
+              local active_rank, total = 0, 0
+              for _, p in ipairs(infos) do
+                total = total + 1
+                if p.is_active then active_rank = total end
+                if p.is_zoomed then any_zoomed = true end
+              end
+
+              if any_zoomed and total > 1 and active_rank > 0 then
+                title = active_rank .. "/" .. total .. " " .. title
+              end
+            end
+          end
+
+          return {
+            { Background = { Color = bg } },
+            { Foreground = { Color = fg } },
+            { Text = " " .. title .. " " },
+          }
+        end)
+
         wezterm.on("update-status", function(window, _pane)
           local kt   = window:active_key_table()
           local mode = kt or "locked"
@@ -290,6 +368,7 @@ in {
         config.default_cursor_style         = "BlinkingBar"
         config.hide_tab_bar_if_only_one_tab = false
         config.use_fancy_tab_bar            = false
+        config.tab_max_width                = 24
 
         config.colors = {
           tab_bar = {
@@ -313,6 +392,11 @@ in {
 
         config.scrollback_lines = 10000
 
+        -- ─── Stacked panes ─────────────────────────────────────────────────────────
+        -- When switching away from a zoomed pane, unzoom it automatically.
+        -- Paired with stack_focus (Alt+j/k) this gives Zellij-style stacked panels.
+        config.unzoom_on_switch_pane = true
+
         -- ─── Key bindings ──────────────────────────────────────────────────────────
         --
         -- Default mode = "locked" (all keys pass through to the shell).
@@ -324,7 +408,7 @@ in {
 
         config.keys = {
           -- Alt+h/l: move focus or switch tab at edge (Zellij MoveFocusOrTab)
-          -- Alt+j/k: move focus between panes
+          -- Alt+j/k: initial bindings (overridden below by stacked-focus variants)
         ${viDirKeys {
           mods = "ALT";
           indent = "          ";
@@ -340,6 +424,21 @@ in {
         }}
           -- Alt+n: new pane (split right)
           { key = "n", mods = "ALT", action = act.SplitHorizontal({ domain = "CurrentPaneDomain" }) },
+          -- Alt+s: split below, then zoom the new pane so stacked mode starts.
+          -- Two separate perform_action calls: the split runs first and focuses
+          -- the new pane, then the second call zooms window:active_pane() which
+          -- is now the new pane (not the original `pane` argument).
+          { key = "s", mods = "ALT", action = wezterm.action_callback(function(window, pane)
+              window:perform_action(act.SplitVertical({ domain = "CurrentPaneDomain" }), pane)
+              window:perform_action(act.SetPaneZoomState(true), window:active_pane())
+            end)
+          },
+          -- Alt+j/k: move_vertical — plain focus move normally, stacked zoom
+          -- when any pane in the tab is already zoomed (mirrors Alt+f state).
+          { key = "j",         mods = "ALT", action = move_vertical("Down") },
+          { key = "k",         mods = "ALT", action = move_vertical("Up") },
+          { key = "DownArrow", mods = "ALT", action = move_vertical("Down") },
+          { key = "UpArrow",   mods = "ALT", action = move_vertical("Up") },
           -- Alt+f: toggle zoom
           { key = "f", mods = "ALT", action = act.TogglePaneZoomState },
           -- Alt+[/]: rotate panes
@@ -352,8 +451,24 @@ in {
           -- Alt+i/o: reorder tabs
           { key = "i", mods = "ALT", action = act.MoveTabRelative(-1) },
           { key = "o", mods = "ALT", action = act.MoveTabRelative(1) },
-          -- Alt+w: close current pane
+          -- Alt+w: close current pane; if tab was in stacked (zoom) mode, re-zoom
-          { key = "w", mods = "ALT", action = act.CloseCurrentPane({ confirm = true }) },
+          -- the new active pane so zoom mode persists across close.
+          -- confirm=false because the callback must run synchronously after close;
+          -- a confirm dialog would make the zoom fire before the user answers.
+          -- Guard: only re-zoom when there will still be panes left after close.
+          { key = "w", mods = "ALT", action = wezterm.action_callback(function(window, pane)
+              local panes = pane:tab():panes()
+              local was_zoomed = tab_is_zoomed(pane)
+              window:perform_action(act.CloseCurrentPane({ confirm = false }), pane)
+              if was_zoomed and #panes > 1 then
+                window:perform_action(act.SetPaneZoomState(true), window:active_pane())
+              end
+            end)
+          },
+          -- Alt+p: command palette
+          { key = "p", mods = "ALT", action = act.ActivateCommandPalette },
+          -- Alt+t: tab navigator (searchable tab list)
+          { key = "t", mods = "ALT", action = act.ShowTabNavigator },
           -- Alt+q: quit
           { key = "q", mods = "ALT", action = act.QuitApplication },
           -- Ctrl+U/D: scroll half page (matches Alacritty)