feat(wm): add dynamic layout selection rules

This commit adds a new feature which allows the user to specify a set of
rules for a specific workspace that will be used to calculate which
layout to apply to that workspace at any given time.

The rule consists of a usize, which identifies the threshold of window
containers which need to be visible on the workspace to activate the
rule, and a layout, which will be applied to the workspace when the rule
is activated.

Both default and custom layouts can be used in workspace layout rules.

When a workspace has layout rules in effect, manually changing the
layout will not work again until the rules for that workspace have been
cleared.

This feature came about after trying but failing to modify the custom
layout code in such a way that the width percentage of a primary column
in a custom layout might be propagated to the fallback columnar layout
when the tertiary column threshold is not met.

Although this new feature introduces more complexity, it is strictly
opt-in and can be completely ignored if the user has no interest in
adjusting layouts based on the visible window count.

re #121

komorebi/src/process_command.rs

@@ -244,6 +244,35 @@ impl WindowManager {
             SocketMessage::WorkspaceLayout(monitor_idx, workspace_idx, layout) => {
                 self.set_workspace_layout_default(monitor_idx, workspace_idx, layout)?;
             }
+            SocketMessage::WorkspaceLayoutRule(
+                monitor_idx,
+                workspace_idx,
+                at_container_count,
+                layout,
+            ) => {
+                self.add_workspace_layout_default_rule(
+                    monitor_idx,
+                    workspace_idx,
+                    at_container_count,
+                    layout,
+                )?;
+            }
+            SocketMessage::WorkspaceLayoutCustomRule(
+                monitor_idx,
+                workspace_idx,
+                at_container_count,
+                path,
+            ) => {
+                self.add_workspace_layout_custom_rule(
+                    monitor_idx,
+                    workspace_idx,
+                    at_container_count,
+                    path,
+                )?;
+            }
+            SocketMessage::ClearWorkspaceLayoutRules(monitor_idx, workspace_idx) => {
+                self.clear_workspace_layout_rules(monitor_idx, workspace_idx)?;
+            }
             SocketMessage::CycleFocusWorkspace(direction) => {
                 // This is to ensure that even on an empty workspace on a secondary monitor, the
                 // secondary monitor where the cursor is focused will be used as the target for

komorebi/src/window_manager.rs

@@ -1277,6 +1277,127 @@ impl WindowManager {
         self.update_focused_workspace(false)
     }
 
+    #[tracing::instrument(skip(self))]
+    pub fn add_workspace_layout_default_rule(
+        &mut self,
+        monitor_idx: usize,
+        workspace_idx: usize,
+        at_container_count: usize,
+        layout: DefaultLayout,
+    ) -> Result<()> {
+        tracing::info!("setting workspace layout");
+
+        let invisible_borders = self.invisible_borders;
+        let offset = self.work_area_offset;
+        let focused_monitor_idx = self.focused_monitor_idx();
+
+        let monitor = self
+            .monitors_mut()
+            .get_mut(monitor_idx)
+            .ok_or_else(|| anyhow!("there is no monitor"))?;
+
+        let work_area = *monitor.work_area_size();
+        let focused_workspace_idx = monitor.focused_workspace_idx();
+
+        let workspace = monitor
+            .workspaces_mut()
+            .get_mut(workspace_idx)
+            .ok_or_else(|| anyhow!("there is no monitor"))?;
+
+        let rules: &mut Vec<(usize, Layout)> = workspace.layout_rules_mut();
+        rules.retain(|pair| pair.0 != at_container_count);
+        rules.push((at_container_count, Layout::Default(layout)));
+        rules.sort_by(|a, b| a.0.cmp(&b.0));
+
+        // If this is the focused workspace on a non-focused screen, let's update it
+        if focused_monitor_idx != monitor_idx && focused_workspace_idx == workspace_idx {
+            workspace.update(&work_area, offset, &invisible_borders)?;
+            Ok(())
+        } else {
+            Ok(self.update_focused_workspace(false)?)
+        }
+    }
+
+    #[tracing::instrument(skip(self))]
+    pub fn add_workspace_layout_custom_rule(
+        &mut self,
+        monitor_idx: usize,
+        workspace_idx: usize,
+        at_container_count: usize,
+        path: PathBuf,
+    ) -> Result<()> {
+        tracing::info!("setting workspace layout");
+
+        let invisible_borders = self.invisible_borders;
+        let offset = self.work_area_offset;
+        let focused_monitor_idx = self.focused_monitor_idx();
+
+        let monitor = self
+            .monitors_mut()
+            .get_mut(monitor_idx)
+            .ok_or_else(|| anyhow!("there is no monitor"))?;
+
+        let work_area = *monitor.work_area_size();
+        let focused_workspace_idx = monitor.focused_workspace_idx();
+
+        let workspace = monitor
+            .workspaces_mut()
+            .get_mut(workspace_idx)
+            .ok_or_else(|| anyhow!("there is no monitor"))?;
+
+        let layout = CustomLayout::from_path_buf(path)?;
+
+        let rules: &mut Vec<(usize, Layout)> = workspace.layout_rules_mut();
+        rules.retain(|pair| pair.0 != at_container_count);
+        rules.push((at_container_count, Layout::Custom(layout)));
+        rules.sort_by(|a, b| a.0.cmp(&b.0));
+
+        // If this is the focused workspace on a non-focused screen, let's update it
+        if focused_monitor_idx != monitor_idx && focused_workspace_idx == workspace_idx {
+            workspace.update(&work_area, offset, &invisible_borders)?;
+            Ok(())
+        } else {
+            Ok(self.update_focused_workspace(false)?)
+        }
+    }
+
+    #[tracing::instrument(skip(self))]
+    pub fn clear_workspace_layout_rules(
+        &mut self,
+        monitor_idx: usize,
+        workspace_idx: usize,
+    ) -> Result<()> {
+        tracing::info!("setting workspace layout");
+
+        let invisible_borders = self.invisible_borders;
+        let offset = self.work_area_offset;
+        let focused_monitor_idx = self.focused_monitor_idx();
+
+        let monitor = self
+            .monitors_mut()
+            .get_mut(monitor_idx)
+            .ok_or_else(|| anyhow!("there is no monitor"))?;
+
+        let work_area = *monitor.work_area_size();
+        let focused_workspace_idx = monitor.focused_workspace_idx();
+
+        let workspace = monitor
+            .workspaces_mut()
+            .get_mut(workspace_idx)
+            .ok_or_else(|| anyhow!("there is no monitor"))?;
+
+        let rules: &mut Vec<(usize, Layout)> = workspace.layout_rules_mut();
+        rules.clear();
+
+        // If this is the focused workspace on a non-focused screen, let's update it
+        if focused_monitor_idx != monitor_idx && focused_workspace_idx == workspace_idx {
+            workspace.update(&work_area, offset, &invisible_borders)?;
+            Ok(())
+        } else {
+            Ok(self.update_focused_workspace(false)?)
+        }
+    }
+
     #[tracing::instrument(skip(self))]
     pub fn set_workspace_layout_default(
         &mut self,

komorebi/src/workspace.rs

@@ -41,6 +41,8 @@ pub struct Workspace {
     floating_windows: Vec<Window>,
     #[getset(get = "pub", get_mut = "pub", set = "pub")]
     layout: Layout,
+    #[getset(get = "pub", get_mut = "pub", set = "pub")]
+    layout_rules: Vec<(usize, Layout)>,
     #[getset(get_copy = "pub", set = "pub")]
     layout_flip: Option<Axis>,
     #[getset(get_copy = "pub", set = "pub")]
@@ -69,6 +71,7 @@ impl Default for Workspace {
             monocle_container_restore_idx: None,
             floating_windows: Vec::default(),
             layout: Layout::Default(DefaultLayout::BSP),
+            layout_rules: vec![],
             layout_flip: None,
             workspace_padding: Option::from(10),
             container_padding: Option::from(10),
@@ -164,6 +167,20 @@ impl Workspace {
 
         self.enforce_resize_constraints();
 
+        if !self.layout_rules().is_empty() {
+            let mut updated_layout = None;
+
+            for rule in self.layout_rules() {
+                if self.containers().len() >= rule.0 {
+                    updated_layout = Option::from(rule.1.clone());
+                }
+            }
+
+            if let Some(updated_layout) = updated_layout {
+                self.set_layout(updated_layout);
+            }
+        }
+
         if *self.tile() {
             if let Some(container) = self.monocle_container_mut() {
                 if let Some(window) = container.focused_window_mut() {