feat: Add support for action modifier keys like ctrl,shift,alt.

crates/pikl-core/src/model/event.rs

@@ -9,6 +9,8 @@
 
 use std::sync::Arc;
 
+use serde::ser::SerializeSeq;
+use serde::Serialize;
 use serde_json::Value;
 
 use crate::hook::HookResponse;
@@ -56,6 +58,64 @@ pub enum Action {
     StreamingDone,
 }
 
+/// Modifier keys held during an action. Serializes as an
+/// array of strings (e.g. `["shift", "ctrl"]`). Empty
+/// modifiers serialize as `[]`.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
+pub struct Modifiers {
+    pub shift: bool,
+    pub ctrl: bool,
+    pub alt: bool,
+}
+
+impl Modifiers {
+    /// True when no modifiers are held.
+    pub fn is_empty(&self) -> bool {
+        !self.shift && !self.ctrl && !self.alt
+    }
+}
+
+impl Serialize for Modifiers {
+    fn serialize<S: serde::Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
+        let count = self.shift as usize + self.ctrl as usize + self.alt as usize;
+        let mut seq = serializer.serialize_seq(Some(count))?;
+        if self.shift {
+            seq.serialize_element("shift")?;
+        }
+        if self.ctrl {
+            seq.serialize_element("ctrl")?;
+        }
+        if self.alt {
+            seq.serialize_element("alt")?;
+        }
+        seq.end()
+    }
+}
+
+/// An [`Action`] paired with the modifier keys that were
+/// held when it was triggered. Frontends produce these,
+/// the menu engine consumes them.
+#[derive(Debug, Clone, PartialEq)]
+pub struct ModifiedAction {
+    pub action: Action,
+    pub modifiers: Modifiers,
+}
+
+impl ModifiedAction {
+    /// Wrap an action with default (empty) modifiers.
+    pub fn new(action: Action) -> Self {
+        Self {
+            action,
+            modifiers: Modifiers::default(),
+        }
+    }
+
+    /// Wrap an action with specific modifiers.
+    pub fn with_modifiers(action: Action, modifiers: Modifiers) -> Self {
+        Self { action, modifiers }
+    }
+}
+
 /// Broadcast from the menu loop to all subscribers
 /// (frontends, tests).
 #[derive(Debug, Clone)]
@@ -125,10 +185,89 @@ pub enum MenuResult {
     Selected {
         items: Vec<(Value, usize)>,
         filter_text: String,
+        modifiers: Modifiers,
     },
     Quicklist {
         items: Vec<(Value, usize)>,
         filter_text: String,
+        modifiers: Modifiers,
+    },
+    Cancelled {
+        modifiers: Modifiers,
     },
-    Cancelled,
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use serde_json::json;
+
+    #[test]
+    fn modifiers_empty_serializes_as_empty_array() {
+        let mods = Modifiers::default();
+        let json = serde_json::to_value(&mods).unwrap_or_default();
+        assert_eq!(json, json!([]));
+    }
+
+    #[test]
+    fn modifiers_single_serializes() {
+        let mods = Modifiers {
+            shift: true,
+            ctrl: false,
+            alt: false,
+        };
+        let json = serde_json::to_value(&mods).unwrap_or_default();
+        assert_eq!(json, json!(["shift"]));
+    }
+
+    #[test]
+    fn modifiers_multiple_serializes() {
+        let mods = Modifiers {
+            shift: true,
+            ctrl: true,
+            alt: false,
+        };
+        let json = serde_json::to_value(&mods).unwrap_or_default();
+        assert_eq!(json, json!(["shift", "ctrl"]));
+    }
+
+    #[test]
+    fn modifiers_all_serializes() {
+        let mods = Modifiers {
+            shift: true,
+            ctrl: true,
+            alt: true,
+        };
+        let json = serde_json::to_value(&mods).unwrap_or_default();
+        assert_eq!(json, json!(["shift", "ctrl", "alt"]));
+    }
+
+    #[test]
+    fn modifiers_is_empty() {
+        assert!(Modifiers::default().is_empty());
+        assert!(!Modifiers {
+            shift: true,
+            ctrl: false,
+            alt: false
+        }
+        .is_empty());
+    }
+
+    #[test]
+    fn modified_action_new_has_empty_modifiers() {
+        let ma = ModifiedAction::new(Action::Confirm);
+        assert!(ma.modifiers.is_empty());
+    }
+
+    #[test]
+    fn modified_action_with_modifiers() {
+        let mods = Modifiers {
+            shift: true,
+            ctrl: false,
+            alt: false,
+        };
+        let ma = ModifiedAction::with_modifiers(Action::Confirm, mods);
+        assert!(ma.modifiers.shift);
+        assert!(!ma.modifiers.ctrl);
+    }
 }