feat: refactor to use gpui event instead of local state (#18)

Reviewed-on: #18
Co-authored-by: Ren Amamiya <reya@lume.nu>
Co-committed-by: Ren Amamiya <reya@lume.nu>

crates/theme/src/notification.rs

@@ -0,0 +1,31 @@
+use gpui::{Pixels, px};
+use serde::{Deserialize, Serialize};
+
+use crate::{Anchor, Edges, TITLEBAR_HEIGHT};
+
+/// The settings for notifications.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct NotificationSettings {
+    /// The placement of the notification, default: [`Anchor::TopRight`]
+    pub placement: Anchor,
+    /// The margins of the notification with respect to the window edges.
+    pub margins: Edges<Pixels>,
+    /// The maximum number of notifications to show at once, default: 10
+    pub max_items: usize,
+}
+
+impl Default for NotificationSettings {
+    fn default() -> Self {
+        let offset = px(16.);
+        Self {
+            placement: Anchor::TopRight,
+            margins: Edges {
+                top: TITLEBAR_HEIGHT + offset, // avoid overlap with title bar
+                right: offset,
+                bottom: offset,
+                left: offset,
+            },
+            max_items: 10,
+        }
+    }
+}