Add agent driven component.

src/alert/sub.rs

@@ -0,0 +1,52 @@
+use super::{Alert, Bus};
+use crate::prelude::*;
+use yew::prelude::*;
+
+pub struct AlertSubscriber {
+    link: ComponentLink<Self>,
+    alert: Option<(Color, String)>,
+    _producer: Box<dyn Bridge<Bus>>,
+}
+
+impl Component for AlertSubscriber {
+    type Message = Option<(Color, String)>;
+    type Properties = ();
+
+    fn create(_: Self::Properties, link: ComponentLink<Self>) -> Self {
+        let _producer = Bus::bridge(link.callback(|msg| msg));
+        let alert = None;
+        Self {
+            link,
+            alert,
+            _producer,
+        }
+    }
+
+    fn update(&mut self, msg: Self::Message) -> ShouldRender {
+        if self.alert == msg {
+            false
+        } else {
+            self.alert = msg;
+            true
+        }
+    }
+
+    fn change(&mut self, _: Self::Properties) -> ShouldRender {
+        false
+    }
+
+    fn view(&self) -> Html {
+        if let Some((color, message)) = self.alert.as_ref() {
+            html! {
+                <Alert
+                    on_close=self.link.callback(|_| None)
+                    color=color
+                >
+                { message }
+                </Alert>
+            }
+        } else {
+            html! {}
+        }
+    }
+}