Add agent driven component.

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bootstrap-rs"
-version = "0.2.12"
+version = "0.2.13"
 authors = ["Thomas Gideon <cmdln@thecommandline.net>"]
 edition = "2018"
 

src/alert/bus.rs

@@ -0,0 +1,61 @@
+use crate::prelude::*;
+use std::collections::HashSet;
+use yew::worker::{Agent, AgentLink, Context, HandlerId};
+
+pub struct Bus {
+    link: AgentLink<Bus>,
+    subscribers: HashSet<HandlerId>,
+}
+
+pub enum Request {
+    Primary(String),
+    Secondary(String),
+    Success(String),
+    Danger(String),
+    Warning(String),
+    Info(String),
+    Clear,
+}
+
+impl Into<Option<(Color, String)>> for &Request {
+    fn into(self) -> Option<(Color, String)> {
+        use Request::*;
+        match self {
+            Primary(alert) => Some((Color::Primary, alert.clone())),
+            Secondary(alert) => Some((Color::Secondary, alert.clone())),
+            Success(alert) => Some((Color::Success, alert.clone())),
+            Danger(alert) => Some((Color::Danger, alert.clone())),
+            Warning(alert) => Some((Color::Warning, alert.clone())),
+            Info(alert) => Some((Color::Info, alert.clone())),
+            Clear => None,
+        }
+    }
+}
+
+impl Agent for Bus {
+    type Reach = Context<Self>;
+    type Message = ();
+    type Input = Request;
+    type Output = Option<(Color, String)>;
+
+    fn create(link: AgentLink<Self>) -> Self {
+        let subscribers = HashSet::new();
+        Self { link, subscribers }
+    }
+
+    fn update(&mut self, _: Self::Message) {}
+
+    fn handle_input(&mut self, input: Self::Input, _id: HandlerId) {
+        for sub in self.subscribers.iter() {
+            self.link.respond(*sub, (&input).into());
+        }
+    }
+
+    fn connected(&mut self, id: HandlerId) {
+        self.subscribers.insert(id);
+    }
+
+    fn disconnected(&mut self, id: HandlerId) {
+        self.subscribers.remove(&id);
+    }
+}

src/alert/mod.rs

@@ -1,7 +1,11 @@
+mod bus;
 mod props;
+mod sub;
 
 use self::props::Props;
 use crate::{prelude::*, render};
+pub use bus::{Bus, Request};
+pub use sub::AlertSubscriber;
 use yew::prelude::*;
 
 pub struct Alert {

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! {}
+        }
+    }
+}