background thread sends ts as mvp

src/gui.rs

@@ -7,6 +7,7 @@ use iced_futures::backend::native::async_std::time::every;
 use handlebars::Handlebars;
 use serde_json::json;
 use std::time::{SystemTime, UNIX_EPOCH};
+use std::thread;
 
 use crate::stream::OutputStream;
 use crate::config::GUI;
@@ -31,7 +32,9 @@ pub fn main(cfg: GUI, output_stream: Box<dyn OutputStream>) -> iced::Result {
 }
 
 struct Main {
-   ntfy: String,
+   c: std::sync::mpsc::Receiver<String>,
+   ntfy1: String,
+   ntfy2: String,
    configuring: Option<Message>,
    inputs: Inputs,
    keys_newly_down: Vec<iced::keyboard::KeyCode>,
@@ -100,6 +103,18 @@ impl Main {
    }
 
    fn exchange(&mut self) {
+      self.exchange_send();
+      self.exchange_recv();
+   }
+
+   fn exchange_recv(&mut self) {
+      match self.c.try_recv() {
+         Ok(msg) => self.ntfy2 = msg,
+         _ => {},
+      };
+   }
+
+   fn exchange_send(&mut self) {
       let mut s = vec![];
       for key_code in self.keys_newly_down.iter() {
          match self.key_code_to_string(key_code) {
@@ -170,8 +185,16 @@ impl Application for Main {
    type Executor = executor::Default;
 
    fn new(flags: Self::Flags) -> (Self, Command<Message>) {
+      let (sender, receiver) = std::sync::mpsc::channel();
+      thread::spawn(move || {
+         Feedback{
+            c: sender,
+         }.listen()
+      });
       return (Self {
-         ntfy: String::from(":wave:"),
+         c: receiver,
+         ntfy1: String::from(":wave:"),
+         ntfy2: String::from(""),
          configuring: None,
          inputs: Inputs{
             stick: Stick {
@@ -223,7 +246,7 @@ impl Application for Main {
                      Message::R => { self.inputs.r = key_code },
                      _ => {},
                   };
-                  self.ntfy = format!("{:?} => {:?}", key_code.clone(), self.configuring.as_ref().unwrap());
+                  self.ntfy1 = format!("{:?} => {:?}", key_code.clone(), self.configuring.as_ref().unwrap());
                   self.configuring = None;
                },
                _ => {},
@@ -268,7 +291,7 @@ impl Application for Main {
          },
          _ => {
             self.configuring = Some(msg.clone());
-            self.ntfy = format!("push a key to bind to {:?}", msg.clone());
+            self.ntfy1 = format!("push a key to bind to {:?}", msg.clone());
          },
       }
       return Command::none();
@@ -296,10 +319,38 @@ impl Application for Main {
                button(text(controller_button_to_string(Message::Y, self.inputs.y))).on_press(Message::Y),
                button(text(controller_button_to_string(Message::L, self.inputs.l))).on_press(Message::L),
                button(text(controller_button_to_string(Message::R, self.inputs.r))).on_press(Message::R),
-               text(self.ntfy.clone()).size(50),
+               text(self.ntfy1.clone()).size(50),
+               text(self.ntfy2.clone()).size(50),
          ]
          .padding(20)
          .align_items(Alignment::Center)
          .into();
     }
 }
+
+struct Feedback {
+   c: std::sync::mpsc::Sender<String>,
+}
+
+impl Feedback {
+   fn listen(&mut self) {
+      loop {
+         std::thread::sleep(std::time::Duration::from_secs(2));
+         match self.read() {
+            Some(msg) if msg.len() > 0 => self.write(msg),
+            _ => {},
+         };
+      }
+   }
+
+   fn read(&mut self) -> Option<String> {
+      return Some(String::from(format!("feedback.read: {:?}", SystemTime::now())));
+   }
+
+   fn write(&mut self, msg: String) {
+      match self.c.send(msg.clone()) {
+         Ok(_) => {},
+         Err(err) => eprintln!("feedback.listen() failed to display {}: {}", msg, err),
+      };
+   }
+}