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use futures::stream::{SplitSink, SplitStream, StreamExt};
use futures::SinkExt;
use std::collections::VecDeque;
use std::sync::Arc;
pub use tokio;
use tokio::sync::RwLock;
use tokio::task;
use tokio_tungstenite::connect_async;
use tokio_tungstenite::tungstenite::Message;
pub use url;
type WebSocketStream = tokio_tungstenite::WebSocketStream<
tokio_tungstenite::stream::Stream<
tokio::net::TcpStream,
tokio_native_tls::TlsStream<tokio::net::TcpStream>,
>,
>;
pub struct Canvas {
buffer: [[u8; 256]; 256],
}
impl Canvas {
pub fn new() -> Self {
Self {
buffer: [[0; 256]; 256],
}
}
pub fn get_pixel(&self, x: u8, y: u8) -> u8 {
self.buffer[y as usize][x as usize]
}
pub fn set_pixel(&mut self, x: u8, y: u8, c: u8) {
self.buffer[y as usize][x as usize] = c;
}
}
pub struct RemoteCanvas {
local_copy: Arc<RwLock<Canvas>>,
_socket_read: Arc<RwLock<SplitStream<WebSocketStream>>>,
socket_write: Arc<RwLock<SplitSink<WebSocketStream, Message>>>,
_updater_task: task::JoinHandle<()>,
fetch_triggers: Arc<RwLock<VecDeque<triggered::Trigger>>>,
}
impl RemoteCanvas {
pub async fn new(server_url: url::Url) -> Result<Self, String> {
let (socket, _) = connect_async(server_url)
.await
.map_err(|err| err.to_string())?;
let (socket_write, socket_read) = {
let (write, read) = socket.split();
(Arc::new(RwLock::new(write)), Arc::new(RwLock::new(read)))
};
let local_copy = Arc::new(RwLock::new(Canvas::new()));
let fetch_triggers = Arc::new(RwLock::new(VecDeque::<triggered::Trigger>::new()));
let updater_task = {
let local_copy_clone = local_copy.clone();
let socket_read_clone = socket_read.clone();
let fetch_triggers_clone = fetch_triggers.clone();
task::spawn(async move {
println!("started update listener");
loop {
println!("waiting for message in update listener loop");
let message = socket_read_clone
.write()
.await
.next()
.await
.unwrap()
.unwrap();
println!("received message");
let mut canvas = local_copy_clone.write().await;
let is_key_frame = process_update(&mut canvas, &message);
if is_key_frame {
if let Some(trigger) = fetch_triggers_clone.write().await.pop_front() {
trigger.trigger();
}
}
}
})
};
let remote_canvas = Self {
local_copy,
_socket_read: socket_read,
socket_write,
_updater_task: updater_task,
fetch_triggers,
};
Ok(remote_canvas)
}
pub async fn set_pixel(&mut self, x: u8, y: u8, c: u8) {
self.local_copy.write().await.set_pixel(x, y, c);
let message = Message::binary(vec![x, y, c]);
self.socket_write.write().await.send(message).await.unwrap()
}
pub async fn get_pixel(&self, x: u8, y: u8) -> u8 {
self.local_copy.read().await.get_pixel(x, y)
}
pub async fn fetch(&mut self) {
let (trigger, listener) = triggered::trigger();
self.fetch_triggers.write().await.push_back(trigger);
let message = Message::text("fetch");
self.socket_write.write().await.send(message).await.unwrap();
println!("sent fetch command");
listener.await;
println!("done awaiting the matching key-frame");
}
}
fn process_update(canvas: &mut Canvas, message: &Message) -> bool {
println!("received message: {}", message);
if let Message::Binary(data) = message {
if !data.is_empty() {
match data[0] {
0 => {
if (data.len() - 1) % 3 == 0 {
let n = (data.len() - 1) / 3;
for i in 0..n {
let x = data[3 * i + 1];
let y = data[3 * i + 2];
let c = data[3 * i + 3];
canvas.set_pixel(x, y, c);
}
} else {
println!(
"[WARN] expected message length of 3n+1, got {}",
message.len()
);
}
false
}
1 => {
if data.len() == 65537 {
for y in 0..=255 {
for x in 0..=255 {
canvas.set_pixel(x as u8, y as u8, data[1 + x + 256 * y]);
}
}
} else {
println!(
"[WARN] expected message length of 65537, got {}",
message.len()
);
}
true
}
2 => {
false
}
_ => false,
}
} else {
println!("[WARN] unexpected empty message: {}", message);
false
}
} else {
println!("[WARN] unexpected message: {}", message);
false
}
}