1 files changed, 85 insertions, 0 deletions
diff --git a/compat/lustre_websocket/src/lustre_websocket.gleam b/compat/lustre_websocket/src/lustre_websocket.gleam
new file mode 100644
index 0000000..ce46a4a
--- /dev/null
+++ b/compat/lustre_websocket/src/lustre_websocket.gleam
@@ -0,0 +1,85 @@
+import lustre/effect.{Effect}
+
+pub type WebSocket
+
+pub type WebSocketCloseReason {
+  // 1000
+  Normal
+  // 1001
+  GoingAway
+  // 1002
+  ProtocolError
+  // 1003
+  UnexpectedTypeOfData
+  // 1004 Reserved
+  // 1005
+  NoCodeFromServer
+  // 1006, no close frame
+  AbnormalClose
+  // 1007
+  IncomprehensibleFrame
+  // 1008
+  PolicyViolated
+  // 1009
+  MessageTooBig
+  // 1010
+  FailedExtensionNegotation
+  // 1011
+  UnexpectedFailure
+  // 1015
+  FailedTLSHandshake
+}
+
+pub type WebSocketEvent {
+  OnOpen(WebSocket)
+  OnMessage(String)
+  OnClose(WebSocketCloseReason)
+}
+
+/// Initialize a websocket. These constructs are fully asynchronous, so you must provide a wrapper
+/// that takes a `WebSocketEvent` and turns it into a lustre message of your application.
+pub fn init(path: String, wrapper: fn(WebSocketEvent) -> a) -> Effect(a) {
+  let ws = do_init(path)
+  use dispatch <- effect.from
+  let on_open = fn() { dispatch(wrapper(OnOpen(ws))) }
+  let on_message = fn(in_msg) { dispatch(wrapper(OnMessage(in_msg))) }
+  let on_close = fn(code) {
+    case code {
+      1000 -> dispatch(wrapper(OnClose(Normal)))
+      1001 -> dispatch(wrapper(OnClose(GoingAway)))
+      1002 -> dispatch(wrapper(OnClose(ProtocolError)))
+      1003 -> dispatch(wrapper(OnClose(UnexpectedTypeOfData)))
+      1005 -> dispatch(wrapper(OnClose(NoCodeFromServer)))
+      1006 -> dispatch(wrapper(OnClose(AbnormalClose)))
+      1007 -> dispatch(wrapper(OnClose(IncomprehensibleFrame)))
+      1008 -> dispatch(wrapper(OnClose(PolicyViolated)))
+      1009 -> dispatch(wrapper(OnClose(MessageTooBig)))
+      1010 -> dispatch(wrapper(OnClose(FailedExtensionNegotation)))
+      1011 -> dispatch(wrapper(OnClose(UnexpectedFailure)))
+      1015 -> dispatch(wrapper(OnClose(FailedTLSHandshake)))
+    }
+  }
+
+  do_register(ws, on_open, on_message, on_close)
+}
+
+external fn do_init(path) -> WebSocket =
+  "./ffi.mjs" "init_websocket"
+
+external fn do_register(
+  ws: WebSocket,
+  on_open: fn() -> Nil,
+  on_message: fn(String) -> Nil,
+  on_close: fn(Int) -> Nil,
+) -> Nil =
+  "./ffi.mjs" "register_websocket_handler"
+
+/// Send a text message over the web socket. This is asynchronous. There is no
+/// expectation of a reply. See `init`. Only works on an Non-Closed socket.
+/// Returns a `Effect(a)` that you must pass as second entry in the lustre `update` return.
+pub fn send(ws: WebSocket, msg: String) -> Effect(a) {
+  effect.from(fn(_) { do_send(ws, msg) })
+}
+
+external fn do_send(ws: WebSocket, msg: String) -> Nil =
+  "./ffi.mjs" "send_over_websocket"