Embed asset files in Nix build

It turns out files under `extra-source-files` are not found at compile time (`file-embed`) unless they're in `rsc` (and not as symlinks), and known to Git (staging makes a difference, which confused me for a while, e.g. in georgefst/hello-hs@fa41589).

.gitignore

@@ -4,5 +4,4 @@ dist*/
 elm-stuff*/
 .ghc.environment.*
 cabal.project.local*
-haskell/rsc
 result

flake.nix

@@ -16,6 +16,7 @@
                 compiler-nix-name = "ghc924";
                 shell.tools = { cabal = { }; };
                 shell = { inherit crossPlatforms; };
+                configureArgs = "-frelease";
               });
           })
 

haskell/rsc/app.css

@@ -0,0 +1,4 @@
+body {
+    /*TODO this may be redundant (except on iOS?) since we also disable scaling via the `viewport` meta tag */
+    touch-action: none
+}

haskell/rsc/common.css

@@ -0,0 +1,6 @@
+body {
+    background-color: rgb(207, 231, 247);
+    overflow: hidden;
+    padding: 0;
+    margin: 0;
+}

haskell/rsc/login.css

@@ -0,0 +1,28 @@
+body {
+    height: 100vh;
+    background-position: center center;
+    background-repeat: no-repeat;
+    background-size: cover;
+    font-family: Helvetica, Arial, sans-serif;
+}
+
+form {
+    padding: 0.5em;
+    text-align: center;
+    font-size: 5vw;
+}
+
+input {
+    font-size: inherit;
+}
+
+.colours {
+    display: flex;
+    flex-direction: row;
+}
+
+.colour {
+    flex-grow: 1;
+    margin: 3vh;
+    height: 10vh;
+}

haskell/rsc/main.js

@@ -0,0 +1,72 @@
+const attr = s => document.currentScript.attributes.getNamedItem(s).value
+
+const params = new URLSearchParams(window.location.search)
+const username = params.get("username")
+
+const wsAddress = "ws://" + location.hostname + ":" + attr("wsPort") + "?" + params
+const ws = new WebSocket(wsAddress)
+ws.onclose = event => {
+    console.log(event)
+    alert("Connection lost. See console for details.")
+}
+
+const layouts = JSON.parse(attr("layouts"))
+const encoding = JSON.parse(attr("encoding"))
+
+ws.onopen = _event => {
+    // Elm
+    elmInitialised = false
+    const app = Elm.Main.init({
+        flags: {
+            username, layouts, encoding,
+            supportsFullscreen: document.documentElement.requestFullscreen != null
+        }
+    })
+    //TODO this (waiting for an initialisation message)
+    // is all just a workaround for the fact that Elm has no built-in way of signalling that 'init' has finished
+    app.ports.initPort.subscribe(() => {
+        elmInitialised = true
+        dispatchEvent(new Event("elmInit"))
+    })
+
+    // fullscreen
+    app.ports.fullscreenPort.subscribe(() => {
+        document.documentElement.requestFullscreen()
+    })
+    document.onfullscreenchange = _event => {
+        app.ports.fullscreenChangePort.send(
+            !(document.fullscreenElement == null)
+        )
+    }
+
+    // update messages
+    app.ports.sendUpdatePortJSON.subscribe(message => ws.send(JSON.stringify(message)))
+    app.ports.sendUpdatePortBinary.subscribe(message => ws.send(Uint8Array.from(message)))
+    ws.addEventListener("message", event => {
+        const send = () => app.ports.receiveUpdatePort.send(JSON.parse(event.data))
+        if (elmInitialised) {
+            send()
+        } else {
+            addEventListener("elmInit", () => {
+                setTimeout(send, 0)
+            })
+        }
+    })
+
+    // reset form
+    app.ports.resetFormPort.subscribe(id => document.getElementById(id).reset())
+
+    // audio
+    app.ports.audioPort.subscribe(url => {
+        audio = new Audio(url)
+        audio.play()
+    })
+
+    // vibration
+    app.ports.vibratePort.subscribe(intervals => {
+        window.navigator.vibrate(intervals)
+    })
+
+    // logging
+    app.ports.logPort.subscribe(console.log)
+}