6 files changed, 199 insertions, 0 deletions
diff --git a/src/content/index.html b/src/content/index.html
new file mode 100644
index 0000000..ca012d4
--- /dev/null
+++ b/src/content/index.html
@@ -0,0 +1,22 @@
+<!DOCTYPE html>
+<html lang="en" manifest="manifest.appcache">
+  <head>
+    <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1" />
+    <!--
+      FIXME
+      - metadata
+      - canonical link
+    -->
+    <link rel="stylesheet"    type="text/css"      href="./style.css" />
+    <link rel="shortcut icon" type="image/svg+xml" href="./img/favicon.svg" />
+    <title>Chat with Freedom | Papo FIXME</title>
+    <script type="module">
+      import { main } from "./papo.js";
+      main();
+    </script>
+  </head>
+  <body>
+    <p id="static-loading">Loading...</p>
+  </body>
+</html>
diff --git a/src/content/papo.js b/src/content/papo.js
new file mode 100644
index 0000000..83dd1b1
--- /dev/null
+++ b/src/content/papo.js
@@ -0,0 +1,34 @@
+// import * as assert from "node:assert/strict";
+
+
+// assert.deepEqual({a: 1}, {a: 1});
+// console.log(123);
+// console.log({ navigator });
+
+
+const f1 = x => x + 1;
+const f2 = x => x - 1;
+
+const registerServiceWorker = async ({ serviceWorkerPath, err }) => {
+	try {
+		await navigator.serviceWorker?.register(path)
+	} catch (e) {
+		err(`Service worker registration failed: ${e}`);
+	}
+};
+
+export const main = async ({
+	serviceWorkerPath = "./service-worker.js",
+	out = console.log,
+	err = console.warn,
+} = {}) => {
+	const env = {
+		serviceWorkerPath,
+		out,
+		err,
+	};
+	await registerServiceWorker(env);
+	out("main called");
+};
+
+// <body onload="setOnline()" ononline="setOnline()"  onoffline="setOnline()" >
diff --git a/src/content/style.css b/src/content/style.css
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/src/content/style.css
diff --git a/src/content/sw.js b/src/content/sw.js
new file mode 100644
index 0000000..9e17707
--- /dev/null
+++ b/src/content/sw.js
@@ -0,0 +1,131 @@
+const CACHE_NAME = "static-shared-assets";
+
+const FALLBACK_PATHS = {
+	img: "/fallback-image-FIXME.svg",
+	data: {
+		static: "/fallback-data-FIXME.json",
+	},
+};
+
+const leafValues = tree =>
+	Object.values(tree).map(x =>
+		typeof x !== "object"
+			? x
+			: leafValues(x)
+	);
+
+const collectLeaves = tree =>
+	leafValues(tree).flat(Infinity);
+
+const DEFAULT_INSTALL_PATHS = [
+	"/",
+	"index.html",
+	"style.css",
+	"img/favicon.svg",
+	"papo.js",
+].concat(collectLeaves(FALLBACK_PATHS));
+
+const mkInstallHandler = ({ self, caches }) => event => {
+	self.skipWaiting();
+	event.waitUntil(
+		caches.open(CACHE_NAME).then(
+			cache => cache.addAll(DEFAULT_INSTALL_PATHS),
+		),
+	);
+};
+
+const store = async (caches, request, response) => {
+	const cache = await caches.open(CACHE_NAME);
+	await cache.put(request, response);
+};
+
+const getPrefixIn = (paths, segments) => {
+	if (paths === undefined) {
+		return null;
+	}
+
+	if (segments.length === 0) {
+		return null;
+	}
+
+	if (typeof paths === "string") {
+		return paths;
+	}
+
+	return getPrefixIn(paths[segments[0]], segments.slice(1));
+};
+
+const maybeFallback = async (caches, request, paths = FALLBACK_PATHS) => {
+	const url          = new URL(request.url)
+	const segments     = url.pathname.split("/").filter(s => !!s)
+	const fallbackPath = getPrefixIn(paths, segments);
+	if (fallbackPath) {
+		return await caches.match(fallbackPath);
+	}
+
+	return null;
+}
+
+const fromCache = async (caches, fetch, { request, preloadResponse }) => {
+	const cachedResponse = await caches.match(request);
+	if (cachedResponse) {
+		fetch(request).then(async freshResponse =>
+			store(caches, request, freshResponse));
+		return cachedResponse;
+	}
+
+	const preloadedResponse = await preloadResponse;
+	if (preloadedResponse) {
+		store(caches, request, preloadeResponse.clone());
+		return preloadedResponse;
+	}
+
+	try {
+		// FIXME: do integration test with real lack of internet.
+		const fetchedResponse = await fetch(request);
+		store(caches, request, fetchedResponse.clone());
+		return fetchedResponse;
+	} catch (e) {
+		const fallbackResponse = await maybeFallback(caches, request);
+		if (fallbackResponse) {
+			return fallbackResponse;
+		}
+
+		throw e;
+	}
+};
+
+const mkFetchHandler = ({ caches }) => (event, mkfetch = () => fetch) => {
+	if (event.request.method !== "GET") {
+		return;
+	}
+
+	event.respondWith(fromCache(caches, mkfetch(), event));
+};
+
+const mkActivateHandler = ({ self, clients }) => event =>
+	event.waitUntil(Promise.all([
+		clients.claim(),
+		self.registration.navigationPreload?.enable(),
+	]));
+
+const registerListeners = env => {
+	env.self.addEventListener("install",   mkInstallHandler(env));
+	env.self.addEventListener("activate", mkActivateHandler(env));
+	env.self.addEventListener("fetch",       mkFetchHandler(env));
+};
+
+const main = ({
+	self,
+	caches,
+	clients,
+	out = console.log,
+	err = console.warn,
+} = {}) =>
+	registerListeners({
+		self,
+		caches,
+		clients,
+		out,
+		err,
+	});
diff --git a/src/exported.sh b/src/exported.sh
new file mode 100755
index 0000000..15e99f6
--- /dev/null
+++ b/src/exported.sh
@@ -0,0 +1,7 @@
+#!/bin/sh
+set -eu
+
+cat "$1"
+printf '%s\n\n\nexport {\n'
+awk '/^const / { printf "\t%s,\n", $2 }' "$1"
+printf '}\n'
diff --git a/src/sw-main.js b/src/sw-main.js
new file mode 100644
index 0000000..be45ba4
--- /dev/null
+++ b/src/sw-main.js
@@ -0,0 +1,5 @@
+main({
+	self,
+	caches,
+	clients,
+});