From 3217f2afc3fb15f54580525e2defd4fa0a7be7fa Mon Sep 17 00:00:00 2001
From: Zef Hemel <zef@zef.me>
Date: Sat, 30 Jul 2022 13:39:40 +0200
Subject: [PATCH] Fixes #6 by implementing link unfurling

---
 packages/plugos/environments/node_worker.ts   |  1 +
 .../plugos/environments/sandbox_worker.ts     | 10 ++-
 packages/plugs/core/core.plug.yaml            | 23 ++++++
 packages/plugs/core/link.ts                   | 79 +++++++++++++++++++
 4 files changed, 112 insertions(+), 1 deletion(-)
 create mode 100644 packages/plugs/core/link.ts

diff --git a/packages/plugos/environments/node_worker.ts b/packages/plugos/environments/node_worker.ts
index 1de9666..0fe9f96 100644
--- a/packages/plugos/environments/node_worker.ts
+++ b/packages/plugos/environments/node_worker.ts
@@ -39,6 +39,7 @@ let vm = new VM({
     clearTimeout,
     setInterval,
     URL,
+    window: {},
     clearInterval,
     fetch: require(`${nodeModulesPath}/node-fetch`),
     WebSocket: require(`${nodeModulesPath}/ws`),
diff --git a/packages/plugos/environments/sandbox_worker.ts b/packages/plugos/environments/sandbox_worker.ts
index a8961c8..90a991d 100644
--- a/packages/plugos/environments/sandbox_worker.ts
+++ b/packages/plugos/environments/sandbox_worker.ts
@@ -11,8 +11,16 @@ let pendingRequests = new Map<
   }
 >();
 
+let isWorker = false;
+
+if (typeof window === "undefined") {
+  // @ts-ignore
+  window = {};
+  isWorker = true;
+}
+
 function workerPostMessage(msg: ControllerMessage) {
-  if (typeof window !== "undefined" && window.parent !== window) {
+  if (!isWorker && window.parent !== window) {
     window.parent.postMessage(msg, "*");
   } else {
     self.postMessage(msg);
diff --git a/packages/plugs/core/core.plug.yaml b/packages/plugs/core/core.plug.yaml
index cd5e147..0862bde 100644
--- a/packages/plugs/core/core.plug.yaml
+++ b/packages/plugs/core/core.plug.yaml
@@ -319,3 +319,26 @@ functions:
       name: "UI: Hide BHS"
       key: "Ctrl-Alt-b"
       mac: "Cmd-Alt-b"
+
+  # Link unfurl infrastructure
+  unfurlLink:
+    path: ./link.ts:unfurlCommand
+    command:
+      name: "Link: Unfurl"
+      key: "Ctrl-Shift-u"
+      mac: "Cmd-Shift-u"
+      contexts:
+        - NakedURL
+  unfurlExec:
+    env: server
+    path: ./link.ts:unfurlExec
+
+  # Title-based link unfurl
+  titleUnfurlOptions:
+    path: ./link.ts:titleUnfurlOptions
+    events:
+      - unfurl:options
+  titleUnfurl:
+    path: ./link.ts:titleUnfurl
+    events:
+      - unfurl:title-unfurl
diff --git a/packages/plugs/core/link.ts b/packages/plugs/core/link.ts
new file mode 100644
index 0000000..727c6b9
--- /dev/null
+++ b/packages/plugs/core/link.ts
@@ -0,0 +1,79 @@
+import { nodeAtPos } from "@silverbulletmd/common/tree";
+import {
+  filterBox,
+  flashNotification,
+  getCursor,
+  getText,
+  replaceRange,
+} from "@silverbulletmd/plugos-silverbullet-syscall/editor";
+import { parseMarkdown } from "@silverbulletmd/plugos-silverbullet-syscall/markdown";
+import { dispatch as dispatchEvent } from "@plugos/plugos-syscall/event";
+import { invokeFunction } from "@silverbulletmd/plugos-silverbullet-syscall/system";
+
+type UnfurlOption = {
+  id: string;
+  name: string;
+};
+
+export async function unfurlCommand() {
+  let mdTree = await parseMarkdown(await getText());
+  let nakedUrlNode = nodeAtPos(mdTree, await getCursor());
+  let url = nakedUrlNode!.children![0].text!;
+  console.log("Got URL to unfurl", url);
+  let optionResponses = await dispatchEvent("unfurl:options", url);
+  let options: UnfurlOption[] = [];
+  for (let resp of optionResponses) {
+    options.push(...resp);
+  }
+  let selectedUnfurl: any = await filterBox(
+    "Unfurl",
+    options,
+    "Select the unfurl strategy of your choice"
+  );
+  if (!selectedUnfurl) {
+    return;
+  }
+  try {
+    let replacement = await invokeFunction(
+      "server",
+      "unfurlExec",
+      selectedUnfurl.id,
+      url
+    );
+    await replaceRange(nakedUrlNode?.from!, nakedUrlNode?.to!, replacement);
+  } catch (e: any) {
+    await flashNotification(e.message, "error");
+  }
+}
+
+export async function titleUnfurlOptions(url: string): Promise<UnfurlOption[]> {
+  return [
+    {
+      id: "title-unfurl",
+      name: "Extract title",
+    },
+  ];
+}
+
+// Run on the server because plugs will likely rely on fetch for this
+export async function unfurlExec(id: string, url: string): Promise<string> {
+  let replacement = await dispatchEvent(`unfurl:${id}`, url);
+  return replacement[0];
+}
+
+const titleRegex = /<title[^>]*>\s*([^<]+)\s*<\/title\s*>/i;
+
+export async function titleUnfurl(url: string): Promise<string> {
+  let response = await fetch(url);
+  if (response.status < 200 || response.status >= 300) {
+    console.error("Unfurl failed", await response.text());
+    throw new Error(`Failed to fetch: ${await response.statusText}`);
+  }
+  let body = await response.text();
+  let match = titleRegex.exec(body);
+  if (match) {
+    return `[${match[1]}](${url})`;
+  } else {
+    throw new Error("No title found");
+  }
+}