From cde6311bcb9f8f8f28505bbf7c71a574c294e69f Mon Sep 17 00:00:00 2001
From: Zef Hemel <zef@zef.me>
Date: Sat, 19 Nov 2022 15:22:43 +0100
Subject: [PATCH] Fixes #122

---
 plugs/directive/command.ts          | 107 ++++++++++++++++++++--------
 plugs/directive/directive.plug.yaml |   4 +-
 plugs/directive/directives.ts       |   7 +-
 3 files changed, 79 insertions(+), 39 deletions(-)

diff --git a/plugs/directive/command.ts b/plugs/directive/command.ts
index 4c94f727..69b77084 100644
--- a/plugs/directive/command.ts
+++ b/plugs/directive/command.ts
@@ -1,39 +1,84 @@
-import { editor, space, system } from "$sb/silverbullet-syscall/mod.ts";
-import { renderDirectives } from "./directives.ts";
+import { editor, markdown, system } from "$sb/silverbullet-syscall/mod.ts";
+import { nodeAtPos } from "$sb/lib/tree.ts";
+import { replaceAsync } from "$sb/lib/util.ts";
+import { directiveRegex, renderDirectives } from "./directives.ts";
+import { extractMeta } from "./data.ts";
 
 export async function updateDirectivesOnPageCommand() {
-  const currentPage = await editor.getCurrentPage();
-  await editor.save();
-  if (
-    await system.invokeFunction(
-      "server",
-      "updateDirectivesOnPage",
-      currentPage,
-    )
-  ) {
-    await editor.reloadPage();
+  const pageName = await editor.getCurrentPage();
+  const text = await editor.getText();
+  const tree = await markdown.parseMarkdown(text);
+  const metaData = extractMeta(tree, ["$disableDirectives"]);
+  if (metaData.$disableDirectives) {
+    // Not updating, directives disabled
+    return;
   }
+
+  // Collect all directives and their body replacements
+  const replacements: { startInst: string; text?: string }[] = [];
+
+  await replaceAsync(
+    text,
+    directiveRegex,
+    async (fullMatch, startInst, _type, _arg, _body, endInst, index) => {
+      const replacement: { startInst: string; text?: string } = { startInst };
+      // Pushing to the replacement array
+      replacements.push(replacement);
+      const currentNode = nodeAtPos(tree, index + 1);
+      if (currentNode?.type !== "CommentBlock") {
+        // If not a comment block, it's likely a code block, ignore
+        // console.log("Not comment block, ingoring", fullMatch);
+        return fullMatch;
+      }
+      try {
+        const replacementText = await system.invokeFunction(
+          "server",
+          "serverRenderDirective",
+          pageName,
+          fullMatch,
+        );
+        replacement.text = replacementText;
+        return replacementText;
+      } catch (e: any) {
+        return `${startInst}\n**ERROR:** ${e.message}\n${endInst}`;
+      }
+    },
+  );
+  let counter = 0;
+  // Iterate again and replace the bodies. Iterating again (not using previous positions)
+  // because text may have changed in the mean time (directive processing may take some time)
+  // Hypothetically in the mean time directives in text may have been changed/swapped, in which
+  // case this will break. This would be a rare edge case, however.
+  await replaceAsync(
+    text,
+    directiveRegex,
+    async (fullMatch, startInst, _type, _arg, _body, endInst, index) => {
+      const replacement = replacements[counter++];
+      if (!replacement.text) {
+        return `${startInst}\n$**ERROR:** Internal error, no replacement found\n${endInst}`;
+      }
+      if (replacement.text === fullMatch) {
+        // No change, no need to dispatch
+        return fullMatch;
+      }
+      // Dispatch the change as a somewhat minimal diff in order not to interfere with current editing
+      await editor.dispatch({
+        changes: {
+          from: index,
+          to: index + fullMatch.length,
+          insert: replacement.text,
+        },
+      });
+      return replacement.text;
+    },
+  );
 }
 
 // Called from client, running on server
-export async function updateDirectivesOnPage(
+// The text passed here is going to be a single directive block (not a full page)
+export function serverRenderDirective(
   pageName: string,
-): Promise<boolean> {
-  let text = "";
-  try {
-    text = await space.readPage(pageName);
-  } catch {
-    console.warn(
-      "Could not read page",
-      pageName,
-      "perhaps it doesn't yet exist",
-    );
-    return false;
-  }
-  const newText = await renderDirectives(pageName, text);
-  if (text !== newText) {
-    await space.writePage(pageName, newText);
-    return true;
-  }
-  return false;
+  text: string,
+): Promise<string> {
+  return renderDirectives(pageName, text);
 }
diff --git a/plugs/directive/directive.plug.yaml b/plugs/directive/directive.plug.yaml
index b7d594d3..be14fe65 100644
--- a/plugs/directive/directive.plug.yaml
+++ b/plugs/directive/directive.plug.yaml
@@ -2,8 +2,8 @@ name: directive
 imports:
   - https://get.silverbullet.md/global.plug.json
 functions:
-  updateDirectivesOnPage:
-    path: ./command.ts:updateDirectivesOnPage
+  serverRenderDirective:
+    path: ./command.ts:serverRenderDirective
   updateDirectivesOnPageCommand:
     path: ./command.ts:updateDirectivesOnPageCommand
     command:
diff --git a/plugs/directive/directives.ts b/plugs/directive/directives.ts
index a51add25..e6b04aa8 100644
--- a/plugs/directive/directives.ts
+++ b/plugs/directive/directives.ts
@@ -52,12 +52,7 @@ export async function renderDirectives(
   text: string,
 ): Promise<string> {
   const tree = await markdown.parseMarkdown(text);
-  const metaData = extractMeta(tree, ["$disableDirectives"]);
-  // console.log("Meta data", pageName, metaData);
-  if (metaData.$disableDirectives) {
-    return text;
-  }
-  text = renderToText(tree);
+
   text = await directiveDispatcher(pageName, text, tree, {
     use: templateDirectiveRenderer,
     "use-verbose": templateDirectiveRenderer,