From 069b36c20d25bd3c2d03b416d45cf2a3e6a3405b Mon Sep 17 00:00:00 2001
From: Stefano Pigozzi <me@steffo.eu>
Date: Fri, 8 Nov 2024 06:38:00 +0100
Subject: [PATCH] Use katex preamble

---
 src/elements/markdown/math.mjs     |  5 ++--
 src/elements/markdown/renderer.mjs | 29 ++++++++++++++++---
 src/elements/vault.mjs             | 46 ++++++++++++++++++++++++++++++
 3 files changed, 73 insertions(+), 7 deletions(-)

diff --git a/src/elements/markdown/math.mjs b/src/elements/markdown/math.mjs
index 982f9d6..745880b 100644
--- a/src/elements/markdown/math.mjs
+++ b/src/elements/markdown/math.mjs
@@ -46,7 +46,7 @@ export class MathElement extends CustomElement {
      * The group to use to store macros in.
      * Should be overridden by the creator element.
      */
-    katexGroup = {}
+    katexMacros = {}
 
     /**
      * The name of the slot where {@link katexElement} should be placed in.
@@ -74,7 +74,7 @@ export class MathElement extends CustomElement {
             {
                 throwOnError: false,
                 globalGroup: true,
-                macros: this.katexGroup,
+                macros: this.katexMacros,
                 trust: true,
             }
         )
@@ -84,7 +84,6 @@ export class MathElement extends CustomElement {
 
     onConnect() {
         super.onConnect()
-
         this.recreateKatexElement()
     }
 }
diff --git a/src/elements/markdown/renderer.mjs b/src/elements/markdown/renderer.mjs
index 973a522..f5abe50 100644
--- a/src/elements/markdown/renderer.mjs
+++ b/src/elements/markdown/renderer.mjs
@@ -1,6 +1,8 @@
 import { Marked } from "https://unpkg.com/marked@9.1.2/lib/marked.esm.js";
 import { CustomElement } from "../base.mjs";
 import {toTitleCase} from "../../utils/case.mjs";
+import {findFirstAncestor} from "../../utils/traversal.mjs";
+import {VaultElement} from "../vault.mjs";
 
 
 /**
@@ -11,10 +13,25 @@ export class MarkdownElement extends CustomElement {
         return document.getElementById("template-markdown")
     }
 
+    /**
+     * Element representing the Obsidian Vault.
+     * Can be recalculated with {@link recalculateAncestors}.
+     * @type {VaultElement}
+     */
+    vault
+
+    /**
+     * Recalculate the value of {@link browse} and {@link vault} using this element's current position in the DOM.
+     * @returns {void}
+     */
+    recalculateAncestors() {
+        this.vault = findFirstAncestor(this, VaultElement)
+    }
+
     /**
      * The group to use to store KaTeX macros in for everything in this {@link MarkdownElement}.
      */
-    katexGroup = {}
+    katexGroup
 
     // noinspection JSUnusedGlobalSymbols
     /**
@@ -222,7 +239,7 @@ export class MarkdownElement extends CustomElement {
     /**
      * Recreate {@link documentElement} using the current value of {@link markdownDocument}.
      */
-    recreateDocumentElement() {
+    async recreateDocumentElement() {
         if(this.documentElement) {
             this.documentElement.remove()
             this.documentElement = null
@@ -232,8 +249,11 @@ export class MarkdownElement extends CustomElement {
         this.documentElement.slot = this.constructor.DOCUMENT_ELEMENT_SLOT
         this.documentElement.innerHTML = this.constructor.MARKED.parse(this.markdownDocument)
 
+        // TODO: await this properly
+        await this.vault.sleepUntilKatexMacrosAreAvailable()
+        this.katexMacros = {...this.vault.katexMacros}
         for(const el of this.documentElement.getElementsByTagName("x-math")) {
-            el.katexGroup = this.katexGroup
+            el.katexMacros = this.katexMacros
         }
 
         this.appendChild(this.documentElement)
@@ -241,6 +261,7 @@ export class MarkdownElement extends CustomElement {
 
     onConnect() {
         super.onConnect()
-        this.recreateDocumentElement()
+        this.recalculateAncestors()
+        this.recreateDocumentElement().then()
     }
 }
diff --git a/src/elements/vault.mjs b/src/elements/vault.mjs
index e7d1a63..3fd2b25 100644
--- a/src/elements/vault.mjs
+++ b/src/elements/vault.mjs
@@ -1,5 +1,6 @@
 import { CustomElement } from "./base.mjs";
 import { sleep } from "../utils/sleep.mjs";
+import {default as katex} from 'https://cdn.jsdelivr.net/npm/katex@0.16.9/dist/katex.mjs';
 
 
 /**
@@ -186,11 +187,56 @@ export class VaultElement extends CustomElement {
         await new Promise(resolve => this.#fileIndexQueue.push(resolve))
     }
 
+    /**
+     * Macros to be used in every single {@link MathElement} of the vault.
+     */
+    katexMacros
+
+    /**
+     * Update {@link katexMacros} by fetching the `preamble.sty` file located at the root of the Vault, and then having KaTeX render it to a string, which is then discarded.
+     * @returns {Promise<void>}
+     */
+    async refetchKatexMacros() {
+        const response = await this.fetchCooldown("preamble.sty")
+        if(response.status >= 400) {
+            this.katexMacros = {}
+            this.#katexMacrosQueue.forEach(resolve => resolve(undefined))
+            return
+        }
+        const preamble = await response.text()
+        this.katexMacros = {}
+        katex.renderToString(preamble, {
+            throwOnError: false,
+            globalGroup: true,
+            macros: this.katexMacros,
+            trust: true,
+        })
+        this.#katexMacrosQueue.forEach(resolve => resolve(undefined))
+    }
+
+    /**
+     * Array of resolve {@link Promise} objects of tasks awaiting {@link sleepUntilKatexPreambleIsAvailable}.
+     * @type {((v: undefined) => void)[]}
+     */
+    #katexMacrosQueue = []
+
+    /**
+     * Await until {@link katexPreamble} becomes available.
+     * @returns {Promise<void>}
+     */
+    async sleepUntilKatexMacrosAreAvailable() {
+        if(this.katexMacros !== undefined) {
+            return
+        }
+        await new Promise(resolve => this.#katexMacrosQueue.push(resolve))
+    }
+
     async onConnect() {
         super.onConnect()
         this.recalculateVaultElement()
         this.#fetchQueueScheduler().then()
         await this.refetchAppearance()
         await this.refetchFileIndex()
+        await this.refetchKatexMacros()
     }
 }
\ No newline at end of file