From a84908b7e8a0e2423afd6b836eccf27a420270b4 Mon Sep 17 00:00:00 2001
From: nsfisis <nsfisis@gmail.com>
Date: Wed, 20 Sep 2023 19:56:52 +0900
Subject: feat(blog/nuldoc): change content format from DocBook to NulDoc

---
 vhosts/blog/nuldoc-src/ndoc/to_html.ts | 235 +++++++++++++++++++++++++++++++++
 1 file changed, 235 insertions(+)
 create mode 100644 vhosts/blog/nuldoc-src/ndoc/to_html.ts

(limited to 'vhosts/blog/nuldoc-src/ndoc/to_html.ts')

diff --git a/vhosts/blog/nuldoc-src/ndoc/to_html.ts b/vhosts/blog/nuldoc-src/ndoc/to_html.ts
new file mode 100644
index 00000000..dc39919b
--- /dev/null
+++ b/vhosts/blog/nuldoc-src/ndoc/to_html.ts
@@ -0,0 +1,235 @@
+// @deno-types="../types/highlight-js.d.ts"
+import hljs from "npm:highlight.js";
+import { Document } from "./document.ts";
+import { DocBookError } from "../errors.ts";
+import {
+  addClass,
+  Element,
+  findFirstChildElement,
+  forEachChild,
+  forEachChildRecursively,
+  Node,
+  RawHTML,
+  Text,
+} from "../dom.ts";
+
+export default function toHtml(doc: Document): Document {
+  removeUnnecessaryTextNode(doc);
+  transformSectionIdAttribute(doc);
+  setSectionTitleAnchor(doc);
+  transformSectionTitleElement(doc);
+  transformCodeBlockElement(doc);
+  transformNoteElement(doc);
+  setDefaultLangAttribute(doc);
+  traverseFootnotes(doc);
+  highlightPrograms(doc);
+  return doc;
+}
+
+function removeUnnecessaryTextNode(doc: Document) {
+  const g = (n: Node) => {
+    if (n.kind !== "element") {
+      return;
+    }
+
+    let changed = true;
+    while (changed) {
+      changed = false;
+      if (n.children.length === 0) {
+        break;
+      }
+      const firstChild = n.children[0];
+      if (firstChild.kind === "text" && firstChild.content.trim() === "") {
+        n.children.shift();
+        changed = true;
+      }
+      if (n.children.length === 0) {
+        break;
+      }
+      const lastChild = n.children[n.children.length - 1];
+      if (lastChild.kind === "text" && lastChild.content.trim() === "") {
+        n.children.pop();
+        changed = true;
+      }
+    }
+
+    forEachChild(n, g);
+  };
+  forEachChild(doc.root, g);
+}
+
+function transformSectionIdAttribute(doc: Document) {
+  forEachChildRecursively(doc.root, (n) => {
+    if (n.kind !== "element" || n.name !== "section") {
+      return;
+    }
+
+    const idAttr = n.attributes.get("id");
+    n.attributes.set("id", `section--${idAttr}`);
+  });
+}
+
+function setSectionTitleAnchor(doc: Document) {
+  const sectionStack: Element[] = [];
+  const g = (c: Node) => {
+    if (c.kind !== "element") {
+      return;
+    }
+
+    if (c.name === "section") {
+      sectionStack.push(c);
+    }
+    forEachChild(c, g);
+    if (c.name === "section") {
+      sectionStack.pop();
+    }
+    if (c.name === "h") {
+      const currentSection = sectionStack[sectionStack.length - 1];
+      if (!currentSection) {
+        throw new DocBookError(
+          "[docbook.tohtml] <h> element must be inside <section>",
+        );
+      }
+      const sectionId = currentSection.attributes.get("id");
+      const aElement: Element = {
+        kind: "element",
+        name: "a",
+        attributes: new Map(),
+        children: c.children,
+      };
+      aElement.attributes.set("href", `#${sectionId}`);
+      c.children = [aElement];
+    }
+  };
+  forEachChild(doc.root, g);
+}
+
+function transformSectionTitleElement(doc: Document) {
+  let sectionLevel = 1;
+  const g = (c: Node) => {
+    if (c.kind !== "element") {
+      return;
+    }
+
+    if (c.name === "section") {
+      sectionLevel += 1;
+      c.attributes.set("--section-level", sectionLevel.toString());
+    }
+    forEachChild(c, g);
+    if (c.name === "section") {
+      sectionLevel -= 1;
+    }
+    if (c.name === "h") {
+      c.name = `h${sectionLevel}`;
+    }
+  };
+  forEachChild(doc.root, g);
+}
+
+function transformCodeBlockElement(doc: Document) {
+  forEachChildRecursively(doc.root, (n) => {
+    if (n.kind !== "element" || n.name !== "codeblock") {
+      return;
+    }
+
+    n.name = "pre";
+    addClass(n, "highlight");
+    const codeElement: Element = {
+      kind: "element",
+      name: "code",
+      attributes: new Map(),
+      children: n.children,
+    };
+    n.children = [codeElement];
+  });
+}
+
+function transformNoteElement(doc: Document) {
+  forEachChildRecursively(doc.root, (n) => {
+    if (n.kind !== "element" || n.name !== "note") {
+      return;
+    }
+
+    const labelElement: Element = {
+      kind: "element",
+      name: "div",
+      attributes: new Map([["class", "admonition-label"]]),
+      children: [{
+        kind: "text",
+        content: "NOTE",
+        raw: false,
+      }],
+    };
+    const contentElement: Element = {
+      kind: "element",
+      name: "div",
+      attributes: new Map([["class", "admonition-content"]]),
+      children: n.children,
+    };
+    n.name = "div";
+    addClass(n, "admonition");
+    n.children = [
+      labelElement,
+      contentElement,
+    ];
+  });
+}
+
+function setDefaultLangAttribute(_doc: Document) {
+  // TODO
+  // if (!e.attributes.has("lang")) {
+  //   e.attributes.set("lang", "ja-JP");
+  // }
+}
+
+function traverseFootnotes(doc: Document) {
+  forEachChildRecursively(doc.root, (n) => {
+    if (n.kind !== "element" || n.name !== "footnote") {
+      return;
+    }
+
+    // TODO
+    // <footnote>x</footnote>
+    //
+    // <sup class="footnote">[<a id="_footnoteref_1" class="footnote" href="#_footnotedef_1">1</a>]</sup>
+    //
+    // <div class="footnote" id="_footnotedef_1">
+    //   <a href="#_footnoteref_1">1</a>. RAS syndrome
+    // </div>
+    n.name = "span";
+    n.children = [];
+  });
+}
+
+function highlightPrograms(doc: Document) {
+  forEachChildRecursively(doc.root, (n) => {
+    if (n.kind !== "element" || n.name !== "pre") {
+      return;
+    }
+    const preClass = n.attributes.get("class") || "";
+    if (!preClass.includes("highlight")) {
+      return;
+    }
+    const codeElement = findFirstChildElement(n, "code");
+    if (!codeElement) {
+      return;
+    }
+    const language = n.attributes.get("language");
+    if (!language) {
+      return;
+    }
+    const sourceCodeNode = codeElement.children[0] as Text | RawHTML;
+    const sourceCode = sourceCodeNode.content;
+
+    if (!hljs.getLanguage(language)) {
+      return;
+    }
+
+    const highlighted =
+      hljs.highlight(sourceCode, { language: language }).value;
+
+    sourceCodeNode.content = highlighted;
+    sourceCodeNode.raw = true;
+    codeElement.attributes.set("class", "highlight");
+  });
+}
-- 
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