feat: 实现 DOCX 可编辑字体嵌入

packages/application/src/theme-registry.ts

@@ -13,7 +13,9 @@ import {
   sep
 } from "node:path";
 import {
+  MAXIMUM_DOCX_FONT_TOTAL_SOURCE_BYTES,
   themeManifestSchema,
+  type DocxFontFace,
   type ThemeManifest
 } from "@md-to-pdf/core";
 
@@ -23,6 +25,10 @@ export interface ThemeRecord {
   source: "bundled" | "local";
 }
 
+export interface ThemeFontAsset extends DocxFontFace {
+  content: Uint8Array;
+}
+
 export interface ThemeRegistryOptions {
   bundledRoot: string;
   localRoot: string;
@@ -48,6 +54,7 @@ const cssImportPattern =
 const maximumCssImportDepth = 8;
 const sharedThemeAssetId = "_shared";
 const sharedThemeAssetScheme = "theme-shared:";
+const sharedFontCssPath = "official-fonts/fonts.css";
 
 function isMissingFileError(error: unknown) {
   return (
@@ -314,6 +321,40 @@ export function createThemeRegistry(options: ThemeRegistryOptions) {
         promise: Promise<ThemeRecord[]>;
       }
     | undefined;
+  let sharedFontCssPromise: Promise<string> | undefined;
+
+  function loadSharedFontCss() {
+    if (!sharedFontCssPromise) {
+      sharedFontCssPromise = (async () => {
+        const sharedRoot = resolve(
+          options.bundledRoot,
+          sharedThemeAssetId
+        );
+        try {
+          const cssPath = await resolveThemeFile(
+            sharedRoot,
+            sharedFontCssPath
+          );
+          return prepareCssSegment(
+            await readFile(cssPath, "utf8"),
+            sharedThemeAssetId,
+            posix.dirname(sharedFontCssPath),
+            createAssetUrl,
+            false
+          );
+        } catch (error) {
+          if (isMissingFileError(error)) {
+            return "";
+          }
+          throw error;
+        }
+      })();
+      void sharedFontCssPromise.catch(() => {
+        sharedFontCssPromise = undefined;
+      });
+    }
+    return sharedFontCssPromise;
+  }
 
   async function scanThemes() {
     const [bundledThemes, localThemes] = await Promise.all([
@@ -366,6 +407,7 @@ export function createThemeRegistry(options: ThemeRegistryOptions) {
 
   function invalidate() {
     cachedThemes = undefined;
+    sharedFontCssPromise = undefined;
   }
 
   async function get(themeId: string) {
@@ -385,13 +427,15 @@ export function createThemeRegistry(options: ThemeRegistryOptions) {
         ? [theme.manifest.print]
         : [])
     ];
-    return (
-      await Promise.all(
+    const css = await Promise.all(
         cssFiles.map((path) =>
           loadThemeCssFile(theme, path, createAssetUrl)
         )
-      )
-    ).join("\n");
+      );
+    if (theme.source === "bundled") {
+      css.unshift(await loadSharedFontCss());
+    }
+    return css.filter(Boolean).join("\n");
   }
 
   async function getAsset(themeId: string, assetPath: string) {
@@ -427,10 +471,54 @@ export function createThemeRegistry(options: ThemeRegistryOptions) {
     };
   }
 
+  async function getDocxFonts(
+    themeId: string
+  ): Promise<ThemeFontAsset[] | undefined> {
+    const theme = await get(themeId);
+    if (!theme) {
+      return undefined;
+    }
+    const faces = theme.manifest.docxFonts?.faces ?? [];
+    const fonts = await Promise.all(
+      faces.map(async (face) => {
+        const shared = face.source.startsWith(
+          sharedThemeAssetScheme
+        );
+        if (shared && theme.source !== "bundled") {
+          throw new Error("本地主题不能嵌入内置共享字体");
+        }
+        const asset = await getAsset(
+          shared ? sharedThemeAssetId : theme.manifest.id,
+          shared
+            ? face.source.slice(sharedThemeAssetScheme.length)
+            : face.source
+        );
+        if (!asset || !asset.contentType.startsWith("font/")) {
+          throw new Error(
+            `DOCX 字体资源无效：${face.source}`
+          );
+        }
+        return {
+          ...face,
+          content: asset.content
+        };
+      })
+    );
+    const totalBytes = fonts.reduce(
+      (total, font) => total + font.content.byteLength,
+      0
+    );
+    if (totalBytes > MAXIMUM_DOCX_FONT_TOTAL_SOURCE_BYTES) {
+      throw new Error("DOCX 字体资源总大小超过限制");
+    }
+    return fonts;
+  }
+
   return {
     get,
     getAsset,
     getCss,
+    getDocxFonts,
     invalidate,
     list
   };