feat: Theme engine

big changes

electron/theme-library.ts

@@ -0,0 +1,92 @@
+import { app } from 'electron';
+import * as fsp from 'fs/promises';
+import * as path from 'path';
+
+export interface SavedThemeFileDescriptor {
+  fileName: string;
+  modifiedAt: number;
+  path: string;
+}
+
+const SAVED_THEME_FILE_NAME_PATTERN = /^[A-Za-z0-9][A-Za-z0-9._-]*\.json$/;
+
+function resolveSavedThemesPath(): string {
+  return path.join(app.getPath('userData'), 'themes');
+}
+
+async function ensureSavedThemesPath(): Promise<string> {
+  const themesPath = resolveSavedThemesPath();
+
+  await fsp.mkdir(themesPath, { recursive: true });
+
+  return themesPath;
+}
+
+function assertSavedThemeFileName(fileName: string): string {
+  const normalized = typeof fileName === 'string'
+    ? fileName.trim()
+    : '';
+
+  if (!SAVED_THEME_FILE_NAME_PATTERN.test(normalized) || normalized.includes('..')) {
+    throw new Error('Invalid saved theme file name.');
+  }
+
+  return normalized;
+}
+
+async function resolveSavedThemeFilePath(fileName: string): Promise<string> {
+  const themesPath = await ensureSavedThemesPath();
+
+  return path.join(themesPath, assertSavedThemeFileName(fileName));
+}
+
+export async function getSavedThemesPath(): Promise<string> {
+  return await ensureSavedThemesPath();
+}
+
+export async function listSavedThemes(): Promise<SavedThemeFileDescriptor[]> {
+  const themesPath = await ensureSavedThemesPath();
+  const entries = await fsp.readdir(themesPath, { withFileTypes: true });
+  const files = entries.filter((entry) => entry.isFile() && entry.name.toLowerCase().endsWith('.json'));
+
+  const descriptors = await Promise.all(files.map(async (entry) => {
+    const filePath = path.join(themesPath, entry.name);
+    const stats = await fsp.stat(filePath);
+
+    return {
+      fileName: entry.name,
+      modifiedAt: Math.round(stats.mtimeMs),
+      path: filePath
+    } satisfies SavedThemeFileDescriptor;
+  }));
+
+  return descriptors.sort((left, right) => right.modifiedAt - left.modifiedAt || left.fileName.localeCompare(right.fileName));
+}
+
+export async function readSavedTheme(fileName: string): Promise<string> {
+  const filePath = await resolveSavedThemeFilePath(fileName);
+
+  return await fsp.readFile(filePath, 'utf8');
+}
+
+export async function writeSavedTheme(fileName: string, text: string): Promise<boolean> {
+  const filePath = await resolveSavedThemeFilePath(fileName);
+
+  await fsp.writeFile(filePath, text, 'utf8');
+  return true;
+}
+
+export async function deleteSavedTheme(fileName: string): Promise<boolean> {
+  const filePath = await resolveSavedThemeFilePath(fileName);
+
+  try {
+    await fsp.unlink(filePath);
+    return true;
+  } catch (error) {
+    if ((error as { code?: string }).code === 'ENOENT') {
+      return true;
+    }
+
+    throw error;
+  }
+}