From e84a0c57171097eb32ab92e82f54e522b5e1e65f Mon Sep 17 00:00:00 2001
From: Kristóf Marussy <kristof@marussy.com>
Date: Sun, 26 Dec 2021 02:43:25 +0100
Subject: feat: Config persistence

---
 packages/main/src/index.ts | 93 ++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 85 insertions(+), 8 deletions(-)

(limited to 'packages')

diff --git a/packages/main/src/index.ts b/packages/main/src/index.ts
index 6a8a74e..a79a6e2 100644
--- a/packages/main/src/index.ts
+++ b/packages/main/src/index.ts
@@ -25,9 +25,15 @@ import {
   ipcMain,
   nativeTheme,
 } from 'electron';
-import { readFile, readFileSync } from 'fs';
+import { readFileSync, watchFile } from 'fs';
+import { readFile, stat, writeFile } from 'fs/promises';
 import { autorun } from 'mobx';
-import { getSnapshot, onPatch } from 'mobx-state-tree';
+import {
+  applySnapshot,
+  getSnapshot,
+  onPatch,
+  onSnapshot,
+} from 'mobx-state-tree';
 import { join } from 'path';
 import {
   ServiceToMainIpcMessage,
@@ -46,6 +52,7 @@ import {
   installDevToolsExtensions,
   openDevToolsWhenReady,
 } from './devTools';
+import { ConfigSnapshotOut } from './stores/Config';
 import { createRootStore } from './stores/RootStore';
 
 const isDevelopment = import.meta.env.MODE === 'development';
@@ -114,6 +121,77 @@ nativeTheme.on('updated', () => {
   store.setShouldUseDarkColors(nativeTheme.shouldUseDarkColors);
 });
 
+const configPath = join(app.getPath('userData'), 'config.json');
+let loadingConfig = false;
+let savingConfig = false;
+let configMtime: Date | null = null;
+
+async function loadConfig(): Promise<void> {
+  let configStr: string;
+  try {
+    configStr = await readFile(configPath, 'utf8');
+  } catch (err) {
+    if ((err as NodeJS.ErrnoException).code === 'ENOENT') {
+      console.log('Creating config', configPath);
+      return saveConfig(getSnapshot(store.config));
+    }
+    throw err;
+  }
+  let configSnapshot: unknown;
+  try {
+    configSnapshot = JSON.parse(configStr);
+  } catch (err) {
+    console.error('Invalid config file', configPath, err);
+    return;
+  }
+  loadingConfig = true;
+  try {
+    applySnapshot(store.config, configSnapshot);
+  } catch (err) {
+    console.error('Falied to apply snaphot', configPath, configSnapshot, err);
+  } finally {
+    loadingConfig = false;
+  }
+}
+
+async function saveConfig(configSnapshot: ConfigSnapshotOut): Promise<void> {
+  const configJson = JSON.stringify(configSnapshot, null, 2);
+  savingConfig = true;
+  try {
+    await writeFile(configPath, configJson, 'utf8');
+    const stats = await stat(configPath);
+    configMtime = stats.mtime;
+  } finally {
+    savingConfig = false;
+  }
+  console.log('Wrote config', configPath);
+}
+
+onSnapshot(store.config, (snapshot) => {
+  if (!loadingConfig) {
+    saveConfig(snapshot).catch((err) => {
+      console.error('Failed to save config', configPath, err);
+    });
+  }
+});
+
+async function initializeConfig(): Promise<void> {
+  await loadConfig();
+  watchFile(configPath, ({ mtime }) => {
+    if (!savingConfig && (configMtime === null || mtime > configMtime)) {
+      loadConfig().catch((err) => {
+        console.error('Failed to reload config', configPath, err);
+      });
+      configMtime = mtime;
+      console.log('Reloaded config', configPath);
+    }
+  });
+}
+
+initializeConfig().catch((err) => {
+  console.error('Failed to load config', configPath, err);
+});
+
 const rendererBaseUrl = getResourceUrl('../renderer/');
 function shouldCancelMainWindowRequest(url: string, method: string): boolean {
   if (method !== 'GET') {
@@ -205,12 +283,11 @@ function createWindow(): Promise<unknown> {
           store.config.setThemeSource(themeSource.parse(args[0]))
           break;
         case RendererToMainIpcMessage.ReloadAllServices:
-          readFile(serviceInjectPath, 'utf8', (err, data) => {
-            if (err === null) {
-              serviceInject.code = data;
-            } else {
-              console.error('Error while reloading', serviceInjectPath, err);
-            }
+          readFile(serviceInjectPath, 'utf8').then((data) => {
+            serviceInject.code = data;
+          }).catch((err) => {
+            console.error('Error while reloading', serviceInjectPath, err);
+          }).then(() => {
             browserView.webContents.reload();
           });
           break;
-- 
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