Add utility functions and tests

This adds some utility functions for common functionality when
working with config files. It also adds some super basic tests
that tests those functionalities.

These tests at present rely on the host to have the Steam snap
installed with at least 1 game installed, and will modify the
host's Steam configs. In the future this needs to be mocked
instead.

Author: ashuntu

packages/game_center/lib/steam/steam_model.dart

@@ -47,29 +47,31 @@ class SteamModel extends _$SteamModel {
     installLocation = install;
 
     // global config
+    final file = File(steamGlobalConfig(installLocation));
+    globalConfig = vdfDecode(await file.readAsString());
+
     final fileSystem = FileWatcher(steamGlobalConfig(installLocation));
     fileSystem.events.listen((event) async {
       switch (event.type) {
         case ChangeType.MODIFY:
           await updateGlobalConfig();
       }
     });
-    final file = File(steamGlobalConfig(installLocation));
-    globalConfig = vdfDecode(await file.readAsString());
 
     // user configs
     final users = await listUserDirs();
     userConfigs = new Map();
     for (final steamID in users) {
+      final file = File(steamUserConfig(installLocation, steamID));
+      userConfigs[steamID] = vdfDecode(await file.readAsString());
+
       final fileSystem = FileWatcher(steamUserConfig(installLocation, steamID));
       fileSystem.events.listen((event) async {
         switch (event.type) {
           case ChangeType.MODIFY:
             await updateUserConfig(steamID);
         }
       });
-      final file = File(steamUserConfig(installLocation, steamID));
-      userConfigs[steamID] = vdfDecode(await file.readAsString());
     }
 
     return (
@@ -103,4 +105,47 @@ class SteamModel extends _$SteamModel {
       userConfigs: userConfigs,
     ));
   }
+
+  /// Enable/disable Steam Play (Proton) for all titles globally. This is
+  /// disabled by default on Steam for Linux, but enabled by default on Steam
+  /// Deck.
+  Future<void> enableSteamPlay(
+      {required bool enable, String? protonVersion}) async {
+    Map<String, dynamic> config = Map.from(globalConfig);
+    if (enable) {
+      config['InstallConfigStore']['Software']['Valve']['Steam']
+          ['CompatToolMapping']['0'] = {
+        'name': protonVersion ?? 'proton_experimental',
+        'config': '',
+        'priority': '75'
+      };
+    } else {
+      config['InstallConfigStore']['Software']['Valve']['Steam']
+          ['CompatToolMapping'] = {};
+    }
+
+    final file = File(steamGlobalConfig(installLocation));
+    await file.writeAsString(vdf.encode(config));
+  }
+
+  /// Get a map of installed Steam apps for the given user.
+  Future<Map<String, dynamic>> listApps({required String steamID}) async {
+    Map<String, dynamic> config = Map.from(userConfigs[steamID]!);
+    Map<dynamic, dynamic> apps =
+        config['UserLocalConfigStore']['Software']['Valve']['Steam']['apps'];
+    return apps.cast<String, dynamic>();
+  }
+
+  /// Set the raw launch options for a specific app.
+  Future<void> setGameLaunchOptions({
+    required String steamID,
+    required String appID,
+    required String options,
+  }) async {
+    Map<String, dynamic> config = Map.from(userConfigs[steamID]!);
+    config['UserLocalConfigStore']['Software']['Valve']['Steam']['apps'][appID]
+        ['LaunchOptions'] = options;
+    final file = File(steamUserConfig(installLocation, steamID));
+    await file.writeAsString(vdf.encode(config));
+  }
 }

packages/game_center/test/steam/steam_model_test.dart

@@ -0,0 +1,81 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:game_center/steam/steam_model.dart';
+
+import 'test_utils.dart';
+
+void main() {
+  test('build', () async {
+    final container = createContainer();
+    final provider = steamModelProvider();
+    final buildResult = await container.read(provider.future);
+
+    expect(buildResult.globalConfig, isNotEmpty);
+    expect(buildResult.userConfigs, isNotEmpty);
+  });
+
+  test('list users', () async {
+    final container = createContainer();
+    final model = container.read(steamModelProvider().notifier);
+    await container.read(steamModelProvider().future);
+
+    expect(await model.listUserDirs(), isNotEmpty);
+  });
+
+  test('enable Steam Play', () async {
+    final container = createContainer();
+    final model = container.read(steamModelProvider().notifier);
+    await container.read(steamModelProvider().future);
+
+    model.enableSteamPlay(enable: false);
+    expect(
+      model.globalConfig['InstallConfigStore']['Software']['Valve']['Steam']
+          ['CompatToolMapping'],
+      isEmpty,
+    );
+
+    model.enableSteamPlay(enable: true);
+    expect(
+      model.globalConfig['InstallConfigStore']['Software']['Valve']['Steam']
+          ['CompatToolMapping'],
+      isNotEmpty,
+    );
+    expect(
+      model.globalConfig['InstallConfigStore']['Software']['Valve']['Steam']
+          ['CompatToolMapping']['0'],
+      isNotEmpty,
+    );
+  });
+
+  test('list apps', () async {
+    final container = createContainer();
+    final model = container.read(steamModelProvider().notifier);
+    await container.read(steamModelProvider().future);
+
+    final users = await model.listUserDirs();
+    for (final user in users) {
+      final apps = await model.listApps(steamID: user);
+      expect(apps, isNotEmpty);
+    }
+  });
+
+  test('set launch options', () async {
+    final container = createContainer();
+    final model = container.read(steamModelProvider().notifier);
+    await container.read(steamModelProvider().future);
+
+    final users = await model.listUserDirs();
+    for (final user in users) {
+      final apps = await model.listApps(steamID: user);
+      model.setGameLaunchOptions(
+        steamID: user,
+        appID: apps.keys.toList()[0],
+        options: '%command%',
+      );
+      expect(
+        model.userConfigs[user]!['UserLocalConfigStore']['Software']['Valve']
+            ['Steam']['apps'][apps.keys.toList()[0]]['LaunchOptions'],
+        equals('%command%'),
+      );
+    }
+  });
+}

packages/game_center/test/steam/test_utils.dart

@@ -0,0 +1,22 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:riverpod/riverpod.dart';
+
+/// A testing utility which creates a [ProviderContainer] and automatically
+/// disposes it at the end of the test.
+///
+/// https://riverpod.dev/docs/essentials/testing
+ProviderContainer createContainer({
+  ProviderContainer? parent,
+  List<Override> overrides = const [],
+  List<ProviderObserver>? observers,
+}) {
+  final container = ProviderContainer(
+    parent: parent,
+    overrides: overrides,
+    observers: observers,
+  );
+
+  addTearDown(container.dispose);
+
+  return container;
+}