callRunner: Use PowerShell to run commands on Windows

PowerShell's `Start-Process` cmdlet & its `-Wait` parameter are used to wait
for a process tree to exit. This means we can now accurately track the "Playing"
 status of games on Windows.

src/backend/launcher.ts

@@ -29,6 +29,7 @@ import {
   flatPakHome,
   isLinux,
   isMac,
+  isWindows,
   isSteamDeckGameMode,
   runtimePath,
   userHome
@@ -862,13 +863,32 @@ async function callRunner(
   runner: RunnerProps,
   options?: CallRunnerOptions
 ): Promise<ExecResult> {
-  const fullRunnerPath = join(runner.dir, runner.bin)
   const appName = commandParts[commandParts.findIndex(() => 'launch') + 1]
 
   // Necessary to get rid of possible undefined or null entries, else
   // TypeError is triggered
   commandParts = commandParts.filter(Boolean)
 
+  let bin = runner.bin
+  let fullRunnerPath = join(runner.dir, bin)
+
+  // On Windows: Use PowerShell's `Start-Process` to wait for the process and
+  // its children to exit
+  if (isWindows) {
+    const argsAsString = commandParts
+      .map((part) => (part.includes(' ') ? `"\`"${part}\`""` : `"${part}"`))
+      .join(',')
+    commandParts = [
+      'Start-Process',
+      `${fullRunnerPath}`,
+      '-Wait',
+      '-ArgumentList',
+      argsAsString,
+      '-NoNewWindow'
+    ]
+    bin = fullRunnerPath = 'powershell'
+  }
+
   const safeCommand = getRunnerCallWithoutCredentials(
     [...commandParts],
     options?.env,
@@ -897,8 +917,6 @@ async function callRunner(
     }
   }
 
-  const bin = runner.bin
-
   // check if the same command is currently running
   // if so, return the same promise instead of running it again
   const key = [runner.name, commandParts].join(' ')
@@ -1055,11 +1073,25 @@ function getRunnerCallWithoutCredentials(
   const modifiedCommand = [...command]
   // Redact sensitive arguments (Authorization Code for Legendary, token for GOGDL)
   for (const sensitiveArg of ['--code', '--token']) {
-    const sensitiveArgIndex = modifiedCommand.indexOf(sensitiveArg)
-    if (sensitiveArgIndex === -1) {
-      continue
+    // PowerShell's argument formatting is quite different, instead of having
+    // arguments as members of `command`, they're all in one specific member
+    // (the one after "-ArgumentList")
+    if (runnerPath === 'powershell') {
+      const argumentListIndex = modifiedCommand.indexOf('-ArgumentList') + 1
+      if (!argumentListIndex) continue
+      modifiedCommand[argumentListIndex] = modifiedCommand[
+        argumentListIndex
+      ].replace(
+        new RegExp(`"${sensitiveArg}","(.*?)"`),
+        `"${sensitiveArg}","<redacted>"`
+      )
+    } else {
+      const sensitiveArgIndex = modifiedCommand.indexOf(sensitiveArg)
+      if (sensitiveArgIndex === -1) {
+        continue
+      }
+      modifiedCommand[sensitiveArgIndex + 1] = '<redacted>'
     }
-    modifiedCommand[sensitiveArgIndex + 1] = '<redacted>'
   }
 
   const formattedEnvVars: string[] = []