separate playtime file

src/runner.js

@@ -77,15 +77,16 @@ function parseArgs(args) {
 
 const GRACE_MS = 60000
 
-// Live playtime: update stats while the game is still running (not only on exit).
-function startPlaytimeTicker({ game, startedAt, onTick }) {
+// Live playtime: while the game runs, update ONLY the tiny playtime file
+// (a number of seconds) every 30s - apps.json is left untouched to spare the
+// disk. lastPlayed is stamped once at start, final totals are mirrored into
+// the registry once on exit.
+function startPlaytimeTicker({ game, startedAt }) {
+  const library = require('./library')
+  const base = game.playSeconds || 0
   const timer = setInterval(() => {
     const counted = Math.max(0, Math.round((Date.now() - startedAt - GRACE_MS) / 1000))
-    require('./library').updateGame(game.id, {
-      lastPlayed: startedAt,
-      playSeconds: (game.playSeconds || 0) + counted
-    })
-    if (onTick) onTick()
+    library.writePlaySeconds(game.id, base + counted)
   }, 30000)
   return () => clearInterval(timer)
 }
@@ -147,6 +148,8 @@ function runGame({ game, wine, systemWine, onExit }) {
     child.unref()
     const startedAt = Date.now()
     const stopTicker = startPlaytimeTicker({ game, startedAt })
+    // stamp "last played" once at start so it is correct even if we crash later
+    require('./library').updateGame(game.id, { lastPlayed: startedAt })
     child.on('exit', (code, signal) => {
       stopTicker()
       ws.end()