From 2b39573eb1aef32fbb6a5afae7444375e97c26b6 Mon Sep 17 00:00:00 2001
From: Ampflower <ampflower@outlook.com>
Date: Thu, 8 Dec 2022 18:36:47 -0600
Subject: [PATCH] Make #updatePresence use ScheduledThreadPool to try to avoid
 crashing.

This tries to resolve the issue of presence updates not occurring as
they should after about 6000 rounds, which sounds suspiciously like a
stack overflow. (The-ProxyFox-Group/ProxyFox#21)
---
 .../main/kotlin/dev/proxyfox/bot/BotUtil.kt   | 22 +++++++----
 .../kotlin/dev/proxyfox/bot/SchedulerUtil.kt  | 37 +++++++++++++++++++
 2 files changed, 52 insertions(+), 7 deletions(-)
 create mode 100644 modules/bot/src/main/kotlin/dev/proxyfox/bot/SchedulerUtil.kt

diff --git a/modules/bot/src/main/kotlin/dev/proxyfox/bot/BotUtil.kt b/modules/bot/src/main/kotlin/dev/proxyfox/bot/BotUtil.kt
index fe66a3e9..f8c6f755 100644
--- a/modules/bot/src/main/kotlin/dev/proxyfox/bot/BotUtil.kt
+++ b/modules/bot/src/main/kotlin/dev/proxyfox/bot/BotUtil.kt
@@ -49,20 +49,29 @@ import kotlinx.datetime.Clock
 import kotlinx.datetime.Instant
 import java.lang.Integer.min
 import java.time.OffsetDateTime
+import java.util.concurrent.Executors
 import kotlin.contracts.ExperimentalContracts
 import kotlin.contracts.InvocationKind
 import kotlin.contracts.contract
 import kotlin.time.Duration
 import kotlin.time.Duration.Companion.milliseconds
+import kotlin.time.Duration.Companion.minutes
 
 const val UPLOAD_LIMIT = 1024 * 1024 * 8
 
+val scheduler = Executors.newScheduledThreadPool(Runtime.getRuntime().availableProcessors())
+
 lateinit var scope: CoroutineScope
 lateinit var kord: Kord
 lateinit var http: HttpClient
 lateinit var startTime: Instant
+private var count: Int = 0
 var shardCount: Int = 0
-val errorChannelId = try { Snowflake(System.getenv("PROXYFOX_LOG")) } catch (_: Throwable) { null }
+val errorChannelId = try {
+    Snowflake(System.getenv("PROXYFOX_LOG"))
+} catch (_: Throwable) {
+    null
+}
 var errorChannel: TextChannel? = null
 
 @OptIn(PrivilegedIntent::class)
@@ -148,29 +157,28 @@ suspend fun login() {
 
 suspend fun updatePresence() {
     startTime = Clock.System.now()
-    var count = 0
-    while (true) {
-        count++
-        count %= 3
+    scheduler.fixedRateAction(Duration.ZERO, 2.minutes) {
+        count = (count + 1) % 3
         val append = when (count) {
             0 -> {
                 val servers = kord.guilds.count()
                 "in $servers servers!"
             }
+
             1 -> {
                 val systemCount = database.fetchTotalSystems()
                 "$systemCount systems registered!"
             }
+
             2 -> {
                 "uptime: ${(Clock.System.now() - startTime).inWholeHours} hours!"
             }
 
-            else -> throw IllegalStateException("Count is not 0, 1, or 2!")
+            else -> throw AssertionError("Count ($count) not in 0..2")
         }
         kord.editPresence {
             watching("for pf>help! $append")
         }
-        delay(120000)
     }
 }
 
diff --git a/modules/bot/src/main/kotlin/dev/proxyfox/bot/SchedulerUtil.kt b/modules/bot/src/main/kotlin/dev/proxyfox/bot/SchedulerUtil.kt
new file mode 100644
index 00000000..2003e502
--- /dev/null
+++ b/modules/bot/src/main/kotlin/dev/proxyfox/bot/SchedulerUtil.kt
@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2022, The ProxyFox Group
+ *
+ * This Source Code is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+package dev.proxyfox.bot
+
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.launch
+import java.util.concurrent.ScheduledExecutorService
+import java.util.concurrent.TimeUnit
+import kotlin.time.Duration
+
+// Created 2022-08-12T16:06:42
+
+/**
+ * Helper functions for [ScheduledExecutorService].
+ *
+ * @author Ampflower
+ * @since 2.0.8
+ **/
+
+/**
+ * Wrapper around [ScheduledExecutorService.scheduleAtFixedRate] to provide a Kotlin Coroutine equivalent.
+ *
+ * @param initialDelay The initial delay. Will be treated as milliseconds.
+ * @param period The period in which future action runs will occur. Will be treated as milliseconds.
+ * @param action The action to execute within a coroutine scope.
+ * */
+fun ScheduledExecutorService.fixedRateAction(initialDelay: Duration, period: Duration, action: suspend CoroutineScope.() -> Unit) {
+    scheduleAtFixedRate({
+        scope.launch(block = action)
+    }, initialDelay.inWholeMilliseconds, period.inWholeMilliseconds, TimeUnit.MILLISECONDS)
+}
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