fix: don't reconnect when command was superseded

We only want to do the reconnect if the previous command was the
schedule reconnect, if the websocket connection got started another way
or was closed, we don't want to do the reconnect.

app/src/main/kotlin/com/github/gotify/service/WebSocketConnection.kt

@@ -1,6 +1,7 @@
 package com.github.gotify.service
 
 import android.app.AlarmManager
+import android.app.AlarmManager.OnAlarmListener
 import android.os.Build
 import android.os.Handler
 import android.os.Looper
@@ -29,9 +30,10 @@ internal class WebSocketConnection(
         private val ID = AtomicLong(0)
     }
 
+    private var alarmManagerCallback: OnAlarmListener? = null
+    private var handlerCallback: Runnable? = null
     private val client: OkHttpClient
     private val reconnectHandler = Handler(Looper.getMainLooper())
-    private val reconnectCallback = Runnable { start() }
     private var errorCount = 0
 
     private var webSocket: WebSocket? = null
@@ -106,6 +108,13 @@ internal class WebSocketConnection(
 
     @Synchronized
     fun close() {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
+            alarmManagerCallback?.run(alarmManager::cancel)
+            alarmManagerCallback = null
+        } else {
+            handlerCallback?.run(reconnectHandler::removeCallbacks)
+            handlerCallback = null
+        }
         if (webSocket != null) {
             webSocket?.close(1000, "")
             closed()
@@ -119,8 +128,10 @@ internal class WebSocketConnection(
         state = State.Disconnected
     }
 
+    fun scheduleReconnectNow(seconds: Long) = scheduleReconnect(ID.get(), seconds)
+
     @Synchronized
-    fun scheduleReconnect(seconds: Long) {
+    fun scheduleReconnect(id: Long, seconds: Long) {
         if (state == State.Connecting || state == State.Connected) {
             return
         }
@@ -130,17 +141,23 @@ internal class WebSocketConnection(
             Logger.info("WebSocket: scheduling a restart in $seconds second(s) (via alarm manager)")
             val future = Calendar.getInstance()
             future.add(Calendar.SECOND, seconds.toInt())
+
+            alarmManagerCallback?.run(alarmManager::cancel)
+            val cb = OnAlarmListener { syncExec(id) { start() } }
+            alarmManagerCallback = cb
             alarmManager.setExact(
                 AlarmManager.RTC_WAKEUP,
                 future.timeInMillis,
                 "reconnect-tag",
-                { start() },
+                cb,
                 null
             )
         } else {
             Logger.info("WebSocket: scheduling a restart in $seconds second(s)")
-            reconnectHandler.removeCallbacks(reconnectCallback)
-            reconnectHandler.postDelayed(reconnectCallback, TimeUnit.SECONDS.toMillis(seconds))
+            handlerCallback?.run(reconnectHandler::removeCallbacks)
+            val cb = Runnable { syncExec(id) { start() } }
+            handlerCallback = cb
+            reconnectHandler.postDelayed(cb, TimeUnit.SECONDS.toMillis(seconds))
         }
     }
 
@@ -190,7 +207,7 @@ internal class WebSocketConnection(
                 val minutes = (errorCount * 2 - 1).coerceAtMost(20)
 
                 onFailure.execute(response?.message ?: "unreachable", minutes)
-                scheduleReconnect(TimeUnit.MINUTES.toSeconds(minutes.toLong()))
+                scheduleReconnect(id, TimeUnit.MINUTES.toSeconds(minutes.toLong()))
             }
             super.onFailure(webSocket, t, response)
         }

app/src/main/kotlin/com/github/gotify/service/WebSocketService.kt

@@ -172,10 +172,7 @@ internal class WebSocketService : Service() {
     }
 
     private fun doReconnect() {
-        if (connection == null) {
-            return
-        }
-        connection!!.scheduleReconnect(15)
+        connection?.scheduleReconnectNow(15)
     }
 
     private fun onFailure(status: String, minutes: Int) {