add a configurable reconnect option for websocket

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

@@ -24,7 +24,9 @@ internal class WebSocketConnection(
     private val baseUrl: String,
     settings: SSLSettings,
     private val token: String?,
-    private val alarmManager: AlarmManager
+    private val alarmManager: AlarmManager,
+    private val reconnectInterval: Int,
+    private val disableBackoff: Boolean
 ) {
     companion object {
         private val ID = AtomicLong(0)
@@ -204,10 +206,16 @@ internal class WebSocketConnection(
                 closed()
 
                 errorCount++
-                val minutes = (errorCount * 2 - 1).coerceAtMost(20)
+                val seconds = if (disableBackoff) {
+                    reconnectInterval
+                } else {
+                    ((errorCount * 2 - 1) * reconnectInterval)
+                        .coerceAtMost(TimeUnit.MINUTES.toSeconds(20).toInt())
+                }
 
-                onFailure.execute(response?.message ?: "unreachable", minutes)
-                scheduleReconnect(id, TimeUnit.MINUTES.toSeconds(minutes.toLong()))
+                val rounded = seconds.coerceAtLeast(5)
+                onFailure.execute(response?.message ?: "unreachable", rounded)
+                scheduleReconnect(id, rounded.toLong())
             }
             super.onFailure(webSocket, t, response)
         }
@@ -221,7 +229,7 @@ internal class WebSocketConnection(
     }
 
     internal fun interface OnNetworkFailureRunnable {
-        fun execute(status: String, minutes: Int)
+        fun execute(status: String, seconds: Int)
     }
 
     internal enum class State {

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

@@ -110,16 +110,30 @@ internal class WebSocketService : Service() {
 
         val cm = getSystemService(CONNECTIVITY_SERVICE) as ConnectivityManager
         val alarmManager = getSystemService(ALARM_SERVICE) as AlarmManager
+        val sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this)
+        var reconnectInterval = sharedPreferences
+            .getString(getString(R.string.setting_key_reconnect_interval), "60")
+            ?.trim()
+            ?.toIntOrNull() ?: 60
+
+        reconnectInterval = reconnectInterval.coerceIn(5, 60)
+
+        val disableBackoff = sharedPreferences.getBoolean(
+            getString(R.string.setting_key_backoff),
+            false
+        )
 
         connection = WebSocketConnection(
             settings.url,
             settings.sslSettings(),
             settings.token,
-            alarmManager
+            alarmManager,
+            reconnectInterval,
+            disableBackoff
         )
             .onOpen { onOpen() }
             .onClose { onClose() }
-            .onFailure { status, minutes -> onFailure(status, minutes) }
+            .onFailure { status, seconds -> onFailure(status, seconds) }
             .onMessage { message -> onMessage(message) }
             .onReconnected { notifyMissedNotifications() }
             .start()
@@ -183,10 +197,14 @@ internal class WebSocketService : Service() {
         connection?.scheduleReconnectNow(15)
     }
 
-    private fun onFailure(status: String, minutes: Int) {
+    private fun onFailure(status: String, seconds: Int) {
         val title = getString(R.string.websocket_error, status)
-        val intervalUnit = resources
-            .getQuantityString(R.plurals.websocket_retry_interval, minutes, minutes)
+        val intervalUnit = if (seconds >= 60) {
+            val minutes = seconds / 60
+            resources.getQuantityString(R.plurals.websocket_retry_interval, minutes, minutes)
+        } else {
+            resources.getQuantityString(R.plurals.websocket_retry_interval_seconds, seconds, seconds)
+        }
         showForegroundNotification(
             title,
             "${getString(R.string.websocket_reconnect)} $intervalUnit"

app/src/main/kotlin/com/github/gotify/settings/SettingsActivity.kt

@@ -74,6 +74,36 @@ internal class SettingsActivity :
                     getString(R.string.setting_key_notification_channels)
                 )?.isEnabled = true
             }
+            findPreference<androidx.preference.EditTextPreference>(
+                getString(R.string.setting_key_reconnect_interval)
+            )?.let {
+                it.setOnBindEditTextListener { editText ->
+                    editText.inputType = android.text.InputType.TYPE_CLASS_NUMBER
+                }
+                it.onPreferenceChangeListener =
+                    Preference.OnPreferenceChangeListener { _, newValue ->
+                        val value = (newValue as String).trim().toIntOrNull() ?: 60
+                        if (value < 5 || value > 60) {
+                            Utils.showSnackBar(requireActivity(), "Please enter a value between 5 and 60")
+                            return@OnPreferenceChangeListener false
+                        }
+
+                        requestWebSocketRestart()
+                        true
+                    }
+            }
+            findPreference<SwitchPreferenceCompat>(
+                getString(R.string.setting_key_backoff)
+            )?.onPreferenceChangeListener =
+                Preference.OnPreferenceChangeListener { _, _ ->
+                    requestWebSocketRestart()
+                    true
+                }
+        }
+
+        private fun requestWebSocketRestart() {
+            val intent = Intent(requireContext(), com.github.gotify.service.WebSocketService::class.java)
+            requireContext().startService(intent)
         }
 
         override fun onViewCreated(view: View, savedInstanceState: Bundle?) {

app/src/main/res/values/arrays.xml

@@ -34,6 +34,7 @@
     </string-array>
     <string name="time_format_value_absolute">time_format_absolute</string>
     <string name="time_format_value_relative">time_format_relative</string>
+
     <bool name="notification_channels">false</bool>
     <bool name="exclude_from_recent">false</bool>
     <bool name="prompt_onreceive_intent">true</bool>

app/src/main/res/values/strings.xml

@@ -120,6 +120,21 @@
         <item quantity="one">in %d minute</item>
         <item quantity="other">in %d minutes</item>
     </plurals>
+    <plurals name="websocket_retry_interval_seconds">
+        <item quantity="one">in %d second</item>
+        <item quantity="other">in %d seconds</item>
+    </plurals>
+    <string name="setting_reconnect_interval">Reconnect Interval (Seconds)</string>
+    <string name="setting_key_reconnect_interval">reconnect_interval</string>
+    <string name="setting_connection">Connection</string>
+    <string name="reconnect_interval_10_seconds">10 seconds</string>
+    <string name="reconnect_interval_30_seconds">30 seconds</string>
+    <string name="reconnect_interval_1_minute">1 minute (Default)</string>
+    <string name="reconnect_interval_5_minutes">5 minutes</string>
+    <string name="setting_reconnect_interval_summary">Wait time between connection attempts</string>
+    <string name="setting_backoff_title">Constant Retry Interval</string>
+    <string name="setting_backoff_summary">Do not increase wait time between retries</string>
+    <string name="setting_key_backoff">reconnect_backoff</string>
 
     <string name="notification_channel_title_foreground">Gotify foreground notification</string>
     <string name="notification_channel_title_min">Min priority messages (&lt;1)</string>

app/src/main/res/xml/root_preferences.xml

@@ -51,4 +51,17 @@
             android:summary="@string/setting_summary_prompt_onreceive_intent" />
     </PreferenceCategory>
 
+    <PreferenceCategory app:title="@string/setting_connection">
+        <EditTextPreference
+            android:defaultValue="60"
+            android:key="@string/setting_key_reconnect_interval"
+            android:title="@string/setting_reconnect_interval"
+            android:summary="@string/setting_reconnect_interval_summary" />
+        <SwitchPreferenceCompat
+            android:key="@string/setting_key_backoff"
+            android:title="@string/setting_backoff_title"
+            android:summary="@string/setting_backoff_summary"
+            android:defaultValue="false" />
+    </PreferenceCategory>
+
 </PreferenceScreen>