Endurain: Initial prefs and online auth implementation

app/build.gradle

@@ -117,6 +117,10 @@ android {
         vectorDrawables.useSupportLibrary = true
         buildConfigField "String", "GIT_HASH_SHORT", "\"${getGitHashShort()}\""
         buildConfigField "boolean", "INTERNET_ACCESS", "false"
+
+        manifestPlaceholders = [
+            appAuthRedirectScheme: "${applicationId}"
+        ]
     }
 
     signingConfigs {
@@ -286,6 +290,9 @@ dependencies {
     implementation libs.androidsvg
     implementation libs.jsoup
 
+    // AppAuth is used for OAuth/PKCE/OIDC functionality, like required by the Endurain integration
+    implementation 'net.openid:appauth:0.11.1'
+
     // Bouncy Castle is included directly in GB, to avoid pulling the entire dependency
     // It's included in the org.bouncycastle.shaded package, to fix conflicts with roboelectric
     //implementation 'org.bouncycastle:bcpkix-jdk18on:1.76'

app/src/main/AndroidManifest.xml

@@ -259,6 +259,10 @@
             android:name=".activities.preferences.HealthConnectPreferencesActivity"
             android:label="@string/healthconnect_settings"
             android:parentActivityName=".activities.SettingsActivity" />
+        <activity
+            android:name=".activities.EndurainPreferencesActivity"
+            android:label="Endurain"
+            android:parentActivityName=".activities.SettingsActivity" />
         <activity
             android:name=".activities.AboutUserPreferencesActivity"
             android:label="@string/activity_prefs_about_you"

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/activities/EndurainPreferencesActivity.kt

@@ -0,0 +1,136 @@
+/*  Copyright (C) 2025 Arjan Schrijver
+
+    This file is part of Gadgetbridge.
+
+    Gadgetbridge is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Affero General Public License as published
+    by the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    Gadgetbridge is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Affero General Public License for more details.
+
+    You should have received a copy of the GNU Affero General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>. */
+package nodomain.freeyourgadget.gadgetbridge.activities
+
+import android.os.Bundle
+import android.widget.LinearLayout
+import android.widget.Toast
+import androidx.appcompat.app.AlertDialog
+import androidx.core.content.edit
+import androidx.core.net.toUri
+import androidx.lifecycle.lifecycleScope
+import androidx.preference.Preference
+import androidx.preference.PreferenceFragmentCompat
+import com.google.android.material.dialog.MaterialAlertDialogBuilder
+import com.google.android.material.textfield.TextInputEditText
+import com.google.android.material.textfield.TextInputLayout
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.launch
+import nodomain.freeyourgadget.gadgetbridge.GBApplication
+import nodomain.freeyourgadget.gadgetbridge.R
+import nodomain.freeyourgadget.gadgetbridge.util.GB
+import nodomain.freeyourgadget.gadgetbridge.util.InternetUtils
+
+class EndurainPreferencesActivity : AbstractSettingsActivityV2() {
+    override fun newFragment(): PreferenceFragmentCompat {
+        return EndurainPreferencesFragment()
+    }
+
+    companion object {
+        class EndurainPreferencesFragment : AbstractPreferenceFragment() {
+            override fun onCreatePreferences(
+                savedInstanceState: Bundle?,
+                rootKey: String?
+            ) {
+                setPreferencesFromResource(R.xml.endurain_preferences, rootKey)
+                val prefs = GBApplication.getPrefs().preferences
+
+                // Hide network required warning when network is available
+                val networkWarning = findPreference<Preference>("pref_key_network_required")
+                networkWarning?.isVisible = !GBApplication.hasInternetAccess()
+
+                // Wire up the login button
+                val loginPref = findPreference<Preference>("pref_key_log_in")
+                loginPref?.onPreferenceClickListener = Preference.OnPreferenceClickListener {
+                    val currentServer = prefs.getString("endurain_server", "https://")
+                    val input = TextInputEditText(requireContext()).apply {
+                        setText(currentServer)
+                        layoutParams = LinearLayout.LayoutParams(
+                            LinearLayout.LayoutParams.MATCH_PARENT,
+                            LinearLayout.LayoutParams.WRAP_CONTENT
+                        )
+                    }
+
+                    val layout = TextInputLayout(requireContext()).apply {
+                        hint = "Example: https://endurain.example.com"
+                        addView(input)
+                    }
+
+                    val dialog = MaterialAlertDialogBuilder(requireContext())
+                        .setTitle("Endurain server")
+                        .setView(layout)
+                        .setNegativeButton(R.string.Cancel, null)
+                        .setPositiveButton(R.string.ok, null) // ← no listener yet
+                        .create()
+
+                    dialog.setOnShowListener {
+                        dialog.getButton(AlertDialog.BUTTON_POSITIVE).setOnClickListener {
+                            val newUrl = input.text.toString().toUri()
+                            val newServer =
+                                if (newUrl.scheme == null || newUrl.host == null) {
+                                    null
+                                } else {
+                                    "${newUrl.scheme}://${newUrl.host}"
+                                }
+
+                            prefs.edit {
+                                putString("endurain_server", newServer)
+                            }
+
+                            dialog.dismiss()
+                            lifecycleScope.launch(Dispatchers.IO) {
+                                doLogin()
+                            }
+                        }
+                    }
+
+                    dialog.show()
+
+                    true
+                }
+
+                // TODO: Wire up the logoff button
+                val logoffPref = findPreference<Preference>("pref_key_log_out")
+                logoffPref?.isVisible = false
+
+                // TODO: Fill the status preference text
+                val statusPref = findPreference<Preference>("pref_key_status")
+                statusPref?.summary = "Not logged in, integration is disabled"
+            }
+
+            private fun doLogin() {
+                val prefs = GBApplication.getPrefs().preferences
+                val server = prefs.getString("endurain_server", "").orEmpty()
+                if (server.isBlank()) return
+
+                val settingsUri = "${server}/api/v1/public/server_settings".toUri()
+                val serverSettings = InternetUtils.doJsonRequest(settingsUri)
+
+                if (serverSettings == null) {
+                    GB.toast("Endurain server is offline", Toast.LENGTH_LONG, GB.ERROR)
+                    return
+                }
+
+                val localLogin = serverSettings.optBoolean("local_login_enabled")
+                val ssoLogin = serverSettings.optBoolean("sso_enabled")
+
+                GB.toast("Endurain local=$localLogin sso=$ssoLogin", Toast.LENGTH_LONG, GB.INFO)
+            }
+
+        }
+    }
+}

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/activities/SettingsActivity.java

@@ -414,6 +414,15 @@ public class SettingsActivity extends AbstractSettingsActivityV2 {
                 });
             }
 
+            pref = findPreference("pref_category_endurain");
+            if (pref != null) {
+                pref.setOnPreferenceClickListener(preference -> {
+                    Intent enableIntent = new Intent(requireContext(), EndurainPreferencesActivity.class);
+                    startActivity(enableIntent);
+                    return true;
+                });
+            }
+
             pref = findPreference("pref_category_notifications");
             if (pref != null) {
                 pref.setOnPreferenceClickListener(preference -> {

app/src/main/res/xml/endurain_preferences.xml

@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="utf-8"?>
+<PreferenceScreen
+    xmlns:android="http://schemas.android.com/apk/res/android">
+    <Preference
+        android:icon="@drawable/ic_warning"
+        android:key="pref_key_network_required"
+        android:title="Network required"
+        android:summary="This integration requires network connectivity. Please install and enable the internet helper add-on app." />
+    <Preference
+        android:icon="@drawable/ic_info"
+        android:key="pref_key_status"
+        android:title="Endurain status"
+        android:summary="Logged in on endurain.example.com" />
+    <Preference
+        android:icon="@drawable/ic_language"
+        android:key="pref_key_log_in"
+        android:title="Log in to Endurain"
+        android:summary="Tap here to enter the Endurain server and log in" />
+    <Preference
+        android:icon="@drawable/ic_language"
+        android:key="pref_key_log_out"
+        android:title="Log out of Endurain"
+        android:summary="Tap here to log out, this disables the integration" />
+</PreferenceScreen>

app/src/main/res/xml/preferences.xml

@@ -387,6 +387,13 @@
             android:key="pref_category_internethelper"
             android:title="@string/prefs_internet_helper_title"
             android:summary="@string/prefs_internet_helper_summary" />
+
+        <!-- FIXME: Use Endurain logo and translate strings -->
+        <PreferenceScreen
+            android:icon="@drawable/ic_shoe"
+            android:key="pref_category_endurain"
+            android:title="Endurain"
+            android:summary="Configure how to reach and use this self-hosted online fitness tracker" />
     </PreferenceScreen>
 
     <Preference