Support login on WearOS

android/.classpath

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<classpath>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.8/"/>
+	<classpathentry kind="con" path="org.eclipse.buildship.core.gradleclasspathcontainer"/>
+	<classpathentry kind="output" path="bin/default"/>
+</classpath>

android/.gitignore

@@ -0,0 +1,8 @@
+*.iml
+.gradle
+/local.properties
+/.idea/workspace.xml
+/.idea/libraries
+.DS_Store
+/build
+/captures

android/.project

@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<projectDescription>
+	<name>flutter_web_auth_2</name>
+	<comment>Project flutter_web_auth_2 created by Buildship.</comment>
+	<projects>
+	</projects>
+	<buildSpec>
+		<buildCommand>
+			<name>org.eclipse.jdt.core.javabuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+		<buildCommand>
+			<name>org.eclipse.buildship.core.gradleprojectbuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+	</buildSpec>
+	<natures>
+		<nature>org.eclipse.jdt.core.javanature</nature>
+		<nature>org.eclipse.buildship.core.gradleprojectnature</nature>
+	</natures>
+</projectDescription>

android/.settings/org.eclipse.buildship.core.prefs

@@ -0,0 +1,2 @@
+connection.project.dir=../example/android
+eclipse.preferences.version=1

android/build.gradle

@@ -0,0 +1,48 @@
+group 'com.teranet.oauth2_client'
+version '1.0-SNAPSHOT'
+
+buildscript {
+    ext.kotlin_version = '1.7.10'
+    repositories {
+        google()
+        mavenCentral()
+    }
+
+    dependencies {
+        classpath 'com.android.tools.build:gradle:7.2.2'
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
+    }
+}
+
+rootProject.allprojects {
+    repositories {
+        google()
+        mavenCentral()
+    }
+}
+
+apply plugin: 'com.android.library'
+apply plugin: 'kotlin-android'
+
+android {
+    compileSdkVersion 31
+
+    sourceSets {
+        main.java.srcDirs += 'src/main/kotlin'
+    }
+    defaultConfig {
+        minSdkVersion 16
+        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
+    }
+    lintOptions {
+        disable 'InvalidPackage'
+    }
+
+    dependencies {
+        implementation 'androidx.browser:browser:1.4.0'
+    }
+}
+
+dependencies {
+    implementation 'androidx.wear:wear-phone-interactions:1.0.1'
+}

android/gradle.properties

@@ -0,0 +1,3 @@
+org.gradle.jvmargs=-Xmx1536M
+android.useAndroidX=true
+android.enableJetifier=true

android/gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,5 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.5.1-bin.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists

android/settings.gradle

@@ -0,0 +1 @@
+rootProject.name = 'flutter_web_auth_2'

android/src/main/AndroidManifest.xml

@@ -0,0 +1,5 @@
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    package="com.teranet.oauth2_client">
+  <uses-sdk tools:overrideLibrary="androidx.security.ktx androidx.wear.phone.interactions" />
+</manifest>

android/src/main/kotlin/com/teranet/oauth2_client/OAuth2ClientPlugin.kt

@@ -0,0 +1,107 @@
+package com.teranet.oauth2_client
+
+import android.content.Context
+import android.content.pm.PackageManager
+import android.net.Uri
+import android.os.Build
+
+import androidx.wear.phone.interactions.authentication.*
+
+import io.flutter.embedding.engine.plugins.FlutterPlugin
+import io.flutter.plugin.common.BinaryMessenger
+import io.flutter.plugin.common.MethodCall
+import io.flutter.plugin.common.MethodChannel
+import io.flutter.plugin.common.MethodChannel.MethodCallHandler
+import io.flutter.plugin.common.PluginRegistry.Registrar
+import java.util.concurrent.Executors
+
+class OAuth2ClientPlugin(private var context: Context? = null, private var channel: MethodChannel? = null): MethodCallHandler, FlutterPlugin {
+  private lateinit var remoteAuthClient: RemoteAuthClient
+
+  companion object {
+    @JvmStatic
+    fun registerWith(registrar: Registrar) {
+      val plugin = OAuth2ClientPlugin()
+      plugin.initInstance(registrar.messenger(), registrar.context())
+    }
+
+  }
+
+  fun initInstance(messenger: BinaryMessenger, context: Context) {
+    this.context = context
+    remoteAuthClient = RemoteAuthClient.create(context)
+    channel = MethodChannel(messenger, "oauth2_client")
+    channel?.setMethodCallHandler(this)
+  }
+
+  override fun onAttachedToEngine(binding: FlutterPlugin.FlutterPluginBinding) {
+    initInstance(binding.binaryMessenger, binding.applicationContext)
+  }
+
+  override fun onDetachedFromEngine(binding: FlutterPlugin.FlutterPluginBinding) {
+    context = null
+    channel = null
+  }
+
+  private fun buildWatchAuthUri(url: Uri): Uri? {
+    return if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N_MR1 && context != null &&
+      context!!.packageManager.hasSystemFeature(PackageManager.FEATURE_WATCH)) {
+      val context = context!!
+      val request = OAuthRequest.Builder(context)
+        .setAuthProviderUrl(url)
+        .build()
+      request.requestUrl
+    } else {
+      null
+    }
+  }
+
+  override fun onMethodCall(call: MethodCall, resultCallback: MethodChannel.Result) {
+    when (call.method) {
+      "authUrl" -> {
+        val url = call.argument<String>("url")
+        val authUri = buildWatchAuthUri(Uri.parse(url))
+        if (authUri == null) {
+          resultCallback.notImplemented()
+          return
+        }
+        resultCallback.success(authUri.toString())
+      }
+      "authenticate" -> {
+        val url = Uri.parse(call.argument("url")!!)
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N_MR1 && context != null &&
+          context!!.packageManager.hasSystemFeature(PackageManager.FEATURE_WATCH)) {
+          val context = context!!
+          val request = OAuthRequest.Builder(context)
+            .setAuthProviderUrl(url)
+            .build()
+          remoteAuthClient.sendAuthorizationRequest(request,
+            Executors.newSingleThreadExecutor(),
+            object : RemoteAuthClient.Callback() {
+              override fun onAuthorizationResponse(
+                request: OAuthRequest,
+                response: OAuthResponse
+              ) {
+                resultCallback.success(response.responseUrl.toString())
+              }
+
+              override fun onAuthorizationError(request: OAuthRequest, errorCode: Int) {
+                val message = when (errorCode) {
+                  RemoteAuthClient.ERROR_UNSUPPORTED -> "Auth not supported"
+                  RemoteAuthClient.ERROR_PHONE_UNAVAILABLE -> "Phone unavailable"
+                  else -> "Unknown error: $errorCode"
+                }
+                resultCallback.error(errorCode.toString(), message, "No details")
+              }
+            }
+          )
+          return
+        } else {
+          // Pass through if not compatible
+          resultCallback.notImplemented()
+        }
+      }
+      else -> resultCallback.notImplemented()
+    }
+  }
+}

lib/authorization_response.dart

@@ -1,3 +1,5 @@
+import 'package:flutter/services.dart';
+
 /// Represents the response to an Authorization Request.
 /// see https://tools.ietf.org/html/rfc6749#page-26
 class AuthorizationResponse {
@@ -8,6 +10,14 @@ class AuthorizationResponse {
   String? error;
   String? errorDescription;
 
+  AuthorizationResponse.fromError(PlatformException exception) {
+    code = exception.code;
+    state = null;
+    queryParams = {};
+    error = exception.code;
+    errorDescription = exception.message;
+  }
+
   AuthorizationResponse.fromRedirectUri(
       String redirectUri, String? checkState) {
     queryParams = Uri.parse(redirectUri).queryParameters;

lib/oauth2_client.dart

@@ -6,10 +6,9 @@ import 'package:oauth2_client/access_token_response.dart';
 import 'package:oauth2_client/authorization_response.dart';
 import 'package:oauth2_client/oauth2_response.dart';
 import 'package:oauth2_client/src/oauth2_utils.dart';
+import 'package:oauth2_client/src/wear_auth.dart';
 import 'package:random_string/random_string.dart';
 
-// import 'package:oauth2_client/src/web_auth.dart';
-
 import 'src/base_web_auth.dart';
 import 'src/web_auth.dart'
 // ignore: uri_does_not_exist
@@ -19,6 +18,15 @@ import 'src/web_auth.dart'
 
 enum CredentialsLocation { header, body }
 
+class AuthorizationWrapper {
+  final AuthorizationResponse authResponse;
+  final String? redirectUrl;
+  AuthorizationWrapper({
+      required this.authResponse,
+      required this.redirectUrl
+  });
+}
+
 /// Base class that implements OAuth2 authorization flows.
 ///
 /// It currently supports the following grants:
@@ -153,7 +161,7 @@ class OAuth2Client {
     }
 
     try {
-      var authResp = await requestAuthorization(
+      var authRespWrapper = await requestAuthorization(
           webAuthClient: webAuthClient,
           clientId: clientId,
           scopes: scopes,
@@ -162,12 +170,18 @@ class OAuth2Client {
           state: state,
           customParams: authCodeParams,
           webAuthOpts: webAuthOpts);
+      var authResp = authRespWrapper.authResponse;
 
       if (authResp.isAccessGranted()) {
         if (afterAuthorizationCodeCb != null) {
           afterAuthorizationCodeCb(authResp);
         }
 
+        final newTokenParams = Map<String, dynamic>.from(accessTokenParams ?? {});
+        if (authRespWrapper.redirectUrl != null) {
+          newTokenParams['redirect_uri'] = authRespWrapper.redirectUrl;
+        }
+
         tknResp = await requestAccessToken(
             httpClient: httpClient,
             //If the authorization request was successfull, the code must be set
@@ -177,7 +191,7 @@ class OAuth2Client {
             scopes: scopes,
             clientSecret: clientSecret,
             codeVerifier: codeVerifier,
-            customParams: accessTokenParams,
+            customParams: newTokenParams,
             customHeaders: accessTokenHeaders);
       } else {
         tknResp = AccessTokenResponse.errorResponse();
@@ -214,7 +228,7 @@ class OAuth2Client {
   }
 
   /// Requests an Authorization Code to be used in the Authorization Code grant.
-  Future<AuthorizationResponse> requestAuthorization(
+  Future<AuthorizationWrapper> requestAuthorization(
       {required String clientId,
       List<String>? scopes,
       String? codeChallenge,
@@ -229,7 +243,7 @@ class OAuth2Client {
       state ??= randomAlphaNumeric(25);
     }
 
-    final authorizeUrl = getAuthorizeUrl(
+    final authorizeUrlStem = getAuthorizeUrl(
         clientId: clientId,
         redirectUri: redirectUri,
         scopes: scopes,
@@ -238,14 +252,24 @@ class OAuth2Client {
         codeChallenge: codeChallenge,
         customParams: customParams);
 
+    final authorizeUrl = await WearAuth.authUrl(url: authorizeUrlStem);
     // Present the dialog to the user
-    final result = await webAuthClient.authenticate(
+    AuthorizationResponse authResp;
+    try {
+      final result = await webAuthClient.authenticate(
         url: authorizeUrl,
         callbackUrlScheme: customUriScheme,
         redirectUrl: redirectUri,
         opts: webAuthOpts);
 
-    return AuthorizationResponse.fromRedirectUri(result, state);
+      authResp = AuthorizationResponse.fromRedirectUri(result, state);
+    } on PlatformException catch(err) {
+      authResp = AuthorizationResponse.fromError(err);
+    }
+    return AuthorizationWrapper(
+      authResponse: authResp,
+      redirectUrl: Uri.parse(authorizeUrl).queryParameters['redirect_uri'],
+    );
   }
 
   /// Requests and Access Token using the provided Authorization [code].

lib/src/io_web_auth.dart

@@ -1,6 +1,8 @@
 import 'package:flutter_web_auth_2/flutter_web_auth_2.dart';
 
 import 'base_web_auth.dart';
+import 'wear_auth.dart';
+import 'package:wear_bridge/wear_bridge.dart';
 
 BaseWebAuth createWebAuth() => IoWebAuth();
 
@@ -11,6 +13,12 @@ class IoWebAuth implements BaseWebAuth {
       required String url,
       required String redirectUrl,
       Map<String, dynamic>? opts}) async {
+    if (await WearBridge.isWatch()) {
+      return await WearAuth.authenticate(
+        url: url,
+        redirectUrl: redirectUrl,
+      );
+    }
     return await FlutterWebAuth2.authenticate(
       callbackUrlScheme: callbackUrlScheme,
       url: url,