fix: Google sign-in from a store shows the real device instead of a Galaxy S23 Ultra (#1252)

app/src/main/java/com/droiddeck/launcher/stores/StoreLoginActivity.kt

@@ -5,6 +5,7 @@ import android.content.res.Configuration
 import android.graphics.Color
 import android.net.Uri
 import android.net.http.SslError
+import android.os.Build
 import android.os.Bundle
 import android.os.Message
 import android.util.Log
@@ -18,6 +19,7 @@ import android.webkit.WebChromeClient
 import android.webkit.WebResourceError
 import android.webkit.WebResourceRequest
 import android.webkit.WebResourceResponse
+import android.webkit.WebSettings
 import android.webkit.WebView
 import android.webkit.WebViewClient
 import android.widget.Button
@@ -40,7 +42,10 @@ class StoreLoginActivity : ComponentActivity() {
         private const val KEY_STATE = "oauth_state"
         private const val KEY_SIGN_IN_CLEARED = "sign_in_cleared"
         @Volatile internal var floodColor: Int? = null
-        internal const val CHROME_UA = "Mozilla/5.0 (Linux; Android 14; SM-S918B) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/127.0.6533.103 Mobile Safari/537.36"
+        internal fun chromeUserAgent(webView: String?): String =
+            webView?.replace(Regex(" Build/[^;)]*"), "")?.replace("; wv)", ")")?.replace(" Version/4.0", "")
+                ?.takeIf { "Chrome/" in it }
+                ?: "Mozilla/5.0 (Linux; Android ${Build.VERSION.RELEASE}; ${Build.MODEL}) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/127.0.6533.103 Mobile Safari/537.36"
 
         fun generateState(): String {
             val bytes = ByteArray(24)
@@ -76,6 +81,7 @@ class StoreLoginActivity : ComponentActivity() {
     private var oauthState: String? = null
     private val captured = AtomicBoolean(false)
     private var flooded = false
+    private val chromeUa by lazy { chromeUserAgent(runCatching { WebSettings.getDefaultUserAgent(this) }.getOrNull()) }
     private var signInCleared = false
 
     private fun dp(value: Int): Int = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, value.toFloat(), resources.displayMetrics).toInt()
@@ -123,7 +129,7 @@ class StoreLoginActivity : ComponentActivity() {
 
     private fun newFlow(state: String): Flow? {
         val url = clientUrl
-        if (url != null) return com.droiddeck.launcher.stores.epic.EpicClient.loginFlow(url)
+        if (url != null) return com.droiddeck.launcher.stores.epic.EpicClient.loginFlow(url, chromeUa)
         return store?.let { LoginFlows.forStore(it, state) }
     }
 
@@ -234,7 +240,7 @@ class StoreLoginActivity : ComponentActivity() {
         override fun onCreateWindow(view: WebView?, isDialog: Boolean, isUserGesture: Boolean, resultMsg: Message?): Boolean {
             if (resultMsg == null) return false
             dismissPopup()
-            val child = newWebView(CHROME_UA, isPopup = true)
+            val child = newWebView(chromeUa, isPopup = true)
             popupWebView = child
             popupHost.addView(child, FrameLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT))
             popupHost.visibility = View.VISIBLE
@@ -306,8 +312,8 @@ class StoreLoginActivity : ComponentActivity() {
             if (f.isRedirect(url) && !f.readsPage) { complete(view, url); return true }
             if (!isPopup && store == Store.GOG) {
                 if (GogAuth.isGogHost(uri.host) && view.settings.userAgentString != f.userAgent) { view.settings.userAgentString = f.userAgent; return false }
-                if (GogAuth.isIdentityProviderHost(uri.host) && view.settings.userAgentString != CHROME_UA) {
-                    view.settings.userAgentString = CHROME_UA
+                if (GogAuth.isIdentityProviderHost(uri.host) && view.settings.userAgentString != chromeUa) {
+                    view.settings.userAgentString = chromeUa
                     CookieManager.getInstance().setAcceptThirdPartyCookies(view, true)
                     view.loadUrl(url)
                     return true

app/src/main/java/com/droiddeck/launcher/stores/epic/EpicClient.kt

@@ -392,10 +392,10 @@ object EpicClient {
         }
     }
 
-    internal fun loginFlow(url: String): StoreLoginActivity.Flow? {
+    internal fun loginFlow(url: String, browserAgent: String): StoreLoginActivity.Flow? {
         val redirect = redirectOf(url) ?: return null
         val agent = runCatching { EpicNative.call("auth.config")?.optString("webViewUserAgent") }.getOrNull()?.ifEmpty { null }
-        return ClientLogin(url, redirect, agent ?: StoreLoginActivity.CHROME_UA)
+        return ClientLogin(url, redirect, agent ?: browserAgent)
     }
 
     private class ClientLogin(

app/src/test/java/com/droiddeck/launcher/stores/StoreLoginUserAgentTest.kt

@@ -0,0 +1,27 @@
+package com.droiddeck.launcher.stores
+
+import android.os.Build
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertFalse
+import org.junit.Assert.assertTrue
+import org.junit.Test
+
+class StoreLoginUserAgentTest {
+    @Test fun theDevicesWebViewAgentIsSentAsChrome() {
+        assertEquals(
+            "Mozilla/5.0 (Linux; Android 16; NP06J) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/141.0.7390.122 Mobile Safari/537.36",
+            StoreLoginActivity.chromeUserAgent(
+                "Mozilla/5.0 (Linux; Android 16; NP06J Build/BP2A.250605.031.A3; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/141.0.7390.122 Mobile Safari/537.36",
+            ),
+        )
+    }
+
+    @Test fun noWebViewAgentFallsBackToChromeWithoutAnotherDevicesModel() {
+        for (agent in listOf(null, "", "Dalvik/2.1.0 (Linux; U; Android 16)")) {
+            val ua = StoreLoginActivity.chromeUserAgent(agent)
+            assertTrue(ua, "Chrome/" in ua)
+            assertFalse(ua, "SM-S918B" in ua)
+            assertTrue(ua, "Android ${Build.VERSION.RELEASE}; ${Build.MODEL})" in ua)
+        }
+    }
+}