fix(android): When chrome is not installed/enabled or the default browser (#2261)

Fixes #2225 
- Set Chrome app has a hard requirement for seamless user experience
with app link.
- Check if Chrome is not installed/enabled, then show an error toast.
- If Chrome is not set as the default browser, use the Chrome stable
version package name to force open the sign-in flow in Chrome.

Fixes #2184 
- Closing webview moves back to sign-in page.




_Applinks is supported in Firefox but is disabled by default
(https://support.mozilla.org/en-US/kb/set-firefox-android-open-links-native-apps)
..why 🤦‍♂️??_

Later based on user's browser we can update the redirected page to
include instructions to enable the link, something like this:


![Screenshot_1696581921](https://github.com/firezone/firezone/assets/1523745/2587b3de-7e85-4b82-aa99-61e58b8dc0b3)

---------

Co-authored-by: Jamil <jamilbk@users.noreply.github.com>

kotlin/android/app/src/main/java/dev/firezone/android/features/auth/ui/AuthActivity.kt

@@ -4,7 +4,7 @@ package dev.firezone.android.features.auth.ui
 import android.content.Intent
 import android.net.Uri
 import android.os.Bundle
-import android.util.Log
+import android.widget.Toast
 import androidx.activity.viewModels
 import androidx.appcompat.app.AlertDialog
 import androidx.appcompat.app.AppCompatActivity
@@ -14,6 +14,7 @@ import dev.firezone.android.R
 import dev.firezone.android.core.presentation.MainActivity
 import dev.firezone.android.databinding.ActivityAuthBinding
 import dev.firezone.android.util.CustomTabsHelper
+import java.lang.Exception
 
 @AndroidEntryPoint
 class AuthActivity : AppCompatActivity(R.layout.activity_auth) {
@@ -38,14 +39,10 @@ class AuthActivity : AppCompatActivity(R.layout.activity_auth) {
 
     private fun setupActionObservers() {
         viewModel.actionLiveData.observe(this) { action ->
-            Log.d("AuthActivity", "setupActionObservers: $action")
             when (action) {
                 is AuthViewModel.ViewAction.LaunchAuthFlow -> setupWebView(action.url)
                 is AuthViewModel.ViewAction.NavigateToSignInFragment -> {
-                    startActivity(
-                        Intent(this, MainActivity::class.java),
-                    )
-                    finish()
+                    navigateToSignIn()
                 }
                 is AuthViewModel.ViewAction.ShowError -> showError()
                 else -> {}
@@ -54,10 +51,40 @@ class AuthActivity : AppCompatActivity(R.layout.activity_auth) {
     }
 
     private fun setupWebView(url: String) {
-        val intent = CustomTabsIntent.Builder().build()
-        intent.intent.setPackage(CustomTabsHelper.getPackageNameToUse(this@AuthActivity))
-        intent.launchUrl(this@AuthActivity, Uri.parse(url))
+        if (CustomTabsHelper.checkIfChromeIsInstalled(this)) {
+            val intent = CustomTabsIntent.Builder().build()
+            val packageName = CustomTabsHelper.getPackageNameToUse(this)
+            if (CustomTabsHelper.checkIfChromeAppIsDefault()) {
+                if (packageName != null) {
+                    intent.intent.setPackage(packageName)
+                }
+            } else {
+                intent.intent.setPackage(CustomTabsHelper.STABLE_PACKAGE)
+            }
+
+            try {
+                intent.launchUrl(this@AuthActivity, Uri.parse(url))
+                finish()
+            } catch (e: Exception) {
+                showChromeAppRequiredError()
+            }
+        } else {
+            showChromeAppRequiredError()
+        }
     }
+
+    private fun showChromeAppRequiredError() {
+        Toast.makeText(this, getString(R.string.signing_in_requires_chrome_browser), Toast.LENGTH_LONG).show()
+        navigateToSignIn()
+    }
+
+    private fun navigateToSignIn() {
+        startActivity(
+            Intent(this, MainActivity::class.java),
+        )
+        finish()
+    }
+
     private fun showError() {
         AlertDialog.Builder(this)
             .setTitle(R.string.error_dialog_title)

kotlin/android/app/src/main/java/dev/firezone/android/features/signin/ui/SignInFragment.kt

@@ -34,7 +34,6 @@ internal class SignInFragment : Fragment(R.layout.fragment_sign_in) {
                         AuthActivity::class.java,
                     ),
                 )
-                requireActivity().finish()
             }
             btSettings.setOnClickListener {
                 findNavController().navigate(

kotlin/android/app/src/main/java/dev/firezone/android/util/CustomTabsHelper.kt

@@ -3,7 +3,10 @@ package dev.firezone.android.util
 
 import android.content.Context
 import android.content.Intent
+import android.content.pm.PackageManager
 import android.net.Uri
+import android.os.Build
+
 class CustomTabsHelper {
     companion object {
         val STABLE_PACKAGE = "com.android.chrome"
@@ -46,5 +49,23 @@ class CustomTabsHelper {
             }
             return sPackageNameToUse
         }
+
+        fun checkIfChromeAppIsDefault() =
+            sPackageNameToUse == STABLE_PACKAGE ||
+                sPackageNameToUse == BETA_PACKAGE ||
+                sPackageNameToUse == DEV_PACKAGE ||
+                sPackageNameToUse == LOCAL_PACKAGE
+
+        fun checkIfChromeIsInstalled(context: Context): Boolean = try {
+            val info = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
+                context.packageManager.getPackageInfo(STABLE_PACKAGE, PackageManager.PackageInfoFlags.of(0L))
+            } else {
+                @Suppress("DEPRECATION")
+                context.packageManager.getPackageInfo(STABLE_PACKAGE, 0)
+            }
+            info.applicationInfo.enabled
+        } catch (e: PackageManager.NameNotFoundException) {
+            false
+        }
     }
 }

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

@@ -27,6 +27,7 @@
 	<string name="request_permission">Request Permission</string>
 	<string name="enter_team_id">Enter team id</string>
 	<string name="sign_in_debug_user">Sign In (Debug User)</string>
+	<string name="signing_in_requires_chrome_browser">Signing in requires chrome browser</string>
 	<!-- Error Dialog -->
 
 </resources>