Only show the custom certificate popup when using EteSync interactively

With this change, we make it so using a self-signed certificate will
have to be authorised on the first login rather than checked every time
on the background.
This was causing annoying issues with networks that mitm SSL
connections, and anyhow, we shouldn't be asking users to trust bad certs
when in 99.9% of the cases it would either be an attack or a broken
network.

Fixes #36

app/src/main/java/com/etesync/syncadapter/HttpClient.kt

@@ -89,7 +89,6 @@ class HttpClient private constructor(
             context?.let {
                 val dbHelper = ServiceDB.OpenHelper(context)
                 val settings = Settings(dbHelper.readableDatabase)
-                val distrustSystemCerts = settings.getBoolean(App.DISTRUST_SYSTEM_CERTIFICATES, false)
 
                 try {
                     if (settings.getBoolean(App.OVERRIDE_PROXY, false)) {
@@ -107,9 +106,6 @@ class HttpClient private constructor(
                 } finally {
                     dbHelper.close()
                 }
-
-                //if (BuildConfig.customCerts)
-                customCertManager(CustomCertManager(context, !distrustSystemCerts))
             }
 
             // use account settings for authentication
@@ -177,6 +173,16 @@ class HttpClient private constructor(
         }
 
         fun build(): HttpClient {
+            //if (BuildConfig.customCerts)
+            context?.let {
+                val dbHelper = ServiceDB.OpenHelper(context)
+                val settings = Settings(dbHelper.readableDatabase)
+
+                // Only make it interactive if app is in foreground
+                customCertManager(CustomCertManager(context, foreground, !settings.getBoolean(App.DISTRUST_SYSTEM_CERTIFICATES, false), foreground))
+                dbHelper.close()
+            }
+
             val trustManager = certManager ?: {
                 val factory = TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm())
                 factory.init(null as KeyStore?)
@@ -225,8 +231,6 @@ class HttpClient private constructor(
             orig.sslSocketFactory(CertTlsSocketFactory(keyManager, trustManager), trustManager)
             orig.hostnameVerifier(hostnameVerifier)
 
-            certManager?.appInForeground = foreground
-
             return HttpClient(orig.build(), certManager)
         }