fix(login): add error catching and logging to login dialog

src/main/xerus/monstercat/api/APIConnection.kt

@@ -33,6 +33,7 @@ import java.io.IOException
 import java.io.InputStream
 import java.lang.ref.WeakReference
 import java.net.URI
+import java.net.UnknownHostException
 import kotlin.math.min
 import kotlin.reflect.KClass
 
@@ -226,20 +227,33 @@ class APIConnection(vararg path: String): HTTPQuery<APIConnection>() {
 			return ConnectResult(connectsid, validity, session)
 		}
 
-		fun login(username: String, password: String): Boolean {
+		enum class LoginStatus{
+			CONNECTED,
+			INVALID,
+			NOINTERNET,
+			UNKNOWNERROR
+		}
+
+		fun login(username: String, password: String): LoginStatus {
 			val connection = APIConnection("v2", "signin")
 			val context = HttpClientContext()
-			connection.execute(HttpPost(connection.uri).apply {
-				setHeader("Accept", "application/json")
-				setHeader("Content-type", "application/json")
-				entity = StringEntity("""{"email":"$username","password":"$password"}""")
-			}, context)
+			try {
+				connection.execute(HttpPost(connection.uri).apply {
+					setHeader("Accept", "application/json")
+					setHeader("Content-type", "application/json")
+					entity = StringEntity("""{"email":"$username","password":"$password"}""")
+				}, context)
+			} catch(e: Exception) {
+				logger.warn("Error when trying to login through API", e)
+				return if(e is UnknownHostException) LoginStatus.NOINTERNET
+				else LoginStatus.UNKNOWNERROR
+			}
 
 			val code = connection.response?.statusLine?.statusCode
 			logger.trace("Login POST returned response code $code")
-			if (code !in 200..206) return false
-			CONNECTSID.value = (context.cookieStore.cookies.find { it.name == "connect.sid" }?.value ?: return false)
-			return true
+			if (code !in 200..206) return LoginStatus.INVALID
+			CONNECTSID.value = (context.cookieStore.cookies.find { it.name == "connect.sid" }?.value ?: return LoginStatus.INVALID)
+			return LoginStatus.CONNECTED
 		}
 
 		fun logout() {

src/main/xerus/monstercat/downloader/TabDownloader.kt

@@ -36,6 +36,7 @@ import xerus.ktutil.javafx.ui.controls.alwaysTruePredicate
 import xerus.ktutil.javafx.ui.initWindowOwner
 import xerus.ktutil.preferences.PropertySetting
 import xerus.monstercat.api.APIConnection
+import xerus.monstercat.api.APIConnection.Companion.LoginStatus.*
 import xerus.monstercat.api.ConnectValidity
 import xerus.monstercat.api.Covers
 import xerus.monstercat.api.response.ArtistRel
@@ -419,7 +420,7 @@ class TabDownloader: VTab() {
 		val emailField = TextField("").apply { promptText = "Email address" }
 		val passwordField = PasswordField().apply { promptText = "Password" }
 
-		val errorMessage = Label("Wrong username / password").apply { isVisible = false; managedProperty().bind(visibleProperty()) }
+		val errorMessage = Label("An error has been encountered").apply { isVisible = false; managedProperty().bind(visibleProperty()) }
 		val loadingGif = ImageView(Image("img/loading-16.gif")).apply { isVisible = false }
 
 		val buttonHBox = HBox()
@@ -437,15 +438,20 @@ class TabDownloader: VTab() {
 				val login = APIConnection.login(emailField.text, passwordField.text)
 				logger.debug("Login as ${emailField.text} returned $login")
 				onFx {
-					if(login) {
-						stage.close()
-					} else {
+					fun showErrorText(message: String) {
+						errorMessage.text = message
 						errorMessage.isVisible = true
 						loadingGif.isVisible = false
 						buttonHBox.isDisable = false
-
 						stage.sizeToScene()
 					}
+
+					when(login) {
+						CONNECTED -> stage.close()
+						INVALID -> showErrorText("Wrong username / password")
+						NOINTERNET -> showErrorText("You are not connected to the Internet")
+						UNKNOWNERROR -> showErrorText("An error has occured.")
+					}
 				}
 			}
 		}