From 85cb35fdba23bfdfa7298d43f52abd5beea40953 Mon Sep 17 00:00:00 2001
From: Maximilian Bauer <bauer.maximilian@web.de>
Date: Tue, 23 Feb 2021 23:52:56 +0100
Subject: [PATCH] LoginVC: detailed login error messages

---
 Amperfy/Api/Ampache/AmpacheXmlServerApi.swift |  5 ++
 Amperfy/Api/BackendProxy.swift                | 49 +++++++++++++++++--
 Amperfy/Screens/ViewController/LoginVC.swift  | 13 ++++-
 3 files changed, 63 insertions(+), 4 deletions(-)

diff --git a/Amperfy/Api/Ampache/AmpacheXmlServerApi.swift b/Amperfy/Api/Ampache/AmpacheXmlServerApi.swift
index 9b3f91c5..77bd6bde 100755
--- a/Amperfy/Api/Ampache/AmpacheXmlServerApi.swift
+++ b/Amperfy/Api/Ampache/AmpacheXmlServerApi.swift
@@ -102,6 +102,11 @@ class AmpacheXmlServerApi {
         let curDelegate = AuthParserDelegate()
         parser.delegate = curDelegate
         let success = parser.parse()
+        if let error = parser.parserError {
+            authHandshake = nil
+            os_log("Error during AuthPars: %s", log: log, type: .error, error.localizedDescription)
+            return
+        }
         if success && curDelegate.authHandshake != nil {
             authHandshake = curDelegate.authHandshake
         } else {
diff --git a/Amperfy/Api/BackendProxy.swift b/Amperfy/Api/BackendProxy.swift
index e8a00d53..16e35af5 100644
--- a/Amperfy/Api/BackendProxy.swift
+++ b/Amperfy/Api/BackendProxy.swift
@@ -15,8 +15,16 @@ enum BackenApiType: Int {
     }
 }
 
-enum AuthenticationError: Error {
-    case notAbleToLogin
+struct AuthenticationError: Error {
+    enum ErrorKind {
+        case notAbleToLogin
+        case invalidUrl
+        case requestStatusError
+        case downloadError
+    }
+    
+    var message: String = ""
+    let kind: ErrorKind
 }
 
 class BackendProxy {
@@ -52,6 +60,7 @@ class BackendProxy {
     }()
 
     func login(credentials: LoginCredentials) throws -> BackenApiType {
+        try checkServerReachablity(credentials: credentials)
         ampacheApi.authenticate(credentials: credentials)
         if ampacheApi.isAuthenticated() {
             selectedApi = .ampache
@@ -62,7 +71,41 @@ class BackendProxy {
             selectedApi = .subsonic
             return .subsonic
         }
-        throw AuthenticationError.notAbleToLogin
+        throw AuthenticationError(kind: .notAbleToLogin)
+    }
+    
+    private func checkServerReachablity(credentials: LoginCredentials) throws {
+        guard let serverUrl = URL(string: credentials.serverUrl) else {
+            throw AuthenticationError(kind: .invalidUrl)
+        }
+            
+        let group = DispatchGroup()
+        group.enter()
+        
+        let sessionConfig = URLSessionConfiguration.default
+        let session = URLSession(configuration: sessionConfig)
+        let request = URLRequest(url: serverUrl)
+        var downloadError: AuthenticationError? = nil
+        let task = session.downloadTask(with: request) { (tempLocalUrl, response, error) in
+            if let error = error {
+                downloadError = AuthenticationError(message: error.localizedDescription, kind: .downloadError)
+            } else {
+                if let statusCode = (response as? HTTPURLResponse)?.statusCode {
+                    if statusCode > 400 {
+                        downloadError = AuthenticationError(message: "\(statusCode)", kind: .requestStatusError)
+                    } else {
+                        os_log("Server url is reachable. Status code: %d", log: self.log, type: .info, statusCode)
+                    }
+                }
+            }
+            group.leave()
+        }
+        task.resume()
+        group.wait()
+        
+        if let error = downloadError {
+            throw error
+        }
     }
 
 }
diff --git a/Amperfy/Screens/ViewController/LoginVC.swift b/Amperfy/Screens/ViewController/LoginVC.swift
index 55bbd000..4e3a7be0 100644
--- a/Amperfy/Screens/ViewController/LoginVC.swift
+++ b/Amperfy/Screens/ViewController/LoginVC.swift
@@ -52,8 +52,19 @@ class LoginVC: UIViewController {
             credentials.backendApi = authenticatedApi
             appDelegate.storage.saveLoginCredentials(credentials: credentials)
             performSegue(withIdentifier: "toSync", sender: self)
+        } catch let e as AuthenticationError {
+            switch e.kind {
+            case .notAbleToLogin:
+                showErrorMsg(message: "Not able to login, please check credentials!")
+            case .invalidUrl:
+                showErrorMsg(message: "Server url is invalid!")
+            case .requestStatusError:
+                showErrorMsg(message: "Requesting server url finished with status response error code '\(e.message)'!")
+            case .downloadError:
+                showErrorMsg(message: e.message)
+            }
         } catch {
-            showErrorMsg(message: "Not able to login, please check credentials!")
+            showErrorMsg(message: "Not able to login!")
         }
     }