From 42508619ee3ed48fa071961b64eba78ca78660cb Mon Sep 17 00:00:00 2001
From: James Turner <zakalawe@mac.com>
Date: Thu, 18 May 2017 09:17:27 +0100
Subject: [PATCH] Validation of METAR in the launcher

---
 src/GUI/LauncherMainWindow.cxx | 20 ++++++++++++++++++++
 src/GUI/LauncherMainWindow.hxx |  3 +++
 src/GUI/Weather.qml            | 21 ++++++++++++++++++++-
 3 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/src/GUI/LauncherMainWindow.cxx b/src/GUI/LauncherMainWindow.cxx
index a1f8a7f2a..2c6acb966 100644
--- a/src/GUI/LauncherMainWindow.cxx
+++ b/src/GUI/LauncherMainWindow.cxx
@@ -14,6 +14,8 @@
 
 // simgear headers
 #include <simgear/package/Install.hxx>
+#include <simgear/environment/metar.hxx>
+#include <simgear/structure/exception.hxx>
 
 // FlightGear headers
 #include <Network/HTTPClient.hxx>
@@ -348,6 +350,8 @@ void LauncherMainWindow::buildEnvironmentSections()
 
 LauncherMainWindow::~LauncherMainWindow()
 {
+    m_qmlEngine->collectGarbage();
+    delete m_qmlEngine;
 }
 
 bool LauncherMainWindow::execInApp()
@@ -1097,3 +1101,19 @@ void LauncherMainWindow::onSettingsSearchChanged()
         ss->setSearchTerm(m_ui->settingsSearchEdit->text());
     }
 }
+
+bool LauncherMainWindow::validateMetarString(QString metar)
+{
+    if (metar.isEmpty()) {
+        return true;
+    }
+
+    try {
+        std::string s = metar.toStdString();
+        SGMetar theMetar(s);
+    } catch (sg_io_exception&) {
+        return false;
+    }
+
+    return true;
+}
diff --git a/src/GUI/LauncherMainWindow.hxx b/src/GUI/LauncherMainWindow.hxx
index 4cf254b47..fc5746c4e 100644
--- a/src/GUI/LauncherMainWindow.hxx
+++ b/src/GUI/LauncherMainWindow.hxx
@@ -57,6 +57,9 @@ public:
     bool execInApp();
 
     bool wasRejected();
+
+    Q_INVOKABLE bool validateMetarString(QString metar);
+
 protected:
     virtual void closeEvent(QCloseEvent *event) override;
 
diff --git a/src/GUI/Weather.qml b/src/GUI/Weather.qml
index 7cdf50032..f7f0598bd 100644
--- a/src/GUI/Weather.qml
+++ b/src/GUI/Weather.qml
@@ -1,4 +1,5 @@
 import FlightGear.Launcher 1.0
+import QtQml 2.2
 
 Section {
     id: weatherSettings
@@ -23,11 +24,29 @@ Section {
 
     LineEdit {
         id: customMETAR
+
+        property bool __cachedValid: true
+
+        function revalidate() {
+            __cachedValid = _launcher.validateMetarString(value);
+        }
+
         visible: weatherScenario.isCustomMETAR
         enabled: !fetchMetar.checked
         label: "METAR"
         placeholder: "XXXX 012345Z 28035G50KT 250V300 9999 TSRA SCT022CB BKN030 13/09 Q1005"
-        description: "Enter a custom METAR string"
+        description: __cachedValid ? "Enter a custom METAR string"
+                                   : "The entered METAR string doesn't seem to be valid."
+
+        onValueChanged: {
+            validateTimeout.restart()
+        }
+    }
+
+    Timer {
+        id: validateTimeout
+        interval: 200
+        onTriggered: customMETAR.revalidate();
     }
 
     onApply: {