Add warning about filteractiondecrypt

There was a warning for the encrypt action but not for the
decrypt action. It should be warned that end-to-end encryption
no longer exists if the decrypted mails are stored in a
remote resource.

src/filter/filteractions/filteractiondecrypt.cpp

@@ -21,6 +21,7 @@
 #include "mailcommon_debug.h"
 #include "util/cryptoutils.h"
 
+#include <KColorScheme>
 #include <KLocalizedString>
 
 #include <KMime/Message>
@@ -29,6 +30,9 @@
 
 #include <Akonadi/KMime/MessageFlags>
 
+#include <QLabel>
+#include <QVBoxLayout>
+
 using namespace MailCommon;
 
 FilterActionDecrypt::FilterActionDecrypt(QObject *parent)
@@ -89,3 +93,24 @@ FilterAction::ReturnCode FilterActionDecrypt::process(ItemContext &context, bool
     context.setNeedsFlagStore();
     return GoOn;
 }
+
+QWidget *FilterActionDecrypt::createParamWidget(QWidget *parent) const
+{
+    auto w = new QWidget(parent);
+    auto l = new QVBoxLayout;
+    w->setLayout(l);
+
+    auto lbl = new QLabel(w);
+
+    auto palette = lbl->palette();
+    palette.setColor(lbl->foregroundRole(), KColorScheme(QPalette::Normal).foreground(KColorScheme::NegativeText).color());
+    lbl->setPalette(palette);
+    lbl->setWordWrap(true);
+
+    lbl->setText(i18n("<b>Warning:</b> Decrypted emails may be uploaded to a server!"));
+    lbl->setToolTip(i18n("<p>If the email folder that you are filtering into is connected to a remote "
+                         "account (like an IMAP-Server) the decrypted content will go there.</p>"));
+    l->addWidget(lbl);
+
+    return w;
+}

src/filter/filteractions/filteractiondecrypt.h

@@ -39,6 +39,8 @@ public:
 
     SearchRule::RequiredPart requiredPart() const override;
     FilterAction::ReturnCode process(ItemContext &context, bool applyOnOutbound) const override;
+
+    QWidget *createParamWidget(QWidget *parent) const override;
 };
 } // namespace MailCommon