Show modal dialog to select default encryption if unknown

Thanks to mbeko for the UX suggestions.

main/CMakeLists.txt

@@ -67,6 +67,7 @@ set(RESOURCE_LIST
     conversation_list_titlebar_csd.ui
     conversation_row.ui
     conversation_view.ui
+    default_encryption_dialog.ui
     file_default_widget.ui
     file_send_overlay.ui
     global_search.ui

main/data/default_encryption_dialog.ui

@@ -0,0 +1,77 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!-- Generated with glade 3.22.2 -->
+<interface>
+  <requires lib="gtk+" version="3.6"/>
+  <object class="GtkDialog" id="dialog">
+    <property name="can_focus">True</property>
+    <property name="modal">True</property>
+    <property name="default_width">320</property>
+    <property name="default_height">260</property>
+    <child type="titlebar">
+      <placeholder/>
+    </child>
+    <child>
+      <object class="GtkBox">
+        <property name="can_focus">False</property>
+        <property name="orientation">vertical</property>
+        <child>
+          <object class="GtkBox">
+            <property name="visible">True</property>
+            <property name="can_focus">False</property>
+            <property name="orientation">vertical</property>
+            <child>
+              <object class="GtkLabel" id="default_encryption_warning_label">
+                <property name="visible">True</property>
+                <property name="can_focus">False</property>
+                <property name="label" translatable="yes">You are opening a new conversation without having set end-to-end encryption by default.
+
+It is strongly recommended to enable it to prevent your messages from being read by third parties.
+
+Please select an option to start this conversation with. Choosing one of the encryption methods will also set it as default in the global settings.
+</property>
+                <property name="wrap">True</property>
+              </object>
+            </child>
+            <child>
+              <object class="GtkCheckButton" id="omemo">
+                <property name="label" translatable="yes">OMEMO (automatic setup)</property>
+                <property name="visible">True</property>
+                <property name="can_focus">True</property>
+                <property name="receives_default">False</property>
+                <property name="active">False</property>
+              </object>
+            </child>
+            <child>
+              <object class="GtkCheckButton" id="openpgp">
+                <property name="label" translatable="yes">OpenPGP (external setup required)</property>
+                <property name="visible">True</property>
+                <property name="can_focus">True</property>
+                <property name="receives_default">False</property>
+                <property name="active">False</property>
+                <property name="group">omemo</property>
+              </object>
+            </child>
+            <child>
+              <object class="GtkCheckButton" id="none">
+                <property name="label" translatable="yes">Unencrypted</property>
+                <property name="visible">True</property>
+                <property name="can_focus">True</property>
+                <property name="receives_default">False</property>
+                <property name="active">False</property>
+                <property name="group">omemo</property>
+              </object>
+            </child>
+            <child>
+              <object class="GtkButton" id="accept_button">
+                <property name="label" translatable="yes">Apply</property>
+                <property name="visible">True</property>
+                <property name="can_focus">True</property>
+                <property name="receives_default">True</property>
+              </object>
+            </child>
+          </object>
+        </child>
+      </object>
+    </child>
+  </object>
+</interface>

main/data/gresource.xml

@@ -16,6 +16,7 @@
     <file>conversation_list_titlebar_csd.ui</file>
     <file>conversation_row.ui</file>
     <file>conversation_view.ui</file>
+    <file>default_encryption_dialog.ui</file>
     <file>dino-conversation-list-placeholder-arrow.svg</file>
     <file>file_default_widget.ui</file>
     <file>file_send_overlay.ui</file>

main/src/ui/chat_input/chat_input_controller.vala

@@ -103,7 +103,7 @@ public class ChatInputController : Object {
     private void on_encryption_changed(Encryption encryption) {
         reset_input_field_status();
 
-        if (encryption == Encryption.NONE) return;
+        if (encryption == Encryption.NONE || encryption == Encryption.UNKNOWN) return;
 
         Application app = GLib.Application.get_default() as Application;
         var encryption_entry = app.plugin_registry.encryption_list_entries[encryption];

main/src/ui/conversation_view_controller.vala

@@ -114,6 +114,89 @@ public class ConversationViewController : Object {
         ((Gtk.Window)view.get_root()).add_shortcut(shortcut);
     }
 
+    private void update_conversation_encryption(Conversation? conversation) {
+        if (conversation == null) {
+            return;
+        }
+
+        bool visible = false;
+
+        // FIXME duplicate logic from encryption_button.vala
+        switch (conversation.type_) {
+            case Conversation.Type.CHAT:
+                visible = true;
+                break;
+            case Conversation.Type.GROUPCHAT_PM:
+                visible = false;
+                break;
+            case Conversation.Type.GROUPCHAT:
+                visible = stream_interactor.get_module(MucManager.IDENTITY).is_private_room(conversation.account, conversation.counterpart);
+                break;
+        }
+
+        if (visible && conversation.encryption == UNKNOWN) {
+            Dino.Entities.Settings settings = Dino.Application.get_default().settings;
+
+            if (settings.default_encryption == UNKNOWN) {
+                var selection_dialog_builder = new Builder.from_resource("/im/dino/Dino/default_encryption_dialog.ui");
+                var selection_dialog = selection_dialog_builder.get_object("dialog") as Dialog;
+                var accept_button = selection_dialog_builder.get_object("accept_button") as Button;
+                var omemo_radio = selection_dialog_builder.get_object("omemo") as CheckButton;
+                var openpgp_radio = selection_dialog_builder.get_object("openpgp") as CheckButton;
+                var none_radio = selection_dialog_builder.get_object("none") as CheckButton;
+                Encryption selected_default = UNKNOWN;
+
+                accept_button.sensitive = false;
+
+                omemo_radio.toggled.connect(() => {
+                    accept_button.sensitive = true;
+                });
+
+                openpgp_radio.toggled.connect(() => {
+                    accept_button.sensitive = true;
+                });
+
+                none_radio.toggled.connect(() => {
+                    accept_button.sensitive = true;
+                });
+
+                accept_button.clicked.connect(() => {
+                    if (omemo_radio.active) {selected_default = OMEMO;}
+                    else if (openpgp_radio.active) {selected_default = PGP;}
+                    else if (none_radio.active) {selected_default = NONE;}
+
+                    selection_dialog.response(selected_default);
+                    selection_dialog.close();
+                });
+
+                selection_dialog.response.connect((response_id) => {
+                    if (response_id == Gtk.ResponseType.DELETE_EVENT) {
+                        conversation.encryption = NONE;
+                    }
+                    else {
+                        conversation.encryption = response_id;
+
+                        if (selected_default != NONE) {
+                            settings.default_encryption = response_id;
+                        }
+                        else {
+                            // Set conversation as unencrypted, but keep
+                            // default encryption setting as undecided.
+                        }
+                    }
+                });
+
+                selection_dialog.show();
+            }
+            else {
+                conversation.encryption = settings.default_encryption;
+            }
+        }
+        else if (!visible) {
+            conversation.encryption = Encryption.NONE;
+        }
+    }
+
     public void select_conversation(Conversation? conversation, bool default_initialize_conversation) {
         if (this.conversation != null) {
             conversation.notify["encryption"].disconnect(update_file_upload_status);
@@ -124,6 +207,8 @@ public class ConversationViewController : Object {
 
         this.conversation = conversation;
 
+        update_conversation_encryption(conversation);
+
         // Set list model onto list view
 //        Dino.Application app = GLib.Application.get_default() as Dino.Application;
 //        var map_list_model = get_conversation_content_model(new ContentItemMetaModel(app.db, conversation, stream_interactor), stream_interactor);