From fce9ee31ec0ded06230fb7bce5b8b959e9968826 Mon Sep 17 00:00:00 2001
From: Stanislaw Halik <sthalik@misaki.pl>
Date: Fri, 6 Apr 2018 06:04:28 +0200
Subject: options/tie: preliminary support for early conversions

---
 options/tie.hpp | 62 ++++++++++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 53 insertions(+), 9 deletions(-)

diff --git a/options/tie.hpp b/options/tie.hpp
index 4ebc1846..014dc84d 100644
--- a/options/tie.hpp
+++ b/options/tie.hpp
@@ -8,9 +8,12 @@
 
 #pragma once
 
-#include "export.hpp"
+#include "value-traits.hpp"
 #include "value.hpp"
 #include "compat/run-in-thread.hpp"
+#include "compat/macros.hpp"
+
+#include <type_traits>
 
 #include <QComboBox>
 #include <QCheckBox>
@@ -23,6 +26,8 @@
 
 #include <cmath>
 
+#include "export.hpp"
+
 #if defined __GNUG__
 #   pragma GCC diagnostic push
 #   pragma GCC diagnostic ignored "-Wattributes"
@@ -30,25 +35,61 @@
 
 namespace options {
 
+namespace detail {
+
 template<typename t>
-std::enable_if_t<std::is_enum<t>::value>
-tie_setting(value<t>& v, QComboBox* cb)
+struct tie_setting_traits_helper
+{
+    using traits = detail::value_traits<t>;
+    using value_type = typename traits::value_type;
+    using element_type = typename traits::element_type;
+
+    static element_type to_element_type(const value<t>& v)
+    {
+        return static_cast<element_type>(static_cast<value_type>(v));
+    }
+};
+
+template<typename t, typename Enable = void>
+struct tie_setting_traits final : tie_setting_traits_helper<t>
 {
-    cb->setCurrentIndex(cb->findData(int(static_cast<t>(v))));
-    v = static_cast<t>(cb->currentData().toInt());
+    static constexpr inline bool should_bind_to_itemdata() { return false; }
+};
+
+template<typename t>
+struct tie_setting_traits<t, std::enable_if_t<std::is_enum_v<t>>> : tie_setting_traits_helper<t>
+{
+    static constexpr inline bool should_bind_to_itemdata() { return true; }
+
+    static t itemdata_to_value(int, const QVariant& var)
+    {
+        return static_cast<t>(var.toInt());
+    }
+};
+
+} // ns options::details
+
+template<typename t, typename traits_type = detail::tie_setting_traits<t>>
+std::enable_if_t<traits_type::should_bind_to_itemdata()>
+tie_setting(value<t>& v, QComboBox* cb, const traits_type& traits = traits_type())
+{
+    using element_type = typename detail::value_traits<t>::element_type;
+
+    cb->setCurrentIndex(cb->findData(traits.to_element_type(v)));
+    v = traits.itemdata_to_value(cb->currentIndex(), cb->currentData());
 
     base_value::connect(cb,
                         static_cast<void (QComboBox::*)(int)>(&QComboBox::currentIndexChanged),
                         &v,
-                        [&v, cb](int idx)
+                        [&v, cb, traits](int idx)
                         {
                             run_in_thread_sync(cb,
-                                               [&]() {
-                                                    v = static_cast<t>(cb->itemData(idx).toInt());
+                                               [&, traits]() {
+                                                    v = traits.itemdata_to_value(idx, cb->currentData());
                                                });
                         },
                         v.DIRECT_CONNTYPE);
-    base_value::connect(&v, base_value::value_changed<int>(),
+    base_value::connect(&v, base_value::value_changed<element_type>(),
                         cb, [cb](int x) {
                             run_in_thread_sync(cb, [&]() { cb->setCurrentIndex(cb->findData(x)); });
                         },
@@ -79,6 +120,9 @@ void tie_setting(value<t>& v, QObject* obj, F&& fun)
                         v.DIRECT_CONNTYPE);
 }
 
+// XXX TODO add combobox transform both ways via std::function
+// need for non-translated `module_settings' dylib names
+
 OTR_OPTIONS_EXPORT void tie_setting(value<int>& v, QComboBox* cb);
 OTR_OPTIONS_EXPORT void tie_setting(value<QString>& v, QComboBox* cb);
 OTR_OPTIONS_EXPORT void tie_setting(value<QVariant>& v, QComboBox* cb);
-- 
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