Input GUI: Add tab to remap controls (#1900)

src/citra_qt/configure_input.h

@@ -0,0 +1,63 @@
+// Copyright 2016 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <QWidget>
+#include <QKeyEvent>
+
+#include "citra_qt/config.h"
+#include "core/settings.h"
+#include "ui_configure_input.h"
+
+class QPushButton;
+class QString;
+class QTimer;
+
+namespace Ui {
+    class ConfigureInput;
+}
+
+class ConfigureInput : public QWidget {
+    Q_OBJECT
+
+public:
+    explicit ConfigureInput(QWidget* parent = nullptr);
+
+    /// Save all button configurations to settings file
+    void applyConfiguration();
+
+private:
+    std::unique_ptr<Ui::ConfigureInput> ui;
+    std::map<Settings::NativeInput::Values, QPushButton*> input_mapping;
+    int key_pressed;
+    QPushButton* changing_button = nullptr; ///< button currently waiting for key press.
+    QString previous_mapping;
+    QTimer* timer;
+
+    /// Load configuration settings into button text
+    void setConfiguration();
+
+    /// Check all inputs for duplicate keys. Clears out any other button with the same value as this button's new value.
+    void removeDuplicates(const QString& newValue);
+
+    /// Handle key press event for input tab when a button is 'waiting'.
+    void keyPressEvent(QKeyEvent* event) override;
+
+    /// Convert key ASCII value to its' letter/name
+    QString getKeyName(int key_code) const;
+
+    /// Convert letter/name of key to its ASCII value.
+    Qt::Key getKeyValue(const QString& text) const;
+
+    /// Set button text to name of key pressed.
+    void setKey();
+
+private slots:
+    /// Event handler for all button released() event.
+    void handleClick();
+
+    /// Restore all buttons to their default values.
+    void restoreDefaults();
+};