sm-26/Source/MenuSystem.h

#pragma once

#include <JuceHeader.h>
#include "SynthParams.h"

class MenuSystem;

struct MenuItem
{
    enum Kind { Action, Value, Submenu, Separator };

    juce::String label;
    Kind kind = Action;
    int paramId = -1;

    std::function<void()> onEnter;
    std::function<void(float delta)> onAdjust;
    std::function<juce::String()> valueText;

    MenuItem& action (std::function<void()> fn)   { onEnter = fn; return *this; }
    MenuItem& param (int id, float lo, float hi)  { paramId = id; return *this; }
    MenuItem& value (std::function<juce::String()> fn) { valueText = fn; kind = Value; return *this; }
    MenuItem& submenu()                           { kind = Submenu; return *this; }
    MenuItem& sep()                               { kind = Separator; return *this; }
};

struct MenuScreen
{
    juce::String title;
    std::vector<MenuItem> items;
    int selected = 0;
};

class MenuSystem
{
public:
    MenuSystem();

    void open();
    void close();
    bool isOpen() const { return ! stack.empty(); }

    void up();
    void down();
    void left();
    void right();
    void enter();
    void escape();

    const MenuScreen& current() const;

    void pushScreen (const MenuScreen& screen);

    using ScreenBuilder = std::function<MenuScreen()>;

    void setRootScreenBuilder (ScreenBuilder fn);

    void refreshCurrent();

private:
    std::vector<MenuScreen> stack;
    ScreenBuilder rootBuilder;
    bool wasOpen = false;

    void rebuildRoot();
};