/**
 * Scrollable menu
 * 
 * Created on 2020/01/05.
 */

#ifndef REFLOWER_SCENE_MENU_H
#define REFLOWER_SCENE_MENU_H

#include <stdint.h>
#include <stdbool.h>
#include <stddef.h>

#define MENUITEM_LABEL_LEN 30

/**
 * One item of the menu
 */
struct MenuItem {
    // menu label
    char label[MENUITEM_LABEL_LEN];
    // item tag (useful with dynamically generated menus)
    uint32_t tag;
};

struct MenuScene;

/**
 * Selection handler.
 *
 * When an item is selected, this abstract method is fired to determine what should happen.
 *
 * The selected item is available as scene.selected.
 * Return SceneEvent to take, e.g. to close the menu, or to open a sub-scene.
 */
typedef struct SceneEvent (*MenuScene_onSelect_t)(struct MenuScene *scene);

struct MenuScene {
    struct Scene base;
    // items array
    struct MenuItem *items;
    // allow wrap-around
    bool wraparound;
    // items count
    size_t items_len;
    // Vertical scroll offset (how many steps is the topmost item moved above the screen)
    int32_t scroll_up;
    // Start X
    int x;
    // Start Y
    int y;
    // Selected item number
    int32_t selected;
    // Horizontal scroll count
    int32_t hscroll;
    // Horizontal scroll timer
    int32_t hscroll_cnt;
    // Number of lines visible at a time
    uint8_t nlines;
    // number of visible characters in a line at a time
    uint8_t ncols;
    // selection handler
    MenuScene_onSelect_t onSelect;
    // Extra field for the subclass's private use.
    void *extra;
    // fp for extra's deinit function
    Scene_deinit_t extra_deinit;
};

/**
 * Create a new items menu.
 *
 * This is normally called from a subclass.
 *
 * @param items - menu items on heap (the MenuScene will free them on close)
 * @param items_len - item count
 * @return the menu
 */
struct MenuScene *NewScene_Menu(struct MenuItem *items, size_t items_len);

#endif //REFLOWER_SCENE_MENU_H