/**
 * Scene event structural enum
 * 
 * Created on 2020/01/05.
 */

#ifndef LIQUID_SCENE_EVENT_H
#define LIQUID_SCENE_EVENT_H

// forward declaration
struct Scene;

enum SceneEvent_Kind {
    SceneEventKind_Close,
    SceneEventKind_OpenChild,
    SceneEventKind_RequestRepaint,
    SceneEventKind_None,
};

/**
 * Scene event, returned from some scene methods.
 *
 * Use the constructor functions to create this struct.
 */
struct SceneEvent {
    /** Event kind enum */
    enum SceneEvent_Kind kind;
    union {
        /* data for Close event kind */
        struct {
            // Status code
            int32_t status;
            // Return data on heap
            void *data;
        } close;
        /* Data for Open event kind */
        struct {
            // Scene (initialized, with options loaded in through the constructor)
            struct Scene *scene;
            // Tag used by parent to identify the open child
            uint32_t tag;
        } open;
    };
};

/**
 * Create empty (null object) scene event.
 *
 * @return event
 */
static inline struct SceneEvent SceneEvent_None(void)
{
    return (struct SceneEvent) {
        .kind = SceneEventKind_None,
    };
}

/**
 * Request scene repaint
 *
 * @return event
 */
static inline struct SceneEvent SceneEvent_Repaint(void)
{
    return (struct SceneEvent) {
        .kind = SceneEventKind_RequestRepaint
    };
}

/**
 * Request a sub-scene to be opened
 *
 * @param child - child scene
 * @param tag - scene tag
 * @return event
 */
static inline struct SceneEvent SceneEvent_OpenChild(struct Scene *child, uint32_t tag) {
    return (struct SceneEvent) {
        .kind = SceneEventKind_OpenChild,
        .open = { .scene = child, .tag=tag },
    };
}

/**
 * Close this scene, returning to parent.
 *
 * @param status - status number for the parent
 * @param data - heap-allocated data for parent, can be NULL; e.g. user input as string.
 * @return event
 */
static inline struct SceneEvent SceneEvent_Close(int32_t status, void *data)
{
    return (struct SceneEvent) {
        .kind = SceneEventKind_Close,
        .close = {.status = status, .data=data},
    };
}

#endif //LIQUID_SCENE_EVENT_H