#ifndef ENTITY_H
#define ENTITY_H

#include "sheet.h"
#include "mixer.h"

/* ========================== *
 * Entity
 * ========================== */

struct entity_handle {
    u64 idx;
    u64 gen;
};

enum entity_prop {
    ENTITY_PROP_NONE,

    ENTITY_PROP_SPRITE_ANIMATED,
    ENTITY_PROP_PLAYER_CONTROLLED,
    ENTITY_PROP_CAMERA,

    /* Test props */

    ENTITY_PROP_TEST,
    ENTITY_PROP_TEST_FOLLOW_MOUSE,
    ENTITY_PROP_TEST_SOUND_EMITTER,

    ENTITY_PROP_COUNT
};

struct entity {
    b32 valid;
    struct entity_handle handle;
    u64 continuity_gen;
    u64 props[(ENTITY_PROP_COUNT + 63) / 64];

    struct entity *next_free;

    /* Tree */
    struct entity_handle parent;
    struct entity_handle next;
    struct entity_handle prev;
    struct entity_handle first;
    struct entity_handle last;

    /* ====================================================================== */
    /* Translation, rotation, scale in relation to parent entity */

    struct trs rel_trs;

    struct mat3x3 world_xform;  /* Calculated post-physics */

    /* ====================================================================== */
    /* Physics */

    struct v2 acceleration;
    struct v2 velocity;

    /* ENTITY_PROP_PLAYER_CONTROLLED */
    f32 player_max_speed;
    f32 player_acceleration;

    /* ====================================================================== */
    /* Sprite */

    struct string sprite_name;
    struct trs sprite_trs;
    struct v2 sprite_pivot_norm;  /* Pivot x & y are each normalized about sprite dimensions. <0, 0> is center, <1, 1> is bottom right corner, etc. */
    u32 sprite_tint;

    /* ====================================================================== */
    /* Animation */

    /* ENTITY_PROP_SPRITE_ANIMATED */
    struct string animation_name;
    u64 animation_flags;
    f64 animation_time_in_frame;
    u64 animation_start_gen;
    u64 animation_gen;
    struct sheet_frame animation_frame;

    /* ====================================================================== */
    /* Testing */

    /* ENTITY_PROP_TEST */
    b32 test_initialized;
    struct trs test_start_rel_trs;
    struct trs test_start_sprite_trs;

    /* ENTITY_PROP_TEST_SOUND_EMITTER */
    struct string sound_name;
    struct mixer_desc sound_desc;
    struct mixer_track_handle sound_handle;

    /* ====================================================================== */

    /* ENTITY_PROP_CAMERA */
    b32 camera_active;
    struct entity_handle camera_follow;
    f32 camera_rot;
    f32 camera_zoom;
};

/* Nil entity */

extern READONLY struct entity _g_entity_nil;

INLINE READONLY struct entity *entity_nil(void)
{
    return &_g_entity_nil;
}

/* Prop */

void entity_enable_prop(struct entity *entity, enum entity_prop prop);
void entity_disable_prop(struct entity *entity, enum entity_prop prop);
b32 entity_has_prop(struct entity *entity, enum entity_prop prop);

/* Animation */

#define ANIMATION_FLAG_NONE       0x0
#define ANIMATION_FLAG_LOOPING    0x1

void entity_start_animation(struct entity *entity, struct string animation_name, u64 flags);

#endif