#ifndef _XAS_SPATIAL_H
#define _XAS_SPATIAL_H

#include <xas/audio.h>

#define XAS_SPATIAL_DEFAULT_OBSERVER_WIDTH   0.18f
#define XAS_SPATIAL_DEFAULT_RADIUS         4000.0f /* metres */
#define XAS_SPATIAL_DEFAULT_SPEED           343.0f /* m/s */
#define XAS_SPATIAL_DEFAULT_CONE_ANGLE       35.0f /* degrees */

typedef struct _xas_spatial_coord {
    float x, y, z;
} xas_spatial_coord;

typedef struct _xas_spatial_cone {
    xas_spatial_coord apex,
                        rotation;

    float angle;
} xas_spatial_cone;

typedef struct _xas_spatial_observer {
    xas_spatial_coord point,
                        rotation;

    float width;
} xas_spatial_observer;

typedef struct _xas_spatial_object xas_spatial_object;

struct _xas_spatial_object {
    float distance_l,
          distance_r;

    size_t delta_l,
           delta_r;

    ssize_t shift_l,
            shift_r;

    xas_audio_stream *source;
    void *ctx;

    xas_spatial_coord point;
    xas_spatial_object *next;
};

typedef struct _xas_spatial_buffer {
    size_t index,
           size;
} xas_spatial_buffer;

typedef struct _xas_spatial_scene {
    xas_audio_format format;

    xas_spatial_observer observer;

    xas_spatial_coord speaker_l,
                        speaker_r;

    float speed,
          radius;

    xas_spatial_object *first,
                         *last;

    xas_spatial_buffer *buffer;
} xas_spatial_scene;

xas_spatial_scene *xas_spatial_scene_new(xas_audio_format format,
                                             xas_spatial_coord speaker_l,
                                             xas_spatial_coord speaker_r);

void xas_spatial_scene_destroy(xas_spatial_scene *scene);

void xas_spatial_scene_set_observer(xas_spatial_scene *scene,
                                      xas_spatial_coord point,
                                      xas_spatial_coord rotation,
                                      float width);

void xas_spatial_scene_set_speaker_coords(xas_spatial_scene *scene,
                                            xas_spatial_coord speaker_l,
                                            xas_spatial_coord speaker_r);

int xas_spatial_scene_set_speed(xas_spatial_scene *scene, float speed);

int xas_spatial_scene_set_radius(xas_spatial_scene *scene, float radius);

xas_spatial_object *xas_spatial_scene_add_object(xas_spatial_scene *scene,
                                                     xas_spatial_coord point,
                                                     xas_audio_stream *source,
                                                     void *ctx);

void xas_spatial_scene_position_object(xas_spatial_scene *scene,
                                         xas_spatial_object *object,
                                         xas_spatial_coord point);

int xas_spatial_object_start(xas_spatial_object *object);

int xas_spatial_object_stop(xas_spatial_object *object);

void xas_spatial_object_get_point(xas_spatial_object *object,
                                    xas_spatial_coord *point);

xas_audio_stream *xas_spatial_scene_stream_new(xas_spatial_scene *scene,
                                                   size_t buffer_size);

#endif /* _XAS_SPATIAL_H */