#ifndef __GAME_H__
# define __GAME_H__

#include "util.h"
#include "render.h"
#include "level.h"

#include <gint/display.h>
#include <libprof.h>

/* A player's movement and data information. */
struct player
{
    //======= Movement =======//

    /* Position in the level (world units). */
    num z;
    /* Movement speed along the z axis (world units/s, ≥ 0). */
    num vz;

    /* Current platform; when rotating, platform the player jumped from
       (0..PLATFORM_COUNT-1) */
    int platform;

    /* Player's current movement stance. */
    enum {
        Running,  /* Running on the ground */
        Jumping,  /* Jumping, with jump key still pressed */
        Falling,  /* Falling, typically after releasing jump key */
    } stance;

    /* Determine the player's animation and frame. */
    void get_anim(struct anim **anim, int *frame);
    /* Current animation frame. */
    int frame;

    /* Whether the player is airborne. */
    bool airborne() const { return this->stance != Running; }

    /* Jump direction.
       * when not jumping: 0
       * when jumping, while rotating: -1, 0 or +1
       * when jumping, after rotating: 0 */
    int jump_dir;
    /* Time spent jumping (s). */
    num jump_t;
    /* Key to watch to end the jump. */
    int jump_key;
    /* Current height relative to current platform (world units). */
    num height;
    /* Vertical speed (world units/s). */
    num vheight;

    /* Player angle relative to -y around +z (depends on the current platform,
       plus some extra during rotations). */
    num world_angle() const;
    vec2 world_angle_vector() const;

    /* Full player position in 3D space. */
    vec3 pos() const;

    /* Unit vectors in the directions of movement, accounting for player's
       rotation around the world cylinder. */
    vec3 forward() const;
    vec3 backward() const;
    vec3 up() const;
    vec3 down() const;

    //======= Data =======//

    /* Energy collected, in percent */
    num energy_percent;

    /* TODO: Skin, others? */
};

/* Dynamic information about one or multiple attempts at a single level. */
struct game
{
    struct level level;
    struct player player;
    struct camera camera;

    /* Absolute time spent in the level. */
    num t;
    /* Number of sections passed. */
    int sections_passed;

    struct {
        bool footer;  /* Show performance footer */
    } debug;

    struct {
        prof_t effect_bpp;
    } perf;
};

//======= Functions on the game world space =======//

/* Initialize constants for the game. */
void space_init(void);

/* Angle, in radians, of a platform arc (2π / PLATFORM_COUNT). */
consteval num space_platform_arc()
{
    return num(2 * 3.14159 / PLATFORM_COUNT);
}

/* Height (in world coordinates in the range [-LEVEL_RADIUS..0]) of a platform
   whose height value in the `struct platform` is given as parameter. */
num space_platform_height(int height_value);

/* Distance between the center of the world and a platform's plane. */
num space_platform_distance(void);

/* Position, in world units, of the provided flat platform. */
struct prect space_platform_position(struct platform const *p);

//======= Game management =======//

/* Advance in the level by discarding platforms that have been passed. */
void game_advance(struct game *game);

/* Get platform height at the provided position. */
num game_height_at(struct game *game, num z, int face);

/* Returns the platform on which the player is running, if any. */
const struct platform *game_platform_under_player(struct game const *game,
    struct player const *player);

#endif /* __GAME_H__   */