/**
 * @file game.h
 * @brief Declares the public game API.
 */

#ifndef _AKGL_GAME_H_
#define _AKGL_GAME_H_

#include <stdint.h>
#include <SDL3_mixer/SDL_mixer.h>
#include "types.h"
#include "tilemap.h"
#include "renderer.h"
#include "physics.h"

#define AKGL_VERSION                     "0.1.0"

#define AKGL_GAME_AUDIO_TRACK_BGM        1
#define AKGL_GAME_AUDIO_MAX_TRACKS       64

#define AKGL_TIME_ONESEC_NS              1000000000
#define AKGL_TIME_ONESEC_MS              1000000

/* ==================== GAME STATE VARIABLES =================== */

/** @brief Describes a renderable frame. */
typedef struct {
    float32_t w;
    float32_t h;
    SDL_Texture *texture;
} akgl_Frame;

/** @brief Stores application-defined game-state flags. */
typedef struct {
    int32_t flags;
} akgl_GameState;

/** @brief Stores game metadata, timing, synchronization, and FPS accounting. */
typedef struct {
    char libversion[32];
    char version[32];
    char name[256];
    char uri[256];
    akgl_GameState state;
    SDL_Mutex *statelock;
    int16_t fps;
    SDL_Time gameStartTime;
    SDL_Time lastIterTime;
    SDL_Time lastFPSTime;
    int16_t framesSinceUpdate;
    void (*lowfpsfunc)(void);
} akgl_Game;

/** @brief SDL window used by the active renderer. */
extern SDL_Window *window;
/** @brief Loaded background-music resource. */
extern MIX_Audio *bgm;
/** @brief Mixer used for game audio playback. */
extern MIX_Mixer *akgl_mixer;
/** @brief Process-wide audio-track table. */
extern MIX_Track *akgl_tracks[AKGL_GAME_AUDIO_MAX_TRACKS];
/** @brief Storage for the default camera. */
extern SDL_FRect _akgl_camera;
/** @brief Process-wide game metadata and timing state. */
extern akgl_Game game;
/** @brief Storage for the default renderer. */
extern akgl_RenderBackend _akgl_renderer;
/** @brief Storage for the default physics backend. */
extern akgl_PhysicsBackend _akgl_physics;
/** @brief Storage for the default tilemap. */
extern akgl_Tilemap _akgl_gamemap;

/** @brief Currently active tilemap. */
extern akgl_Tilemap *gamemap;
/** @brief Currently active renderer. */
extern akgl_RenderBackend *renderer;
/** @brief Currently active physics backend. */
extern akgl_PhysicsBackend *physics;
/** @brief Currently active camera. */
extern SDL_FRect *camera;

#define AKGL_BITMASK_HAS(x, y) (x & y) == y
#define AKGL_BITMASK_HASNOT(x, y) (x & y) != y
#define AKGL_BITMASK_ADD(x, y) x |= y
#define AKGL_BITMASK_DEL(x, y) x &= ~(y)
#define AKGL_BITMASK_CLEAR(x)  x = 0;

/**
 * @brief Game init.
 * @return `NULL` on success, otherwise an error context owned by the caller.
 * @throws AKERR_NULLPOINTER When the corresponding validation or operation fails.
 * @throws AKGL_ERR_SDL When the corresponding validation or operation fails.
 */
akerr_ErrorContext AKERR_NOIGNORE *akgl_game_init();
/**
 * @brief Game init screen.
 * @return `NULL` on success, otherwise an error context owned by the caller.
 * @throws AKERR_* Propagates an error reported by a delegated operation.
 */
akerr_ErrorContext AKERR_NOIGNORE *akgl_game_init_screen();
/**
 * @brief Game updatefps.
 */
void akgl_game_updateFPS();
/**
 * @brief Game save.
 * @param fpath Path to the input or output file.
 * @return `NULL` on success, otherwise an error context owned by the caller.
 * @throws AKERR_NULLPOINTER When the corresponding validation or operation fails.
 */
akerr_ErrorContext AKERR_NOIGNORE *akgl_game_save(char *fpath);
/**
 * @brief Game load.
 * @param fpath Path to the input or output file.
 * @return `NULL` on success, otherwise an error context owned by the caller.
 * @throws AKERR_API When the corresponding validation or operation fails.
 * @throws AKERR_NULLPOINTER When the corresponding validation or operation fails.
 */
akerr_ErrorContext AKERR_NOIGNORE *akgl_game_load(char *fpath);
/**
 * @brief Game lowfps.
 */
void akgl_game_lowfps(void);
/**
 * @brief Game state lock.
 * @return `NULL` on success, otherwise an error context owned by the caller.
 * @throws AKGL_ERR_SDL When the corresponding validation or operation fails.
 */
akerr_ErrorContext AKERR_NOIGNORE *akgl_game_state_lock(void);
/**
 * @brief Game state unlock.
 * @return `NULL` on success, otherwise an error context owned by the caller.
 * @throws AKERR_* Propagates an error reported by a delegated operation.
 */
akerr_ErrorContext AKERR_NOIGNORE *akgl_game_state_unlock(void);
/**
 * @brief Game update.
 * @param opflags Optional iterator operation flags; `NULL` selects defaults.
 * @return `NULL` on success, otherwise an error context owned by the caller.
 * @throws AKERR_* Propagates an error reported by a delegated operation.
 */
akerr_ErrorContext AKERR_NOIGNORE *akgl_game_update(akgl_Iterator *opflags);

#endif //_AKGL_GAME_H_