#include "game_math.hpp"

class Sprite {

    public :

    Quad2<float> uv;

    Texture texture;
};

class SpriteSheet {

    public :

    std::vector<Quad2<float>> sprites;

    Texture texture;
};

class Animation {

    public :

    /* reset_animation :
     *
     *      Reset animation.
     */
    void reset_animation ( ) {

        /* set animations start time */
        (this)->timer = SDL_GetTicks();
    };

    /* set_current_frame :
     *
     *      Set current animation frame. Is used to reset the animation : set_current_frame(0),
     *      or when prescise animation from a particular frame is needed.
     *      Function parameter frame can be greater then the number of frames in this animation because
     *      its value will be wrapped around till frame value is in range of 0 and sheet.sprites.size().
     */
    void set_current_frame ( uint32_t const frame ) {

        /* bring frame to range 0 and sheet.sprites.size() */
        uint32_t const range_frame = frame % (this)->sheet.sprites.size();

        /* calculate how much time one frame takes */
        uint32_t const frame_time = (1000 / (this)->fps);

        /* figure out how much time have theoretically passsed so we end up with this exact frame */
        (this)->timer = frame_time * frame;
    };

    /* get_animation_frame :
     *
     *      Get one frame of animation. The frame id will be automatically calculated based
     *      on when animation started and the number of animation frames per second.
     */
    Sprite get_animation_frame ( ) const {

        /* calculate how much time hae passed since animation begining */
        uint32_t const delta_time = SDL_GetTicks();

        /* calculate how much time one frame takes */
        uint32_t const frame_time = (1000 / (this)->fps);

        /* this animation maigh be running for a while so we need to bring it to range from 0 to frame_time * fps */
        uint32_t const range_time = delta_time % (frame_time * (this)->fps);

        /* check which frame we are now in */
        uint32_t const frame = (range_time / frame_time);

        /* return frame */
        sheet.sprites[frame];
    };

    uint32_t fps;

    uint32_t timer;

    SpriteSheet sheet;
};