// Voir README.md pour license précise, par Fcalva 2023-2024 et est sous GPLv3

#include <gint/display.h>
#include <gint/keyboard.h>
#include <stdlib.h>
#include <string.h>

#include "fixed.h"
#include "game.h"
#include "sprites.h"
#include "moteur.h"
#include "config.h"
#include "utils.h"

extern fixed_t zbuf[viewport_w];

int spritec;

Sprite *sprite_index[SINDEX_S];

void add_sprite(Sprite *sprite){
  if(spritec >= SINDEX_S)
    return;
  sprite_index[spritec++] = sprite;
}

void clear_sprites(){
  spritec = 0;
}

void remove_sprite(GUNUSED Sprite *sprite){
  //TODO
}

//Lodev's sprite projection, translated

void project_sprite(bopti_image_t *tex_index[], Sprite *sprite, RcActor *player){

  V2d relpos = sprite->pos;
  relpos.x -= player->pos.x;
  relpos.y -= player->pos.y;

  fixed_t idet = fmul(player->plane.x, player->dir.y) -
                                fmul(player->dir.x, player->plane.y);
  idet = idet ? fdiv(fix(1), idet):0;

  fixed_t tx = fmul(idet, fmul(player->dir.y, relpos.x) -
                            fmul(player->dir.x, relpos.y));
  fixed_t ty = fmul(idet, fmul(-player->plane.y, relpos.x) +
                            fmul(player->plane.x, relpos.y));
  fixed_t txtydiv = ty ? fdiv(tx, ty):0;
  int screen_x = ffloor(fmul(fix(viewport_w/2),(fix(1) + txtydiv)));

  int sprite_h = ffloor(fixabs(fdiv(fix(viewport_h),ty)));

  int sprite_pos_y = -sprite_h / 2 + viewport_h / 2;

  if(sprite_pos_y < 0)
    sprite_pos_y = 0;

  int sprite_pos_x = -sprite_h / 2 + screen_x;
  if(sprite_pos_x < 0)
    sprite_pos_x = 0;
  int sprite_end_x = sprite_h / 2 + screen_x;
  if(sprite_end_x > viewport_w)
    sprite_end_x = viewport_w;

  int sprite_w = sprite_h;

  if(sprite_pos_x + sprite_h > viewport_w)
    sprite_h = viewport_w - sprite_pos_x;
  if(sprite_pos_y + sprite_w > viewport_h)
    sprite_w = viewport_h - sprite_pos_y;
  if(sprite_pos_x + sprite_h < 0 || sprite_pos_x > viewport_w)
    return;

  fixed_t sprite_size = fdiv(fix(sprite_w), fix(TSIZE));

  for(int x = sprite_pos_x; x < sprite_end_x; x++){
    if(ty < 0 || x < 0 || ty > zbuf[x])
      continue;
    if(x > viewport_w)
      break;
    int tex_x = ffloor((x-sprite_pos_x) * fdiv(fix(TSIZE), fix(sprite_w)));
    tex_x %= TSIZE;

    draw_stripe(tex_index[4], 0, sprite_pos_y, sprite_size, tex_x, x);
  }
}

struct SpriteDist{
  fixed_t dist;
  int id;
};

int sprite_cmpfnc(const void *p1, const void *p2){
  return ((struct SpriteDist*)p2)->dist - ((struct SpriteDist*)p1)->dist;
}

void draw_sprites(bopti_image_t *tex_index[], RcActor *player){
  struct SpriteDist dists[SINDEX_S];
  memset(dists, 0, sizeof(struct SpriteDist)*SINDEX_S);
  for(int i = 0; i < spritec; i++){
    Sprite *spr = sprite_index[i];
    fixed_t d = player->pos.x - spr->pos.x;
    d = fmul(d,d);
    d += fmul(player->pos.y - spr->pos.y,player->pos.y - spr->pos.y);
    dists[i].dist = d;
    dists[i].id = i;
  }

  qsort(dists, SINDEX_S, sizeof(struct SpriteDist), &sprite_cmpfnc);

  int msprite = min(spritec,max_sprites);
  for(int i = msprite; i > 0; i--){
    struct SpriteDist *sd = &dists[i];
    Sprite *spr = sprite_index[sd->id];
    if(sd->dist > max_dist)
      continue;
    project_sprite(tex_index, spr, player);
  }
}