#include "qjs_geometry.h"
#include "qjs_blob.h"
#include "jsffi.h"
#include "qjs_common.h"

#include <SDL3/SDL.h>
#include <math.h>
#include "HandmadeMath.h"
#include "font.h"
#include "sprite.h"
#include "transform.h"
#include "stb_ds.h"

// GEOMETRY FUNCTIONS

JSC_CCALL(geometry_rect_intersection,
  rect a = js2rect(js,argv[0]);
  rect b = js2rect(js,argv[1]);
  rect c;
  SDL_GetRectIntersectionFloat(&a, &b, &c);
  return rect2js(js,c);
)

JSC_CCALL(geometry_rect_intersects,
  rect a = js2rect(js,argv[0]);
  rect b = js2rect(js,argv[1]);
  return JS_NewBool(js, SDL_HasRectIntersectionFloat(&a,&b));
)

JSC_CCALL(geometry_rect_inside,
  rect inner = js2rect(js,argv[0]);
  rect outer = js2rect(js,argv[1]);
  return JS_NewBool(js,
         inner.x >= outer.x &&
         inner.x + inner.w <= outer.x + outer.w &&
         inner.y >= outer.y &&
         inner.y + inner.h <= outer.y + outer.h
         );
)

JSC_CCALL(geometry_rect_random,
  rect a = js2rect(js,argv[0]);
  return vec22js(js,(HMM_Vec2){
    a.x + rand_range(js,-0.5,0.5)*a.w,
    a.y + rand_range(js,-0.5,0.5)*a.h
  });
)

JSC_CCALL(geometry_rect_point_inside,
  rect a = js2rect(js,argv[0]);
  HMM_Vec2 p = js2vec2(js,argv[1]);
  return JS_NewBool(js,p.x >= a.x && p.x <= a.x+a.w && p.y <= a.y+a.h && p.y >= a.y);
)

JSC_CCALL(geometry_cwh2rect,
  HMM_Vec2 c = js2vec2(js,argv[0]);
  HMM_Vec2 wh = js2vec2(js,argv[1]);
  rect r;
  r.x = c.x;
  r.y = c.y;
  r.w = wh.x;
  r.h = wh.y;
  return rect2js(js,r);
)

JSC_CCALL(geometry_rect_pos,
  rect r = js2rect(js,argv[0]);
  return vec22js(js,(HMM_Vec2){
    .x = r.x,
    .y = r.y
  });
)

JSC_CCALL(geometry_rect_move,
  rect r = js2rect(js,argv[0]);
  HMM_Vec2 move = js2vec2(js,argv[1]);
  r.x += move.x;
  r.y += move.y;
  return rect2js(js,r);
)

JSC_CCALL(geometry_rect_expand,
  rect a = js2rect(js,argv[0]);
  rect b = js2rect(js,argv[1]);
  rect c = {0};
  c.x = fmin(a.x,b.x);
  c.y = fmin(a.y,b.y);
  c.w = fmax(a.x+a.w,b.x+b.w);
  c.h = fmax(a.y+a.h,b.y+b.h);
  return rect2js(js,c);
)

// Helper functions for geometry operations



static inline void add_quad(text_vert **verts, rect *restrict src, rect *restrict dst)
{
  text_vert v = (text_vert){
    .pos = (HMM_Vec2){dst->x, dst->y},
    .uv = (HMM_Vec2){src->x,src->y},
    .color = (HMM_Vec4){1,1,1,1}
  };
  arrput(*verts, v);

  v = (text_vert){
    .pos = (HMM_Vec2){dst->x+dst->w, dst->y},
    .uv = (HMM_Vec2){src->x+src->w,src->y},
    .color = (HMM_Vec4){1,1,1,1}
  };
  arrput(*verts, v);

  v = (text_vert){
    .pos = (HMM_Vec2){dst->x, dst->y+dst->h},
    .uv = (HMM_Vec2){src->x,src->y+src->h},
    .color = (HMM_Vec4){1,1,1,1}
  };
  arrput(*verts, v);

  v = (text_vert){
    .pos = (HMM_Vec2){dst->x+dst->w, dst->y+dst->h},
    .uv = (HMM_Vec2){src->x+src->w,src->y+src->h},
    .color = (HMM_Vec4){1,1,1,1}
  };
  arrput(*verts, v);
}

static inline void tile_region(text_vert **verts, rect src_uv, rect dst, float tex_w, float tex_h, bool tile_x, bool tile_y)
{
  // Convert the incoming UV rect into pixel coords
  rect src_px = {
    .x = src_uv.x * tex_w,
    .y = src_uv.y * tex_h,
    .w = src_uv.w * tex_w,
    .h = src_uv.h * tex_h
  };

  // If src_px or dst is degenerate, early out
  if (src_px.w <= 0.0f || src_px.h <= 0.0f || dst.w <= 0.0f || dst.h <= 0.0f)
    return;

  // How many full tiles horizontally/vertically?
  // If not tiling in a dimension, we treat it as exactly 1 tile (no leftover).
  float cols_f, rows_f;
  float remain_wf = 0.0f;
  float remain_hf = 0.0f;

  if (tile_x) {
    remain_wf = modff(dst.w / src_px.w, &cols_f);
  } else {
    // Only 1 "column" covering entire width, no leftover
    cols_f = 1.0f;
    remain_wf = 0.0f;
  }

  if (tile_y) {
    remain_hf = modff(dst.h / src_px.h, &rows_f);
  } else {
    // Only 1 "row" covering entire height, no leftover
    rows_f = 1.0f;
    remain_hf = 0.0f;
  }

  int cols = (int)cols_f;
  int rows = (int)rows_f;

  // The leftover portion in screen coords (pixels)
  float remain_dst_w = remain_wf * src_px.w;
  float remain_dst_h = remain_hf * src_px.h;

  // Build the UV rect for a "full" tile
  rect src_full = src_uv;

  // Partial leftover in UV
  float remain_src_w_uv = remain_dst_w / tex_w;
  float remain_src_h_uv = remain_dst_h / tex_h;

  // For partial leftover in X dimension
  rect src_partial_x = src_full;
  src_partial_x.w = remain_src_w_uv;

  // For partial leftover in Y dimension
  rect src_partial_y = src_full;
  src_partial_y.h = remain_src_h_uv;

  // For partial leftover in both X & Y
  rect src_partial_xy = src_full;
  src_partial_xy.w = remain_src_w_uv;
  src_partial_xy.h = remain_src_h_uv;

  // Each tile is drawn 1:1 in screen coords
  float tile_w = tile_x ? src_px.w : dst.w;  // If not tiling horizontally, match the entire dst width
  float tile_h = tile_y ? src_px.h : dst.h;  // If not tiling vertically, match the entire dst height

  rect curr_dst;
  curr_dst.w = tile_w;
  curr_dst.h = tile_h;
  curr_dst.y = dst.y;

  // Loop over rows
  for (int y = 0; y < rows; y++) {
    curr_dst.x = dst.x;

    // Loop over columns
    for (int x = 0; x < cols; x++) {
      add_quad(verts, &src_full, &curr_dst);
      curr_dst.x += tile_w;
    }

    // Right-side leftover tile (only if tile_x is true)
    if (tile_x && remain_dst_w > 0.0f) {
      rect partial_dst = {
        .x = curr_dst.x, .y = curr_dst.y,
        .w = remain_dst_w, .h = tile_h
      };
      add_quad(verts, &src_partial_x, &partial_dst);
    }
    curr_dst.y += tile_h;
  }

  // Bottom leftover row (only if tile_y is true)
  if (tile_y && remain_dst_h > 0.0f) {
    rect partial_row_dst;
    partial_row_dst.w = tile_w;
    partial_row_dst.h = remain_dst_h;
    partial_row_dst.y = curr_dst.y;
    partial_row_dst.x = dst.x;

    // Full columns in leftover row
    for (int x = 0; x < cols; x++) {
      add_quad(verts, &src_partial_y, &partial_row_dst);
      partial_row_dst.x += tile_w;
    }

    // Partial leftover corner (both X & Y leftover)
    if (tile_x && remain_dst_w > 0.0f) {
      rect partial_corner_dst = {
        .x = partial_row_dst.x, .y = partial_row_dst.y,
        .w = remain_dst_w,     .h = remain_dst_h
      };
      add_quad(verts, &src_partial_xy, &partial_corner_dst);
    }
  }
}

JSC_CCALL(gpu_slice9,
  JSValue jstex = argv[0];
  rect dst = js2rect(js, argv[1]);

  // Full texture in UV coords
  rect src = {
    .x = 0, .y = 0,
    .w = 1, .h = 1
  };

  // The "slice" LRTB in PIXELS, but we convert to UV below
  lrtb src_slice = js2lrtb(js, argv[2]);
  lrtb dst_slice = src_slice;

  HMM_Vec2 size;
  JS_GETPROP(js, size.x, jstex, width,  number)
  JS_GETPROP(js, size.y, jstex, height, number)
  
  JSValue info = argv[3];
  int tile_top, tile_bottom, tile_left, tile_right, center_x, center_y;
  JS_GETPROP(js,tile_top, info, tile_top, bool)
  JS_GETPROP(js,tile_bottom,info,tile_bottom,bool)
  JS_GETPROP(js,tile_left,info,tile_left,bool)  
  JS_GETPROP(js,tile_right,info,tile_right,bool)
  JS_GETPROP(js, center_x, info, tile_center_x, bool)
  JS_GETPROP(js, center_y, info, tile_center_y, bool)
  
  // Convert the slice edges from pixel to UV
  src_slice.l /= size.x;
  src_slice.r /= size.x;
  src_slice.t /= size.y;
  src_slice.b /= size.y;

  text_vert *verts = NULL;
  rect curr_src;
  rect curr_dst;

  // bottom-left corner (single quad)
  curr_src = src;
  curr_src.w = src_slice.l;
  curr_src.h = src_slice.b;

  curr_dst = dst;
  curr_dst.w = dst_slice.l;
  curr_dst.h = dst_slice.b;
  add_quad(&verts, &curr_src, &curr_dst);

  // top-left corner (single quad)
  curr_src = src;
  curr_src.x = src.x;
  curr_src.y = src.y + src.h - src_slice.t;
  curr_src.w = src_slice.l;
  curr_src.h = src_slice.t;

  curr_dst = dst;
  curr_dst.x = dst.x;
  curr_dst.y = dst.y + dst.h - dst_slice.t;
  curr_dst.w = dst_slice.l;
  curr_dst.h = dst_slice.t;
  add_quad(&verts, &curr_src, &curr_dst);

  // bottom-right corner (single quad)
  curr_src = src;
  curr_src.x = src.x + src.w - src_slice.r;
  curr_src.y = src.y;
  curr_src.w = src_slice.r;
  curr_src.h = src_slice.b;

  curr_dst = dst;
  curr_dst.x = dst.x + dst.w - dst_slice.r;
  curr_dst.y = dst.y;
  curr_dst.w = dst_slice.r;
  curr_dst.h = dst_slice.b;
  add_quad(&verts, &curr_src, &curr_dst);

  // top-right corner (single quad)
  curr_src = src;
  curr_src.x = src.x + src.w - src_slice.r;
  curr_src.y = src.y + src.h - src_slice.t;
  curr_src.w = src_slice.r;
  curr_src.h = src_slice.t;

  curr_dst = dst;
  curr_dst.x = dst.x + dst.w - dst_slice.r;
  curr_dst.y = dst.y + dst.h - dst_slice.t;
  curr_dst.w = dst_slice.r;
  curr_dst.h = dst_slice.t;
  add_quad(&verts, &curr_src, &curr_dst);

  // left bar (tiled)
  curr_src = src;
  curr_src.x = src.x;
  curr_src.y = src.y + src_slice.b;
  curr_src.w = src_slice.l;
  curr_src.h = src.h - src_slice.t - src_slice.b;

  curr_dst = dst;
  curr_dst.x = dst.x;
  curr_dst.y = dst.y + dst_slice.b;
  curr_dst.w = dst_slice.l;
  curr_dst.h = dst.h - dst_slice.t - dst_slice.b;
  tile_region(&verts, curr_src, curr_dst, size.x, size.y,tile_left,tile_left);

  // right bar (tiled)
  curr_src = src;
  curr_src.x = src.x + src.w - src_slice.r;
  curr_src.y = src.y + src_slice.b;
  curr_src.w = src_slice.r;
  curr_src.h = src.h - src_slice.t - src_slice.b;

  curr_dst = dst;
  curr_dst.x = dst.x + dst.w - dst_slice.r;
  curr_dst.y = dst.y + dst_slice.b;
  curr_dst.w = dst_slice.r;
  curr_dst.h = dst.h - dst_slice.t - dst_slice.b;
  tile_region(&verts, curr_src, curr_dst, size.x, size.y,tile_right,tile_right);

  // bottom bar (tiled)
  curr_src = src;
  curr_src.x = src.x + src_slice.l;
  curr_src.y = src.y;
  curr_src.w = src.w - src_slice.l - src_slice.r;
  curr_src.h = src_slice.b;

  curr_dst = dst;
  curr_dst.x = dst.x + dst_slice.l;
  curr_dst.y = dst.y;
  curr_dst.w = dst.w - dst_slice.l - dst_slice.r;
  curr_dst.h = dst_slice.b;
  tile_region(&verts, curr_src, curr_dst, size.x, size.y,tile_bottom,tile_bottom);

  // top bar (tiled)
  curr_src = src;
  curr_src.x = src.x + src_slice.l;
  curr_src.y = src.y + src.h - src_slice.t;
  curr_src.w = src.w - src_slice.l - src_slice.r;
  curr_src.h = src_slice.t;

  curr_dst = dst;
  curr_dst.x = dst.x + dst_slice.l;
  curr_dst.y = dst.y + dst.h - dst_slice.t;
  curr_dst.w = dst.w - dst_slice.l - dst_slice.r;
  curr_dst.h = dst_slice.t;
  tile_region(&verts, curr_src, curr_dst, size.x, size.y,tile_top,tile_top);

  // center (tiled)
  curr_src = src;
  curr_src.x = src.x + src_slice.l;
  curr_src.y = src.y + src_slice.b;
  curr_src.w = src.w - src_slice.l - src_slice.r;
  curr_src.h = src.h - src_slice.t - src_slice.b;

  curr_dst = dst;
  curr_dst.x = dst.x + dst_slice.l;
  curr_dst.y = dst.y + dst_slice.b;
  curr_dst.w = dst.w - dst_slice.l - dst_slice.r;
  curr_dst.h = dst.h - dst_slice.t - dst_slice.b;
  tile_region(&verts, curr_src, curr_dst, size.x, size.y, center_x,center_y);

  JSValue mesh = quads_to_mesh(js, verts);
  arrfree(verts);
  ret = mesh;
)

JSC_CCALL(gpu_tile,
  HMM_Vec2 size;
  JSValue jstex = argv[0];
  JS_GETATOM(js,size.x,jstex,width,number)
  JS_GETATOM(js, size.y, jstex, height, number)

  rect src_pixels = js2rect(js, argv[1]); // 'src' as pixel dimensions
  rect dst = js2rect(js, argv[2]);        // 'dst' as screen coords
  
  int tilex, tiley;
  JSValue jstile = argv[3];
  JS_GETPROP(js,tilex,jstile,repeat_x,bool)
  JS_GETPROP(js,tiley,jstile,repeat_y,bool)
  
  text_vert *verts = NULL;
  tile_region(&verts, src_pixels, dst, size.x, size.y,tilex,tiley);
  ret = quads_to_mesh(js,verts);
  arrfree(verts);
)

// Sprite mesh generation functions
typedef struct {
  JSValue val;
  void *ptr;
  size_t size;
  int need_new;
} BufferCheckResult;

static BufferCheckResult get_or_extend_buffer(
  JSContext *js,
  JSValue old_mesh,
  const char *prop,
  size_t needed_size,
  int type,
  int elements_per_item,
  int copy,
  int index
) {
  BufferCheckResult res = { JS_UNDEFINED, NULL, 0, 0 };
  if (!JS_IsUndefined(old_mesh)) {
    JSValue old_buf = JS_GetPropertyStr(js, old_mesh, prop);
    if (!JS_IsUndefined(old_buf)) {
      size_t old_size;
      void *data = get_gpu_buffer(js, old_buf, NULL, &old_size);
      if (data && old_size >= needed_size) {
        // Old buffer is large enough
        res.val = old_buf; // keep it
        res.ptr = data;
        res.size = old_size;
        return res;
      }
      JS_FreeValue(js, old_buf);
    }
  }
  // If we reach here, we need a new buffer
  res.need_new = 1;
  return res;
}

static HMM_Vec3 base_quad[4] = {
  {0.0,0.0,1.0},
  {1.0,0.0,1.0},
  {0.0,1.0,1.0},
  {1.0,1.0,1.0}
};

JSC_CCALL(gpu_make_sprite_mesh,
  size_t quads = JS_ArrayLength(js, argv[0]);
  size_t verts = quads*4;
  size_t count = quads*6;

  // Prepare arrays on CPU
  HMM_Vec2 *posdata = malloc(sizeof(*posdata)*verts);
  HMM_Vec2 *uvdata = malloc(sizeof(*uvdata)*verts);
  HMM_Vec4 *colordata = malloc(sizeof(*colordata)*verts);

  for (int i = 0; i < quads; i++) {
    JSValue sub = JS_GetPropertyUint32(js,argv[0],i);
    
    transform *tr;
    rect src;
    HMM_Vec4 color;
    JS_GETATOM(js,src,sub,src,rect)
    JS_GETATOM(js,color,sub,color,color)
    JS_GETATOM(js,tr,sub,transform,transform)
    JS_FreeValue(js,sub);

    size_t base = i*4;
    if (tr) {
      HMM_Mat3 trmat = transform2mat3(tr);
      for (int j = 0; j < 4; j++)
        posdata[base+j] = HMM_MulM3V3(trmat, base_quad[j]).xy;
    } else {
      rect dst;
      JS_GETATOM(js,dst,sub,rect,rect);
      posdata[base+0] = (HMM_Vec2){dst.x,dst.y};
      posdata[base + 1] = (HMM_Vec2){ dst.x+dst.w, dst.y      };
      posdata[base + 2] = (HMM_Vec2){ dst.x,      dst.y+dst.h };
      posdata[base + 3] = (HMM_Vec2){ dst.x+dst.w, dst.y+dst.h };
    }

    uvdata[base+0] = (HMM_Vec2){src.x,         src.y+src.h};
    uvdata[base+1] = (HMM_Vec2){src.x+src.w,   src.y+src.h};
    uvdata[base+2] = (HMM_Vec2){src.x,         src.y};
    uvdata[base+3] = (HMM_Vec2){src.x+src.w,   src.y};

    colordata[base+0] = color;
    colordata[base+1] = color;
    colordata[base+2] = color;
    colordata[base+3] = color;
  }

  // Check old mesh
  JSValue old_mesh = JS_UNDEFINED;
  if (argc > 1)
    old_mesh = argv[1];

  // Needed sizes
  size_t pos_size = sizeof(*posdata)*verts;
  size_t uv_size = sizeof(*uvdata)*verts;
  size_t color_size = sizeof(*colordata)*verts;

  BufferCheckResult pos_chk = get_or_extend_buffer(js, old_mesh, "pos", pos_size, JS_TYPED_ARRAY_FLOAT32, 2, 1, 0);
  BufferCheckResult uv_chk = get_or_extend_buffer(js, old_mesh, "uv", uv_size, JS_TYPED_ARRAY_FLOAT32, 2, 1, 0);
  BufferCheckResult color_chk = get_or_extend_buffer(js, old_mesh, "color", color_size, JS_TYPED_ARRAY_FLOAT32, 4, 1, 0);

  int need_new_all = pos_chk.need_new || uv_chk.need_new || color_chk.need_new;

  ret = JS_NewObject(js);

  if (need_new_all) {
    // Create all new buffers
    JSValue new_pos = make_gpu_buffer(js, posdata, pos_size, JS_TYPED_ARRAY_FLOAT32, 2, 1,0);
    JSValue new_uv = make_gpu_buffer(js, uvdata, uv_size, JS_TYPED_ARRAY_FLOAT32, 2, 1,0);
    JSValue new_color = make_gpu_buffer(js, colordata, color_size, JS_TYPED_ARRAY_FLOAT32, 0, 1,0);

    JS_SetPropertyStr(js, ret, "pos", new_pos);
    JS_SetPropertyStr(js, ret, "uv", new_uv);
    JS_SetPropertyStr(js, ret, "color", new_color);

    // Indices
    JSValue indices = make_quad_indices_buffer(js, quads); 
    JS_SetPropertyStr(js, ret, "indices", indices);
  } else {
    // Reuse the old buffers
    // Just copy data into existing buffers via their pointers
    memcpy(pos_chk.ptr, posdata, pos_size);
    memcpy(uv_chk.ptr, uvdata, uv_size);
    memcpy(color_chk.ptr, colordata, color_size);

    // Duplicate old references since we're returning a new object
    JS_SetPropertyStr(js, ret, "pos", JS_DupValue(js, pos_chk.val));
    JS_SetPropertyStr(js, ret, "uv", JS_DupValue(js, uv_chk.val));
    JS_SetPropertyStr(js, ret, "color", JS_DupValue(js, color_chk.val));

    // Indices can remain the same if they were also large enough. If using a shared global index buffer:
    JSValue indices = make_quad_indices_buffer(js, quads);
    JS_SetPropertyStr(js, ret, "indices", indices);
  }

  JS_SetPropertyStr(js, ret, "vertices", number2js(js, verts));
  JS_SetPropertyStr(js, ret, "count", number2js(js, count));
  JS_SetPropertyStr(js,ret,"num_indices", number2js(js,count));

  // Free temporary CPU arrays
  free(posdata);
  free(uvdata);
  free(colordata);

  // Free old buffer values if they were fetched
  if (!JS_IsUndefined(pos_chk.val)) JS_FreeValue(js, pos_chk.val);
  if (!JS_IsUndefined(uv_chk.val)) JS_FreeValue(js, uv_chk.val);
  if (!JS_IsUndefined(color_chk.val)) JS_FreeValue(js, color_chk.val);

  return ret;
)

struct quad_buffers {
  HMM_Vec2 *pos;
  HMM_Vec2 *uv;
  HMM_Vec4 *color;
  int verts;
};

struct quad_buffers quad_buffers_new(int verts)
{
  struct quad_buffers b;
  b.verts = verts;
  b.pos = malloc(sizeof(HMM_Vec2)*verts);
  b.uv = malloc(sizeof(HMM_Vec2)*verts);
  b.color = malloc(sizeof(HMM_Vec4)*verts);
  return b;
}

JSValue quadbuffers_to_mesh(JSContext *js, struct quad_buffers buffers)
{
  JSValue jspos = make_gpu_buffer(js, buffers.pos, sizeof(HMM_Vec2)*buffers.verts, JS_TYPED_ARRAY_FLOAT32, 2, 0, 0);
  JSValue jsuv = make_gpu_buffer(js, buffers.uv, sizeof(HMM_Vec2)*buffers.verts, JS_TYPED_ARRAY_FLOAT32, 2,0,0);
  JSValue jscolor = make_gpu_buffer(js, buffers.color, sizeof(HMM_Vec4)*buffers.verts, JS_TYPED_ARRAY_FLOAT32, 4,0,0);

  size_t quads = buffers.verts/4;
  size_t count = buffers.verts/2*3;
  JSValue jsidx = make_quad_indices_buffer(js, quads);

  JSValue ret = JS_NewObject(js);
  JS_SetPropertyStr(js, ret, "pos", jspos);
  JS_SetPropertyStr(js, ret, "uv", jsuv);
  JS_SetPropertyStr(js, ret, "color", jscolor);
  JS_SetPropertyStr(js, ret, "indices", jsidx);
  JS_SetPropertyStr(js, ret, "vertices", number2js(js, buffers.verts));
  JS_SetPropertyStr(js,ret,"num_indices", number2js(js,count));
  
  return ret;
}

int sort_sprite(const sprite *a, const sprite *b)
{
  if (a->layer != b->layer) return a->layer - b->layer;
  
  if (a->pos.Y != b->pos.Y)
    return (b->pos.Y - a->pos.Y);
    
  if (JS_VALUE_GET_PTR(a->image) != JS_VALUE_GET_PTR(b->image))
    return JS_VALUE_GET_PTR(a->image) < JS_VALUE_GET_PTR(b->image) ? -1 : 1;  
  return 0;
}

JSC_CCALL(gpu_make_sprite_queue,
  sprite *sprites = NULL;
  size_t quads = 0;
  int needfree = 1;

  if (js_is_blob(js, argv[0])) {
    // test for fastest  
    size_t size;  
    sprite *sprites = js_get_blob_data(js, &size, argv[0]);
    quads = size/sizeof(*sprites);
    needfree = 0;
    for (int i = 0; i < quads; i++)
      JS_DupValue(js,sprites[i].image);
  } else {
    quads = JS_ArrayLength(js, argv[0]);
    if (quads == 0)
      return JS_ThrowReferenceError(js, "Expected an array of sprites with length > 0.");
      
    arrsetcap(sprites, quads);

    for (int i = 0; i < quads; i++) {
      JSValue sub = JS_GetPropertyUint32(js, argv[0], i);
      sprite *jsp = js2sprite(js, sub);
      if (jsp) {
        arrput(sprites, *jsp);
        JS_DupValue(js,jsp->image);
      }
      else {
        sprite sp = {0};
        JS_GETATOM(js, sp.pos, sub, pos, vec2)
        JS_GETATOM(js, sp.center, sub, center, vec2)
        JS_GETATOM(js, sp.skew, sub, skew, vec2)
        JS_GETATOM(js, sp.scale, sub, scale, vec2)
        JS_GETATOM(js, sp.color,sub,color,color)
        JS_GETATOM(js, sp.layer,sub,layer,number)
        sp.image = JS_GetPropertyStr(js,sub,"image");
        sprite_apply(&sp);
        arrput(sprites,sp);
     }
      JS_FreeValue(js, sub);
    }
  }
  
  qsort(sprites, quads, sizeof(sprite), sort_sprite);

  struct quad_buffers buffers = quad_buffers_new(quads*4);
  
  const HMM_Vec2 local[4] = { {0,0}, {1,0}, {0,1}, {1,1} };
  
  rect uv;
  rect uv_px;
  JSValue cur_img = JS_UNDEFINED;

  for (size_t i = 0; i < quads; i++) {
    sprite *s = &sprites[i];  
    if (JS_IsUndefined(cur_img) || !JS_StrictEq(js, s->image, cur_img)) {
      cur_img = s->image;
      JS_GETATOM(js, uv, cur_img, rect, rect)
      JS_GETATOM(js, uv_px, cur_img, rect_px, rect)
    }
  
    HMM_Vec2 px_size = {
      uv_px.w * s->scale.X,
      uv_px.h * s->scale.Y
    };
  
    HMM_Vec2 anchor = {
      px_size.X * s->center.X,
      px_size.Y * s->center.Y
    };
  
    size_t base = i * 4;
  
    for (int v = 0; v < 4; v++) {
      HMM_Vec2 lp = {
        local[v].X * px_size.X - anchor.X,
        local[v].Y * px_size.Y - anchor.Y
      };
  
      HMM_Vec2 world = HMM_AddV2(s->pos, HMM_MulM2V2(s->affine, lp));
  
      buffers.pos[base + v]   = world;
      buffers.color[base + v] = s->color;
    }
  
    /* UVs are still top-left-origin pixel coords, so keep previous packing    */
    buffers.uv[base + 0] = (HMM_Vec2){ uv.x,        uv.y + uv.h };
    buffers.uv[base + 1] = (HMM_Vec2){ uv.x + uv.w, uv.y + uv.h };
    buffers.uv[base + 2] = (HMM_Vec2){ uv.x,        uv.y        };
    buffers.uv[base + 3] = (HMM_Vec2){ uv.x + uv.w, uv.y        };
  }
  
  JSValue mesh = quadbuffers_to_mesh(js, buffers);

  ret = JS_NewArray(js);
  int first_index = 0;
  int count = 0;
  int n = 0;
  JSValue img = JS_UNDEFINED;

  for (int i = 0; i < quads; i++) {
    if (!JS_SameValue(js, sprites[i].image, img)) {
      if (count > 0) {
        JSValue q = JS_NewObject(js);
        JS_SetPropertyStr(js, q, "type",       JS_NewString(js, "geometry"));
        JS_SetPropertyStr(js, q, "mesh",       JS_DupValue(js, mesh));
        JS_SetPropertyStr(js, q, "pipeline",   JS_DupValue(js, argv[2]));
        JS_SetPropertyStr(js, q, "image",      img);
        JS_SetPropertyStr(js, q, "first_index", number2js(js, first_index));
        JS_SetPropertyStr(js, q, "num_indices", number2js(js, count * 6));
        JS_SetPropertyUint32(js, ret, n++, q);
      }
      first_index = i*6;
      count = 1;
      img = JS_DupValue(js, sprites[i].image);
    } else count++;
    JS_FreeValue(js,sprites[i].image);
  }

  if (count > 0) {
    JSValue q = JS_NewObject(js);
    JS_SetPropertyStr(js, q, "type",       JS_NewString(js, "geometry"));
    JS_SetPropertyStr(js, q, "mesh",       JS_DupValue(js, mesh));
    JS_SetPropertyStr(js, q, "pipeline",   JS_DupValue(js, argv[2]));
    JS_SetPropertyStr(js, q, "image",      img);
    JS_SetPropertyStr(js, q, "first_index", number2js(js, first_index));
    JS_SetPropertyStr(js, q, "num_indices", number2js(js, count * 6));
    JS_SetPropertyUint32(js, ret, n++, q);
  }

  if (needfree)
    arrfree(sprites);
    
  JS_FreeValue(js, mesh);
)

JSC_CCALL(geometry_rect_transform,
  // argv[0] = world‐space rect
  rect r        = js2rect(js, argv[0]);
  // argv[1] = world_to_projection (16 floats)
  size_t byte_len;
  float *data12 = js_get_blob_data(js, &byte_len, argv[1]);
  HMM_Mat4 wp; memcpy(wp.Elements, data12, sizeof(wp.Elements));

  // make our two corners at z=0
  HMM_Vec4 p0 = { r.x,         r.y,         0.0f, 1.0f };
  HMM_Vec4 p1 = { r.x + r.w,   r.y + r.h,   0.0f, 1.0f };

  // transform into clip space
  HMM_Vec4 t0 = HMM_MulM4V4(wp, p0);
  HMM_Vec4 t1 = HMM_MulM4V4(wp, p1);

  // perspective divide → NDC
  float ndc_x0 = t0.X / t0.W, ndc_y0 = t0.Y / t0.W;
  float ndc_x1 = t1.X / t1.W, ndc_y1 = t1.Y / t1.W;

  // NDC → UV
  float u0 = ndc_x0 * 0.5f + 0.5f;
  float v0 = ndc_y0 * 0.5f + 0.5f;
  float u1 = ndc_x1 * 0.5f + 0.5f;
  float v1 = ndc_y1 * 0.5f + 0.5f;

  // (Optionally multiply by pixel‐size here, or do that in JS)
  rect newrect = {
    .x = u0,
    .y = v0,
    .w = u1 - u0,
    .h = v1 - v0
  };

  return rect2js(js, newrect);
)

JSC_CCALL(geometry_tilemap_to_data,
  JSValue tilemap_obj = argv[0];
  
  // Get tilemap properties
  double offset_x, offset_y, size_x, size_y;
  JS_GETPROP(js, offset_x, tilemap_obj, offset_x, number)
  JS_GETPROP(js, offset_y, tilemap_obj, offset_y, number)
  JS_GETPROP(js, size_x, tilemap_obj, size_x, number)
  JS_GETPROP(js, size_y, tilemap_obj, size_y, number)
  
  JSValue tiles_array = JS_GetPropertyStr(js, tilemap_obj, "tiles");
  if (!JS_IsArray(js, tiles_array)) {
    JS_FreeValue(js, tiles_array);
    return JS_ThrowTypeError(js, "tilemap.tiles must be an array");
  }
  
  // Count tiles
  int tile_count = 0;
  int tiles_len = JS_ArrayLength(js, tiles_array);
  for (int x = 0; x < tiles_len; x++) {
    JSValue col = JS_GetPropertyUint32(js, tiles_array, x);
    if (JS_IsArray(js, col)) {
      int col_len = JS_ArrayLength(js, col);
      for (int y = 0; y < col_len; y++) {
        JSValue tile = JS_GetPropertyUint32(js, col, y);
        if (!JS_IsUndefined(tile) && !JS_IsNull(tile)) {
          tile_count++;
        }
        JS_FreeValue(js, tile);
      }
    }
    JS_FreeValue(js, col);
  }
  
  if (tile_count == 0) {
    JS_FreeValue(js, tiles_array);
    return JS_NewObject(js);
  }
  
  // Allocate buffers - 4 vertices per tile
  int vertex_count = tile_count * 4;
  int index_count = tile_count * 6;
  
  float *xy_data = malloc(vertex_count * 2 * sizeof(float));
  float *uv_data = malloc(vertex_count * 2 * sizeof(float));
  SDL_FColor *color_data = malloc(vertex_count * sizeof(SDL_FColor));
  uint16_t *index_data = malloc(index_count * sizeof(uint16_t));
  
  // Generate vertices
  int vertex_idx = 0;
  int index_idx = 0;
  
  for (int x = 0; x < tiles_len; x++) {
    JSValue col = JS_GetPropertyUint32(js, tiles_array, x);
    if (JS_IsArray(js, col)) {
      int col_len = JS_ArrayLength(js, col);
      for (int y = 0; y < col_len; y++) {
        JSValue tile = JS_GetPropertyUint32(js, col, y);
        if (!JS_IsUndefined(tile) && !JS_IsNull(tile)) {
          // Calculate world position
          float world_x = (x + offset_x) * size_x;
          float world_y = (y + offset_y) * size_y;
          
          // Set vertex positions (4 corners of the tile)
          int base = vertex_idx * 2;
          xy_data[base + 0] = world_x;
          xy_data[base + 1] = world_y;
          xy_data[base + 2] = world_x + size_x;
          xy_data[base + 3] = world_y;
          xy_data[base + 4] = world_x;
          xy_data[base + 5] = world_y + size_y;
          xy_data[base + 6] = world_x + size_x;
          xy_data[base + 7] = world_y + size_y;
          
          // Set UVs (normalized 0-1 for now)
          uv_data[base + 0] = 0.0f;
          uv_data[base + 1] = 0.0f;
          uv_data[base + 2] = 1.0f;
          uv_data[base + 3] = 0.0f;
          uv_data[base + 4] = 0.0f;
          uv_data[base + 5] = 1.0f;
          uv_data[base + 6] = 1.0f;
          uv_data[base + 7] = 1.0f;
          
          // Set colors (check if tile has color property)
          SDL_FColor default_color = {1.0f, 1.0f, 1.0f, 1.0f};
          if (JS_IsObject(tile)) {
            JSValue color_val = JS_GetPropertyStr(js, tile, "color");
            if (!JS_IsUndefined(color_val)) {
              HMM_Vec4 color = js2color(js, color_val);
              default_color.r = color.r;
              default_color.g = color.g;
              default_color.b = color.b;
              default_color.a = color.a;
              JS_FreeValue(js, color_val);
            }
          }
          
          for (int i = 0; i < 4; i++) {
            color_data[vertex_idx + i] = default_color;
          }
          
          // Set indices (two triangles per tile)
          uint16_t base_idx = vertex_idx;
          index_data[index_idx++] = base_idx + 0;
          index_data[index_idx++] = base_idx + 1;
          index_data[index_idx++] = base_idx + 2;
          index_data[index_idx++] = base_idx + 1;
          index_data[index_idx++] = base_idx + 3;
          index_data[index_idx++] = base_idx + 2;
          
          vertex_idx += 4;
        }
        JS_FreeValue(js, tile);
      }
    }
    JS_FreeValue(js, col);
  }
  
  JS_FreeValue(js, tiles_array);
  
  // Create result object with blob data
  ret = JS_NewObject(js);
  
  // Create blobs for each data type
  JSValue xy_blob = js_new_blob_stoned_copy(js, xy_data, vertex_count * 2 * sizeof(float));
  JSValue uv_blob = js_new_blob_stoned_copy(js, uv_data, vertex_count * 2 * sizeof(float));
  JSValue color_blob = js_new_blob_stoned_copy(js, color_data, vertex_count * sizeof(SDL_FColor));
  JSValue index_blob = js_new_blob_stoned_copy(js, index_data, index_count * sizeof(uint16_t));
  
  JS_SetPropertyStr(js, ret, "xy", xy_blob);
  JS_SetPropertyStr(js, ret, "xy_stride", JS_NewInt32(js, 2 * sizeof(float)));
  JS_SetPropertyStr(js, ret, "uv", uv_blob);
  JS_SetPropertyStr(js, ret, "uv_stride", JS_NewInt32(js, 2 * sizeof(float)));
  JS_SetPropertyStr(js, ret, "color", color_blob);
  JS_SetPropertyStr(js, ret, "color_stride", JS_NewInt32(js, sizeof(SDL_FColor)));
  JS_SetPropertyStr(js, ret, "indices", index_blob);
  JS_SetPropertyStr(js, ret, "num_vertices", JS_NewInt32(js, vertex_count));
  JS_SetPropertyStr(js, ret, "num_indices", JS_NewInt32(js, index_count));
  JS_SetPropertyStr(js, ret, "size_indices", JS_NewInt32(js, 2)); // using uint16_t
  
  free(xy_data);
  free(uv_data);
  free(color_data);
  free(index_data);
)

static const JSCFunctionListEntry js_geometry_funcs[] = {
  MIST_FUNC_DEF(geometry, rect_intersection, 2),
  MIST_FUNC_DEF(geometry, rect_intersects, 2),
  MIST_FUNC_DEF(geometry, rect_expand, 2),
  MIST_FUNC_DEF(geometry, rect_inside, 2),
  MIST_FUNC_DEF(geometry, rect_random, 1),
  MIST_FUNC_DEF(geometry, cwh2rect, 2),
  MIST_FUNC_DEF(geometry, rect_point_inside, 2),
  MIST_FUNC_DEF(geometry, rect_pos, 1),
  MIST_FUNC_DEF(geometry, rect_move, 2),
  MIST_FUNC_DEF(geometry, rect_transform, 2),
  MIST_FUNC_DEF(geometry, tilemap_to_data, 1),
  MIST_FUNC_DEF(gpu, tile, 4),
  MIST_FUNC_DEF(gpu, slice9, 3),
  MIST_FUNC_DEF(gpu, make_sprite_mesh, 2),
  MIST_FUNC_DEF(gpu, make_sprite_queue, 4),
};

JSValue js_geometry_use(JSContext *js) {
  JSValue mod = JS_NewObject(js);
  JS_SetPropertyFunctionList(js,mod,js_geometry_funcs,countof(js_geometry_funcs));
  return mod;
}