#include "cell.h"
#include <string.h>
#include <stdlib.h>
#include "stb_image_common.h"

// PNG decoding
JSValue js_png_decode(JSContext *js, JSValue this_val, int argc, JSValueConst *argv)
{
  size_t len;
  void *raw = js_get_blob_data(js, &len, argv[0]);
  if (raw == NULL) return JS_EXCEPTION;
  if (!raw) return JS_ThrowReferenceError(js, "could not get PNG data from blob");

  int n, width, height;
  void *data = stbi_load_from_memory(raw, len, &width, &height, &n, 4);

  if (!data)
    return JS_ThrowReferenceError(js, "failed to decode PNG: %s", stbi_failure_reason());

  if (width <= 0 || height <= 0) {
    stbi_image_free(data);
    return JS_ThrowReferenceError(js, "decoded PNG has invalid size: %dx%d", width, height);
  }

  int pitch = width * 4;
  size_t pixels_size = pitch * height;

  JS_FRAME(js);
  JS_ROOT(obj, JS_NewObject(js));
  JS_SetPropertyStr(js, obj.val, "width", JS_NewInt32(js, width));
  JS_SetPropertyStr(js, obj.val, "height", JS_NewInt32(js, height));
  JSValue fmt_str = JS_NewString(js, "rgba32");
  JS_SetPropertyStr(js, obj.val, "format", fmt_str);
  JS_SetPropertyStr(js, obj.val, "pitch", JS_NewInt32(js, pitch));
  JSValue pixels_blob = js_new_blob_stoned_copy(js, data, pixels_size);
  JS_SetPropertyStr(js, obj.val, "pixels", pixels_blob);
  JS_SetPropertyStr(js, obj.val, "depth", JS_NewInt32(js, 8));
  JS_SetPropertyStr(js, obj.val, "hdr", JS_NewBool(js, 0));

  stbi_image_free(data);
  JS_RETURN(obj.val);
}

// PNG encoding
JSValue js_png_encode(JSContext *js, JSValue this_val, int argc, JSValueConst *argv)
{
  if (argc < 1)
    return JS_ThrowTypeError(js, "png.encode requires an image object");

  JSValue width_val = JS_GetPropertyStr(js, argv[0], "width");
  JSValue height_val = JS_GetPropertyStr(js, argv[0], "height");

  if (JS_IsNull(width_val) || JS_IsNull(height_val)) {
    return JS_ThrowTypeError(js, "png.encode requires width and height properties");
  }

  int width, height;
  if (JS_ToInt32(js, &width, width_val) < 0 || JS_ToInt32(js, &height, height_val) < 0) {
    return JS_ThrowTypeError(js, "width and height must be numbers");
  }

  if (width < 1 || height < 1)
    return JS_ThrowRangeError(js, "width and height must be at least 1");

  JSValue pixels_val = JS_GetPropertyStr(js, argv[0], "pixels");
  size_t pixel_len;
  void *pixel_data = js_get_blob_data(js, &pixel_len, pixels_val);

  if (pixel_data == NULL) return JS_EXCEPTION;
  if (!pixel_data) return JS_ThrowTypeError(js, "pixels blob has no data");
  size_t required_size = width * height * 4;
  if (pixel_len < required_size)
    return JS_ThrowRangeError(js, "pixels buffer too small (need %zu, got %zu)", required_size, pixel_len);

  stbi_mem_buf buf = {0};
  stbi_write_png_to_func(stbi_mem_write, &buf, width, height, 4, pixel_data, width * 4);

  if (!buf.data || buf.size == 0) {
    if (buf.data) free(buf.data);
    return JS_ThrowInternalError(js, "failed to encode PNG");
  }

  JS_FRAME(js);
  JS_ROOT(result, JS_NewObject(js));
  JS_SetPropertyStr(js, result.val, "width", JS_NewInt32(js, width));
  JS_SetPropertyStr(js, result.val, "height", JS_NewInt32(js, height));
  JSValue enc_fmt = JS_NewString(js, "png");
  JS_SetPropertyStr(js, result.val, "format", enc_fmt);
  JSValue enc_blob = js_new_blob_stoned_copy(js, buf.data, buf.size);
  JS_SetPropertyStr(js, result.val, "pixels", enc_blob);

  free(buf.data);
  JS_RETURN(result.val);
}

static const JSCFunctionListEntry js_png_funcs[] = {
  MIST_FUNC_DEF(png, decode, 1),
  MIST_FUNC_DEF(png, encode, 1)
};

CELL_USE_FUNCS(js_png_funcs)