#include "ruby.h"
#include "rubyspec.h"

#ifdef __cplusplus
extern "C" {
#endif

VALUE registered_tagged_value;
VALUE registered_reference_value;
VALUE registered_before_rb_gc_register_address;
VALUE registered_before_rb_global_variable_string;
VALUE registered_before_rb_global_variable_bignum;
VALUE registered_before_rb_global_variable_float;
VALUE registered_after_rb_global_variable_string;
VALUE registered_after_rb_global_variable_bignum;
VALUE registered_after_rb_global_variable_float;
VALUE rb_gc_register_address_outside_init;

VALUE rb_gc_register_mark_object_not_referenced_float;

static VALUE spec_RB_GC_GUARD_keep_alive(VALUE self, VALUE array_with_string) {
  VALUE string = rb_ary_entry(array_with_string, 0);
  char* ptr = RSTRING_PTR(string);
  // Without the RB_GC_GUARD(string) below, string could be GC'd, and ptr become invalid
  rb_gc();
  char copy[4];
  copy[0] = ptr[0];
  copy[1] = ptr[1];
  copy[2] = ptr[2];
  copy[3] = '\0';
  RB_GC_GUARD(string);
  return rb_str_new_cstr(copy);
}

static VALUE spec_RB_GC_GUARD(VALUE self, VALUE object) {
  RB_GC_GUARD(object);
  return object;
}

static VALUE spec_RB_GC_GUARD_raw(VALUE self, VALUE number) {
  long l = NUM2LONG(number);
  VALUE value = (VALUE) l;
  RB_GC_GUARD(value);
  return Qnil;
}

static VALUE registered_tagged_address(VALUE self) {
  return registered_tagged_value;
}

static VALUE registered_reference_address(VALUE self) {
  return registered_reference_value;
}

static VALUE get_registered_before_rb_gc_register_address(VALUE self) {
  return registered_before_rb_gc_register_address;
}

static VALUE get_registered_before_rb_global_variable_string(VALUE self) {
  return registered_before_rb_global_variable_string;
}

static VALUE get_registered_before_rb_global_variable_bignum(VALUE self) {
  return registered_before_rb_global_variable_bignum;
}

static VALUE get_registered_before_rb_global_variable_float(VALUE self) {
  return registered_before_rb_global_variable_float;
}

static VALUE get_registered_after_rb_global_variable_string(VALUE self) {
  return registered_after_rb_global_variable_string;
}

static VALUE get_registered_after_rb_global_variable_bignum(VALUE self) {
  return registered_after_rb_global_variable_bignum;
}

static VALUE get_registered_after_rb_global_variable_float(VALUE self) {
  return registered_after_rb_global_variable_float;
}

static VALUE gc_spec_rb_gc_register_address(VALUE self) {
  rb_gc_register_address(&rb_gc_register_address_outside_init);
  rb_gc_register_address_outside_init = rb_str_new_cstr("rb_gc_register_address() outside Init_");
  return rb_gc_register_address_outside_init;
}

static VALUE gc_spec_rb_gc_unregister_address(VALUE self) {
  rb_gc_unregister_address(&rb_gc_register_address_outside_init);
  return Qnil;
}

static VALUE gc_spec_rb_gc_enable(VALUE self) {
  return rb_gc_enable();
}

static VALUE gc_spec_rb_gc_disable(VALUE self) {
  return rb_gc_disable();
}

static VALUE gc_spec_rb_gc(VALUE self) {
  rb_gc();
  return Qnil;
}

static VALUE gc_spec_rb_gc_latest_gc_info(VALUE self, VALUE hash_or_key) {
  return rb_gc_latest_gc_info(hash_or_key);
}

static VALUE gc_spec_rb_gc_adjust_memory_usage(VALUE self, VALUE diff) {
  rb_gc_adjust_memory_usage(NUM2SSIZET(diff));
  return Qnil;
}

static VALUE gc_spec_rb_gc_register_mark_object(VALUE self, VALUE obj) {
  rb_gc_register_mark_object(obj);
  return Qnil;
}

static VALUE gc_spec_rb_gc_register_mark_object_not_referenced_float(VALUE self) {
  return rb_gc_register_mark_object_not_referenced_float;
}

void Init_gc_spec(void) {
  VALUE cls = rb_define_class("CApiGCSpecs", rb_cObject);

  rb_gc_register_address(&registered_tagged_value);
  rb_gc_register_address(&registered_reference_value);
  rb_gc_register_address(&registered_before_rb_gc_register_address);
  rb_global_variable(&registered_before_rb_global_variable_string);
  rb_global_variable(&registered_before_rb_global_variable_bignum);
  rb_global_variable(&registered_before_rb_global_variable_float);

  registered_tagged_value    = INT2NUM(10);
  registered_reference_value = rb_str_new2("Globally registered data");
  registered_before_rb_gc_register_address = rb_str_new_cstr("registered before rb_gc_register_address()");

  registered_before_rb_global_variable_string = rb_str_new_cstr("registered before rb_global_variable()");
  registered_before_rb_global_variable_bignum = LL2NUM(INT64_MAX);
  registered_before_rb_global_variable_float = DBL2NUM(3.14);

  registered_after_rb_global_variable_string = rb_str_new_cstr("registered after rb_global_variable()");
  rb_global_variable(&registered_after_rb_global_variable_string);
  registered_after_rb_global_variable_bignum = LL2NUM(INT64_MAX);
  rb_global_variable(&registered_after_rb_global_variable_bignum);
  registered_after_rb_global_variable_float = DBL2NUM(6.28);
  rb_global_variable(&registered_after_rb_global_variable_float);

  rb_gc_register_mark_object_not_referenced_float = DBL2NUM(1.61);
  rb_gc_register_mark_object(rb_gc_register_mark_object_not_referenced_float);

  rb_define_method(cls, "RB_GC_GUARD_keep_alive", spec_RB_GC_GUARD_keep_alive, 1);
  rb_define_method(cls, "RB_GC_GUARD", spec_RB_GC_GUARD, 1);
  rb_define_method(cls, "RB_GC_GUARD_raw", spec_RB_GC_GUARD_raw, 1);
  rb_define_method(cls, "registered_tagged_address", registered_tagged_address, 0);
  rb_define_method(cls, "registered_reference_address", registered_reference_address, 0);
  rb_define_method(cls, "registered_before_rb_gc_register_address", get_registered_before_rb_gc_register_address, 0);
  rb_define_method(cls, "registered_before_rb_global_variable_string", get_registered_before_rb_global_variable_string, 0);
  rb_define_method(cls, "registered_before_rb_global_variable_bignum", get_registered_before_rb_global_variable_bignum, 0);
  rb_define_method(cls, "registered_before_rb_global_variable_float", get_registered_before_rb_global_variable_float, 0);
  rb_define_method(cls, "registered_after_rb_global_variable_string", get_registered_after_rb_global_variable_string, 0);
  rb_define_method(cls, "registered_after_rb_global_variable_bignum", get_registered_after_rb_global_variable_bignum, 0);
  rb_define_method(cls, "registered_after_rb_global_variable_float", get_registered_after_rb_global_variable_float, 0);
  rb_define_method(cls, "rb_gc_register_address", gc_spec_rb_gc_register_address, 0);
  rb_define_method(cls, "rb_gc_unregister_address", gc_spec_rb_gc_unregister_address, 0);
  rb_define_method(cls, "rb_gc_enable", gc_spec_rb_gc_enable, 0);
  rb_define_method(cls, "rb_gc_disable", gc_spec_rb_gc_disable, 0);
  rb_define_method(cls, "rb_gc", gc_spec_rb_gc, 0);
  rb_define_method(cls, "rb_gc_adjust_memory_usage", gc_spec_rb_gc_adjust_memory_usage, 1);
  rb_define_method(cls, "rb_gc_register_mark_object", gc_spec_rb_gc_register_mark_object, 1);
  rb_define_method(cls, "rb_gc_register_mark_object_not_referenced_float", gc_spec_rb_gc_register_mark_object_not_referenced_float, 0);
  rb_define_method(cls, "rb_gc_latest_gc_info", gc_spec_rb_gc_latest_gc_info, 1);
}

#ifdef __cplusplus
}
#endif
