#include <gtest/gtest.h>
#include "trick/units_conv.h"

#define TOL 1e-13
/*
double tolerance(int exp)
{
  return pow(10, exp);
}
*/
/*********************WARNING******************************************
 * 1. new_units allocates memory for a Units_t object using new
 * Use clean_up_Units_t() to deallocate the memory and set the pointer to NULL
 *
 * 2. Do not call clean_up_Units_t() on unitialized pointers!
 * Initialize/Define pointers at declaration
 * Declared pointers that don't point to a valid address or NULL will
 * cause an error
**********************************************************************/

void clean_up_Units_t(Units_t** ptr)
{
  if(*ptr != (Units_t*) NULL)
  {
      delete *ptr;
  }
  else
  {
    std::cerr << "WARNING: Call to clean_up_Units_t() on a NULL pointer" << std::endl
              << "Calling function should check for non-NULL value of pointer" << std::endl
              << "before calling clean_up_Units_t()" << std::endl;
  }
  *ptr = (Units_t*) NULL;
}

TEST(UnitsInterface, BogusUnit)
{
  Units_t *Bogus = (Units_t*) NULL;

  std::cerr << "The purpose of this test is to throw to an exception. Error messages are expected." << std::endl;

  ASSERT_EQ((Units_t*) NULL, Bogus = new_units("foo"));
}

TEST(UnitsInterface, Newton_to_Pound)
{
  UnitsConvFn_t Newton_to_Pound;
  UnitsConvFn_t Newton_to_Pound2;
  Units_t* Newton = (Units_t*) NULL;
  Units_t* Pound = (Units_t*) NULL;
  double pounds;

  ASSERT_EQ(CONV_OK, conv_fn_s("kg*m/s2", "lbm*ft/s2", &Newton_to_Pound));

  Newton = new_units("kg*m/s2");
  Pound = new_units("lbm*ft/s2");

  ASSERT_NE((Units_t*) NULL, Newton);
  ASSERT_NE((Units_t*) NULL, Pound);

  ASSERT_EQ(CONV_OK, conv_fn_u(Newton, Pound, &Newton_to_Pound2));

  EXPECT_EQ(0, memcmp(&Newton_to_Pound, &Newton_to_Pound2, sizeof(UnitsConvFn_t)));

  pounds = convert_units(1.0, &Newton_to_Pound);

  ASSERT_NEAR((1.0/(0.4535923697760192*0.3048)), pounds, TOL);

  clean_up_Units_t(&Newton);
  clean_up_Units_t(&Pound);
  ASSERT_EQ((Units_t*) NULL, Newton);
  ASSERT_EQ((Units_t*) NULL, Pound);
}