#ifndef SASS_UNITS_H

#define SASS_UNITS_H

#include <cmath>

#include <string>

#include <sstream>

namespace Sass {

  const double PI = std::acos(-1);

  enum UnitClass {

    LENGTH = 0x000,

    ANGLE = 0x100,

    TIME = 0x200,

    FREQUENCY = 0x300,

    RESOLUTION = 0x400,

    INCOMMENSURABLE = 0x500

  };

  enum UnitType {

    // size units

    IN = UnitClass::LENGTH,

    CM,

    PC,

    MM,

    PT,

    PX,

    // angle units

    DEG = ANGLE,

    GRAD,

    RAD,

    TURN,

    // time units

    SEC = TIME,

    MSEC,

    // frequency units

    HERTZ = FREQUENCY,

    KHERTZ,

    // resolutions units

    DPI = RESOLUTION,

    DPCM,

    DPPX,

    // for unknown units

    UNKNOWN = INCOMMENSURABLE

  };

  extern const double size_conversion_factors[6][6];

  extern const double angle_conversion_factors[4][4];

  extern const double time_conversion_factors[2][2];

  extern const double frequency_conversion_factors[2][2];

  extern const double resolution_conversion_factors[3][3];

  enum Sass::UnitType string_to_unit(const std::string&);

  const char* unit_to_string(Sass::UnitType unit);

  enum Sass::UnitClass get_unit_type(Sass::UnitType unit);

  std::string get_unit_class(Sass::UnitType unit);

  std::string unit_to_class(const std::string&);

  // throws incompatibleUnits exceptions

  double conversion_factor(const std::string&, const std::string&, bool = true);

}

#endif