#pragma region CPL License
/*
Nuclex Native Framework
Copyright (C) 2002-2015 Nuclex Development Labs

This library is free software; you can redistribute it and/or
modify it under the terms of the IBM Common Public License as
published by the IBM Corporation; either version 1.0 of the
License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
IBM Common Public License for more details.

You should have received a copy of the IBM Common Public
License along with this library
*/
#pragma endregion // CPL License

#ifndef NUCLEX_GEOMETRY_LINECONTACTS_H
#define NUCLEX_GEOMETRY_LINECONTACTS_H

#include "Nuclex/Geometry/Config.h"
#include "Nuclex/Geometry/Math.h"

#include <limits>

namespace Nuclex { namespace Geometry {

  // ------------------------------------------------------------------------------------------- //

  /// <summary>Stores the entry and exit intervals of a line through a shape</summary>
  template<typename TScalar>
  struct LineContacts {

    /// <summary>Contact times used if a line doesn't touch the shape at all</summary>
    public: static const LineContacts None;

    /// <summary>Constructs uninitialized line contacts</summary>
    public: LineContacts() = default;

    /// <summary>Initializes new line contacts using the specified times</summary>
    /// <param name="entryTime">Time at which the line has entered the shape</param>
    /// <param name="exitTime">Time at which the line has exited the shape</param>
    public: LineContacts(TScalar entryTime, TScalar exitTime) :
      EntryTime(entryTime), ExitTime(exitTime) {}

    /// <summary>Builds line contacts by using the extremes of the values</summary>
    /// <param name="first">First value that will be used for the line contacts</param>
    /// <param name="second">Second value that will be used for the line contacts</param>
    /// <returns>
    ///   Line contacts with the smaller value for entry time and larger one for exit time
    /// </returns>
    public: static LineContacts FromExtremes(TScalar first, TScalar second) {
      if(first < second) {
        return LineContacts(first, second);
      } else {
        return LineContacts(second, first);
      }
    }

    /// <summary>Builds line contacts by using the extremes of the values</summary>
    /// <param name="first">First value that will be used for the line contacts</param>
    /// <param name="second">Second value that will be used for the line contacts</param>
    /// <param name="third">Third value that will be used for the line contacts</param>
    /// <returns>
    ///   Line contacts with the smallest value for entry time and largest one for exit time
    /// </returns>
    public: static LineContacts FromExtremes(TScalar first, TScalar second, TScalar third) {
      if(first < second) {
        if(third < first) {
          return LineContacts(third, second); // third - first - second
        } else if(third < second) {
          return LineContacts(first, second); // first - third - second
        } else {
          return LineContacts(first, third); // first - second - third
        }
      } else {
        if(third < second) {
          return LineContacts(third, first); // third - second - first
        } else if(third < first) {
          return LineContacts(second, first); // second - third - first
        } else {
          return LineContacts(second, third); // second - first - third
        }
      }
    }

    /// <summary>Whether the line has missed the shape</summary>
    /// <returns>True if the line has missed the shape, otherwise false</returns>
    public: bool HasMissed() const {
      return Math<TScalar>::IsNan(this->EntryTime);
    }

    /// <summary>Whether the line has missed the shape</summary>
    /// <returns>True if the line has missed the shape, otherwise false</returns>
    public: bool HasHit() const {
      return !Math<TScalar>::IsNan(this->EntryTime);
    }

    /// <summary>Time at which the line has entered the shape</summary>
    public: TScalar EntryTime;
    /// <summary>Time at which the line has entered the shape</summary>
    public: TScalar ExitTime;

  };

  // ------------------------------------------------------------------------------------------- //

  template<typename TScalar>
  const LineContacts<TScalar> LineContacts<TScalar>::None(
    std::numeric_limits<TScalar>::signaling_NaN(),
    std::numeric_limits<TScalar>::signaling_NaN()
  );

  // ------------------------------------------------------------------------------------------- //

}} // namespace Nuclex::Geometry

#endif // NUCLEX_GEOMETRY_LINECONTACTS_H