/*
* All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
* its licensors.
*
* For complete copyright and license terms please see the LICENSE at the root of this
* distribution (the "License"). All use of this software is governed by the License,
* or, if provided, by the license below or the license accompanying this file. Do not
* remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
*
*/
// Original file Copyright Crytek GMBH or its affiliates, used under license.

#ifndef CRYINCLUDE_CRYAISYSTEM_POLYGONSETOPS_LINESEG_H
#define CRYINCLUDE_CRYAISYSTEM_POLYGONSETOPS_LINESEG_H
#pragma once

#include "Utils.h"

#include <vector>

/**
* @brief A simple oriented 2D line segment implementation.
*/
template <typename VectorT>
class LineSeg
{
    VectorT m_start;
    VectorT m_end;
public:
    LineSeg (const VectorT& start, const VectorT& end);
    const VectorT& Start () const;
    const VectorT& End () const;
    /// Inverts this line segment's direction.
    void Invert ();
    VectorT Dir () const;
    /// Takes parameter and returns point corresponding to that parameter.
    VectorT Pt (float t) const;
    float GetParam (const VectorT& pt) const;
    /// Returns (unnormalized) normal vector to this lineseg.
    VectorT Normal () const;
};

template <typename VectorT>
inline LineSeg<VectorT>::LineSeg (const VectorT& start, const VectorT& end)
    : m_start (start)
    , m_end (end)
{
}

template <typename VectorT>
inline const VectorT& LineSeg<VectorT>::Start () const
{
    return m_start;
}

template <typename VectorT>
inline const VectorT& LineSeg<VectorT>::End () const
{
    return m_end;
}

template <typename VectorT>
inline void LineSeg<VectorT>::Invert ()
{
    std::swap (m_start, m_end);
}

template <typename VectorT>
inline VectorT LineSeg<VectorT>::Dir () const
{
    return m_end - m_start;
}

template <typename VectorT>
inline VectorT LineSeg<VectorT>::Pt (float t) const
{
    return m_start + Dir() * t;
}

template <typename VectorT>
inline float LineSeg<VectorT>::GetParam (const VectorT& pt) const
{
    const VectorT toPt = pt - m_start;
    const VectorT thisDir = Dir();
    const int sign = toPt.Dot(thisDir) > 0.0f ? 1 : -1;
    return sign * toPt.GetLength() / thisDir.GetLength();
}

template <typename VectorT>
inline VectorT LineSeg<VectorT>::Normal () const
{
    return Dir ().Perp ();
}

typedef LineSeg<Vector2d> LineSeg2d;
typedef std::vector <LineSeg2d> LineSegVec;

#endif // CRYINCLUDE_CRYAISYSTEM_POLYGONSETOPS_LINESEG_H