/*=========================================================================

   Library: iMSTK

   Copyright (c) Kitware, Inc. & Center for Modeling, Simulation,
   & Imaging in Medicine, Rensselaer Polytechnic Institute.

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

      http://www.apache.org/licenses/LICENSE-2.0.txt

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.

=========================================================================*/

#include "gtest/gtest.h"

#include "imstkPbdPointEdgeConstraint.h"

using namespace imstk;

///
/// \brief TODO
///
class imstkPbdPointEdgeConstraintTest : public ::testing::Test
{
protected:
    PbdPointEdgeConstraint m_constraint;
};

///
/// \brief Test that a point and edge meet on touching
///
TEST_F(imstkPbdPointEdgeConstraintTest, TestConvergence1)
{
    Vec3d a = Vec3d(-0.5, 0.0, 0.0);
    Vec3d b = Vec3d(0.5, 0.0, 0.0);

    Vec3d x = Vec3d(0.0, -1.0, 0.0);

    Vec3d zeroVelocity = Vec3d::Zero();
    m_constraint.initConstraint(
        { &x, 1.0, &zeroVelocity },
        { &a, 1.0, &zeroVelocity },
        { &b, 1.0, &zeroVelocity },
        1.0, 1.0);
    for (int i = 0; i < 3; i++)
    {
        m_constraint.solvePosition();
    }

    EXPECT_NEAR(x[1], a[1], IMSTK_DOUBLE_EPS);
    EXPECT_NEAR(x[1], b[1], IMSTK_DOUBLE_EPS);
    EXPECT_NEAR(a[1], b[1], IMSTK_DOUBLE_EPS);
}

///
/// \brief Test that a point and edge meet on touching
///
TEST_F(imstkPbdPointEdgeConstraintTest, TestConvergence2)
{
    Vec3d a = Vec3d(-0.5, 0.0, 0.0);
    Vec3d b = Vec3d(0.5, 0.0, 0.0);

    Vec3d x = Vec3d(0.0, 1.0, 0.0);

    Vec3d zeroVelocity = Vec3d::Zero();
    m_constraint.initConstraint(
        { &x, 1.0, &zeroVelocity },
        { &a, 1.0, &zeroVelocity },
        { &b, 1.0, &zeroVelocity },
        1.0, 1.0);
    for (int i = 0; i < 3; i++)
    {
        m_constraint.solvePosition();
    }

    EXPECT_NEAR(x[1], a[1], IMSTK_DOUBLE_EPS);
    EXPECT_NEAR(x[1], b[1], IMSTK_DOUBLE_EPS);
    EXPECT_NEAR(a[1], b[1], IMSTK_DOUBLE_EPS);
}

///
/// \brief Test that a point not within bounds of edge does not move (left)
///
TEST_F(imstkPbdPointEdgeConstraintTest, TestNoConvergence1)
{
    Vec3d       a     = Vec3d(-0.5, 0.0, 0.0);
    const Vec3d aInit = a;
    Vec3d       b     = Vec3d(0.5, 0.0, 0.0);
    const Vec3d bInit = b;

    Vec3d       x     = Vec3d(-1.0, -1.0, 0.0);
    const Vec3d xInit = x;

    Vec3d zeroVelocity = Vec3d::Zero();
    m_constraint.initConstraint(
        { &x, 1.0, &zeroVelocity },
        { &a, 1.0, &zeroVelocity },
        { &b, 1.0, &zeroVelocity },
        1.0, 1.0);
    for (int i = 0; i < 3; i++)
    {
        m_constraint.solvePosition();
    }

    EXPECT_EQ(xInit[0], x[0]);
    EXPECT_EQ(xInit[1], x[1]);
    EXPECT_EQ(xInit[2], x[2]);

    EXPECT_EQ(aInit[0], a[0]);
    EXPECT_EQ(aInit[1], a[1]);
    EXPECT_EQ(aInit[2], a[2]);

    EXPECT_EQ(bInit[0], b[0]);
    EXPECT_EQ(bInit[1], b[1]);
    EXPECT_EQ(bInit[2], b[2]);
}

///
/// \brief Test that a point not within bounds of edge does not move (right)
///
TEST_F(imstkPbdPointEdgeConstraintTest, TestNoConvergence2)
{
    Vec3d       a     = Vec3d(-0.5, 0.0, 0.0);
    const Vec3d aInit = a;
    Vec3d       b     = Vec3d(0.5, 0.0, 0.0);
    const Vec3d bInit = b;

    Vec3d       x     = Vec3d(1.0, -1.0, 0.0);
    const Vec3d xInit = x;

    Vec3d zeroVelocity = Vec3d::Zero();
    m_constraint.initConstraint(
        { &x, 1.0, &zeroVelocity },
        { &a, 1.0, &zeroVelocity },
        { &b, 1.0, &zeroVelocity },
        1.0, 1.0);
    for (int i = 0; i < 3; i++)
    {
        m_constraint.solvePosition();
    }

    EXPECT_EQ(xInit[0], x[0]);
    EXPECT_EQ(xInit[1], x[1]);
    EXPECT_EQ(xInit[2], x[2]);

    EXPECT_EQ(aInit[0], a[0]);
    EXPECT_EQ(aInit[1], a[1]);
    EXPECT_EQ(aInit[2], a[2]);

    EXPECT_EQ(bInit[0], b[0]);
    EXPECT_EQ(bInit[1], b[1]);
    EXPECT_EQ(bInit[2], b[2]);
}

///
/// \brief TODO
///
int
imstkPbdPointEdgeConstraintTest(int argc, char* argv[])
{
    // Init Google Test & Mock
    ::testing::InitGoogleTest(&argc, argv);

    // Run tests with gtest
    return RUN_ALL_TESTS();
}
