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

   This file is part of the JUCE library.
   Copyright (c) 2017 - ROLI Ltd.

   JUCE is an open source library subject to commercial or open-source
   licensing.

   By using JUCE, you agree to the terms of both the JUCE 5 End-User License
   Agreement and JUCE 5 Privacy Policy (both updated and effective as of the
   27th April 2017).

   End User License Agreement: www.juce.com/juce-5-licence
   Privacy Policy: www.juce.com/juce-5-privacy-policy

   Or: You may also use this code under the terms of the GPL v3 (see
   www.gnu.org/licenses).

   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
   DISCLAIMED.

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

AffineTransform::AffineTransform() noexcept
    : mat00 (1.0f), mat01 (0), mat02 (0),
      mat10 (0), mat11 (1.0f), mat12 (0)
{
}

AffineTransform::AffineTransform (const AffineTransform& other) noexcept
  : mat00 (other.mat00), mat01 (other.mat01), mat02 (other.mat02),
    mat10 (other.mat10), mat11 (other.mat11), mat12 (other.mat12)
{
}

AffineTransform::AffineTransform (const float m00, const float m01, const float m02,
                                  const float m10, const float m11, const float m12) noexcept
 :  mat00 (m00), mat01 (m01), mat02 (m02),
    mat10 (m10), mat11 (m11), mat12 (m12)
{
}

AffineTransform& AffineTransform::operator= (const AffineTransform& other) noexcept
{
    mat00 = other.mat00;
    mat01 = other.mat01;
    mat02 = other.mat02;
    mat10 = other.mat10;
    mat11 = other.mat11;
    mat12 = other.mat12;

    return *this;
}

bool AffineTransform::operator== (const AffineTransform& other) const noexcept
{
    return mat00 == other.mat00
        && mat01 == other.mat01
        && mat02 == other.mat02
        && mat10 == other.mat10
        && mat11 == other.mat11
        && mat12 == other.mat12;
}

bool AffineTransform::operator!= (const AffineTransform& other) const noexcept
{
    return ! operator== (other);
}

//==============================================================================
bool AffineTransform::isIdentity() const noexcept
{
    return (mat01 == 0.0f)
        && (mat02 == 0.0f)
        && (mat10 == 0.0f)
        && (mat12 == 0.0f)
        && (mat00 == 1.0f)
        && (mat11 == 1.0f);
}

#if JUCE_ALLOW_STATIC_NULL_VARIABLES
const AffineTransform AffineTransform::identity;
#endif

//==============================================================================
AffineTransform AffineTransform::followedBy (const AffineTransform& other) const noexcept
{
    return AffineTransform (other.mat00 * mat00 + other.mat01 * mat10,
                            other.mat00 * mat01 + other.mat01 * mat11,
                            other.mat00 * mat02 + other.mat01 * mat12 + other.mat02,
                            other.mat10 * mat00 + other.mat11 * mat10,
                            other.mat10 * mat01 + other.mat11 * mat11,
                            other.mat10 * mat02 + other.mat11 * mat12 + other.mat12);
}

AffineTransform AffineTransform::translated (const float dx, const float dy) const noexcept
{
    return AffineTransform (mat00, mat01, mat02 + dx,
                            mat10, mat11, mat12 + dy);
}

AffineTransform AffineTransform::translation (const float dx, const float dy) noexcept
{
    return AffineTransform (1.0f, 0, dx,
                            0, 1.0f, dy);
}

AffineTransform AffineTransform::withAbsoluteTranslation (const float tx, const float ty) const noexcept
{
    return AffineTransform (mat00, mat01, tx,
                            mat10, mat11, ty);
}

AffineTransform AffineTransform::rotated (const float rad) const noexcept
{
    const float cosRad = std::cos (rad);
    const float sinRad = std::sin (rad);

    return AffineTransform (cosRad * mat00 + -sinRad * mat10,
                            cosRad * mat01 + -sinRad * mat11,
                            cosRad * mat02 + -sinRad * mat12,
                            sinRad * mat00 + cosRad * mat10,
                            sinRad * mat01 + cosRad * mat11,
                            sinRad * mat02 + cosRad * mat12);
}

AffineTransform AffineTransform::rotation (const float rad) noexcept
{
    const float cosRad = std::cos (rad);
    const float sinRad = std::sin (rad);

    return AffineTransform (cosRad, -sinRad, 0,
                            sinRad, cosRad, 0);
}

AffineTransform AffineTransform::rotation (const float rad, const float pivotX, const float pivotY) noexcept
{
    const float cosRad = std::cos (rad);
    const float sinRad = std::sin (rad);

    return AffineTransform (cosRad, -sinRad, -cosRad * pivotX + sinRad * pivotY + pivotX,
                            sinRad, cosRad, -sinRad * pivotX + -cosRad * pivotY + pivotY);
}

AffineTransform AffineTransform::rotated (const float angle, const float pivotX, const float pivotY) const noexcept
{
    return followedBy (rotation (angle, pivotX, pivotY));
}

AffineTransform AffineTransform::scaled (const float factorX, const float factorY) const noexcept
{
    return AffineTransform (factorX * mat00, factorX * mat01, factorX * mat02,
                            factorY * mat10, factorY * mat11, factorY * mat12);
}

AffineTransform AffineTransform::scaled (const float factor) const noexcept
{
    return AffineTransform (factor * mat00, factor * mat01, factor * mat02,
                            factor * mat10, factor * mat11, factor * mat12);
}

AffineTransform AffineTransform::scale (const float factorX, const float factorY) noexcept
{
    return AffineTransform (factorX, 0, 0, 0, factorY, 0);
}

AffineTransform AffineTransform::scale (const float factor) noexcept
{
    return AffineTransform (factor, 0, 0, 0, factor, 0);
}

AffineTransform AffineTransform::scaled (const float factorX, const float factorY,
                                         const float pivotX, const float pivotY) const noexcept
{
    return AffineTransform (factorX * mat00, factorX * mat01, factorX * mat02 + pivotX * (1.0f - factorX),
                            factorY * mat10, factorY * mat11, factorY * mat12 + pivotY * (1.0f - factorY));
}

AffineTransform AffineTransform::scale (const float factorX, const float factorY,
                                        const float pivotX, const float pivotY) noexcept
{
    return AffineTransform (factorX, 0, pivotX * (1.0f - factorX),
                            0, factorY, pivotY * (1.0f - factorY));
}

AffineTransform AffineTransform::shear (float shearX, float shearY) noexcept
{
    return AffineTransform (1.0f, shearX, 0,
                            shearY, 1.0f, 0);
}

AffineTransform AffineTransform::sheared (const float shearX, const float shearY) const noexcept
{
    return AffineTransform (mat00 + shearX * mat10,
                            mat01 + shearX * mat11,
                            mat02 + shearX * mat12,
                            mat10 + shearY * mat00,
                            mat11 + shearY * mat01,
                            mat12 + shearY * mat02);
}

AffineTransform AffineTransform::verticalFlip (const float height) noexcept
{
    return AffineTransform (1.0f, 0, 0, 0, -1.0f, height);
}

AffineTransform AffineTransform::inverted() const noexcept
{
    double determinant = (mat00 * mat11 - mat10 * mat01);

    if (determinant != 0.0)
    {
        determinant = 1.0 / determinant;

        const float dst00 = (float) ( mat11 * determinant);
        const float dst10 = (float) (-mat10 * determinant);
        const float dst01 = (float) (-mat01 * determinant);
        const float dst11 = (float) ( mat00 * determinant);

        return AffineTransform (dst00, dst01, -mat02 * dst00 - mat12 * dst01,
                                dst10, dst11, -mat02 * dst10 - mat12 * dst11);
    }

    // singularity..
    return *this;
}

bool AffineTransform::isSingularity() const noexcept
{
    return (mat00 * mat11 - mat10 * mat01) == 0.0f;
}

AffineTransform AffineTransform::fromTargetPoints (const float x00, const float y00,
                                                   const float x10, const float y10,
                                                   const float x01, const float y01) noexcept
{
    return AffineTransform (x10 - x00, x01 - x00, x00,
                            y10 - y00, y01 - y00, y00);
}

AffineTransform AffineTransform::fromTargetPoints (const float sx1, const float sy1, const float tx1, const float ty1,
                                                   const float sx2, const float sy2, const float tx2, const float ty2,
                                                   const float sx3, const float sy3, const float tx3, const float ty3) noexcept
{
    return fromTargetPoints (sx1, sy1, sx2, sy2, sx3, sy3)
            .inverted()
            .followedBy (fromTargetPoints (tx1, ty1, tx2, ty2, tx3, ty3));
}

bool AffineTransform::isOnlyTranslation() const noexcept
{
    return (mat01 == 0.0f)
        && (mat10 == 0.0f)
        && (mat00 == 1.0f)
        && (mat11 == 1.0f);
}

float AffineTransform::getScaleFactor() const noexcept
{
    return (std::abs (mat00) + std::abs (mat11)) / 2.0f;
}
