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

   This file is part of the JUCE framework.
   Copyright (c) Raw Material Software Limited

   JUCE is an open source framework subject to commercial or open source
   licensing.

   By downloading, installing, or using the JUCE framework, or combining the
   JUCE framework with any other source code, object code, content or any other
   copyrightable work, you agree to the terms of the JUCE End User Licence
   Agreement, and all incorporated terms including the JUCE Privacy Policy and
   the JUCE Website Terms of Service, as applicable, which will bind you. If you
   do not agree to the terms of these agreements, we will not license the JUCE
   framework to you, and you must discontinue the installation or download
   process and cease use of the JUCE framework.

   JUCE End User Licence Agreement: https://juce.com/legal/juce-9-licence/
   JUCE Privacy Policy: https://juce.com/juce-privacy-policy
   JUCE Website Terms of Service: https://juce.com/juce-website-terms-of-service/

   Or:

   You may also use this code under the terms of the AGPLv3:
   https://www.gnu.org/licenses/agpl-3.0.en.html

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

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

namespace juce
{

ColourGradient::ColourGradient() noexcept  : isRadial (false)
{
   #if JUCE_DEBUG
    point1.setX (987654.0f);
    #define JUCE_COLOURGRADIENT_CHECK_COORDS_INITIALISED jassert (! exactlyEqual (point1.x, 987654.0f));
   #else
    #define JUCE_COLOURGRADIENT_CHECK_COORDS_INITIALISED
   #endif
}

ColourGradient::ColourGradient (Colour colour1, float x1, float y1,
                                Colour colour2, float x2, float y2, bool radial)
    : ColourGradient (colour1, Point<float> (x1, y1),
                      colour2, Point<float> (x2, y2), radial)
{
}

ColourGradient::ColourGradient (Colour colour1, Point<float> p1,
                                Colour colour2, Point<float> p2, bool radial)
    : point1 (p1),
      point2 (p2),
      isRadial (radial)
{
    colours.add (ColourPoint { 0.0, colour1 },
                 ColourPoint { 1.0, colour2 });
}

ColourGradient ColourGradient::vertical (Colour c1, float y1, Colour c2, float y2)
{
    return { c1, 0, y1, c2, 0, y2, false };
}

ColourGradient ColourGradient::horizontal (Colour c1, float x1, Colour c2, float x2)
{
    return { c1, x1, 0, c2, x2, 0, false };
}

struct PointComparisons
{
    auto tie() const { return std::tie (point->x, point->y); }

    bool operator== (const PointComparisons& other) const { return tie() == other.tie(); }
    bool operator!= (const PointComparisons& other) const { return tie() != other.tie(); }
    bool operator<  (const PointComparisons& other) const { return tie() <  other.tie(); }

    const Point<float>* point = nullptr;
};

struct ColourGradient::ColourPointArrayComparisons
{
    bool operator== (const ColourPointArrayComparisons& other) const { return *array == *other.array; }
    bool operator!= (const ColourPointArrayComparisons& other) const { return *array != *other.array; }

    bool operator<  (const ColourPointArrayComparisons& other) const
    {
        return std::lexicographical_compare (array->begin(), array->end(), other.array->begin(), other.array->end());
    }

    const Array<ColourGradient::ColourPoint>* array = nullptr;
};

auto ColourGradient::tie() const
{
    return std::tuple (PointComparisons { &point1 },
                       PointComparisons { &point2 },
                       isRadial,
                       ColourPointArrayComparisons { &colours });
}

bool ColourGradient::operator== (const ColourGradient& other) const noexcept { return tie() == other.tie(); }
bool ColourGradient::operator!= (const ColourGradient& other) const noexcept { return tie() != other.tie(); }

bool ColourGradient::operator<  (const ColourGradient& other) const noexcept { return tie() <  other.tie(); }
bool ColourGradient::operator<= (const ColourGradient& other) const noexcept { return tie() <= other.tie(); }
bool ColourGradient::operator>  (const ColourGradient& other) const noexcept { return tie() >  other.tie(); }
bool ColourGradient::operator>= (const ColourGradient& other) const noexcept { return tie() >= other.tie(); }

//==============================================================================
void ColourGradient::clearColours()
{
    colours.clear();
}

int ColourGradient::addColour (const double proportionAlongGradient, Colour colour)
{
    // must be within the two end-points
    jassert (proportionAlongGradient >= 0 && proportionAlongGradient <= 1.0);

    if (proportionAlongGradient <= 0)
    {
        colours.set (0, { 0.0, colour });
        return 0;
    }

    auto pos = jmin (1.0, proportionAlongGradient);

    int i;
    for (i = 0; i < colours.size(); ++i)
        if (colours.getReference (i).position > pos)
            break;

    colours.insert (i, { pos, colour });
    return i;
}

void ColourGradient::removeColour (int index)
{
    jassert (isPositiveAndBelow (index, colours.size()));
    colours.remove (index);
}

void ColourGradient::multiplyOpacity (const float multiplier) noexcept
{
    for (auto& c : colours)
        c.colour = c.colour.withMultipliedAlpha (multiplier);
}

//==============================================================================
int ColourGradient::getNumColours() const noexcept
{
    return colours.size();
}

double ColourGradient::getColourPosition (int index) const noexcept
{
    if (isPositiveAndBelow (index, colours.size()))
        return colours.getReference (index).position;

    return 0;
 }

Colour ColourGradient::getColour (int index) const noexcept
{
    if (isPositiveAndBelow (index, colours.size()))
        return colours.getReference (index).colour;

    return {};
}

void ColourGradient::setColour (int index, Colour newColour) noexcept
{
    if (isPositiveAndBelow (index, colours.size()))
        colours.getReference (index).colour = newColour;
}

Colour ColourGradient::getColourAtPosition (double position) const noexcept
{
    jassert (approximatelyEqual (colours.getReference (0).position, 0.0)); // the first colour specified has to go at position 0

    if (position <= 0 || colours.size() <= 1)
        return colours.getReference (0).colour;

    int i = colours.size() - 1;
    while (position < colours.getReference (i).position)
        --i;

    auto& p1 = colours.getReference (i);

    if (i >= colours.size() - 1)
        return p1.colour;

    auto& p2 = colours.getReference (i + 1);

    return p1.colour.interpolatedWith (p2.colour, (float) ((position - p1.position) / (p2.position - p1.position)));
}

//==============================================================================
void ColourGradient::createLookupTable (PixelARGB* const lookupTable, const int numEntries) const noexcept
{
    JUCE_COLOURGRADIENT_CHECK_COORDS_INITIALISED // Trying to use this object without setting its coordinates?
    jassert (colours.size() >= 2);
    jassert (numEntries > 0);

    auto paddedColours = colours;
    const auto colour0 = colours.getReference (0);

    if (! approximatelyEqual (colour0.position, 0.0))
        paddedColours.insert (0, { 0.0, colour0.colour });

    int index = 0;

    for (int j = 0; j < paddedColours.size() - 1; ++j)
    {
        const auto& o = paddedColours.getReference (j + 0);
        const auto& p = paddedColours.getReference (j + 1);
        const auto numToDo = roundToInt (p.position * (numEntries - 1)) - index;
        const auto pix1 = o.colour.getNonPremultipliedPixelARGB();
        const auto pix2 = p.colour.getNonPremultipliedPixelARGB();

        for (auto i = 0; i < numToDo; ++i)
        {
            auto blended = pix1;
            blended.tween (pix2, (uint32) ((i << 8) / numToDo));
            blended.premultiply();

            jassert (0 <= index && index < numEntries);
            lookupTable[index++] = blended;
        }
    }

    std::fill (lookupTable + index, lookupTable + numEntries, paddedColours.getLast().colour.getPixelARGB());
}

int ColourGradient::createLookupTable (const AffineTransform& transform, HeapBlock<PixelARGB>& lookupTable) const
{
    JUCE_COLOURGRADIENT_CHECK_COORDS_INITIALISED // Trying to use this object without setting its coordinates?
    jassert (colours.size() >= 2);

    const auto maxExtent = std::invoke ([&]
    {
        if (! isRadial)
        {
            return 3 * (int) point1.transformedBy (transform)
                                   .getDistanceFrom (point2.transformedBy (transform));
        }

        detail::RadialGradientView rg { this };

        // If the transform is skewed the maximum extent could be in any direction
        const auto r = rg.getEndCircle().r;
        Point<float> extentX { r, 0.0f };
        Point<float> extentY { 0.0f, r };

        return roundToInt (jmax (extentX.transformedBy (transform).getDistanceFromOrigin(),
                                 extentY.transformedBy (transform).getDistanceFromOrigin()));
    });

    const auto numEntries = jlimit (1, jmax (1, (colours.size() - 1) << 8), 3 * (int) maxExtent);
    lookupTable.malloc (numEntries);
    createLookupTable (lookupTable, numEntries);
    return numEntries;
}

bool ColourGradient::isOpaque() const noexcept
{
    for (auto& c : colours)
        if (! c.colour.isOpaque())
            return false;

    return true;
}

bool ColourGradient::isInvisible() const noexcept
{
    for (auto& c : colours)
        if (! c.colour.isTransparent())
            return false;

    return true;
}

auto ColourGradient::ColourPoint::tie() const
{
    return std::tuple (position, colour.getPixelARGB().getNativeARGB());
}

bool ColourGradient::ColourPoint::operator== (ColourPoint other) const noexcept
{
    return tie() == other.tie();
}

bool ColourGradient::ColourPoint::operator!= (ColourPoint other) const noexcept
{
    return tie() != other.tie();
}

bool ColourGradient::ColourPoint::operator<  (ColourPoint other) const noexcept
{
    return tie() <  other.tie();
}

} // namespace juce
