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

   This file is part of the JUCE 6 technical preview.
   Copyright (c) 2017 - ROLI Ltd.

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

   For this technical preview, this file is not subject to commercial licensing.

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

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

namespace juce
{

namespace ColourHelpers
{
    static uint8 floatToUInt8 (const float n) noexcept
    {
        return n <= 0.0f ? 0 : (n >= 1.0f ? 255 : static_cast<uint8> (n * 255.996f));
    }

    //==============================================================================
    struct HSB
    {
        HSB (Colour col) noexcept
        {
            const int r = col.getRed();
            const int g = col.getGreen();
            const int b = col.getBlue();

            const int hi = jmax (r, g, b);
            const int lo = jmin (r, g, b);

            if (hi != 0)
            {
                saturation = (hi - lo) / (float) hi;

                if (saturation > 0)
                {
                    const float invDiff = 1.0f / (hi - lo);

                    const float red   = (hi - r) * invDiff;
                    const float green = (hi - g) * invDiff;
                    const float blue  = (hi - b) * invDiff;

                    if (r == hi)
                        hue = blue - green;
                    else if (g == hi)
                        hue = 2.0f + red - blue;
                    else
                        hue = 4.0f + green - red;

                    hue *= 1.0f / 6.0f;

                    if (hue < 0)
                        ++hue;
                }
                else
                {
                    hue = 0;
                }
            }
            else
            {
                saturation = hue = 0;
            }

            brightness = hi / 255.0f;
        }

        Colour toColour (Colour original) const noexcept
        {
            return Colour (hue, saturation, brightness, original.getAlpha());
        }

        static PixelARGB toRGB (float h, float s, float v, const uint8 alpha) noexcept
        {
            v = jlimit (0.0f, 255.0f, v * 255.0f);
            const uint8 intV = (uint8) roundToInt (v);

            if (s <= 0)
                return PixelARGB (alpha, intV, intV, intV);

            s = jmin (1.0f, s);
            h = (h - std::floor (h)) * 6.0f + 0.00001f; // need a small adjustment to compensate for rounding errors
            const float f = h - std::floor (h);
            const uint8 x = (uint8) roundToInt (v * (1.0f - s));

            if (h < 1.0f)   return PixelARGB (alpha, intV,    (uint8) roundToInt (v * (1.0f - (s * (1.0f - f)))), x);
            if (h < 2.0f)   return PixelARGB (alpha,          (uint8) roundToInt (v * (1.0f - s * f)), intV, x);
            if (h < 3.0f)   return PixelARGB (alpha, x, intV, (uint8) roundToInt (v * (1.0f - (s * (1.0f - f)))));
            if (h < 4.0f)   return PixelARGB (alpha, x,       (uint8) roundToInt (v * (1.0f - s * f)), intV);
            if (h < 5.0f)   return PixelARGB (alpha,          (uint8) roundToInt (v * (1.0f - (s * (1.0f - f)))), x, intV);
            return                 PixelARGB (alpha, intV, x, (uint8) roundToInt (v * (1.0f - s * f)));
        }

        float hue, saturation, brightness;
    };

    //==============================================================================
    struct YIQ
    {
        YIQ (Colour c) noexcept
        {
            const float r = c.getFloatRed();
            const float g = c.getFloatGreen();
            const float b = c.getFloatBlue();

            y = 0.2999f * r + 0.5870f * g + 0.1140f * b;
            i = 0.5957f * r - 0.2744f * g - 0.3212f * b;
            q = 0.2114f * r - 0.5225f * g - 0.3113f * b;
            alpha = c.getFloatAlpha();
        }

        Colour toColour() const noexcept
        {
            return Colour::fromFloatRGBA (y + 0.9563f * i + 0.6210f * q,
                                          y - 0.2721f * i - 0.6474f * q,
                                          y - 1.1070f * i + 1.7046f * q,
                                          alpha);
        }

        float y, i, q, alpha;
    };
}

//==============================================================================
bool Colour::operator== (const Colour& other) const noexcept    { return argb.getNativeARGB() == other.argb.getNativeARGB(); }
bool Colour::operator!= (const Colour& other) const noexcept    { return argb.getNativeARGB() != other.argb.getNativeARGB(); }

//==============================================================================
Colour::Colour (const uint32 col) noexcept
    : argb (static_cast<uint8> ((col >> 24) & 0xff),
            static_cast<uint8> ((col >> 16) & 0xff),
            static_cast<uint8> ((col >> 8) & 0xff),
            static_cast<uint8> (col & 0xff))
{
}

Colour::Colour (const uint8 red, const uint8 green, const uint8 blue) noexcept
{
    argb.setARGB (0xff, red, green, blue);
}

Colour Colour::fromRGB (const uint8 red, const uint8 green, const uint8 blue) noexcept
{
    return Colour (red, green, blue);
}

Colour::Colour (const uint8 red, const uint8 green, const uint8 blue, const uint8 alpha) noexcept
{
    argb.setARGB (alpha, red, green, blue);
}

Colour Colour::fromRGBA (const uint8 red, const uint8 green, const uint8 blue, const uint8 alpha) noexcept
{
    return Colour (red, green, blue, alpha);
}

Colour::Colour (const uint8 red, const uint8 green, const uint8 blue, const float alpha) noexcept
{
    argb.setARGB (ColourHelpers::floatToUInt8 (alpha), red, green, blue);
}

Colour Colour::fromFloatRGBA (const float red, const float green, const float blue, const float alpha) noexcept
{
    return Colour (ColourHelpers::floatToUInt8 (red),
                   ColourHelpers::floatToUInt8 (green),
                   ColourHelpers::floatToUInt8 (blue), alpha);
}

Colour::Colour (const float hue, const float saturation, const float brightness, const float alpha) noexcept
    : argb (ColourHelpers::HSB::toRGB (hue, saturation, brightness, ColourHelpers::floatToUInt8 (alpha)))
{
}

Colour Colour::fromHSV (const float hue, const float saturation, const float brightness, const float alpha) noexcept
{
    return Colour (hue, saturation, brightness, alpha);
}

Colour::Colour (const float hue, const float saturation, const float brightness, const uint8 alpha) noexcept
    : argb (ColourHelpers::HSB::toRGB (hue, saturation, brightness, alpha))
{
}

Colour::Colour (PixelARGB argb_) noexcept
    : argb (argb_)
{
}

Colour::Colour (PixelRGB rgb) noexcept
    : argb (Colour (rgb.getInARGBMaskOrder()).argb)
{
}

Colour::Colour (PixelAlpha alpha) noexcept
    : argb (Colour (alpha.getInARGBMaskOrder()).argb)
{
}

//==============================================================================
const PixelARGB Colour::getPixelARGB() const noexcept
{
    PixelARGB p (argb);
    p.premultiply();
    return p;
}

uint32 Colour::getARGB() const noexcept
{
    return argb.getInARGBMaskOrder();
}

//==============================================================================
bool Colour::isTransparent() const noexcept
{
    return getAlpha() == 0;
}

bool Colour::isOpaque() const noexcept
{
    return getAlpha() == 0xff;
}

Colour Colour::withAlpha (const uint8 newAlpha) const noexcept
{
    PixelARGB newCol (argb);
    newCol.setAlpha (newAlpha);
    return Colour (newCol);
}

Colour Colour::withAlpha (const float newAlpha) const noexcept
{
    jassert (newAlpha >= 0 && newAlpha <= 1.0f);

    PixelARGB newCol (argb);
    newCol.setAlpha (ColourHelpers::floatToUInt8 (newAlpha));
    return Colour (newCol);
}

Colour Colour::withMultipliedAlpha (const float alphaMultiplier) const noexcept
{
    jassert (alphaMultiplier >= 0);

    PixelARGB newCol (argb);
    newCol.setAlpha ((uint8) jmin (0xff, roundToInt (alphaMultiplier * newCol.getAlpha())));
    return Colour (newCol);
}

//==============================================================================
Colour Colour::overlaidWith (Colour src) const noexcept
{
    const int destAlpha = getAlpha();

    if (destAlpha <= 0)
        return src;

    const int invA = 0xff - (int) src.getAlpha();
    const int resA = 0xff - (((0xff - destAlpha) * invA) >> 8);

    if (resA <= 0)
        return *this;

    const int da = (invA * destAlpha) / resA;

    return Colour ((uint8) (src.getRed()   + ((((int) getRed()   - src.getRed())   * da) >> 8)),
                   (uint8) (src.getGreen() + ((((int) getGreen() - src.getGreen()) * da) >> 8)),
                   (uint8) (src.getBlue()  + ((((int) getBlue()  - src.getBlue())  * da) >> 8)),
                   (uint8) resA);
}

Colour Colour::interpolatedWith (Colour other, float proportionOfOther) const noexcept
{
    if (proportionOfOther <= 0)
        return *this;

    if (proportionOfOther >= 1.0f)
        return other;

    PixelARGB c1 (getPixelARGB());
    const PixelARGB c2 (other.getPixelARGB());
    c1.tween (c2, (uint32) roundToInt (proportionOfOther * 255.0f));
    c1.unpremultiply();

    return Colour (c1);
}

//==============================================================================
float Colour::getFloatRed() const noexcept      { return getRed()   / 255.0f; }
float Colour::getFloatGreen() const noexcept    { return getGreen() / 255.0f; }
float Colour::getFloatBlue() const noexcept     { return getBlue()  / 255.0f; }
float Colour::getFloatAlpha() const noexcept    { return getAlpha() / 255.0f; }

//==============================================================================
void Colour::getHSB (float& h, float& s, float& v) const noexcept
{
    const ColourHelpers::HSB hsb (*this);
    h = hsb.hue;
    s = hsb.saturation;
    v = hsb.brightness;
}

float Colour::getHue() const noexcept           { return ColourHelpers::HSB (*this).hue; }
float Colour::getSaturation() const noexcept    { return ColourHelpers::HSB (*this).saturation; }
float Colour::getBrightness() const noexcept    { return ColourHelpers::HSB (*this).brightness; }

Colour Colour::withHue (float h) const noexcept          { ColourHelpers::HSB hsb (*this); hsb.hue = h;        return hsb.toColour (*this); }
Colour Colour::withSaturation (float s) const noexcept   { ColourHelpers::HSB hsb (*this); hsb.saturation = s; return hsb.toColour (*this); }
Colour Colour::withBrightness (float v) const noexcept   { ColourHelpers::HSB hsb (*this); hsb.brightness = v; return hsb.toColour (*this); }

float Colour::getPerceivedBrightness() const noexcept
{
    return std::sqrt (0.241f * square (getFloatRed())
                    + 0.691f * square (getFloatGreen())
                    + 0.068f * square (getFloatBlue()));
}

//==============================================================================
Colour Colour::withRotatedHue (const float amountToRotate) const noexcept
{
    ColourHelpers::HSB hsb (*this);
    hsb.hue += amountToRotate;
    return hsb.toColour (*this);
}

Colour Colour::withMultipliedSaturation (const float amount) const noexcept
{
    ColourHelpers::HSB hsb (*this);
    hsb.saturation = jmin (1.0f, hsb.saturation * amount);
    return hsb.toColour (*this);
}

Colour Colour::withMultipliedBrightness (const float amount) const noexcept
{
    ColourHelpers::HSB hsb (*this);
    hsb.brightness = jmin (1.0f, hsb.brightness * amount);
    return hsb.toColour (*this);
}

//==============================================================================
Colour Colour::brighter (float amount) const noexcept
{
    amount = 1.0f / (1.0f + amount);

    return Colour ((uint8) (255 - (amount * (255 - getRed()))),
                   (uint8) (255 - (amount * (255 - getGreen()))),
                   (uint8) (255 - (amount * (255 - getBlue()))),
                   getAlpha());
}

Colour Colour::darker (float amount) const noexcept
{
    amount = 1.0f / (1.0f + amount);

    return Colour ((uint8) (amount * getRed()),
                   (uint8) (amount * getGreen()),
                   (uint8) (amount * getBlue()),
                   getAlpha());
}

//==============================================================================
Colour Colour::greyLevel (const float brightness) noexcept
{
    const uint8 level = ColourHelpers::floatToUInt8 (brightness);
    return Colour (level, level, level);
}

//==============================================================================
Colour Colour::contrasting (const float amount) const noexcept
{
   return overlaidWith ((getPerceivedBrightness() >= 0.5f
                           ? Colours::black
                           : Colours::white).withAlpha (amount));
}

Colour Colour::contrasting (Colour target, float minContrast) const noexcept
{
    const ColourHelpers::YIQ bg (*this);
    ColourHelpers::YIQ fg (target);

    if (std::abs (bg.y - fg.y) >= minContrast)
        return target;

    const float y1 = jmax (0.0f, bg.y - minContrast);
    const float y2 = jmin (1.0f, bg.y + minContrast);
    fg.y = (std::abs (y1 - bg.y) > std::abs (y2 - bg.y)) ? y1 : y2;

    return fg.toColour();
}

Colour Colour::contrasting (Colour colour1,
                            Colour colour2) noexcept
{
    const float b1 = colour1.getPerceivedBrightness();
    const float b2 = colour2.getPerceivedBrightness();
    float best = 0.0f;
    float bestDist = 0.0f;

    for (float i = 0.0f; i < 1.0f; i += 0.02f)
    {
        const float d1 = std::abs (i - b1);
        const float d2 = std::abs (i - b2);
        const float dist = jmin (d1, d2, 1.0f - d1, 1.0f - d2);

        if (dist > bestDist)
        {
            best = i;
            bestDist = dist;
        }
    }

    return colour1.overlaidWith (colour2.withMultipliedAlpha (0.5f))
                  .withBrightness (best);
}

//==============================================================================
String Colour::toString() const
{
    return String::toHexString ((int) argb.getInARGBMaskOrder());
}

Colour Colour::fromString (StringRef encodedColourString)
{
    return Colour ((uint32) CharacterFunctions::HexParser<int>::parse (encodedColourString.text));
}

String Colour::toDisplayString (const bool includeAlphaValue) const
{
    return String::toHexString ((int) (argb.getInARGBMaskOrder() & (includeAlphaValue ? 0xffffffff : 0xffffff)))
                  .paddedLeft ('0', includeAlphaValue ? 8 : 6)
                  .toUpperCase();
}

} // namespace juce