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

   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.

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

namespace juce
{

struct ColourComponentSlider  : public Slider
{
    ColourComponentSlider (const String& name)  : Slider (name)
    {
        setRange (0.0, 255.0, 1.0);
    }

    String getTextFromValue (double value) override
    {
        return String::toHexString ((int) value).toUpperCase().paddedLeft ('0', 2);
    }

    double getValueFromText (const String& text) override
    {
        return (double) text.getHexValue32();
    }
};

//==============================================================================
class ColourSelector::ColourSpaceView  : public Component
{
public:
    ColourSpaceView (ColourSelector& cs, float& hue, float& sat, float& val, int edgeSize)
        : owner (cs), h (hue), s (sat), v (val), edge (edgeSize)
    {
        addAndMakeVisible (marker);
        setMouseCursor (MouseCursor::CrosshairCursor);
    }

    void paint (Graphics& g) override
    {
        if (colours.isNull())
        {
            auto width = getWidth() / 2;
            auto height = getHeight() / 2;
            colours = Image (Image::RGB, width, height, false);

            Image::BitmapData pixels (colours, Image::BitmapData::writeOnly);

            for (int y = 0; y < height; ++y)
            {
                auto val = 1.0f - y / (float) height;

                for (int x = 0; x < width; ++x)
                {
                    auto sat = x / (float) width;
                    pixels.setPixelColour (x, y, Colour (h, sat, val, 1.0f));
                }
            }
        }

        g.setOpacity (1.0f);
        g.drawImageTransformed (colours,
                                RectanglePlacement (RectanglePlacement::stretchToFit)
                                    .getTransformToFit (colours.getBounds().toFloat(),
                                                        getLocalBounds().reduced (edge).toFloat()),
                                false);
    }

    void mouseDown (const MouseEvent& e) override
    {
        mouseDrag (e);
    }

    void mouseDrag (const MouseEvent& e) override
    {
        auto sat =        (e.x - edge) / (float) (getWidth()  - edge * 2);
        auto val = 1.0f - (e.y - edge) / (float) (getHeight() - edge * 2);

        owner.setSV (sat, val);
    }

    void updateIfNeeded()
    {
        if (lastHue != h)
        {
            lastHue = h;
            colours = {};
            repaint();
        }

        updateMarker();
    }

    void resized() override
    {
        colours = {};
        updateMarker();
    }

private:
    ColourSelector& owner;
    float& h;
    float& s;
    float& v;
    float lastHue = 0;
    const int edge;
    Image colours;

    struct ColourSpaceMarker  : public Component
    {
        ColourSpaceMarker()
        {
            setInterceptsMouseClicks (false, false);
        }

        void paint (Graphics& g) override
        {
            g.setColour (Colour::greyLevel (0.1f));
            g.drawEllipse (1.0f, 1.0f, getWidth() - 2.0f, getHeight() - 2.0f, 1.0f);
            g.setColour (Colour::greyLevel (0.9f));
            g.drawEllipse (2.0f, 2.0f, getWidth() - 4.0f, getHeight() - 4.0f, 1.0f);
        }
    };

    ColourSpaceMarker marker;

    void updateMarker()
    {
        auto markerSize = jmax (14, edge * 2);
        auto area = getLocalBounds().reduced (edge);

        marker.setBounds (Rectangle<int> (markerSize, markerSize)
                            .withCentre (area.getRelativePoint (s, 1.0f - v)));
    }

    JUCE_DECLARE_NON_COPYABLE (ColourSpaceView)
};

//==============================================================================
class ColourSelector::HueSelectorComp  : public Component
{
public:
    HueSelectorComp (ColourSelector& cs, float& hue, int edgeSize)
        : owner (cs), h (hue), edge (edgeSize)
    {
        addAndMakeVisible (marker);
    }

    void paint (Graphics& g) override
    {
        ColourGradient cg;
        cg.isRadial = false;
        cg.point1.setXY (0.0f, (float) edge);
        cg.point2.setXY (0.0f, (float) getHeight());

        for (float i = 0.0f; i <= 1.0f; i += 0.02f)
            cg.addColour (i, Colour (i, 1.0f, 1.0f, 1.0f));

        g.setGradientFill (cg);
        g.fillRect (getLocalBounds().reduced (edge));
    }

    void resized() override
    {
        auto markerSize = jmax (14, edge * 2);
        auto area = getLocalBounds().reduced (edge);

        marker.setBounds (Rectangle<int> (getWidth(), markerSize)
                            .withCentre (area.getRelativePoint (0.5f, h)));
    }

    void mouseDown (const MouseEvent& e) override
    {
        mouseDrag (e);
    }

    void mouseDrag (const MouseEvent& e) override
    {
        owner.setHue ((e.y - edge) / (float) (getHeight() - edge * 2));
    }

    void updateIfNeeded()
    {
        resized();
    }

private:
    ColourSelector& owner;
    float& h;
    const int edge;

    struct HueSelectorMarker  : public Component
    {
        HueSelectorMarker()
        {
            setInterceptsMouseClicks (false, false);
        }

        void paint (Graphics& g) override
        {
            auto cw = (float) getWidth();
            auto ch = (float) getHeight();

            Path p;
            p.addTriangle (1.0f, 1.0f,
                           cw * 0.3f, ch * 0.5f,
                           1.0f, ch - 1.0f);

            p.addTriangle (cw - 1.0f, 1.0f,
                           cw * 0.7f, ch * 0.5f,
                           cw - 1.0f, ch - 1.0f);

            g.setColour (Colours::white.withAlpha (0.75f));
            g.fillPath (p);

            g.setColour (Colours::black.withAlpha (0.75f));
            g.strokePath (p, PathStrokeType (1.2f));
        }
    };

    HueSelectorMarker marker;

    JUCE_DECLARE_NON_COPYABLE (HueSelectorComp)
};

//==============================================================================
class ColourSelector::SwatchComponent   : public Component
{
public:
    SwatchComponent (ColourSelector& cs, int itemIndex)
        : owner (cs), index (itemIndex)
    {
    }

    void paint (Graphics& g) override
    {
        auto col = owner.getSwatchColour (index);

        g.fillCheckerBoard (getLocalBounds().toFloat(), 6.0f, 6.0f,
                            Colour (0xffdddddd).overlaidWith (col),
                            Colour (0xffffffff).overlaidWith (col));
    }

    void mouseDown (const MouseEvent&) override
    {
        PopupMenu m;
        m.addItem (1, TRANS("Use this swatch as the current colour"));
        m.addSeparator();
        m.addItem (2, TRANS("Set this swatch to the current colour"));

        m.showMenuAsync (PopupMenu::Options().withTargetComponent (this),
                         ModalCallbackFunction::forComponent (menuStaticCallback, this));
    }

private:
    ColourSelector& owner;
    const int index;

    static void menuStaticCallback (int result, SwatchComponent* comp)
    {
        if (comp != nullptr)
        {
            if (result == 1)  comp->setColourFromSwatch();
            if (result == 2)  comp->setSwatchFromColour();
        }
    }

    void setColourFromSwatch()
    {
        owner.setCurrentColour (owner.getSwatchColour (index));
    }

    void setSwatchFromColour()
    {
        if (owner.getSwatchColour (index) != owner.getCurrentColour())
        {
            owner.setSwatchColour (index, owner.getCurrentColour());
            repaint();
        }
    }

    JUCE_DECLARE_NON_COPYABLE (SwatchComponent)
};

//==============================================================================
ColourSelector::ColourSelector (int sectionsToShow, int edge, int gapAroundColourSpaceComponent)
    : colour (Colours::white),
      flags (sectionsToShow),
      edgeGap (edge)
{
    // not much point having a selector with no components in it!
    jassert ((flags & (showColourAtTop | showSliders | showColourspace)) != 0);

    updateHSV();

    if ((flags & showSliders) != 0)
    {
        sliders[0].reset (new ColourComponentSlider (TRANS ("red")));
        sliders[1].reset (new ColourComponentSlider (TRANS ("green")));
        sliders[2].reset (new ColourComponentSlider (TRANS ("blue")));
        sliders[3].reset (new ColourComponentSlider (TRANS ("alpha")));

        addAndMakeVisible (sliders[0].get());
        addAndMakeVisible (sliders[1].get());
        addAndMakeVisible (sliders[2].get());
        addChildComponent (sliders[3].get());

        sliders[3]->setVisible ((flags & showAlphaChannel) != 0);

        for (auto& slider : sliders)
        { // braces needed here to avoid a VS2013 compiler bug
            slider->onValueChange = [this] { changeColour(); };
        }
    }

    if ((flags & showColourspace) != 0)
    {
        colourSpace.reset (new ColourSpaceView (*this, h, s, v, gapAroundColourSpaceComponent));
        hueSelector.reset (new HueSelectorComp (*this, h, gapAroundColourSpaceComponent));

        addAndMakeVisible (colourSpace.get());
        addAndMakeVisible (hueSelector.get());
    }

    update (dontSendNotification);
}

ColourSelector::~ColourSelector()
{
    dispatchPendingMessages();
    swatchComponents.clear();
}

//==============================================================================
Colour ColourSelector::getCurrentColour() const
{
    return ((flags & showAlphaChannel) != 0) ? colour : colour.withAlpha ((uint8) 0xff);
}

void ColourSelector::setCurrentColour (Colour c, NotificationType notification)
{
    if (c != colour)
    {
        colour = ((flags & showAlphaChannel) != 0) ? c : c.withAlpha ((uint8) 0xff);

        updateHSV();
        update (notification);
    }
}

void ColourSelector::setHue (float newH)
{
    newH = jlimit (0.0f, 1.0f, newH);

    if (h != newH)
    {
        h = newH;
        colour = Colour (h, s, v, colour.getFloatAlpha());
        update (sendNotification);
    }
}

void ColourSelector::setSV (float newS, float newV)
{
    newS = jlimit (0.0f, 1.0f, newS);
    newV = jlimit (0.0f, 1.0f, newV);

    if (s != newS || v != newV)
    {
        s = newS;
        v = newV;
        colour = Colour (h, s, v, colour.getFloatAlpha());
        update (sendNotification);
    }
}

//==============================================================================
void ColourSelector::updateHSV()
{
    colour.getHSB (h, s, v);
}

void ColourSelector::update (NotificationType notification)
{
    if (sliders[0] != nullptr)
    {
        sliders[0]->setValue ((int) colour.getRed(),   notification);
        sliders[1]->setValue ((int) colour.getGreen(), notification);
        sliders[2]->setValue ((int) colour.getBlue(),  notification);
        sliders[3]->setValue ((int) colour.getAlpha(), notification);
    }

    if (colourSpace != nullptr)
    {
        colourSpace->updateIfNeeded();
        hueSelector->updateIfNeeded();
    }

    if ((flags & showColourAtTop) != 0)
        repaint (previewArea);

    if (notification != dontSendNotification)
        sendChangeMessage();

    if (notification == sendNotificationSync)
        dispatchPendingMessages();
}

//==============================================================================
void ColourSelector::paint (Graphics& g)
{
    g.fillAll (findColour (backgroundColourId));

    if ((flags & showColourAtTop) != 0)
    {
        auto currentColour = getCurrentColour();

        g.fillCheckerBoard (previewArea.toFloat(), 10.0f, 10.0f,
                            Colour (0xffdddddd).overlaidWith (currentColour),
                            Colour (0xffffffff).overlaidWith (currentColour));

        g.setColour (Colours::white.overlaidWith (currentColour).contrasting());
        g.setFont (Font (14.0f, Font::bold));
        g.drawText (currentColour.toDisplayString ((flags & showAlphaChannel) != 0),
                    previewArea, Justification::centred, false);
    }

    if ((flags & showSliders) != 0)
    {
        g.setColour (findColour (labelTextColourId));
        g.setFont (11.0f);

        for (auto& slider : sliders)
        {
            if (slider->isVisible())
                g.drawText (slider->getName() + ":",
                            0, slider->getY(),
                            slider->getX() - 8, slider->getHeight(),
                            Justification::centredRight, false);
        }
    }
}

void ColourSelector::resized()
{
    const int swatchesPerRow = 8;
    const int swatchHeight = 22;

    const int numSliders = ((flags & showAlphaChannel) != 0) ? 4 : 3;
    const int numSwatches = getNumSwatches();

    const int swatchSpace = numSwatches > 0 ? edgeGap + swatchHeight * ((numSwatches + 7) / swatchesPerRow) : 0;
    const int sliderSpace = ((flags & showSliders) != 0)  ? jmin (22 * numSliders + edgeGap, proportionOfHeight (0.3f)) : 0;
    const int topSpace = ((flags & showColourAtTop) != 0) ? jmin (30 + edgeGap * 2, proportionOfHeight (0.2f)) : edgeGap;

    previewArea.setBounds (edgeGap, edgeGap, getWidth() - edgeGap * 2, topSpace - edgeGap * 2);

    int y = topSpace;

    if ((flags & showColourspace) != 0)
    {
        const int hueWidth = jmin (50, proportionOfWidth (0.15f));

        colourSpace->setBounds (edgeGap, y,
                                getWidth() - hueWidth - edgeGap - 4,
                                getHeight() - topSpace - sliderSpace - swatchSpace - edgeGap);

        hueSelector->setBounds (colourSpace->getRight() + 4, y,
                                getWidth() - edgeGap - (colourSpace->getRight() + 4),
                                colourSpace->getHeight());

        y = getHeight() - sliderSpace - swatchSpace - edgeGap;
    }

    if ((flags & showSliders) != 0)
    {
        auto sliderHeight = jmax (4, sliderSpace / numSliders);

        for (int i = 0; i < numSliders; ++i)
        {
            sliders[i]->setBounds (proportionOfWidth (0.2f), y,
                                   proportionOfWidth (0.72f), sliderHeight - 2);

            y += sliderHeight;
        }
    }

    if (numSwatches > 0)
    {
        const int startX = 8;
        const int xGap = 4;
        const int yGap = 4;
        const int swatchWidth = (getWidth() - startX * 2) / swatchesPerRow;
        y += edgeGap;

        if (swatchComponents.size() != numSwatches)
        {
            swatchComponents.clear();

            for (int i = 0; i < numSwatches; ++i)
            {
                auto* sc = new SwatchComponent (*this, i);
                swatchComponents.add (sc);
                addAndMakeVisible (sc);
            }
        }

        int x = startX;

        for (int i = 0; i < swatchComponents.size(); ++i)
        {
            auto* sc = swatchComponents.getUnchecked(i);

            sc->setBounds (x + xGap / 2,
                           y + yGap / 2,
                           swatchWidth - xGap,
                           swatchHeight - yGap);

            if (((i + 1) % swatchesPerRow) == 0)
            {
                x = startX;
                y += swatchHeight;
            }
            else
            {
                x += swatchWidth;
            }
        }
    }
}

void ColourSelector::changeColour()
{
    if (sliders[0] != nullptr)
        setCurrentColour (Colour ((uint8) sliders[0]->getValue(),
                                  (uint8) sliders[1]->getValue(),
                                  (uint8) sliders[2]->getValue(),
                                  (uint8) sliders[3]->getValue()));
}

//==============================================================================
int ColourSelector::getNumSwatches() const
{
    return 0;
}

Colour ColourSelector::getSwatchColour (int) const
{
    jassertfalse; // if you've overridden getNumSwatches(), you also need to implement this method
    return Colours::black;
}

void ColourSelector::setSwatchColour (int, const Colour&)
{
    jassertfalse; // if you've overridden getNumSwatches(), you also need to implement this method
}

} // namespace juce
