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

   This file is part of the JUCE 7 technical preview.
   Copyright (c) 2022 - Raw Material Software Limited

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

   For the technical preview this file cannot be licensed commercially.

   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
{

constexpr uint8 whiteNotes[] = { 0, 2, 4, 5, 7, 9, 11 };
constexpr uint8 blackNotes[] = { 1, 3, 6, 8, 10 };

//==============================================================================
struct KeyboardComponentBase::UpDownButton  : public Button
{
    UpDownButton (KeyboardComponentBase& c, int d)
        : Button ({}), owner (c), delta (d)
    {
    }

    void clicked() override
    {
        auto note = owner.getLowestVisibleKey();

        note = delta < 0 ? (note - 1) / 12 : note / 12 + 1;

        owner.setLowestVisibleKey (note * 12);
    }

    using Button::clicked;

    void paintButton (Graphics& g, bool shouldDrawButtonAsHighlighted, bool shouldDrawButtonAsDown) override
    {
        owner.drawUpDownButton (g, getWidth(), getHeight(),
                                shouldDrawButtonAsHighlighted, shouldDrawButtonAsDown,
                                delta > 0);
    }

private:
    KeyboardComponentBase& owner;
    int delta;

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (UpDownButton)
};

//==============================================================================
KeyboardComponentBase::KeyboardComponentBase (Orientation o)  : orientation (o)
{
    scrollDown = std::make_unique<UpDownButton> (*this, -1);
    scrollUp   = std::make_unique<UpDownButton> (*this, 1);

    addChildComponent (*scrollDown);
    addChildComponent (*scrollUp);

    colourChanged();
}

//==============================================================================
void KeyboardComponentBase::setKeyWidth (float widthInPixels)
{
    jassert (widthInPixels > 0);

    if (keyWidth != widthInPixels) // Prevent infinite recursion if the width is being computed in a 'resized()' callback
    {
        keyWidth = widthInPixels;
        resized();
    }
}

void KeyboardComponentBase::setScrollButtonWidth (int widthInPixels)
{
    jassert (widthInPixels > 0);

    if (scrollButtonWidth != widthInPixels)
    {
        scrollButtonWidth = widthInPixels;
        resized();
    }
}

void KeyboardComponentBase::setOrientation (Orientation newOrientation)
{
    if (orientation != newOrientation)
    {
        orientation = newOrientation;
        resized();
    }
}

void KeyboardComponentBase::setAvailableRange (int lowestNote, int highestNote)
{
    jassert (lowestNote >= 0 && lowestNote <= 127);
    jassert (highestNote >= 0 && highestNote <= 127);
    jassert (lowestNote <= highestNote);

    if (rangeStart != lowestNote || rangeEnd != highestNote)
    {
        rangeStart = jlimit (0, 127, lowestNote);
        rangeEnd = jlimit (0, 127, highestNote);
        firstKey = jlimit ((float) rangeStart, (float) rangeEnd, firstKey);
        resized();
    }
}

void KeyboardComponentBase::setLowestVisibleKey (int noteNumber)
{
    setLowestVisibleKeyFloat ((float) noteNumber);
}

void KeyboardComponentBase::setLowestVisibleKeyFloat (float noteNumber)
{
    noteNumber = jlimit ((float) rangeStart, (float) rangeEnd, noteNumber);

    if (noteNumber != firstKey)
    {
        bool hasMoved = (((int) firstKey) != (int) noteNumber);
        firstKey = noteNumber;

        if (hasMoved)
            sendChangeMessage();

        resized();
    }
}

float KeyboardComponentBase::getWhiteNoteLength() const noexcept
{
    return (orientation == horizontalKeyboard) ? (float) getHeight() : (float) getWidth();
}

void KeyboardComponentBase::setBlackNoteLengthProportion (float ratio) noexcept
{
    jassert (ratio >= 0.0f && ratio <= 1.0f);

    if (blackNoteLengthRatio != ratio)
    {
        blackNoteLengthRatio = ratio;
        resized();
    }
}

float KeyboardComponentBase::getBlackNoteLength() const noexcept
{
    auto whiteNoteLength = orientation == horizontalKeyboard ? getHeight() : getWidth();
    return (float) whiteNoteLength * blackNoteLengthRatio;
}

void KeyboardComponentBase::setBlackNoteWidthProportion (float ratio) noexcept
{
    jassert (ratio >= 0.0f && ratio <= 1.0f);

    if (blackNoteWidthRatio != ratio)
    {
        blackNoteWidthRatio = ratio;
        resized();
    }
}

void KeyboardComponentBase::setScrollButtonsVisible (bool newCanScroll)
{
    if (canScroll != newCanScroll)
    {
        canScroll = newCanScroll;
        resized();
    }
}

//==============================================================================
Range<float> KeyboardComponentBase::getKeyPos (int midiNoteNumber) const
{
    return getKeyPosition (midiNoteNumber, keyWidth)
             - xOffset
             - getKeyPosition (rangeStart, keyWidth).getStart();
}

float KeyboardComponentBase::getKeyStartPosition (int midiNoteNumber) const
{
    return getKeyPos (midiNoteNumber).getStart();
}

float KeyboardComponentBase::getTotalKeyboardWidth() const noexcept
{
    return getKeyPos (rangeEnd).getEnd();
}

KeyboardComponentBase::NoteAndVelocity KeyboardComponentBase::getNoteAndVelocityAtPosition (Point<float> pos, bool children)
{
    if (! reallyContains (pos, children))
        return { -1, 0.0f };

    auto p = pos;

    if (orientation != horizontalKeyboard)
    {
        p = { p.y, p.x };

        if (orientation == verticalKeyboardFacingLeft)
            p = { p.x, (float) getWidth() - p.y };
        else
            p = { (float) getHeight() - p.x, p.y };
    }

    return remappedXYToNote (p + Point<float> (xOffset, 0));
}

KeyboardComponentBase::NoteAndVelocity KeyboardComponentBase::remappedXYToNote (Point<float> pos) const
{
    auto blackNoteLength = getBlackNoteLength();

    if (pos.getY() < blackNoteLength)
    {
        for (int octaveStart = 12 * (rangeStart / 12); octaveStart <= rangeEnd; octaveStart += 12)
        {
            for (int i = 0; i < 5; ++i)
            {
                auto note = octaveStart + blackNotes[i];

                if (rangeStart <= note && note <= rangeEnd)
                {
                    if (getKeyPos (note).contains (pos.x - xOffset))
                    {
                        return { note, jmax (0.0f, pos.y / blackNoteLength) };
                    }
                }
            }
        }
    }

    for (int octaveStart = 12 * (rangeStart / 12); octaveStart <= rangeEnd; octaveStart += 12)
    {
        for (int i = 0; i < 7; ++i)
        {
            auto note = octaveStart + whiteNotes[i];

            if (note >= rangeStart && note <= rangeEnd)
            {
                if (getKeyPos (note).contains (pos.x - xOffset))
                {
                    auto whiteNoteLength = (orientation == horizontalKeyboard) ? getHeight() : getWidth();
                    return { note, jmax (0.0f, pos.y / (float) whiteNoteLength) };
                }
            }
        }
    }

    return { -1, 0 };
}

Rectangle<float> KeyboardComponentBase::getRectangleForKey (int note) const
{
    jassert (note >= rangeStart && note <= rangeEnd);

    auto pos = getKeyPos (note);
    auto x = pos.getStart();
    auto w = pos.getLength();

    if (MidiMessage::isMidiNoteBlack (note))
    {
        auto blackNoteLength = getBlackNoteLength();

        switch (orientation)
        {
            case horizontalKeyboard:            return { x, 0, w, blackNoteLength };
            case verticalKeyboardFacingLeft:    return { (float) getWidth() - blackNoteLength, x, blackNoteLength, w };
            case verticalKeyboardFacingRight:   return { 0, (float) getHeight() - x - w, blackNoteLength, w };
            default:                            jassertfalse; break;
        }
    }
    else
    {
        switch (orientation)
        {
            case horizontalKeyboard:            return { x, 0, w, (float) getHeight() };
            case verticalKeyboardFacingLeft:    return { 0, x, (float) getWidth(), w };
            case verticalKeyboardFacingRight:   return { 0, (float) getHeight() - x - w, (float) getWidth(), w };
            default:                            jassertfalse; break;
        }
    }

    return {};
}

//==============================================================================
void KeyboardComponentBase::setOctaveForMiddleC (int octaveNum)
{
    octaveNumForMiddleC = octaveNum;
    repaint();
}

//==============================================================================
void KeyboardComponentBase::drawUpDownButton (Graphics& g, int w, int h, bool mouseOver, bool buttonDown, bool movesOctavesUp)
{
    g.fillAll (findColour (upDownButtonBackgroundColourId));

    float angle = 0;

    switch (getOrientation())
    {
        case horizontalKeyboard:            angle = movesOctavesUp ? 0.0f  : 0.5f;  break;
        case verticalKeyboardFacingLeft:    angle = movesOctavesUp ? 0.25f : 0.75f; break;
        case verticalKeyboardFacingRight:   angle = movesOctavesUp ? 0.75f : 0.25f; break;
        default:                            jassertfalse; break;
    }

    Path path;
    path.addTriangle (0.0f, 0.0f, 0.0f, 1.0f, 1.0f, 0.5f);
    path.applyTransform (AffineTransform::rotation (MathConstants<float>::twoPi * angle, 0.5f, 0.5f));

    g.setColour (findColour (upDownButtonArrowColourId)
                  .withAlpha (buttonDown ? 1.0f : (mouseOver ? 0.6f : 0.4f)));

    g.fillPath (path, path.getTransformToScaleToFit (1.0f, 1.0f, (float) w - 2.0f, (float) h - 2.0f, true));
}

Range<float> KeyboardComponentBase::getKeyPosition (int midiNoteNumber, float targetKeyWidth) const
{
    auto ratio = getBlackNoteWidthProportion();

    static const float notePos[] = { 0.0f, 1 - ratio * 0.6f,
                                     1.0f, 2 - ratio * 0.4f,
                                     2.0f,
                                     3.0f, 4 - ratio * 0.7f,
                                     4.0f, 5 - ratio * 0.5f,
                                     5.0f, 6 - ratio * 0.3f,
                                     6.0f };

    auto octave = midiNoteNumber / 12;
    auto note   = midiNoteNumber % 12;

    auto start = (float) octave * 7.0f * targetKeyWidth + notePos[note] * targetKeyWidth;
    auto width = MidiMessage::isMidiNoteBlack (note) ? blackNoteWidthRatio * targetKeyWidth : targetKeyWidth;

    return { start, start + width };
}

//==============================================================================
void KeyboardComponentBase::paint (Graphics& g)
{
    drawKeyboardBackground (g, getLocalBounds().toFloat());

    for (int octaveBase = 0; octaveBase < 128; octaveBase += 12)
    {
        for (auto noteNum : whiteNotes)
        {
            const auto key = octaveBase + noteNum;

            if (rangeStart <= key && key <= rangeEnd)
                drawWhiteKey (key, g, getRectangleForKey (key));
        }

        for (auto noteNum : blackNotes)
        {
            const auto key = octaveBase + noteNum;

            if (rangeStart <= key && key <= rangeEnd)
                drawBlackKey (key, g, getRectangleForKey (key));
        }
    }
}

void KeyboardComponentBase::resized()
{
    auto w = getWidth();
    auto h = getHeight();

    if (w > 0 && h > 0)
    {
        if (orientation != horizontalKeyboard)
            std::swap (w, h);

        auto kx2 = getKeyPos (rangeEnd).getEnd();

        if ((int) firstKey != rangeStart)
        {
            auto kx1 = getKeyPos (rangeStart).getStart();

            if (kx2 - kx1 <= (float) w)
            {
                firstKey = (float) rangeStart;
                sendChangeMessage();
                repaint();
            }
        }

        scrollDown->setVisible (canScroll && firstKey > (float) rangeStart);

        xOffset = 0;

        if (canScroll)
        {
            auto scrollButtonW = jmin (scrollButtonWidth, w / 2);
            auto r = getLocalBounds();

            if (orientation == horizontalKeyboard)
            {
                scrollDown->setBounds (r.removeFromLeft  (scrollButtonW));
                scrollUp  ->setBounds (r.removeFromRight (scrollButtonW));
            }
            else if (orientation == verticalKeyboardFacingLeft)
            {
                scrollDown->setBounds (r.removeFromTop    (scrollButtonW));
                scrollUp  ->setBounds (r.removeFromBottom (scrollButtonW));
            }
            else
            {
                scrollDown->setBounds (r.removeFromBottom (scrollButtonW));
                scrollUp  ->setBounds (r.removeFromTop    (scrollButtonW));
            }

            auto endOfLastKey = getKeyPos (rangeEnd).getEnd();

            auto spaceAvailable = w;
            auto lastStartKey = remappedXYToNote ({ endOfLastKey - (float) spaceAvailable, 0 }).note + 1;

            if (lastStartKey >= 0 && ((int) firstKey) > lastStartKey)
            {
                firstKey = (float) jlimit (rangeStart, rangeEnd, lastStartKey);
                sendChangeMessage();
            }

            xOffset = getKeyPos ((int) firstKey).getStart();
        }
        else
        {
            firstKey = (float) rangeStart;
        }

        scrollUp->setVisible (canScroll && getKeyPos (rangeEnd).getStart() > (float) w);
        repaint();
    }
}

//==============================================================================
void KeyboardComponentBase::mouseWheelMove (const MouseEvent&, const MouseWheelDetails& wheel)
{
    auto amount = (orientation == horizontalKeyboard && wheel.deltaX != 0)
                       ? wheel.deltaX : (orientation == verticalKeyboardFacingLeft ? wheel.deltaY
                                                                                   : -wheel.deltaY);

    setLowestVisibleKeyFloat (firstKey - amount * keyWidth);
}

} // namespace juce