#include "EnvelopeDisplay.h"

namespace serum
{

void EnvelopeDisplay::setParams (float a, float d, float s, float r, float c)
{
    attack = a; decay = d; sustain = s; release = r; curve = c;
}

void EnvelopeDisplay::paint (juce::Graphics& g)
{
    const auto b = getLocalBounds().toFloat().reduced (4.0f);
    g.setColour (juce::Colours::black.withAlpha (0.4f));
    g.fillRoundedRectangle (b.expanded (4.0f), 4.0f);
    g.setColour (theme::outline);
    g.drawRoundedRectangle (b.expanded (4.0f).reduced (0.5f), 4.0f, 1.0f);

    const float atkShape = 0.3f + curve * 2.7f;
    const float decShape = 3.0f - curve * 2.7f;

    // Normalise durations for display (attack 0..1, decay 0..0.6, release 0..0.6).
    const float aSec = maps::toSeconds (attack);
    const float dSec = maps::toSeconds (decay);
    const float rSec = maps::toSeconds (release);
    const float total = aSec + dSec + rSec + 0.01f;
    const float ax = (aSec / total);
    const float dx = (dSec / total);
    const float rx = (rSec / total);

    const float left = b.getX();
    const float right = b.getRight();
    const float bottom = b.getBottom();
    const float top = b.getY();
    const float sustainY = bottom - sustain * b.getHeight();

    juce::Path path;
    path.startNewSubPath (left, bottom);
    path.lineTo (left, top);

    // Attack (curve-shaped).
    const int steps = 48;
    const float peakX = left + ax * b.getWidth();
    for (int i = 0; i <= steps; ++i)
    {
        const float p = (float) i / steps;
        const float y = top + (bottom - top) * std::pow (p, atkShape);
        path.lineTo (left + p * (peakX - left), y);
    }

    // Decay to sustain.
    const float decX = peakX + dx * b.getWidth();
    for (int i = 0; i <= steps; ++i)
    {
        const float p = (float) i / steps;
        const float y = sustainY + (bottom - sustainY) * std::pow (1.0f - p, decShape);
        path.lineTo (peakX + p * (decX - peakX), y);
    }
    path.lineTo (decX, sustainY);
    path.lineTo (right - rx * b.getWidth(), sustainY);

    // Release.
    const float relStartX = right - rx * b.getWidth();
    for (int i = 0; i <= steps; ++i)
    {
        const float p = (float) i / steps;
        const float y = sustainY + (bottom - sustainY) * std::pow (1.0f - p, decShape);
        path.lineTo (relStartX + p * (right - relStartX), y);
    }

    g.setColour (theme::accent2.withAlpha (0.3f));
    juce::Path fill = path;
    fill.lineTo (right, bottom);
    fill.closeSubPath();
    g.fillPath (fill);
    g.setColour (theme::accent2);
    g.strokePath (path, juce::PathStrokeType (1.5f));
}

} // namespace serum