#include "AudioLevelMeter.h"

#include <QPainter>

#include <algorithm>

AudioLevelMeter::AudioLevelMeter(QWidget *parent) : QWidget(parent) {
  setAutoFillBackground(false);
  setAttribute(Qt::WA_OpaquePaintEvent);
}

void AudioLevelMeter::setLevel(float level) {
  m_level = std::clamp(level, 0.0f, 1.0f);

  if (m_level >= m_peakHold) {
    m_peakHold = m_level;
    m_peakHoldFrames = 0;
  } else {
    ++m_peakHoldFrames;
    if (m_peakHoldFrames > kPeakHoldDuration) {
      m_peakHold = std::max(0.0f, m_peakHold - kPeakDecayRate);
    }
  }

  update();
}

float AudioLevelMeter::level() const { return m_level; }

float AudioLevelMeter::peakHold() const { return m_peakHold; }

void AudioLevelMeter::resetPeakHold() {
  m_peakHold = 0.0f;
  m_peakHoldFrames = 0;
  update();
}

QSize AudioLevelMeter::sizeHint() const { return {40, 160}; }

QSize AudioLevelMeter::minimumSizeHint() const { return {12, 40}; }

void AudioLevelMeter::paintEvent(QPaintEvent *) {
  QPainter painter(this);
  painter.setRenderHint(QPainter::Antialiasing, false);

  QRect r = rect();
  painter.fillRect(r, QColor(24, 24, 28));

  if (m_level <= 0.0f && m_peakHold <= 0.0f)
    return;

  int barHeight = static_cast<int>(m_level * r.height());
  int barTop = r.height() - barHeight;

  if (barHeight > 0) {
    float greenEnd = 0.7f * r.height();
    float yellowEnd = 0.9f * r.height();

    int greenH = std::min(barHeight, static_cast<int>(greenEnd));
    if (greenH > 0) {
      painter.fillRect(r.left(), r.bottom() - greenH + 1, r.width(), greenH,
                       QColor(76, 175, 80));
    }

    if (barHeight > static_cast<int>(greenEnd)) {
      int yellowH =
          std::min(barHeight - static_cast<int>(greenEnd),
                   static_cast<int>(yellowEnd) - static_cast<int>(greenEnd));
      if (yellowH > 0) {
        painter.fillRect(r.left(), r.bottom() - static_cast<int>(greenEnd) - yellowH + 1,
                         r.width(), yellowH, QColor(255, 193, 7));
      }
    }

    if (barHeight > static_cast<int>(yellowEnd)) {
      int redH = barHeight - static_cast<int>(yellowEnd);
      if (redH > 0) {
        painter.fillRect(r.left(), barTop, r.width(), redH,
                         QColor(244, 67, 54));
      }
    }
  }

  if (m_peakHold > 0.0f) {
    int peakY = r.height() - static_cast<int>(m_peakHold * r.height());
    peakY = std::clamp(peakY, r.top(), r.bottom());
    painter.setPen(QColor(255, 255, 255));
    painter.drawLine(r.left(), peakY, r.right(), peakY);
  }
}