#include "Visualization/SqpColorScale.h"

#include <Data/DataSeriesUtils.h>

#include <Visualization/QCPColorMapIterator.h>

Q_LOGGING_CATEGORY(LOG_SqpColorScale, "SqpColorScale")

namespace {

const auto DEFAULT_GRADIENT_PRESET = QCPColorGradient::gpJet;
const auto DEFAULT_RANGE = QCPRange{1.0e3, 1.7e7};

} // namespace

std::pair<double, double> SqpColorScale::computeThresholds(const SqpColorScale &scale)
{
    auto qcpScale = scale.m_Scale;

    auto colorMaps = qcpScale->colorMaps();
    if (colorMaps.size() != 1) {
        return {std::numeric_limits<double>::quiet_NaN(), std::numeric_limits<double>::quiet_NaN()};
    }

    // Computes thresholds
    auto isLogarithmicScale = qcpScale->dataScaleType() == QCPAxis::stLogarithmic;
    auto colorMapData = colorMaps.first()->data();
    QCPColorMapIterator begin{colorMapData, true};
    QCPColorMapIterator end{colorMapData, false};

    return DataSeriesUtils::thresholds(begin, end, isLogarithmicScale);
}

SqpColorScale::SqpColorScale(QCustomPlot &plot)
        : m_Scale{new QCPColorScale{&plot}},
          m_AutomaticThreshold{true},
          m_GradientPreset{DEFAULT_GRADIENT_PRESET}
{
    m_Scale->setGradient(m_GradientPreset);
    m_Scale->setDataRange(DEFAULT_RANGE);
}

void SqpColorScale::updateDataRange() noexcept
{
    // Updates data range only if mode is automatic
    if (!m_AutomaticThreshold) {
        return;
    }

    double minThreshold, maxThreshold;
    std::tie(minThreshold, maxThreshold) = computeThresholds(*this);
    if (std::isnan(minThreshold) || std::isnan(maxThreshold)) {
        qCCritical(LOG_SqpColorScale())
            << "Can't update data range of color scale: thresholds computed are invalid";
        return;
    }

    // Updates thresholds
    m_Scale->setDataRange({minThreshold, maxThreshold});
}