// SPDX-FileCopyrightText: Copyright (c) Kitware Inc.
// SPDX-FileCopyrightText: Copyright (c) Sandia Corporation
// SPDX-License-Identifier: BSD-3-Clause
#include "pqSeriesGeneratorDialog.h"
#include "ui_pqSeriesGeneratorDialog.h"

#include <QPushButton>
#include <QTextStream>

#include <cassert>
#include <cmath>

class pqSeriesGeneratorDialog::pqInternals
{
public:
  enum Mode
  {
    LINEAR,
    LOGARITHMIC,
    GEOMETRIC_SAMPLES,
    GEOMETRIC_RATIO,
  };
  Ui::SeriesGeneratorDialog Ui;
  double DataMin;
  double DataMax;

  bool validate();
  QVector<double> values() const;

  void highlightIfNeeded()
  {
    double min = this->Ui.min->text().toDouble();
    double max = this->Ui.max->text().toDouble();
    this->Ui.reset->highlight(min == this->DataMin && max == this->DataMax);
  }
};

//-----------------------------------------------------------------------------
bool pqSeriesGeneratorDialog::pqInternals::validate()
{
  auto& ui = this->Ui;
  const double start = ui.min->text().toDouble();
  const double end = ui.max->text().toDouble();
  const double min = std::min(start, end);
  const double max = std::max(start, end);

  QString msg;
  switch (ui.comboBox->currentIndex())
  {
    case LINEAR: // linear
      break;

    case LOGARITHMIC: // log
      if (min < 0.0 && max > 0.0)
      {
        msg = tr("Error: range cannot contain 0 for log.");
      }
      break;

    case GEOMETRIC_SAMPLES:
      if (start == 0.0 || end == 0.0)
      {
        msg = tr("Error: range cannot begin or end with 0 for a geometric series.");
      }
      else if (min < 0.0 && max > 0.0)
      {
        msg = tr("Error: range cannot contain 0 for a geometric series.");
      }
      break;

    case GEOMETRIC_RATIO:
      if (start == 0.0)
      {
        msg = tr("Error: range cannot begin with 0 for a geometric series.");
      }
      else if (ui.ratio->text().toDouble() == 0.0)
      {
        msg = tr("Error: common ratio cannot be 0 for a geometric series.");
      }
      break;
  }

  ui.message->setText(msg);
  auto generateButton = ui.buttonBox->button(QDialogButtonBox::Ok);
  generateButton->setEnabled(msg.isEmpty());

  if (msg.isEmpty())
  {
    auto sampleValues = this->values();
    QString txt;
    QTextStream stream(&txt);

    stream << tr("Sample series: ");
    bool add_comma = false;
    for (auto& val : sampleValues)
    {
      stream << (add_comma ? ", " : "") << val;
      add_comma = true;
    }
    ui.message->setText(txt);
    return true;
  }

  return false;
}

//-----------------------------------------------------------------------------
QVector<double> pqSeriesGeneratorDialog::pqInternals::values() const
{
  auto& ui = this->Ui;
  const int mode = ui.comboBox->currentIndex();
  const double start = ui.min->text().toDouble();
  const double end = ui.max->text().toDouble();
  const int nsamples = ui.nsamples->value();
  const double ratio = ui.ratio->text().toDouble();

  QVector<double> values;
  if (nsamples == 1)
  {
    values.push_back(start);
    return values;
  }
  else if (nsamples == 2)
  {
    values.push_back(start);
    values.push_back(end);
    return values;
  }

  assert(nsamples > 2);
  values.resize(nsamples);

  if (mode == LINEAR)
  {
    const double delta = (end - start) / (nsamples - 1);
    for (int cc = 0; cc < nsamples; ++cc)
    {
      values[cc] = start + delta * cc;
    }
  }
  else if (mode == LOGARITHMIC)
  {
    const double sign = start < 0 ? -1.0 : 1.0;
    const double log_start = std::log10(std::abs(start ? start : 1.0e-6 * (start - end)));
    const double log_end = std::log10(std::abs(end ? end : 1.0e-6 * (end - start)));

    const double delta = (log_end - log_start) / (nsamples - 1);
    for (int cc = 0; cc < nsamples; ++cc)
    {
      const double log_value = log_start + delta * cc;
      values[cc] = sign * pow(10.0, log_value);
    }
  }
  else if (mode == GEOMETRIC_SAMPLES)
  {
    const double log_cratio = std::log10(end / start) / (nsamples - 1);
    const double cratio = pow(10.0, log_cratio);

    for (int cc = 0; cc < nsamples; ++cc)
    {
      values[cc] = start * pow(cratio, cc);
    }
  }
  else if (mode == GEOMETRIC_RATIO)
  {
    assert(ratio != 0.0);
    for (int cc = 0; cc < nsamples; ++cc)
    {
      values[cc] = start * pow(ratio, cc);
    }
  }

  return values;
}

//-----------------------------------------------------------------------------
pqSeriesGeneratorDialog::pqSeriesGeneratorDialog(
  double min, double max, QWidget* parentObject, Qt::WindowFlags f)
  : Superclass(parentObject, f)
  , Internals(new pqSeriesGeneratorDialog::pqInternals())
{
  auto& internals = (*this->Internals);
  internals.DataMin = min;
  internals.DataMax = max;
  internals.Ui.setupUi(this);
  internals.Ui.min->setValidator(new QDoubleValidator(this));
  internals.Ui.max->setValidator(new QDoubleValidator(this));
  internals.Ui.ratio->setValidator(new QDoubleValidator(this));
  internals.Ui.label_ratio->hide();
  internals.Ui.ratio->hide();
  internals.Ui.buttonBox->button(QDialogButtonBox::Ok)->setText(tr("&Generate"));

  QObject::connect(internals.Ui.comboBox, QOverload<int>::of(&QComboBox::currentIndexChanged),
    [&internals](int idx) {
      if (idx == pqInternals::GEOMETRIC_RATIO)
      {
        internals.Ui.max->setEnabled(false);
        internals.Ui.label_ratio->show();
        internals.Ui.ratio->show();
      }
      else
      {
        internals.Ui.max->setEnabled(true);
        internals.Ui.label_ratio->hide();
        internals.Ui.ratio->hide();
      }

      internals.validate();
    });

  auto callback = [&internals]() {
    internals.validate();
    internals.highlightIfNeeded();
  };

  QObject::connect(internals.Ui.max, &pqLineEdit::textChanged, callback);
  QObject::connect(internals.Ui.min, &pqLineEdit::textChanged, callback);
  QObject::connect(internals.Ui.ratio, &pqLineEdit::textChanged, callback);
  QObject::connect(internals.Ui.nsamples, QOverload<int>::of(&QSpinBox::valueChanged), callback);
  QObject::connect(internals.Ui.reset, &QPushButton::clicked, this,
    &pqSeriesGeneratorDialog::resetRangeToDataRange);

  internals.Ui.min->setText(QVariant(min).toString());
  internals.Ui.max->setText(QVariant(max).toString());
}

//-----------------------------------------------------------------------------
pqSeriesGeneratorDialog::~pqSeriesGeneratorDialog() = default;

//-----------------------------------------------------------------------------
void pqSeriesGeneratorDialog::setDataRange(double dataMin, double dataMax, bool reset)
{
  auto& internals = (*this->Internals);
  internals.DataMin = dataMin;
  internals.DataMax = dataMax;
  internals.highlightIfNeeded();
  if (reset)
  {
    this->resetRangeToDataRange();
  }
}

//-----------------------------------------------------------------------------
void pqSeriesGeneratorDialog::resetRangeToDataRange()
{
  auto& internals = (*this->Internals);
  internals.Ui.min->setText(QVariant(internals.DataMin).toString());
  internals.Ui.max->setText(QVariant(internals.DataMax).toString());
  internals.Ui.reset->clear();
}

//-----------------------------------------------------------------------------
QVector<double> pqSeriesGeneratorDialog::series() const
{
  auto& internals = (*this->Internals);
  return internals.validate() ? internals.values() : QVector<double>();
}
