/*
 Copyright 2020-2021 Brad Parker

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
*/

#include <QCloseEvent>
#include <QResizeEvent>
#include <QPainter>
#include <QScrollArea>
#include <QVBoxLayout>
#include <QFormLayout>
#include <QComboBox>
#include <QToolButton>
#include <QAction>
#include <QTimer>
#include <QLabel>

#include "coreoptionsdialog.h"
#include "core.h"

// adapted from RetroArch's core options dialog that I originally wrote here: https://github.com/libretro/RetroArch/blob/v1.8.6/ui/drivers/qt/coreoptionsdialog.cpp

CoreOptionsDialog::CoreOptionsDialog(QWidget *parent, Core *core) :
  QDialog(parent)
  ,m_layout()
  ,m_scrollArea()
  ,m_core(core)
{
  setWindowTitle(tr("Core Options"));
  setWindowFlags(Qt::Widget); // no close button exists otherwise
  setObjectName("coreOptionsDialog");

  resize(720, 480);

  QTimer::singleShot(0, this, SLOT(clearLayout()));
}

CoreOptionsDialog::~CoreOptionsDialog() {
}

void CoreOptionsDialog::resizeEvent(QResizeEvent *event) {
  QDialog::resizeEvent(event);

  if(!m_scrollArea)
    return;

  m_scrollArea->resize(event->size());

  emit resized(event->size());
}

void CoreOptionsDialog::closeEvent(QCloseEvent *event) {
  QDialog::closeEvent(event);

  emit closed();
}

void CoreOptionsDialog::paintEvent(QPaintEvent *event) {
  QStyleOption o;
  QPainter p;
  o.initFrom(this);
  p.begin(this);
  style()->drawPrimitive(QStyle::PE_Widget, &o, &p, this);
  p.end();

  QDialog::paintEvent(event);
}

void CoreOptionsDialog::clearLayout() {
  QWidget *widget = nullptr;

  if(m_scrollArea) {
    for(QObject *obj : children()) {
      obj->deleteLater();
    }
  }

  m_layout = new QVBoxLayout();

  widget = new QWidget();
  widget->setLayout(m_layout);
  widget->setObjectName("coreOptionsWidget");

  m_scrollArea = new QScrollArea();

  m_scrollArea->setParent(this);
  m_scrollArea->setWidgetResizable(true);
  m_scrollArea->setWidget(widget);
  m_scrollArea->setObjectName("coreOptionsScrollArea");
  m_scrollArea->show();
}

void CoreOptionsDialog::reload() {
  buildLayout();
}

void CoreOptionsDialog::onCoreOptionComboBoxCurrentIndexChanged(int index) {
  QMap<QString, Core::CoreOption> &coreOptions = m_core->getCoreOptions();
  QComboBox *comboBox = qobject_cast<QComboBox*>(sender());
  QString key, val;

  if(!comboBox)
    return;

  key = comboBox->itemData(index, Qt::UserRole).toString();
  val = comboBox->itemText(index);

  if(coreOptions.size() > 0) {
    Core::CoreOption &option = coreOptions[key];

    for(int k = 0; k < option.values.size(); k++) {
      QString str = option.values.at(k);

      if(!str.isEmpty() && str == val) {
        option.val = str;
        option.valArray = option.val.toUtf8();
        option.valData = option.valArray.constData();

        m_core->setVariablesChanged(true);
      }
    }
  }
}

void CoreOptionsDialog::buildLayout() {
  QFormLayout *form = nullptr;
  const QMap<QString, Core::CoreOption> &coreOptions = m_core->getCoreOptions();

  clearLayout();

  if(coreOptions.size() > 0) {
    form = new QFormLayout();

    QToolButton *resetAllButton = new QToolButton(this);

    resetAllButton->setDefaultAction(new QAction(tr("Reset All"), this));
    connect(resetAllButton, &QToolButton::clicked, this, &CoreOptionsDialog::onCoreOptionResetAllClicked);

    const QList<Core::CoreOption> &options = coreOptions.values();

    for(int j = 0; j < coreOptions.size(); j++) {
      const Core::CoreOption &option = options.at(j);
      const QString &desc = option.name;
      const QString &val = option.val;
      QComboBox *comboBox = nullptr;
      QLabel *descLabel = nullptr;
      QHBoxLayout *comboLayout = nullptr;
      QToolButton *resetButton = nullptr;

      if(desc.isEmpty())
        continue;

      if(option.values.size() == 0)
        continue;

      comboLayout = new QHBoxLayout();
      descLabel = new QLabel(desc, this);
      comboBox = new QComboBox(this);
      comboBox->setObjectName("coreOptionComboBox");
      resetButton = new QToolButton(this);
      resetButton->setObjectName("resetButton");
      resetButton->setDefaultAction(new QAction(tr("Reset"), this));
      resetButton->setProperty("comboBox", QVariant::fromValue(comboBox));

      connect(resetButton, &QToolButton::clicked, this, &CoreOptionsDialog::onCoreOptionResetClicked);

      for(int k = 0; k < option.values.size(); k++) {
        comboBox->addItem(option.values.at(k), option.key);
      }

      comboBox->setCurrentText(val);
      // NOTE: if new core options interface is added, default may be one other than the first
      comboBox->setProperty("default_index", 0);

      // Only connect the signal after setting the default item
      connect(comboBox, QOverload<int>::of(&QComboBox::currentIndexChanged), this, &CoreOptionsDialog::onCoreOptionComboBoxCurrentIndexChanged);

      comboLayout->addWidget(comboBox);
      comboLayout->addWidget(resetButton);

      form->addRow(descLabel, comboLayout);
    }

    form->addRow(resetAllButton, new QWidget(this));

    m_layout->addLayout(form);
  }else{
    QLabel *noParamsLabel = new QLabel(tr("No core options available."), this);
    noParamsLabel->setAlignment(Qt::AlignCenter);

    m_layout->addWidget(noParamsLabel);
  }

  m_layout->addItem(new QSpacerItem(20, 20, QSizePolicy::Minimum, QSizePolicy::Expanding));

  resize(width() + 1, height());
  show();
  resize(width() - 1, height());
}

void CoreOptionsDialog::onCoreOptionResetClicked() {
  QToolButton *button = qobject_cast<QToolButton*>(sender());
  QComboBox *comboBox = nullptr;
  int default_index = 0;
  bool ok = false;

  if(!button)
    return;

  comboBox = qobject_cast<QComboBox*>(button->property("comboBox").value<QComboBox*>());

  if(!comboBox)
    return;

  default_index = comboBox->property("default_index").toInt(&ok);

  if(!ok)
    return;

  if(default_index >= 0 && default_index < comboBox->count())
    comboBox->setCurrentIndex(default_index);
}

void CoreOptionsDialog::onCoreOptionResetAllClicked() {
  QList<QComboBox*> comboBoxes = findChildren<QComboBox*>("coreOptionComboBox");

  for(int i = 0; i < comboBoxes.count(); i++) {
    QComboBox *comboBox = comboBoxes.at(i);
    int default_index = 0;
    bool ok = false;

    if(!comboBox)
      continue;

    default_index = comboBox->property("default_index").toInt(&ok);

    if(!ok)
      continue;

    if(default_index >= 0 && default_index < comboBox->count())
      comboBox->setCurrentIndex(default_index);
  }
}