/*
 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 <iostream>
#include <QApplication>
#include <QMessageBox>
#include <QTimer>
#include <QCloseEvent>

#ifndef NO_SOUND
// only needed for Core::audioReady signal connection
#include <QAudioFormat>
#endif

#include "mainwindow.h"
#include "../core/core.h"
#include "../core/coreoptionsdialog.h"

static MainWindow *s_mainwindow = nullptr;

MainWindow::MainWindow(QWidget *parent) :
  QOpenGLWidget(parent)
  ,m_core(nullptr)
#ifndef NO_SOUND
  ,m_audioOutput(nullptr)
#endif
  ,m_audioReady(false)
  ,m_audioStream(nullptr)
  ,m_corePath()
  ,m_romPath()
  ,m_coreOptionsDialog()
  ,m_settings(qApp->applicationName() + ".ini", QSettings::IniFormat, this)
{
  s_mainwindow = this;
  m_core = Core::instance();
  setCursor(QCursor(Qt::BlankCursor));
  setMouseTracking(true);
  setAttribute(Qt::WA_OpaquePaintEvent);
}

MainWindow::~MainWindow() {
  //std::cout << "mainwindow dtor" << std::endl;
}

MainWindow* MainWindow::instance() {
  return s_mainwindow;
}

void MainWindow::openCoreOptionsDialog() {
  if(m_coreOptionsDialog)
    delete m_coreOptionsDialog;

  m_coreOptionsDialog = new CoreOptionsDialog(nullptr, m_core);

  // layout is cleared after a single shot timer in the constructor, so we cannot build a new layout until after that
  QTimer::singleShot(0, this, [this]() {
    m_coreOptionsDialog->show();
    m_coreOptionsDialog->reload();
  });
}

void MainWindow::setCorePath(QString path) {
  m_corePath = path;
}

void MainWindow::setROMPath(QString path) {
  m_romPath = path;
}

void MainWindow::loadCore() {
  std::cout << "Loading core." << std::endl;

  connect(m_core, &Core::repaint, this, QOverload<>::of(&MainWindow::repaint));
  connect(this, &MainWindow::frameSwapped, m_core, &Core::onGotFrameSwap);

  if(m_coreOptionsDialog)
    delete m_coreOptionsDialog;

#ifndef NO_SOUND
  connect(m_core, &Core::audioReady, this, &MainWindow::startAudio);
#endif
  connect(m_core, &Core::gotAudioSample, this, &MainWindow::onAudioSample);
  connect(m_core, &Core::gotAudioSampleBatch, this, &MainWindow::onAudioSampleBatch);
  connect(m_core, &Core::coreOptionsChanged, this, &MainWindow::onCoreOptionsChanged);
  connect(this, &MainWindow::audioStreamReady, m_core, &Core::onAudioStreamReady);

  m_core->load(m_corePath);

  if(!m_core->isLoaded()) {
    std::cout << "could not load core" << std::endl;
    QMessageBox::critical(this, "Error", "Could not load core.");
    QTimer::singleShot(0, qApp, &QApplication::quit);
    return;
  }

  if(!m_core->isResolved()) {
    std::cerr << "could not resolve required functions" << std::endl;
    QMessageBox::critical(this, "Error", "Error loading core properly, the file may be corrupt.");
    QTimer::singleShot(0, qApp, &QApplication::quit);
    return;
  }
}

void MainWindow::loadContent() {
  if(m_romPath.isEmpty() && !m_core->supportsNoGame()) {
    std::cerr << "No ROM specified." << std::endl;
    QTimer::singleShot(0, qApp, &QApplication::quit);
    return;
  }

  if(!m_core->run(m_romPath)) {
    QTimer::singleShot(0, qApp, &QApplication::quit);
    return;
  }
}

void MainWindow::closeEvent(QCloseEvent *e) {
  if(m_coreOptionsDialog && m_coreOptionsDialog->isVisible())
    m_coreOptionsDialog->close();

  // always try to save your SRAM and core options before even trying to stop the core, there is a chance it may crash
  if(m_core) {
    m_core->saveSRAM();
    saveCoreOptions();
  }

  if(m_core && m_core->isLoaded())
    m_core->unload();

  QOpenGLWidget::closeEvent(e);
}

void MainWindow::saveCoreOptions() {
  const QMap<QString, Core::CoreOption> &options = m_core->getCoreOptions();
  const QStringList keys = options.keys();

  m_settings.beginGroup("core_options");

  for(int i = 0; i < options.size(); ++i) {
    const Core::CoreOption &op = options.value(keys.at(i));

    m_settings.setValue(op.key, op.val);
  }

  m_settings.endGroup();
  m_settings.sync();
  //std::cout << "saved settings to " << qUtf8Printable(m_settings.fileName()) << std::endl;
}

void MainWindow::saveState() {
  if(m_core->saveState()) {
    std::cout << "State saved." << std::endl;
  }else{
    std::cout << "State save failed." << std::endl;
  }
}

void MainWindow::loadState() {
  if(m_core->loadState()) {
    std::cout << "State loaded." << std::endl;
  }else{
    std::cout << "State load failed." << std::endl;
  }
}

void MainWindow::setCoreMuted(bool on) {
  m_core->setMuted(on);
}

void MainWindow::onCoreOptionsChanged() {
  std::cout << "core options changed, loading current values from settings." << std::endl;

  QMap<QString, Core::CoreOption> &options = m_core->getCoreOptions();

  m_settings.beginGroup("core_options");

  QStringList keys = options.keys();

  for(int i = 0; i < keys.size(); ++i) {
    const QString &key = keys.at(i);
    QString val = m_settings.value(key).toString();

    if(val.isEmpty())
      continue;

    Core::CoreOption &op = options[key];
    op.val = val;
    op.valArray = val.toUtf8();
    op.valData = op.valArray.constData();

    //std::cout << "found key " << qUtf8Printable(key) << ", setting to " << qUtf8Printable(val) << std::endl;
  }

  m_settings.endGroup();

  m_core->setVariablesChanged(true);

  std::cout << "loaded core options from disk." << std::endl;
}

void MainWindow::go() {
  loadCore();
  loadContent();
}