/*
 * imageplugin.cpp - plugin
 * Copyright (C) 2016 rkfg
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 *
 */

#include "psiplugin.h"
#include "plugininfoprovider.h"
#include "optionaccessinghost.h"
#include "optionaccessor.h"
#include "chattabaccessor.h"
#include "applicationinfoaccessor.h"
#include "applicationinfoaccessinghost.h"
#include "ScrollKeeper.h"
#include <QDomElement>
#include <QByteArray>
#include <QLabel>
#include <QMessageBox>
#include <QVBoxLayout>
#include <QMenu>
#include <QApplication>
#include <QDebug>
#include <QTextEdit>
#include <QNetworkAccessManager>
#include <QNetworkReply>
#include <QNetworkRequest>
#include <QNetworkProxy>
#include <QImageReader>
#include <QTextDocumentFragment>
#include <QSpinBox>
#include <QComboBox>
#include <QCheckBox>
#ifdef HAVE_WEBKIT
#include <QWebView>
#include <QWebFrame>
#include <QWebElementCollection>
#endif
#ifdef HAVE_WEBENGINE
#include <QWebEngineView>
#include <QWebEnginePage>
#endif
#include <stdexcept>

#undef AUTOREDIRECTS
#if (QT_VERSION >= QT_VERSION_CHECK(5, 6, 0))
#define AUTOREDIRECTS
#endif

//#define IMGPREVIEW_DEBUG
#define constVersion "0.1.1"
#define sizeLimitName "imgpreview-size-limit"
#define previewSizeName "imgpreview-preview-size"
#define allowUpscaleName "imgpreview-allow-upscale"
#define MAX_REDIRECTS 2

class Origin: public QObject {
	Q_OBJECT
public:
	Origin(QWidget* chat) :
	QObject(chat), originalUrl_(""), chat_(chat)
#ifndef AUTOREDIRECTS
	, redirectsLeft_(0)
#endif
	{}
	QString originalUrl_;
	QWidget* chat_;
#ifndef AUTOREDIRECTS
	int redirectsLeft_;
#endif
};

class ImagePreviewPlugin: public QObject,
		public PsiPlugin,
		public PluginInfoProvider,
		public OptionAccessor,
		public ChatTabAccessor,
		public ApplicationInfoAccessor {
Q_OBJECT
#ifdef HAVE_QT5
Q_PLUGIN_METADATA(IID "com.psi-plus.ImagePreviewPlugin")
#endif
Q_INTERFACES(PsiPlugin PluginInfoProvider OptionAccessor ChatTabAccessor ApplicationInfoAccessor)
public:
	ImagePreviewPlugin();
	virtual QString name() const;
	virtual QString shortName() const;
	virtual QString version() const;
	virtual QWidget* options();
	virtual bool enable();
	virtual bool disable();

	virtual void applyOptions();
	virtual void restoreOptions();
	virtual void setOptionAccessingHost(OptionAccessingHost *host);
	virtual void optionChanged(const QString &) {
	}
	virtual QString pluginInfo();
	virtual QPixmap icon() const;
	virtual void setupChatTab(QWidget* widget, int, const QString&) {
		connect(widget, SIGNAL(messageAppended(const QString &, QWidget*)),
				SLOT(messageAppended(const QString &, QWidget*)));
	}
	virtual void setupGCTab(QWidget* widget, int, const QString&) {
		connect(widget, SIGNAL(messageAppended(const QString &, QWidget*)),
				SLOT(messageAppended(const QString &, QWidget*)));
	}

	virtual bool appendingChatMessage(int, const QString&, QString&, QDomElement&, bool) {
		return false;
	}
	virtual void setApplicationInfoAccessingHost(ApplicationInfoAccessingHost* host);
	void updateProxy();
	~ImagePreviewPlugin() {
		manager->deleteLater();
	}
private slots:
	void messageAppended(const QString &, QWidget*);
	void imageReply(QNetworkReply* reply);
private:
	OptionAccessingHost *psiOptions;
	bool enabled;
	QNetworkAccessManager* manager;
	QSet<QString> pending, failed;
	int previewSize;
	QPointer<QSpinBox> sb_previewSize;
	int sizeLimit;
	QPointer<QComboBox> cb_sizeLimit;
	bool allowUpscale;
	QPointer<QCheckBox> cb_allowUpscale;
	ApplicationInfoAccessingHost* appInfoHost;
	void queueUrl(const QString& url, Origin* origin);
};

#ifndef HAVE_QT5
Q_EXPORT_PLUGIN(ImagePreviewPlugin)
#endif

ImagePreviewPlugin::ImagePreviewPlugin() :
		psiOptions(0), enabled(false), manager(new QNetworkAccessManager(this)), previewSize(0), sizeLimit(0), allowUpscale(
				false), appInfoHost(0) {
	connect(manager, SIGNAL(finished(QNetworkReply *)), SLOT(imageReply(QNetworkReply *)));
}

QString ImagePreviewPlugin::name() const {
	return "Image Preview Plugin";
}

QString ImagePreviewPlugin::shortName() const {
	return "imgpreview";
}
QString ImagePreviewPlugin::version() const {
	return constVersion;
}

bool ImagePreviewPlugin::enable() {
	enabled = true;
	sizeLimit = psiOptions->getPluginOption(sizeLimitName, 1024 * 1024).toInt();
	previewSize = psiOptions->getPluginOption(previewSizeName, 150).toInt();
	allowUpscale = psiOptions->getPluginOption(allowUpscaleName, true).toBool();
	updateProxy();
	return enabled;
}

bool ImagePreviewPlugin::disable() {
	enabled = false;
	return true;
}

QWidget* ImagePreviewPlugin::options() {
	if (!enabled) {
		return 0;
	}
	QWidget *optionsWid = new QWidget();
	QVBoxLayout *vbox = new QVBoxLayout(optionsWid);
	cb_sizeLimit = new QComboBox(optionsWid);
	cb_sizeLimit->addItem(tr("512 Kb"), 512 * 1024);
	cb_sizeLimit->addItem(tr("1 Mb"), 1024 * 1024);
	cb_sizeLimit->addItem(tr("2 Mb"), 2 * 1024 * 1024);
	cb_sizeLimit->addItem(tr("5 Mb"), 5 * 1024 * 1024);
	cb_sizeLimit->addItem(tr("10 Mb"), 10 * 1024 * 1024);
	vbox->addWidget(new QLabel(tr("Maximum image size")));
	vbox->addWidget(cb_sizeLimit);
	sb_previewSize = new QSpinBox(optionsWid);
	sb_previewSize->setMinimum(1);
	sb_previewSize->setMaximum(65535);
	vbox->addWidget(new QLabel(tr("Image preview size in pixels")));
	vbox->addWidget(sb_previewSize);
	cb_allowUpscale = new QCheckBox(tr("Allow upscale"));
	vbox->addWidget(cb_allowUpscale);
	vbox->addStretch();
	updateProxy();
	return optionsWid;
}

void ImagePreviewPlugin::setOptionAccessingHost(OptionAccessingHost *host) {
	psiOptions = host;
}

QString ImagePreviewPlugin::pluginInfo() {
	return tr("Author: ") + "rkfg\n\n" + trUtf8("This plugin shows the preview image for an image URL.\n");
}

QPixmap ImagePreviewPlugin::icon() const {
	return QPixmap(":/imagepreviewplugin/imagepreviewplugin.png");
}

void ImagePreviewPlugin::queueUrl(const QString& url, Origin* origin) {
	if (!pending.contains(url) && !failed.contains(url)) {
		pending.insert(url);
		QNetworkRequest req;
		origin->originalUrl_ = url;
#ifndef AUTOREDIRECTS
		origin->redirectsLeft_ = MAX_REDIRECTS;
#endif
		req.setUrl(QUrl::fromUserInput(url));
		req.setOriginatingObject(origin);
		req.setRawHeader("User-Agent",
				"Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/53.0.2785.143 Safari/537.36");
#ifdef AUTOREDIRECTS
		req.setAttribute(QNetworkRequest::FollowRedirectsAttribute, true);
		req.setMaximumRedirectsAllowed(MAX_REDIRECTS);
#endif
		manager->head(req);
	}
}

void ImagePreviewPlugin::messageAppended(const QString &, QWidget* logWidget) {
	if (!enabled) {
		return;
	}
	ScrollKeeper sk(logWidget);
	QTextEdit* te_log = qobject_cast<QTextEdit*>(logWidget);
	if (te_log) {
		QTextCursor cur = te_log->textCursor();
		te_log->moveCursor(QTextCursor::End, QTextCursor::MoveAnchor);
		te_log->moveCursor(QTextCursor::StartOfBlock, QTextCursor::MoveAnchor);
		QTextCursor found = te_log->textCursor();
		while (!(found = te_log->document()->find(QRegExp("https?://\\S*"), found)).isNull()) {
			QString url = found.selectedText();
#ifdef IMGPREVIEW_DEBUG
			qDebug() << "URL FOUND:" << url;
#endif
			queueUrl(url, new Origin(te_log));
		};
		te_log->setTextCursor(cur);
	}
	else {
#ifdef HAVE_WEBKIT
		QWebView* wv_log = qobject_cast<QWebView*>(logWidget);
		QWebFrame* mainFrame = wv_log->page()->mainFrame();
		QWebElementCollection elems = mainFrame->findAllElements("a[href]");
		for (QWebElementCollection::const_iterator i = elems.constEnd() - 1;; i--) {
			if ((*i).isNull()) {
				break;
			}
			// skip nick links and already processed anchors
			if (!(*i).classes().contains("nicklink", Qt::CaseInsensitive)
					&& (*i).firstChild().tagName().toLower() != "img") {
				QString url = (*i).attribute("href", "");
				if (url.startsWith("http://") || url.startsWith("https://")) {
					queueUrl(url, new Origin(wv_log));
				}
			}
		}
#endif
#ifdef HAVE_WEBENGINE
  #ifdef __GNUC__
  #warning "ImagePreviewPlugin TODO: add support for webengine"
  #endif
#endif
	}

}

void ImagePreviewPlugin::imageReply(QNetworkReply* reply) {
	bool ok;
	int size = 0;
	QStringList contentTypes;
	QStringList allowedTypes;
	allowedTypes.append("image/jpeg");
	allowedTypes.append("image/png");
	allowedTypes.append("image/gif");
	Origin* origin = qobject_cast<Origin*>(reply->request().originatingObject());
	QString urlStr = origin->originalUrl_;
	QString urlStrEscaped = reply->url().toString();
#ifdef IMGPREVIEW_DEBUG
	qDebug() << "Original URL " << urlStr << " / Escaped: " << urlStrEscaped;
#endif
	switch (reply->operation()) {
	case QNetworkAccessManager::HeadOperation: {
#ifndef AUTOREDIRECTS
		int status = reply->attribute(QNetworkRequest::HttpStatusCodeAttribute).toInt(&ok);
		if (ok && (status == 301 || status == 302 || status == 303)) {
			if (origin->redirectsLeft_ == 0) {
				qWarning() << "Redirect count exceeded for" << urlStr;
				origin->deleteLater();
				pending.remove(urlStr);
				break;
			}
			origin->redirectsLeft_--;
			QUrl location = reply->attribute(QNetworkRequest::RedirectionTargetAttribute).toUrl();
			if (location.isRelative()) {
				location = location.resolved(reply->request().url());
			}
#ifdef IMGPREVIEW_DEBUG
			qDebug() << "Redirected to" << location;
#endif
			QNetworkRequest req = reply->request();
			req.setUrl(location);
			manager->head(req);
		} else
#endif
		{
			size = reply->header(QNetworkRequest::ContentLengthHeader).toInt(&ok);
			if (reply->error() == QNetworkReply::NoError) {
				ok = true;
			}
			contentTypes = reply->header(QNetworkRequest::ContentTypeHeader).toString().split(",");
			QString lastType = contentTypes.last().trimmed();
#ifdef IMGPREVIEW_DEBUG
			qDebug() << "URL:" << urlStr << "RESULT:" << reply->error() << "SIZE:" << size << "Content-type:"
					<< contentTypes << " Last type: " << lastType;
#endif
			if (ok && allowedTypes.contains(lastType, Qt::CaseInsensitive) && size < sizeLimit) {
				manager->get(reply->request());
			} else {
#ifdef IMGPREVIEW_DEBUG
				qDebug() << "Failed url " << origin->originalUrl_;
#endif
				failed.insert(origin->originalUrl_);
				origin->deleteLater();
				pending.remove(urlStr);
			}
		}
		break;
	}
	case QNetworkAccessManager::GetOperation:
		try {
			QImageReader imageReader(reply);
			QImage image = imageReader.read();
			if (imageReader.error() != QImageReader::UnknownError) {
				throw std::runtime_error(imageReader.errorString().toStdString());
			}
			if (image.width() > previewSize || image.height() > previewSize || allowUpscale) {
				image = image.scaled(previewSize, previewSize, Qt::KeepAspectRatio, Qt::SmoothTransformation);
			}
#ifdef IMGPREVIEW_DEBUG
			qDebug() << "Image size:" << image.size();
#endif
			ScrollKeeper sk(origin->chat_);
			QTextEdit* te_log = qobject_cast<QTextEdit*>(origin->chat_);
			if (te_log) {
				te_log->document()->addResource(QTextDocument::ImageResource, urlStrEscaped, image);
				QTextCursor saved = te_log->textCursor();
				te_log->moveCursor(QTextCursor::End);
				QRegExp rawUrlRE = QRegExp("(<a href=\"[^\"]*\">)(.*)(</a>)");
				while (te_log->find(urlStr, QTextDocument::FindBackward)) {
					QTextCursor cur = te_log->textCursor();
					QString html = cur.selection().toHtml();
					if (html.contains(rawUrlRE)) {
						html.replace(rawUrlRE, QString("\\1<img src='%1'/>\\3").arg(urlStrEscaped));
						cur.insertHtml(html);
					}
				}
				te_log->setTextCursor(saved);
			}
			else {		
#ifdef HAVE_WEBKIT
				QByteArray imageBytes;
				QBuffer imageBuf(&imageBytes);
				image.save(&imageBuf, "jpg", 60);
				QWebView* wv_log = qobject_cast<QWebView*>(origin->chat_);
				QWebFrame* mainFrame = wv_log->page()->mainFrame();
				mainFrame->evaluateJavaScript(QString("var links = document.body.querySelectorAll('a[href=\"%1\"]');"
						"for (var i = 0; i < links.length; i++) {"
						"  var elem = links[i];"
						"  elem.innerHTML = \"<img src='data:image/jpeg;base64,%2'/>\";"
						"}").arg(urlStr).arg(QString(imageBytes.toBase64())));
#endif
#ifdef HAVE_WEBENGINE
  #ifdef __GNUC__
  #warning "ImagePreviewPlugin TODO: add support for webengine"
  #endif
#endif
			}
		} catch (std::exception& e) {
			failed.insert(origin->originalUrl_);
			qWarning() << "ERROR: " << e.what();
		}
		origin->deleteLater();
		pending.remove(urlStr);
		break;
	default:
		break;
	}
	reply->deleteLater();
}

void ImagePreviewPlugin::applyOptions() {
	psiOptions->setPluginOption(previewSizeName, previewSize = sb_previewSize->value());
	psiOptions->setPluginOption(sizeLimitName, sizeLimit =
			cb_sizeLimit->itemData(cb_sizeLimit->currentIndex()).toInt());
	psiOptions->setPluginOption(allowUpscaleName, allowUpscale = cb_allowUpscale->checkState() == Qt::Checked);
}

void ImagePreviewPlugin::restoreOptions() {
	sb_previewSize->setValue(previewSize);
	cb_sizeLimit->setCurrentIndex(cb_sizeLimit->findData(sizeLimit));
	cb_allowUpscale->setCheckState(allowUpscale ? Qt::Checked : Qt::Unchecked);
}

void ImagePreviewPlugin::setApplicationInfoAccessingHost(ApplicationInfoAccessingHost* host) {
	appInfoHost = host;
}

void ImagePreviewPlugin::updateProxy() {
	Proxy proxy = appInfoHost->getProxyFor(name());
#ifdef IMGPREVIEW_DEBUG
	qDebug() << "Proxy:" << "T:" << proxy.type << "H:" << proxy.host << "Pt:" << proxy.port << "U:" << proxy.user
			<< "Ps:" << proxy.pass;
#endif
	if (proxy.type.isEmpty()) {
		manager->setProxy(QNetworkProxy());
		return;
	}
	QNetworkProxy netProxy(proxy.type == "socks" ? QNetworkProxy::Socks5Proxy : QNetworkProxy::HttpProxy, proxy.host,
			proxy.port, proxy.user, proxy.pass);
	manager->setProxy(netProxy);
}

#include "imagepreviewplugin.moc"