#include "gui/pages/torrents.h"
#include "core/filesystem.h"
#include "core/http.h"
#include "core/session.h"
#include "core/strings.h"
#include "gui/widgets/text.h"
#include "track/media.h"

#include <QByteArray>
#include <QDataStream>
#include <QDebug>
#include <QHeaderView>
#include <QThread>
#include <QToolBar>
#include <QTreeView>
#include <QVBoxLayout>
#include <QtGlobal>

#include <algorithm>
#include <fstream>
#include <iostream>
#include <sstream>

#include "anitomy/anitomy.h"
#include "pugixml.hpp"

/* This file is very, very similar to the anime list page.
 *
 * It differs from Taiga in that it uses tabs instead of
 * those "groups", but those are custom painted and a pain in the ass to
 * maintain over multiple platforms.
 */

TorrentsPageListSortFilter::TorrentsPageListSortFilter(QObject* parent) : QSortFilterProxyModel(parent) {
}

bool TorrentsPageListSortFilter::lessThan(const QModelIndex& l, const QModelIndex& r) const {
	QVariant left = sourceModel()->data(l, sortRole());
	QVariant right = sourceModel()->data(r, sortRole());

	switch (left.userType()) {
		case QMetaType::Int:
		case QMetaType::UInt:
		case QMetaType::LongLong:
		case QMetaType::ULongLong: return left.toInt() < right.toInt();
		case QMetaType::QDate: return left.toDate() < right.toDate();
		case QMetaType::QString:
		default: return QString::compare(left.toString(), right.toString(), Qt::CaseInsensitive) < 0;
	}
}

/* -------------------------------------------- */

TorrentsPageListModel::TorrentsPageListModel(QObject* parent) : QAbstractListModel(parent) {
}

void TorrentsPageListModel::DownloadTorrents(QItemSelection selection) {
	const auto indexes = selection.indexes();

	for (const auto& index : indexes) {
		/* a torrent file IS literally text... */
		const std::string link = list.at(index.row()).GetLink();
		const std::string filename = list.at(index.row()).GetFilename() + ".torrent";

		const std::filesystem::path torrents_dir = Filesystem::GetTorrentsPath();
		std::filesystem::create_directories(torrents_dir);

		/* this sucks */
		HTTP::RequestThread* thread = new HTTP::RequestThread(link, {}, "", HTTP::Type::Get, this);

		connect(thread, &HTTP::RequestThread::ReceivedData, this, [this, torrents_dir, filename](const QByteArray& data) {
			std::ofstream file(torrents_dir / filename, std::ofstream::out | std::ofstream::trunc);
			if (!file)
				return; // wat

			file.write(data.data(), data.size());
			file.close();
		});
		connect(thread, &HTTP::RequestThread::finished, thread, &HTTP::RequestThread::deleteLater);

		thread->start();
	}
}

QByteArray TorrentsPageListModel::DownloadTorrentList() {
	return HTTP::Request(session.config.torrents.feed_link);
}

void TorrentsPageListModel::ParseFeedDescription(const std::string& description, Torrent& torrent) {
	/* Parse description... */
	enum class Keys {
		SIZE,
		AUTHORIZED,
		SUBMITTER,
		COMMENT
	};

	const std::unordered_map<std::string, Keys> KeyMap = {
	    {"Size",       Keys::SIZE      },
	    {"Authorized", Keys::AUTHORIZED},
	    {"Submitter",  Keys::SUBMITTER },
	    {"Comment",    Keys::COMMENT   }
    };

	/* Parse size from description */
	std::istringstream descstream(description);

	for (std::string line; std::getline(descstream, line);) {
		const size_t pos = line.find_first_of(':', 0);
		if (pos == std::string::npos)
			continue;

		const std::string key = line.substr(0, pos);
		const std::string value = line.substr(line.find_first_not_of(": ", pos));

		switch (KeyMap.at(key)) {
			case Keys::COMMENT: torrent.SetDescription(value); break;
			case Keys::SIZE: torrent.SetSize(Strings::HumanReadableSizeToBytes(value)); break;
			case Keys::AUTHORIZED:
				if (torrent.GetGroup().empty() && value != "N/A")
					torrent.SetGroup(value);
				break;
			default: break;
		}
	}
}

void TorrentsPageListModel::ParseTorrentList(const QByteArray& ba) {
	std::istringstream stdstream(Strings::ToUtf8String(ba));

	pugi::xml_document doc;
	if (!doc.load(stdstream))
		return; // peace out

	/* my extra special dumb hack. */
	if (!rowCount(index(0))) {
		beginInsertRows(QModelIndex(), 0, 0);
		endInsertRows();
	}

	beginResetModel();

	list.clear();
	/* this is just an rss parser; it should be in a separate class... */
	for (pugi::xml_node item : doc.child("rss").child("channel").children("item")) {
		TorrentModelItem torrent;
		torrent.SetFilename(item.child_value("title")); /* "title" == filename */
		{
			anitomy::Anitomy anitomy;
			anitomy.Parse(torrent.GetFilename());

			const auto& elements = anitomy.elements();

			/* todo: patch Anitomy so that it doesn't use wide strings */
			torrent.SetTitle(Strings::ToUtf8String(elements.get(anitomy::kElementAnimeTitle)));
			std::string episode = Strings::ToUtf8String(elements.get(anitomy::kElementEpisodeNumber));
			Strings::RemoveLeadingChars(episode, '0');
			torrent.SetEpisode(episode);
			torrent.SetGroup(Strings::ToUtf8String(elements.get(anitomy::kElementReleaseGroup)));
			torrent.SetResolution(Strings::ToUtf8String(elements.get(anitomy::kElementVideoResolution)));
		}

		std::string description = item.child_value("description");
		Strings::TextifySynopsis(description);
		ParseFeedDescription(description, torrent);

		torrent.SetLink(item.child_value("link"));
		torrent.SetGuid(item.child_value("guid"));
		{
			const QString date_str = Strings::ToQString(item.child_value("pubDate"));
			torrent.SetDate(QDateTime::fromString(date_str, "ddd, dd MMM yyyy HH:mm:ss t"));
		}
		list.push_back(torrent);
	}

	endResetModel();
}

void TorrentsPageListModel::RefreshTorrentList() {
	ParseTorrentList(DownloadTorrentList());
}

int TorrentsPageListModel::rowCount(const QModelIndex& parent) const {
	return list.size();
	(void)(parent);
}

int TorrentsPageListModel::columnCount(const QModelIndex& parent) const {
	return NB_COLUMNS;
	(void)(parent);
}

QVariant TorrentsPageListModel::headerData(const int section, const Qt::Orientation orientation, const int role) const {
	switch (role) {
		case Qt::DisplayRole: {
			switch (section) {
				case TL_TITLE: return tr("Anime title");
				case TL_EPISODE: return tr("Episode");
				case TL_GROUP: return tr("Group");
				case TL_SIZE: return tr("Size");
				case TL_RESOLUTION: return tr("Resolution"); /* "Video" in Taiga */
				case TL_SEEDERS: return tr("S");
				case TL_LEECHERS: return tr("L");
				case TL_DOWNLOADS: return tr("D");
				case TL_DESCRIPTION: return tr("Description");
				case TL_FILENAME: return tr("Filename");
				case TL_RELEASEDATE: return tr("Release date");
				default: return {};
			}
			break;
		}
		case Qt::TextAlignmentRole: {
			switch (section) {
				case TL_FILENAME:
				case TL_GROUP:
				case TL_DESCRIPTION:
				case TL_RESOLUTION:
				case TL_TITLE: return QVariant(Qt::AlignLeft | Qt::AlignVCenter);
				case TL_SEEDERS:
				case TL_LEECHERS:
				case TL_DOWNLOADS:
				case TL_SIZE:
				case TL_EPISODE:
				case TL_RELEASEDATE: return QVariant(Qt::AlignRight | Qt::AlignVCenter);
				default: return {};
			}
			break;
		}
	}
	return QAbstractListModel::headerData(section, orientation, role);
}

bool TorrentsPageListModel::setData(const QModelIndex& index, const QVariant& value, int role) {
	TorrentModelItem& item = list.at(index.row());

	if (index.column() == 0) {
		switch (role) {
			case Qt::EditRole: return false;
			case Qt::CheckStateRole:
				item.SetChecked(value.toBool());
				emit dataChanged(index, index);
				return true;
		}
	}

	return QAbstractItemModel::setData(index, value, role);
}

QVariant TorrentsPageListModel::data(const QModelIndex& index, int role) const {
	if (!index.isValid())
		return QVariant();

	const TorrentModelItem& item = list.at(index.row());

	switch (role) {
		case Qt::DisplayRole:
			switch (index.column()) {
				case TL_TITLE: return Strings::ToQString(item.GetTitle());
				case TL_EPISODE: return Strings::ToQString(item.GetEpisode());
				case TL_GROUP: return Strings::ToQString(item.GetGroup());
				case TL_SIZE: return Strings::ToQString(Strings::BytesToHumanReadableSize(item.GetSize()));
				case TL_RESOLUTION: return Strings::ToQString(item.GetResolution());
				case TL_SEEDERS: return item.GetSeeders();
				case TL_LEECHERS: return item.GetLeechers();
				case TL_DOWNLOADS: return item.GetDownloads();
				case TL_DESCRIPTION: return Strings::ToQString(item.GetDescription());
				case TL_FILENAME: return Strings::ToQString(item.GetFilename());
				case TL_RELEASEDATE: return item.GetDate();
				default: return {};
			}
			break;
		case Qt::UserRole:
			switch (index.column()) {
				case TL_EPISODE: return Strings::ToInt(item.GetEpisode(), -1);
				/* We have to use this to work around some stupid
				 * "conversion ambiguous" error on Linux
				 */
				case TL_SIZE: return QVariant::fromValue(item.GetSize());
				default: return data(index, Qt::DisplayRole);
			}
			break;
		case Qt::SizeHintRole: {
			switch (index.column()) {
				default: {
					/* max horizontal size of 100, height size = size of current font */
					const QString d = data(index, Qt::DisplayRole).toString();
					const QFontMetrics metric = QFontMetrics(QFont());

					return QSize(std::max(metric.boundingRect(d).width(), 100), metric.height());
				}
			}
			break;
		}
		case Qt::TextAlignmentRole:
			switch (index.column()) {
				case TL_FILENAME:
				case TL_GROUP:
				case TL_DESCRIPTION:
				case TL_RESOLUTION:
				case TL_TITLE: return QVariant(Qt::AlignLeft | Qt::AlignVCenter);
				case TL_SEEDERS:
				case TL_LEECHERS:
				case TL_DOWNLOADS:
				case TL_SIZE:
				case TL_EPISODE:
				case TL_RELEASEDATE: return QVariant(Qt::AlignRight | Qt::AlignVCenter);
				default: return {};
			}
			break;
	}
	return QVariant();
}

Qt::ItemFlags TorrentsPageListModel::flags(const QModelIndex& index) const {
	if (!index.isValid())
		return Qt::NoItemFlags;

	return Qt::ItemIsEnabled | Qt::ItemIsSelectable;
}

TorrentsPage::TorrentsPage(QWidget* parent) : QFrame(parent) {
	setFrameShape(QFrame::Box);
	setFrameShadow(QFrame::Sunken);

	QVBoxLayout* layout = new QVBoxLayout(this);
	layout->setContentsMargins(0, 0, 0, 0);
	layout->setSpacing(0);

	{
		/* Toolbar */
		QToolBar* toolbar = new QToolBar(this);
		toolbar->setToolButtonStyle(Qt::ToolButtonTextBesideIcon);
		toolbar->setIconSize(QSize(16, 16));
		toolbar->setMovable(false);

		{
			/* this needs to be stored somewhere to replicate Taiga's
			   "timer" feature */
			toolbar->addAction(QIcon(":/icons/16x16/arrow-circle-315.png"), tr("&Check new torrents"),
			                   [this] { Refresh(); });
		}

		toolbar->addSeparator();

		{
			toolbar->addAction(QIcon(":/icons/16x16/navigation-270-button.png"), tr("Download &marked torrents"),
			                   [this] { DownloadSelection(); });
		}

		{ toolbar->addAction(QIcon(":/icons/16x16/cross-button.png"), tr("&Discard all")); }

		toolbar->addSeparator();

		{ toolbar->addAction(QIcon(":/icons/16x16/gear.png"), tr("&Settings")); }

		layout->addWidget(toolbar);
	}

	{
		QFrame* line = new QFrame(this);
		line->setFrameShape(QFrame::HLine);
		line->setFrameShadow(QFrame::Sunken);
		line->setLineWidth(1);
		layout->addWidget(line);
	}

	{
		treeview = new QTreeView(this);
		treeview->setUniformRowHeights(true);
		treeview->setAllColumnsShowFocus(false);
		treeview->setAlternatingRowColors(true);
		treeview->setSortingEnabled(true);
		treeview->setSelectionMode(QAbstractItemView::ExtendedSelection);
		treeview->setItemsExpandable(false);
		treeview->setRootIsDecorated(false);
		treeview->setContextMenuPolicy(Qt::CustomContextMenu);
		treeview->setFrameShape(QFrame::NoFrame);

		{
			sort_model = new TorrentsPageListSortFilter(treeview);
			model = new TorrentsPageListModel(treeview);
			sort_model->setSourceModel(model);
			sort_model->setSortRole(Qt::UserRole);
			sort_model->setSortCaseSensitivity(Qt::CaseInsensitive);
			treeview->setModel(sort_model);
		}

		// set column sizes
		treeview->setColumnWidth(TorrentsPageListModel::TL_TITLE, 240);
		treeview->setColumnWidth(TorrentsPageListModel::TL_EPISODE, 60);
		treeview->setColumnWidth(TorrentsPageListModel::TL_GROUP, 100);
		treeview->setColumnWidth(TorrentsPageListModel::TL_SIZE, 70);
		treeview->setColumnWidth(TorrentsPageListModel::TL_RESOLUTION, 100);
		treeview->setColumnWidth(TorrentsPageListModel::TL_SEEDERS, 20);
		treeview->setColumnWidth(TorrentsPageListModel::TL_LEECHERS, 20);
		treeview->setColumnWidth(TorrentsPageListModel::TL_DOWNLOADS, 20);
		treeview->setColumnWidth(TorrentsPageListModel::TL_DESCRIPTION, 200);
		treeview->setColumnWidth(TorrentsPageListModel::TL_FILENAME, 200);
		treeview->setColumnWidth(TorrentsPageListModel::TL_RELEASEDATE, 190);

		treeview->header()->setStretchLastSection(false);

		layout->addWidget(treeview);
	}
}

void TorrentsPage::DownloadSelection() {
	if (!model)
		return;

	const QItemSelection selection = sort_model->mapSelectionToSource(treeview->selectionModel()->selection());

	model->DownloadTorrents(selection);
}

void TorrentsPage::Refresh() {
	if (!model)
		return;

	HTTP::RequestThread* thread = new HTTP::RequestThread(session.config.torrents.feed_link);

	connect(thread, &HTTP::RequestThread::ReceivedData, this, [&](const QByteArray& ba) {
		/* This is to make sure we aren't in a different thread
		 * messing around with GUI stuff
		 */
		treeview->setUpdatesEnabled(false);
		model->ParseTorrentList(ba);
		treeview->setUpdatesEnabled(true);
	});
	connect(thread, &HTTP::RequestThread::finished, thread, &HTTP::RequestThread::deleteLater);

	thread->start();
}