/*
 * scribiu -- read notebooks and voice memos from Livescribe pens
 * Copyright (C) 2015 Javier S. Pedro <javier@javispedro.com>
 *
 * 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 3 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 program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <QtCore/QDebug>
#include <QtCore/QSettings>
#include <QtGui/QIcon>
#include <QtGui/QDesktopServices>
#include <QtWidgets/QApplication>
#include <QtWidgets/QStyle>
#include "paperreplay.h"
#include "afdnotebook.h"
#include "notebookmodel.h"

#define NUM_COLUMNS 3
#define PEN_INDEX_ID 0xFFFFFFFFU

#define PEN_EXTENSION "pen"
#define ARCHIVE_EXTENSION "archive"

NotebookModel::NotebookModel(QObject *parent) :
    QAbstractItemModel(parent),
    _dataDir(userDataDirectory()),
    _watcher()
{
	if (!_dataDir.exists()) {
		if (!_dataDir.mkpath(".")) {
			qWarning() << "Cannot create my data directory:" << _dataDir.absolutePath();
		}
	}
	_watcher.addPath(_dataDir.absolutePath());
	connect(&_watcher, SIGNAL(directoryChanged(QString)), SLOT(handleChangedDirectory(QString)));
	refresh();
}

QString NotebookModel::defaultDataDirectory()
{
	QString path = QStandardPaths::writableLocation(QStandardPaths::AppDataLocation);
	if (path.isEmpty()) {
		path = QDir::home().absoluteFilePath(".scribiu");
	}
	return path;
}

QString NotebookModel::userDataDirectory()
{
	QSettings settings;
	QString path = settings.value("data/directory").toString();
	if (path.isEmpty()) {
		path = defaultDataDirectory();
		settings.setValue("data/directory", QString());
	}
	return path;
}

QString NotebookModel::penDirectory(const QString &name) const
{
	return _dataDir.filePath(name);
}

NotebookModel::PenTime NotebookModel::penUserTime(const QString &name) const
{
	QDir penDir = penDirectory(name);
	QFile userTimeFile(penDir.filePath(PEN_USER_TIME_FILE));
	if (userTimeFile.open(QIODevice::ReadOnly | QIODevice::Text)) {
		QString data = QString::fromUtf8(userTimeFile.readLine(32));
		userTimeFile.close();
		return data.toULongLong();
	}

	qWarning() << "Could not read last user time for pen" << name << "; shown dates are likely to be off";

	return 0;
}

QString NotebookModel::notebookDirectory(const QString &penName, const QString &nbName) const
{
	return _dataDir.filePath(penName + "/" + nbName);
}

QString NotebookModel::notebookDirectory(const QModelIndex &index) const
{
	if (!index.isValid()) return QString();
	quint32 id = index.internalId();
	if (id != PEN_INDEX_ID) {
		const QString &penName = _pens[id];
		const QStringList &notebooks = _notebooks[penName];
		const QString &notebookName = notebooks.at(index.row());
		return notebookDirectory(penName, notebookName);
	}
	return QString();
}

QString NotebookModel::paperReplayDirectory(const QString &name) const
{
	return _dataDir.filePath(name + "/" + PAPER_REPLAY);
}

QVariant NotebookModel::data(const QModelIndex &index, int role) const
{
	if (!index.isValid()) return QVariant();
	quint32 id = index.internalId();
	if (id == PEN_INDEX_ID) {
		int penIndex = index.row();
		if (penIndex < 0 || penIndex >= _pens.size()) return QVariant();
		const QString &penName = _pens[penIndex];
		switch (role) {
		case Qt::DisplayRole:
			switch (index.column()) {
			case 0:
				return penDisplayName(penName);
			}
			break;
		case Qt::DecorationRole:
			switch (index.column()) {
			case 0:
				return penIcon(penName);
			case 2:
				if (isPenLocked(penName)) {
					return QApplication::style()->standardIcon(QStyle::SP_BrowserReload);
				}
				break;
			}
			break;
		case FileNameRole:
			return penName;
			break;
		}
	} else {
		const QString &penName = _pens[id];
		const QStringList &notebooks = _notebooks[penName];
		const QString &notebookName = notebooks.at(index.row());
		switch (role) {
		case Qt::DisplayRole:
			switch (index.column()) {
			case 0:
				return notebookDisplayName(penName, notebookName);
			case 1:
				if (notebookName != PAPER_REPLAY) {
					return estimatePagesOfNotebook(penName, notebookName);
				}
				break;
			}
			break;
		case Qt::DecorationRole:
			switch (index.column()) {
			case 0:
				return notebookIcon(penName, notebookName);
			case 1:
				return QVariant();
			case 2:
				if (isNotebookLocked(penName, notebookName)) {
					return QApplication::style()->standardIcon(QStyle::SP_BrowserReload);
				}
				break;
			}
			break;
		case Qt::TextAlignmentRole:
			switch (index.column()) {
			case 0:
				return QVariant::fromValue<int>(Qt::AlignLeft | Qt::AlignVCenter);
			case 1:
			case 2:
				return Qt::AlignCenter;
			}
			break;
		case FileNameRole:
			return notebookName;
		}
	}
	return QVariant();
}

Qt::ItemFlags NotebookModel::flags(const QModelIndex &index) const
{
	switch (index.column()) {
	case 0:
		return Qt::ItemIsSelectable | Qt::ItemIsEnabled;
	default:
		return Qt::ItemIsSelectable;
	}
}

QModelIndex NotebookModel::index(int row, int column, const QModelIndex &parent) const
{
	if (parent.isValid()) {
		quint32 id = parent.internalId();
		if (id == PEN_INDEX_ID) {
			// Pen index
			const quint32 penIndex = parent.row();
			const QString &penName = _pens.at(penIndex);
			const QStringList &notebooks = _notebooks[penName];
			if (row >= 0 && row < notebooks.size() && column >= 0 && column < NUM_COLUMNS) {
				return createIndex(row, column, penIndex);
			} else {
				return QModelIndex();
			}
		} else {
			// Notebook index
			return QModelIndex(); // Nothing inside notebooks
		}
	} else if (row >= 0 && row < _pens.size() && column >= 0 && column < NUM_COLUMNS) {
		return createIndex(row, column, PEN_INDEX_ID);
	} else {
		return QModelIndex();
	}
}

QModelIndex NotebookModel::parent(const QModelIndex &child) const
{
	if (child.isValid()) {
		quint32 id = child.internalId();
		if (id == PEN_INDEX_ID) {
			return QModelIndex(); // Pens have no parent
		} else {
			return createIndex(id, 0, PEN_INDEX_ID);
		}
	} else {
		return QModelIndex();
	}
}

int NotebookModel::rowCount(const QModelIndex &parent) const
{
	if (parent.isValid()) {
		quint32 id = parent.internalId();
		if (id == PEN_INDEX_ID) {
			const quint32 penIndex = parent.row();
			const QString &penName = _pens.at(penIndex);
			const QStringList &notebooks = _notebooks[penName];
			return notebooks.size();
		} else {
			return 0; // Nothing inside notebooks
		}
	} else {
		return _pens.size();
	}
}

int NotebookModel::columnCount(const QModelIndex &parent) const
{
	Q_UNUSED(parent);
	return NUM_COLUMNS;
}

void NotebookModel::refresh()
{
	QStringList pens = _dataDir.entryList(QStringList{"*." PEN_EXTENSION, "*." ARCHIVE_EXTENSION}, QDir::Dirs, QDir::Name);

	// Insert/remove new/deleted pens
	int i = 0, j = 0;
	while (i < _pens.size() && j < pens.size()) {
		int comp = QString::compare(_pens[i], pens[j], Qt::CaseInsensitive);
		if (comp == 0) {
			++i;
			++j;
		} else if (comp > 0) { /* _pens[i] > pens[j] */
			beginInsertRows(QModelIndex(), i, i);
			_pens.insert(i, pens[j]);
			endInsertRows();
			++i;
			++j;
		} else { /* _pens[i] < pens[j] */
			beginRemoveRows(QModelIndex(), i, i);
			_notebooks.remove(_pens[i]);
			_pens.removeAt(i);
			endRemoveRows();
		}
	}
	if (i < _pens.size()) {
		Q_ASSERT(j == pens.size());
		beginRemoveRows(QModelIndex(), i, _pens.size() - 1);
		while (i < _pens.size()) {
			_notebooks.remove(_pens[i]);
			_pens.removeAt(i);
		}
		endRemoveRows();
	} else if (j < pens.size()) {
		Q_ASSERT(i == _pens.size());
		beginInsertRows(QModelIndex(), i, i + (pens.size() - j));
		_pens.append(pens.mid(j));
		endInsertRows();
	}

	foreach (const QString &pen, _pens) {
		refreshPen(pen);
	}
}

void NotebookModel::refreshPen(const QString &name)
{
	QDir penDir(penDirectory(name));
	if (!penDir.exists()) {
		return;
	}

	_iconCache.clear();
	_watcher.addPath(penDir.canonicalPath());

	QStringList &curNotebooks = _notebooks[name];
	QStringList diskNotebooks = penDir.entryList(QStringList("*." AFD_NOTEBOOK_EXTENSION), QDir::Dirs, QDir::Name);
	if (penDir.exists(PAPER_REPLAY)) diskNotebooks.append(PAPER_REPLAY);

	QModelIndex penIndex = index(indexOfPen(name), 0, QModelIndex());

	emit dataChanged(penIndex, index(penIndex.row(), NUM_COLUMNS - 1, QModelIndex()));

	int i = 0, j = 0;
	while (i < curNotebooks.size() && j < diskNotebooks.size()) {
		int comp = QString::compare(curNotebooks[i], diskNotebooks[j], Qt::CaseInsensitive);
		if (comp == 0) {
			++i;
			++j;
		} else if (comp > 0) { /* _pens[i] > pens[j] */
			beginInsertRows(penIndex, i, i);
			curNotebooks.insert(i, diskNotebooks[j]);
			endInsertRows();
			++i;
			++j;
		} else { /* _pens[i] < pens[j] */
			beginRemoveRows(penIndex, i, i);
			curNotebooks.removeAt(i);
			endRemoveRows();
		}
	}
	if (i < curNotebooks.size()) {
		Q_ASSERT(j == diskNotebooks.size());
		beginRemoveRows(penIndex, i, curNotebooks.size() - 1);
		curNotebooks.erase(curNotebooks.begin() + i, curNotebooks.end());
		endRemoveRows();
	} else if (j < diskNotebooks.size()) {
		Q_ASSERT(i == curNotebooks.size());
		beginInsertRows(penIndex, i, i + (diskNotebooks.size() - j));
		curNotebooks.append(diskNotebooks.mid(j));
		endInsertRows();
	}

	qDebug() << "Found" << curNotebooks.size() << "notebooks for pen" << name;
}

int NotebookModel::indexOfPen(const QString &name)
{
	auto it = std::lower_bound(_pens.begin(), _pens.end(), name);
	if (it == _pens.end()) {
		return -1;
	} else {
		return it - _pens.begin();
	}
}

QDir NotebookModel::penDir(const QString &pen) const
{
	return QDir(penDirectory(pen));
}

QDir NotebookModel::notebookDir(const QString &pen, const QString &notebook) const
{
	return QDir(notebookDirectory(pen, notebook));
}

QString NotebookModel::penDisplayName(const QString &pen) const
{
	if (pen.endsWith("." PEN_EXTENSION, Qt::CaseInsensitive)) {
		return pen.chopped(strlen("." PEN_EXTENSION));
	} else if (pen.endsWith("." ARCHIVE_EXTENSION, Qt::CaseInsensitive)) {
		return pen.chopped(strlen("." ARCHIVE_EXTENSION));
	} else {
		return pen;
	}
}

QString NotebookModel::notebookDisplayName(const QString &pen, const QString &notebook) const
{
	Q_UNUSED(pen);
	if (notebook.endsWith("." AFD_NOTEBOOK_EXTENSION, Qt::CaseInsensitive)) {
		return notebook.chopped(strlen("." AFD_NOTEBOOK_EXTENSION));
	} else if (notebook == PAPER_REPLAY) {
		return tr("Voice recordings");
	} else {
		return notebook;
	}
}

QIcon NotebookModel::penIcon(const QString &pen) const
{
	if (isPenArchive(pen)) {
		return QApplication::style()->standardIcon(QStyle::SP_DirOpenIcon);
	} else {
		return QIcon::fromTheme("scribiu");
	}
}

QIcon NotebookModel::notebookIcon(const QString &pen, const QString &notebook) const
{
	if (notebook == PAPER_REPLAY) {
		return QApplication::style()->standardIcon(QStyle::SP_MediaVolume);
	}

	QDir dir = notebookDir(pen, notebook);

	QIcon icon = _iconCache.value(dir.path());
	if (icon.isNull() && dir.exists()) {
		static const QStringList candidates{"userdata/icon/Notebook.png",
			                                "userdata/icon/active_64x64.png",
			                                "userdata/icon/active_32x32.png",
			                                "userdata/icon/active_16x16.png"};
		foreach (const QString &candidate, candidates) {
			if (dir.exists(candidate)) {
				icon.addFile(dir.filePath(candidate));
			}
		}

		_iconCache.insert(dir.path(), icon);
	}

	return icon;
}

bool NotebookModel::isPenArchive(const QString &pen) const
{
	return pen.endsWith("." ARCHIVE_EXTENSION);
}

bool NotebookModel::isPenLocked(const QString &pen) const
{
	QDir dir = penDir(pen);
	if (dir.exists(PEN_SYNC_LOCK_FILE)) {
		return true; // TODO check if stale
	} else {
		return false;
	}
}

bool NotebookModel::isNotebookLocked(const QString &pen, const QString &notebook) const
{
	QDir dir = notebookDir(pen, notebook);
	if (dir.exists(PEN_SYNC_LOCK_FILE)) {
		return true;
	} else {
		return false;
	}
}

bool NotebookModel::isPaperReplayLocked(const QString &pen) const
{
	return isNotebookLocked(pen, PAPER_REPLAY);
}

int NotebookModel::estimatePagesOfNotebook(const QString &pen, const QString &notebook) const
{
	QDir dataDir(notebookDirectory(pen, notebook) + "/data");
	QStringList pages = dataDir.entryList(QDir::Dirs | QDir::NoDotAndDotDot);
	return pages.count();
}

void NotebookModel::handleChangedDirectory(const QString &path)
{
	qDebug() << "changed" << path;
	if (path == _dataDir.absolutePath()) {
		refresh();
	} else if (path.endsWith("." PEN_EXTENSION, Qt::CaseInsensitive)
	           || path.endsWith("." ARCHIVE_EXTENSION, Qt::CaseInsensitive)) {
		QFileInfo finfo(path);
		refreshPen(finfo.fileName());
	}
}