/***************************************************************************
 *   Copyright (C) 2008 by Volker Lanz <vl@fidra.de>                       *
 *                                                                         *
 *   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 program; if not, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA            *
 ***************************************************************************/

#include "util/capacity.h"

#include "core/partition.h"
#include "core/device.h"

#include <kglobal.h>
#include <klocale.h>
#include <kdebug.h>

const QString Capacity::m_InvalidString = "---";

/** Creates a new Capacity instance.
	@param size the size in bytes
*/
Capacity::Capacity(qint64 size) :
	m_Size(size)
{
}

/** Creates a new Capacity instance.
	@param p the Partition
	@param t type of Capacity
*/
Capacity::Capacity(const Partition& p, Type t) :
	m_Size(-1)
{
	switch(t)
	{
		case Used: m_Size = p.used(); break;
		case Available: m_Size = p.available(); break;
		case Total: m_Size = p.capacity(); break;
		default: break;
	}
}

/** Creates a new Capacity instance.
	@param d the Device
*/
Capacity::Capacity(const Device& d) :
	m_Size(d.capacity())
{
}

/** Returns the Capacity as string.
	@param f flags to set how to format the Capacity
	@return the Capacity as string */
QString Capacity::toString(Flags f) const
{
	return toString(bestUnit(), f);
}

/** Returns the Capacity as string.
	@param u the unit to use
	@param f flags to set how to format the Capacity
	@return the Capacity as string */
QString Capacity::toString(Unit u, Flags f) const
{
	QString s = toStringInternal(u);
	if ((f & AppendUnit) && s != invalidString())
		s += ' ' + unitName(u);
	if ((f & AppendBytes) && s != invalidString())
		s += " (" + KGlobal::locale()->formatNumber(m_Size, 0) + ' ' + unitName(Byte) + ')';

	return s;
}

/** @return the Capacity as bytes */
qint64 Capacity::toInt() const
{
	return static_cast<qint64>(m_Size / unitFactor(Byte, bestUnit()));
}

/** Returns the Capacity converted to the given Unit.
	@param u the Unit to use
	@return the Capacity in the given Unit */
qint64 Capacity::toInt(Unit u) const
{
	return static_cast<qint64>(m_Size / unitFactor(Byte, u));
}

/** Returns a factor to convert between two Units.
	@param from the Unit to convert from
	@param to the Unit to convert to
	@return the factor to use for conversion
*/
qint64 Capacity::unitFactor(Unit from, Unit to)
{
	Q_ASSERT(from <= to);

	if (from > to)
	{
		kWarning() << "from: " << from << ", to: " << to;
		return 1;
	}

	qint64 result = 1;

	qint32 a = from;
	qint32 b = to;

	while(b-- > a)
		result *= 1024;

	return result;
}

/** Determine the best Unit to use for the Capacity.
	@return the best Unit to use
*/
Capacity::Unit Capacity::bestUnit() const
{
	qint32 u = Byte;
	qint64 size = m_Size;

	while (size > 850)
	{
		size /= 1024;
		u++;
	}

	return static_cast<Unit>(u);
}

/** @return the name of the Unit used in bestUnit() */
QString Capacity::unitName() const
{
	return unitName(bestUnit());
}

/** Returns the name of a given Unit.
	@param u the Unit to find the name for
	@return the name
*/
QString Capacity::unitName(Unit u)
{
	static QString unitNames[] =
	{
		i18nc("@info/plain unit", "Byte"),
		i18nc("@info/plain unit", "KiB"),
		i18nc("@info/plain unit", "MiB"),
		i18nc("@info/plain unit", "GiB"),
		i18nc("@info/plain unit", "TiB"),
		i18nc("@info/plain unit", "PiB"),
		i18nc("@info/plain unit", "EiB"),
		i18nc("@info/plain unit", "ZiB"),
		i18nc("@info/plain unit", "YiB")
	};

	if (static_cast<quint32>(u) >= sizeof(unitNames) / sizeof(unitNames[0]))
		return i18nc("@info/plain unit", "(unknown unit)");

	return unitNames[u];
}

/** Determine if the capacity is valid.
	@return true if it is valid
*/
bool Capacity::isValid() const
{
	return m_Size >= 0;
}

QString Capacity::toStringInternal(Unit u) const
{
	if (m_Size < 0)
		return invalidString();

	qint64 unitSize = unitFactor(Byte, u);
	const double num = static_cast<double>(m_Size) / static_cast<double>(unitSize);
	return KGlobal::locale()->formatNumber(num, u == Byte ? 0 : -1);
}