/***************************************************************************
 *   Copyright (C) 2007-2009 Sergio Pistone (sergio_pistone@yahoo.com.ar)  *
 *                                                                         *
 *   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 "subtitleiterator.h"
#include "subtitleline.h"

using namespace SubtitleComposer;

SubtitleIterator::SubtitleIterator(const Subtitle &subtitle, const RangeList &ranges, bool gotoLast) :
	QObject(0),
	m_subtitle(&subtitle),
	m_autoSync(false),
	m_autoCircle(false),
	m_ranges(ranges),
	m_linesIterator(m_subtitle->m_lines.begin()),
	m_linesIteratorStart(m_subtitle->m_lines.begin())
{
	if(m_subtitle->isEmpty())
		m_ranges.clear();
	else
		m_ranges.trimToIndex(m_subtitle->lastIndex());

	m_isFullIterator = m_ranges.isFullRange(m_subtitle->lastIndex());

	if(m_ranges.isEmpty()) {
		m_index = Invalid;              // no operations allowed
		if(m_subtitle->linesCount())
			qDebug() << "SubtitleIterator requested with empty ranges list";
	} else {
		m_index = Invalid - 1;  // a non INVALID index (needed only for initialization)
		if(gotoLast)
			toLast();
		else
			toFirst();
	}
}

SubtitleIterator::SubtitleIterator(const SubtitleIterator &it) :
	QObject(0),
	m_subtitle(it.m_subtitle),
	m_autoSync(false),
	m_autoCircle(it.m_autoCircle),
	m_ranges(it.m_ranges),
	m_isFullIterator(it.m_isFullIterator),
	m_index(it.m_index),
	m_rangesIterator(it.m_rangesIterator),
	m_linesIterator(it.m_linesIterator),
	m_linesIteratorStart(it.m_linesIteratorStart)
{
	setAutoSync(it.m_autoSync);
}

SubtitleIterator &
SubtitleIterator::operator=(const SubtitleIterator &it)
{
	if(&it != this) {
		setAutoSync(false);

		m_subtitle = it.m_subtitle;
		m_autoCircle = it.m_autoCircle;
		m_ranges = it.m_ranges;
		m_isFullIterator = it.m_isFullIterator;
		m_index = it.m_index;
		m_rangesIterator = it.m_rangesIterator;
		m_linesIterator = it.m_linesIterator;
		m_linesIteratorStart = it.m_linesIteratorStart;

		setAutoSync(it.m_autoSync);
	}

	return *this;
}

SubtitleIterator::~SubtitleIterator()
{
	setAutoSync(false);
}

bool
SubtitleIterator::isAutoSync() const
{
	return m_autoSync;
}

void
SubtitleIterator::setAutoSync(bool value)
{
	if(m_autoSync != value) {
		if(m_autoSync) {
			disconnect(m_subtitle, SIGNAL(linesInserted(int, int)), this, SLOT(onSubtitleLinesInserted(int, int)));
			disconnect(m_subtitle, SIGNAL(linesRemoved(int, int)), this, SLOT(onSubtitleLinesRemoved(int, int)));
		}

		m_autoSync = value;

		if(m_autoSync) {
			connect(m_subtitle, SIGNAL(linesInserted(int, int)), this, SLOT(onSubtitleLinesInserted(int, int)));
			connect(m_subtitle, SIGNAL(linesRemoved(int, int)), this, SLOT(onSubtitleLinesRemoved(int, int)));
		}
	}
}

bool
SubtitleIterator::isAutoCircle() const
{
	return m_autoCircle;
}

void
SubtitleIterator::setAutoCircle(bool value)
{
	if(m_autoCircle != value) {
		m_autoCircle = value;

		if(m_index == AfterLast)
			toFirst();
		else if(m_index == BehindFirst)
			toLast();
	}
}

bool
SubtitleIterator::isFullIterator() const
{
	return m_isFullIterator;
}

RangeList
SubtitleIterator::ranges() const
{
	return m_ranges;
}

void
SubtitleIterator::toFirst()
{
	if(m_index == Invalid)
		return;

	m_rangesIterator = m_ranges.begin();

	m_linesIteratorStart = m_subtitle->m_lines.begin();

	m_linesIterator = m_linesIteratorStart;

	m_index = m_ranges.firstIndex();
	if(m_index)
		m_linesIterator += m_index; // safe because indexes within m_ranges are all valid lines
}

void
SubtitleIterator::toLast()
{
	if(m_index == Invalid)
		return;

	m_rangesIterator = m_ranges.end();
	m_rangesIterator--;                     // safe because m_ranges is not empty (otherwise m_index would be INVALID).

	m_linesIteratorStart = m_subtitle->m_lines.begin();

	m_linesIterator = m_linesIteratorStart;

	m_index = m_ranges.lastIndex();
	if(m_index)
		m_linesIterator += m_index; // safe because indexes within m_ranges are all valid lines
}

bool
SubtitleIterator::toIndex(const int index)
{
	Q_ASSERT(index >= 0);
	Q_ASSERT(index <= Range::MaxIndex);

	if(m_index == Invalid)
		return false;

	bool savedAutoCircle = m_autoCircle;    // auto circling interferes with what we have to do

	m_autoCircle = false;

	if(m_index < index) {
		while(m_index < index) {
			operator++();
			if(m_index == AfterLast) {
				toLast();               // equivalent to operator--() in this case
				break;
			}
		}
	} else if(m_index > index) {
		while(m_index > index) {
			operator--();
			if(m_index == BehindFirst) {
				toFirst();              // equivalent to operator++() in this case
				break;
			}
		}
	}

	m_autoCircle = savedAutoCircle;

	return m_index == index;
}

SubtitleIterator &
SubtitleIterator::operator++()
{
	if(m_index == Invalid || m_index == AfterLast)
		return *this;

	if(m_index == BehindFirst)
		toFirst();
	else {
		m_index++;
		++m_linesIterator;

		int currentRangeEnd = (*m_rangesIterator).end();
		if(m_index > currentRangeEnd) {
			m_rangesIterator++;
			if(m_rangesIterator == m_ranges.end())
				m_index = AfterLast;
			else {
				m_index = (*m_rangesIterator).start();
				m_linesIterator += (m_index - (currentRangeEnd + 1));
			}
		}
	}

	if(m_autoCircle && m_index == AfterLast)
		toFirst();

	return *this;
}

SubtitleIterator &
SubtitleIterator::operator--()
{
	if(m_index == Invalid || m_index == BehindFirst)
		return *this;

	if(m_index == AfterLast)
		toLast();
	else {
		m_index--;
		--m_linesIterator;

		int currentRangeStart = (*m_rangesIterator).start();
		if(m_index < currentRangeStart) {
			if(m_rangesIterator == m_ranges.begin())
				m_index = BehindFirst;
			else {
				m_rangesIterator--;
				m_index = (*m_rangesIterator).end();
				m_linesIterator -= (currentRangeStart - (m_index + 1));
			}
		}
	}

	if(m_autoCircle && m_index == BehindFirst)
		toLast();

	return *this;
}

SubtitleIterator &
SubtitleIterator::operator+=(int steps)
{
	if(steps > 0) {
		for(int i = 0; i < steps; ++i)
			operator++();
	} else if(steps < 0) {
		for(int i = 0; i > steps; --i)
			operator--();
	}

	return *this;
}

SubtitleIterator &
SubtitleIterator::operator-=(int steps)
{
	if(steps > 0) {
		for(int i = 0; i < steps; ++i)
			operator--();
	} else if(steps < 0) {
		for(int i = 0; i > steps; --i)
			operator++();
	}

	return *this;
}

void
SubtitleIterator::onSubtitleLinesInserted(int firstIndex, int lastIndex)
{
	if(m_index == Invalid)
		return;

	int prevIndex = m_index;
	Range insertedRange(firstIndex, lastIndex);

	m_ranges.shiftIndexesForwards(firstIndex, insertedRange.length(), true);
	if(m_isFullIterator)
		m_ranges << insertedRange;

	m_index = Invalid - 1;          // a non Invalid index (needed only for initialization)

	if(prevIndex == AfterLast) {
		if(lastIndex == m_ranges.lastIndex()) { // lines were inserted at the end
			toFirst();                      // restore internal variables to a valid state
			toIndex(firstIndex);    // point to the first newly inserted item
		} else {
			toLast();                       // restore internal variables to a valid state
			operator++();           // point again to AfterLast
		}
	} else if(prevIndex == BehindFirst) {
		toFirst();                              // restore internal variables to a valid state
		operator--();                   // point again to BehindFirst
	} else {
		toFirst();                              // restore internal variables to a valid state
		if(prevIndex >= firstIndex)
			toIndex(prevIndex + insertedRange.length()); // point to the previously pointed line
		else
			toIndex(prevIndex); // point to the previously pointed line
	}

	emit syncronized(firstIndex, lastIndex, true);
}

void
SubtitleIterator::onSubtitleLinesRemoved(int firstIndex, int lastIndex)
{
	if(m_index == Invalid)
		return;

	int prevIndex = m_index;
	Range removedRange(firstIndex, lastIndex);

	qDebug() << "PREV RANGES" << m_ranges.inspect();
	m_ranges.shiftIndexesBackwards(firstIndex, removedRange.length());
	qDebug() << "NEW RANGES" << m_ranges.inspect();

	if(m_ranges.isEmpty())
		m_index = Invalid;
	else {
		m_index = Invalid - 1;  // a non Invalid index (needed only for initialization)

		if(prevIndex == AfterLast) {
			toLast();                       // restore internal variables to a valid state
			operator++();           // point again to AfterLast
		} else if(prevIndex == BehindFirst) {
			toFirst();                      // restore internal variables to a valid state
			operator--();           // point again to BehindFirst
		} else {
			toFirst();                      // restore internal variables to a valid state
			if(prevIndex < firstIndex)
				toIndex(prevIndex);
			else if(m_index > lastIndex)
				toIndex(prevIndex - removedRange.length());
			else // prevIndex was one of the removed lines
				toIndex(firstIndex);
		}
	}

	emit syncronized(firstIndex, lastIndex, false);
}


