/*
 * Olive Community Edition - Non-Linear Video Editor
 * Copyright (C) 2025 Olive CE Team
 *
 * 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 "trackview.h"

#include <QDebug>
#include <QResizeEvent>
#include <QScrollBar>
#include <QSplitter>
#include <QVBoxLayout>

#include "trackviewitem.h"

namespace olive
{

TrackView::TrackView(Qt::Alignment vertical_alignment, QWidget *parent)
	: QScrollArea(parent)
	, list_(nullptr)
	, alignment_(vertical_alignment)
{
	setAlignment(Qt::AlignLeft | alignment_);

	QWidget *central = new QWidget();
	setWidget(central);
	setWidgetResizable(true);

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

	if (alignment_ == Qt::AlignBottom) {
		layout->addStretch();

		connect(verticalScrollBar(), &QScrollBar::rangeChanged, this,
				&TrackView::ScrollbarRangeChanged);
		last_scrollbar_max_ = verticalScrollBar()->maximum();
	}

	splitter_ = new TrackViewSplitter(alignment_);
	splitter_->setChildrenCollapsible(false);
	layout->addWidget(splitter_);

	if (alignment_ == Qt::AlignTop) {
		layout->addStretch();
	}

	connect(splitter_, &TrackViewSplitter::TrackHeightChanged, this,
			&TrackView::TrackHeightChanged);
	setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
	setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
}

void TrackView::ConnectTrackList(TrackList *list)
{
	if (list_ != nullptr) {
		// Remove tracks
		for (int i = 0; i < list_->GetTrackCount(); i++) {
			splitter_->Remove(0);
		}

		disconnect(list_, &TrackList::TrackAdded, this,
				   &TrackView::InsertTrack);
		disconnect(list_, &TrackList::TrackRemoved, this,
				   &TrackView::RemoveTrack);
	}

	list_ = list;

	if (list_ != nullptr) {
		foreach (Track *track, list_->GetTracks()) {
			InsertTrack(track);
		}

		connect(list_, &TrackList::TrackAdded, this, &TrackView::InsertTrack);
		connect(list_, &TrackList::TrackRemoved, this, &TrackView::RemoveTrack);
	}
}

void TrackView::DisconnectTrackList()
{
	ConnectTrackList(nullptr);
}

void TrackView::resizeEvent(QResizeEvent *e)
{
	QScrollArea::resizeEvent(e);

	splitter_->SetSpacerHeight(height() / 2);
}

void TrackView::ScrollbarRangeChanged(int, int max)
{
	if (max != last_scrollbar_max_) {
		int ba_val = last_scrollbar_max_ - verticalScrollBar()->value();
		int new_val = max - ba_val;

		verticalScrollBar()->setValue(new_val);
		emit verticalScrollBar() -> valueChanged(new_val);

		last_scrollbar_max_ = max;
	}
}

void TrackView::TrackHeightChanged(int index, int height)
{
	list_->GetTrackAt(index)->SetTrackHeightInPixels(height);
}

void TrackView::InsertTrack(Track *track)
{
	TrackViewItem *tvi = new TrackViewItem(track);

	connect(tvi, &TrackViewItem::AboutToDeleteTrack, this,
			&TrackView::AboutToDeleteTrack);

	splitter_->Insert(track->Index(), track->GetTrackHeightInPixels(), tvi);
}

void TrackView::RemoveTrack(Track *track)
{
	splitter_->Remove(track->Index());
}

}