#include "slideview.hpp"

#include <QPainter>
#include <QMouseEvent>
#include <QDateTime>

const double speed_slow_unit = 0.25;

SlideView::SlideView(QWidget * parent) : QWidget(parent),
	is_pressed_(false),
	msec_time_(0),
	speed_(0.0),
	move_direction_(Stable)
{
	slide_timer_.setInterval(150);
	connect(&slide_timer_, &QTimer::timeout, this, [=]() {
		if (is_pressed_)
		{
			if (cur_x_ != this->pos().x())
			{
				double offset = this->pos().x() - cur_x_;
				speed_ = offset / slide_timer_.interval();
			}
			else
			{
				speed_ = 0.0;
			}

			cur_x_ = this->pos().x();
		}
	});

	speed_timer_.setInterval(20);
	speed_timer_.setSingleShot(false);
	connect(&speed_timer_, &QTimer::timeout, this, [=]() {
		int offset = speed_ * 10;
		
		int now_x = this->pos().x();
		int now_y = this->pos().y();
		
		if (now_x + offset < 0)
		{
			now_x = 0;
			speed_timer_.stop();
			return;
		}

		if (now_x + offset + width() > 1400)
		{
			now_x = 1400 - width();
			speed_timer_.stop();
			return;
		}

		now_x += offset;
		move(now_x, now_y);

		if (speed_ > speed_slow_unit)
		{
			speed_ -= speed_slow_unit;
		}
		else if (speed_ < -speed_slow_unit)
		{
			speed_ += speed_slow_unit;
		}
		else
		{
			speed_ = 0.0;
			speed_timer_.stop();
		}
	});
}

SlideView::~SlideView() {
	
}

void SlideView::paintEvent(QPaintEvent*)
{
	QPainter painter(this);
	painter.fillRect(0, 0, width(), height(), QColor(Qt::red));
}

void SlideView::mousePressEvent(QMouseEvent* ptr_event)
{
	speed_timer_.stop();

	cur_x_ = pos().x();
	msec_time_ = QDateTime::currentDateTime().toMSecsSinceEpoch();
	is_pressed_ = true;

	speed_ = 0.0;
}

void SlideView::mouseMoveEvent(QMouseEvent* ptr_event)
{
	if (is_pressed_)
	{
		move(pos().x() + ptr_event->x(), pos().y());

		MoveDirection direction = ptr_event->x() > 0 ? MoveRight : MoveLeft;
		if (direction != move_direction_)
		{
			move_direction_ = direction;
			speed_ = 0.0;
			msec_time_ = QDateTime::currentDateTime().toMSecsSinceEpoch();
		}

		if (!slide_timer_.isActive())
			slide_timer_.start();
	}
}

void SlideView::mouseReleaseEvent(QMouseEvent* ptr_event)
{
	if (is_pressed_)
	{
		if (speed_ >= 0.000001 || speed_ <= -0.000001)
		{
			speed_timer_.start();
		}
		else
		{
			time_t inteval = QDateTime::currentDateTime().toMSecsSinceEpoch() - msec_time_;
			if (inteval <= 200 && cur_x_ != this->pos().x())
			{
				double offset = this->pos().x() - cur_x_;
				speed_ = offset / inteval;

				speed_timer_.start();
			}
		}

		move_direction_ = Stable;
		pre_x_ = 0;
		cur_x_ = 0;
		is_pressed_ = false;
		msec_time_ = 0;
	}

	slide_timer_.stop();
}