//Copyright 2017 Ryan Wick

//This file is part of Bandage

//Bandage 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.

//Bandage 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 Bandage.  If not, see <http://www.gnu.org/licenses/>.


#include "mygraphicsview.h"
#include <QMouseEvent>
#include "../program/globals.h"
#include "../program/settings.h"
#include <QFont>
#include "graphicsviewzoom.h"
#include <qmath.h>
#include <QMessageBox>
#include <math.h>
#include "../graph/graphicsitemnode.h"

MyGraphicsView::MyGraphicsView(QObject * /*parent*/) :
    QGraphicsView(), m_rotation(0.0)
{
    setDragMode(QGraphicsView::RubberBandDrag);
    setAntialiasing(g_settings->antialiasing);
    setViewportUpdateMode(QGraphicsView::FullViewportUpdate);
    setBackgroundBrush(QBrush(Qt::white));
}



void MyGraphicsView::mousePressEvent(QMouseEvent * event)
{
    if (event->modifiers() == Qt::CTRL)
        setDragMode(QGraphicsView::ScrollHandDrag);
    else if (event->button() == Qt::RightButton)
        g_settings->nodeDragging = ONE_PIECE;

    m_previousPos = event->pos();

    QGraphicsView::mousePressEvent(event);
}

void MyGraphicsView::mouseReleaseEvent(QMouseEvent * event)
{
    QGraphicsView::mouseReleaseEvent(event);
    setDragMode(QGraphicsView::RubberBandDrag);
    g_settings->nodeDragging = NEARBY_PIECES;
}

void MyGraphicsView::mouseMoveEvent(QMouseEvent * event)
{
    //If the user drags the right mouse button while holding control,
    //the view rotates.
    bool rightButtonDown = event->buttons() & Qt::RightButton;
    if (event->modifiers() == Qt::CTRL && rightButtonDown)
    {
        QPointF viewCentre(width() / 2.0, height() / 2.0);
        double angle = angleBetweenTwoLines(viewCentre, m_previousPos, viewCentre, event->pos());
        angle *= 57.295779513; //convert to degrees

        rotate(angle);
        m_rotation += angle;

        m_previousPos = event->pos();

        g_settings->nodeDragging = NO_DRAGGING;
    }
    else
    {
        QGraphicsView::mouseMoveEvent(event);
    }
}


void MyGraphicsView::mouseDoubleClickEvent(QMouseEvent * event)
{
    //Find the node beneath the cursor.
    QGraphicsItem * item = itemAt(event->pos());

    GraphicsItemNode * graphicsItemNode = dynamic_cast<GraphicsItemNode *>(item);
    if (graphicsItemNode != 0)
        emit doubleClickedNode(graphicsItemNode->m_deBruijnNode);
}

//Adapted from:
//http://stackoverflow.com/questions/2663570/how-to-calculate-both-positive-and-negative-angle-between-two-lines
double MyGraphicsView::angleBetweenTwoLines(QPointF line1Start, QPointF line1End, QPointF line2Start, QPointF line2End)
{
    double a = line1End.x() - line1Start.x();
    double b = line1End.y() - line1Start.y();
    double c = line2End.x() - line2Start.x();
    double d = line2End.y() - line2Start.y();

    double atanA = atan2(a, b);
    double atanB = atan2(c, d);

    return atanA - atanB;
}

double MyGraphicsView::distance(double x1, double y1, double x2, double y2)
{
    double xDiff = x1 - x2;
    double yDiff = y1 - y2;
    return sqrt(xDiff * xDiff + yDiff * yDiff);
}

void MyGraphicsView::keyPressEvent(QKeyEvent * event)
{
    //This function uses angle in the same way that the mouse wheel code
    //in GraphicsViewZoom does.  This keeps the zoom steps consistent
    //between keyboard and mouse wheel.
    int angle = 0;


    bool shiftPressed = event->modifiers().testFlag(Qt::ShiftModifier);

    //Ctrl+C (Command+C on Mac) copies the selected sequences to the clipboard.
    if (event->key() == Qt::Key_C && (event->modifiers() & Qt::ControlModifier))
        emit copySelectedSequencesToClipboard();

    //Ctrl+S (Command+S on Mac) saves the selected sequences to a FASTA file.
    else if (event->key() == Qt::Key_S && (event->modifiers() & Qt::ControlModifier))
        emit saveSelectedSequencesToFile();

    //Ctrl+plus (Command+plus on Mac) zooms the view in.  If shift is pressed
    //as well, then it rotates clockwise.
    else if (event->matches(QKeySequence::ZoomIn) ||
            event->key() == Qt::Key_Equal ||
            event->key() == Qt::Key_Plus)
    {
        if (shiftPressed)
            changeRotation(1.0);
        else
            angle = 120;
    }

    //Ctrl+minus (Command+mins on Mac) zooms the view out.  If shift is pressed
    //as well, then it rotates anticlockwise.
    else if (event->matches(QKeySequence::ZoomOut) ||
             event->key() == Qt::Key_Minus ||
             event->key() == Qt::Key_Underscore)
    {
        if (shiftPressed)
            changeRotation(-1.0);
        else
            angle = -120;
    }

    //Actually change the zoom now, if appropriate.
    if (angle != 0)
    {
        double factor = qPow(m_zoom->m_zoomFactorBase, angle);
        m_zoom->gentleZoom(factor, KEYBOARD);
    }

    //The event press event handling of QGraphicsView will take care of using
    //the arrow keys to adjust scroll bars.
    QGraphicsView::keyPressEvent(event);
}

void MyGraphicsView::setAntialiasing(bool antialiasingOn)
{
    if (antialiasingOn)
    {
        setRenderHint(QPainter::Antialiasing, true);
        setRenderHint(QPainter::TextAntialiasing, true);
        g_settings->labelFont.setStyleStrategy(QFont::PreferDefault);
    }
    else
    {
        setRenderHint(QPainter::Antialiasing, false);
        setRenderHint(QPainter::TextAntialiasing, false);
        g_settings->labelFont.setStyleStrategy(QFont::NoAntialias);
    }
}

bool MyGraphicsView::isPointVisible(QPointF p)
{
    QPointF corner1, corner2, corner3, corner4;
    getFourViewportCornersInSceneCoordinates(&corner1, &corner2, &corner3, &corner4);
    QLineF boundary1(corner1, corner2);
    QLineF boundary2(corner2, corner3);
    QLineF boundary3(corner3, corner4);
    QLineF boundary4(corner4, corner1);

    return !(differentSidesOfLine(p, corner3, boundary1) || differentSidesOfLine(p, corner4, boundary2) ||
             differentSidesOfLine(p, corner1, boundary3) || differentSidesOfLine(p, corner2, boundary4));
}


//This function tests to see if two given points, p1 and p2, are on different sides of a line.
bool MyGraphicsView::differentSidesOfLine(QPointF p1, QPointF p2, QLineF line)
{
    bool p1Side = sideOfLine(p1, line);
    bool p2Side = sideOfLine(p2, line);
    return (p1Side != p2Side);
}
//This function tests to see if all four points are the same side of a line (returns false) or
//some are on different sides (returns true).
bool MyGraphicsView::differentSidesOfLine(QPointF p1, QPointF p2, QPointF p3, QPointF p4, QLineF line)
{
    bool p1Side = sideOfLine(p1, line);
    bool p2Side = sideOfLine(p2, line);
    if (p1Side != p2Side)
        return true;

    bool p3Side = sideOfLine(p3, line);
    if (p1Side != p3Side)
        return true;

    bool p4Side = sideOfLine(p4, line);
    return (p1Side != p4Side);
}

bool MyGraphicsView::sideOfLine(QPointF p, QLineF line)
{
    return ((p.y() - line.p1().y() - (p.x() - line.p1().x())*(line.p2().y() - line.p1().y())/(line.p2().x() - line.p1().x())) > 0);
}


//This function assumes that the line does intersect with the viewport
//boundary - i.e. one end of the line is in the viewport and one is not.
QPointF MyGraphicsView::findIntersectionWithViewportBoundary(QLineF line)
{
    QPointF c1, c2, c3, c4;
    getFourViewportCornersInSceneCoordinates(&c1, &c2, &c3, &c4);
    QLineF boundary1(c1, c2);
    QLineF boundary2(c2, c3);
    QLineF boundary3(c3, c4);
    QLineF boundary4(c4, c1);

    QPointF intersection;

    if (line.intersects(boundary1, &intersection) == QLineF::BoundedIntersection)
        return intersection;
    if (line.intersects(boundary2, &intersection) == QLineF::BoundedIntersection)
        return intersection;
    if (line.intersects(boundary3, &intersection) == QLineF::BoundedIntersection)
        return intersection;
    if (line.intersects(boundary4, &intersection) == QLineF::BoundedIntersection)
        return intersection;

    //The code should not get here, as the line should intersect with one of
    //the boundaries.
    return intersection;
}


//If a line intersections the scene rectangle but both of its end points are
//outside the scene rectangle, then this function will return the part of the
//line which is in the scene rectangle.
QLineF MyGraphicsView::findVisiblePartOfLine(QLineF line, bool * success)
{
    QPointF c1, c2, c3, c4;
    getFourViewportCornersInSceneCoordinates(&c1, &c2, &c3, &c4);
    QLineF boundary1(c1, c2);
    QLineF boundary2(c2, c3);
    QLineF boundary3(c3, c4);
    QLineF boundary4(c4, c1);

    QPointF intersection1;
    QPointF intersection2;
    QPointF intersection3;
    QPointF intersection4;

    *success = true;

    bool b1Intersects = (line.intersects(boundary1, &intersection1) == QLineF::BoundedIntersection);
    bool b2Intersects = (line.intersects(boundary2, &intersection2) == QLineF::BoundedIntersection);
    if (b1Intersects && b2Intersects)
        return QLineF(intersection1, intersection2);

    bool b3Intersects = (line.intersects(boundary3, &intersection3) == QLineF::BoundedIntersection);
    if (b1Intersects && b3Intersects)
        return QLineF(intersection1, intersection3);
    if (b2Intersects && b3Intersects)
        return QLineF(intersection2, intersection3);

    bool b4Intersects = (line.intersects(boundary4, &intersection4) == QLineF::BoundedIntersection);
    if (b1Intersects && b4Intersects)
        return QLineF(intersection1, intersection4);
    if (b2Intersects && b4Intersects)
        return QLineF(intersection2, intersection4);
    if (b3Intersects && b4Intersects)
        return QLineF(intersection3, intersection4);

    *success = false;
    return QLineF();
}


void MyGraphicsView::getFourViewportCornersInSceneCoordinates(QPointF * c1, QPointF * c2, QPointF * c3, QPointF * c4)
{
    *c1 = mapToScene(QPoint(0, 0));
    *c2 = mapToScene(QPoint(viewport()->width(), 0));
    *c3 = mapToScene(QPoint(viewport()->width(), viewport()->height()));
    *c4 = mapToScene(QPoint(0, viewport()->height()));
}

void MyGraphicsView::setRotation(double newRotation)
{
    undoRotation();
    changeRotation(newRotation);
}

void MyGraphicsView::changeRotation(double rotationChange)
{
    rotate(rotationChange);
    m_rotation += rotationChange;
}

void MyGraphicsView::undoRotation()
{
    rotate(-g_graphicsView->m_rotation);
    m_rotation = 0.0;
}