/* === This file is part of Calamares - <https://github.com/calamares> ===
 *
 *   Copyright 2014-2015, Teo Mrnjavac <teo@kde.org>
 *   Copyright 2017-2018, Adriaan de Groot <groot@kde.org>
 *
 *   Originally from the Manjaro Installation Framework
 *   by Roland Singer <roland@manjaro.org>
 *   Copyright (C) 2007 Free Software Foundation, Inc.
 *
 *   Calamares 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.
 *
 *   Calamares 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 Calamares. If not, see <http://www.gnu.org/licenses/>.
 */

#include <cmath>

#include "utils/Logger.h"

#include "timezonewidget.h"


static constexpr double MAP_Y_OFFSET = 0.125;
static constexpr double MAP_X_OFFSET = -0.0370;
constexpr static double MATH_PI = 3.14159265;

#ifdef DEBUG_TIMEZONES
// Adds a label to the timezone with this name
constexpr static QLatin1Literal ZONE_NAME( "zone" );
#endif

TimeZoneWidget::TimeZoneWidget( QWidget* parent ) :
    QWidget( parent )
{
    setMouseTracking( false );
    setCursor( Qt::PointingHandCursor );

    // Font
    font.setPointSize( 12 );
    font.setBold( false );

    // Images
    background = QImage( ":/images/bg.png" ).scaled( X_SIZE, Y_SIZE, Qt::IgnoreAspectRatio, Qt::SmoothTransformation );
    pin = QImage( ":/images/pin.png" );

    // Set size
    setMinimumSize( background.size() );
    setMaximumSize( background.size() );

    // Zone images
    QStringList zones = QString( ZONES ).split( " ", QString::SkipEmptyParts );
    for ( int i = 0; i < zones.size(); ++i )
    {
        timeZoneImages.append( QImage( ":/images/timezone_" + zones.at( i ) + ".png" ).scaled( X_SIZE, Y_SIZE, Qt::IgnoreAspectRatio, Qt::SmoothTransformation ) );
#ifdef DEBUG_TIMEZONES
        timeZoneImages.last().setText( ZONE_NAME, zones.at( i ) );
#endif
    }
}


void TimeZoneWidget::setCurrentLocation( QString region, QString zone )
{
    QHash<QString, QList<LocaleGlobal::Location> > hash = LocaleGlobal::getLocations();

    if ( !hash.contains( region ) )
        return;

    QList<LocaleGlobal::Location> locations = hash.value( region );
    for ( int i = 0; i < locations.size(); ++i )
    {
        if ( locations.at( i ).zone == zone )
        {
            setCurrentLocation( locations.at( i ) );
            break;
        }
    }
}


void TimeZoneWidget::setCurrentLocation( LocaleGlobal::Location location )
{
    currentLocation = location;

    // Set zone
    QPoint pos = getLocationPosition( currentLocation.longitude, currentLocation.latitude );

#ifdef DEBUG_TIMEZONES
    cDebug() << "Setting location" << location.region << location.zone << location.country;
    cDebug() << Logger::SubEntry << "longitude" << location.longitude << "latitude" << location.latitude;
    cDebug() << Logger::SubEntry << "pixel x" << pos.x() << "pixel y" << pos.y();

    bool found = false;
#endif


    for ( int i = 0; i < timeZoneImages.size(); ++i )
    {
        QImage zone = timeZoneImages[i];

        // If not transparent set as current
        if ( zone.pixel( pos ) != RGB_TRANSPARENT )
        {
#ifdef DEBUG_TIMEZONES
            // Log *all* the zones that contain this point,
            // but only pick the first.
            if ( !found )
            {
                currentZoneImage = zone;
                found = true;
                cDebug() << Logger::SubEntry << "First zone found" << i << zone.text( ZONE_NAME );
            }
            else
                cDebug() << Logger::SubEntry << "Also in zone" << i << zone.text( ZONE_NAME );
#else
            currentZoneImage = zone;
            break;
#endif
        }
    }

    // Repaint widget
    repaint();
}



//###
//### Private
//###


QPoint TimeZoneWidget::getLocationPosition( double longitude, double latitude )
{
    const int width = this->width();
    const int height = this->height();

    double x = ( width / 2.0 + ( width / 2.0 ) * longitude / 180.0 ) + MAP_X_OFFSET * width;
    double y = ( height / 2.0 - ( height / 2.0 ) * latitude / 90.0 ) + MAP_Y_OFFSET * height;

    // Far north, the MAP_Y_OFFSET no longer holds, cancel the Y offset; it's noticeable
    // from 62 degrees north, so scale those 28 degrees as if the world is flat south
    // of there, and we have a funny "rounded" top of the world. In practice the locations
    // of the different cities / regions looks ok -- at least Thule ends up in the right
    // country, and Inuvik isn't in the ocean.
    if ( latitude > 70.0 )
        y -= sin( MATH_PI * ( latitude - 70.0 ) / 56.0 ) * MAP_Y_OFFSET * height * 0.8;
    if ( latitude > 74.0 )
        y += 4;
    if ( latitude > 69.0 )
        y -= 2;
    if ( latitude > 59.0 )
        y -= 4 * int( ( latitude - 54.0 ) / 5.0 );
    if ( latitude > 54.0 )
        y -= 2;
    if ( latitude > 49.0 )
        y -= int ( (latitude - 44.0) / 5.0 );
    // Far south, some stretching occurs as well, but it is less pronounced.
    // Move down by 1 pixel per 5 degrees past 10 south
    if ( latitude < 0 )
        y += int( (-latitude) / 5.0 );
    // Antarctica isn't shown on the map, but you could try clicking there
    if ( latitude < -60 )
        y = height - 1;

    if ( x < 0 )
        x = width+x;
    if ( x >= width )
        x -= width;
    if ( y < 0 )
        y = height+y;
    if ( y >= height )
        y -= height;

    return QPoint( int(x), int(y) );
}


void TimeZoneWidget::paintEvent( QPaintEvent* )
{
    const int width = this->width();
    const int height = this->height();
    QFontMetrics fontMetrics( font );
    QPainter painter( this );

    painter.setRenderHint( QPainter::Antialiasing );
    painter.setFont( font );

    // Draw background
    painter.drawImage( 0, 0, background );

    // Draw zone image
    painter.drawImage( 0, 0, currentZoneImage );

#ifdef DEBUG_TIMEZONES
    QPoint point = getLocationPosition( currentLocation.longitude, currentLocation.latitude );
    // Draw latitude lines
    for ( int y_lat = -50; y_lat < 80 ; y_lat+=5 )
    {
        QPen p( y_lat ? Qt::black : Qt::red );
        p.setWidth( 0 );
        painter.setPen( p );
        QPoint latLine0( getLocationPosition( 0, y_lat ) );
        int llx = latLine0.x() + ((y_lat & 1) ? -10 : 0);
        int lly = latLine0.y();

        for ( int c = 0 ; c < width ; ++c )
            painter.drawPoint( c, lly );
    }
    // Just a dot in the selected location, no label
    painter.setPen( Qt::red );
    painter.drawPoint( point );
#else
    // Draw pin at current location
    QPoint point = getLocationPosition( currentLocation.longitude, currentLocation.latitude );

    painter.drawImage( point.x() - pin.width()/2, point.y() - pin.height()/2, pin );

    // Draw text and box
    const int textWidth = fontMetrics.width( LocaleGlobal::Location::pretty( currentLocation.zone ) );
    const int textHeight = fontMetrics.height();

    QRect rect = QRect( point.x() - textWidth/2 - 5, point.y() - textHeight - 8, textWidth + 10, textHeight - 2 );

    if ( rect.x() <= 5 )
        rect.moveLeft( 5 );
    if ( rect.right() >= width-5 )
        rect.moveRight( width - 5 );
    if ( rect.y() <= 5 )
        rect.moveTop( 5 );
    if ( rect.y() >= height-5 )
        rect.moveBottom( height-5 );

    painter.setPen( QPen() ); // no pen
    painter.setBrush( QColor( 40, 40, 40 ) );
    painter.drawRoundedRect( rect, 3, 3 );
    painter.setPen( Qt::white );
    painter.drawText( rect.x() + 5, rect.bottom() - 4, LocaleGlobal::Location::pretty( currentLocation.zone ) );
#endif

    painter.end();
}



void TimeZoneWidget::mousePressEvent( QMouseEvent* event )
{
    if ( event->button() != Qt::LeftButton )
        return;

    // Set nearest location
    int nX = 999999, mX = event->pos().x();
    int nY = 999999, mY = event->pos().y();
    QHash<QString, QList<LocaleGlobal::Location> > hash = LocaleGlobal::getLocations();
    QHash<QString, QList<LocaleGlobal::Location> >::iterator iter = hash.begin();

    while ( iter != hash.end() )
    {
        QList<LocaleGlobal::Location> locations = iter.value();

        for ( int i = 0; i < locations.size(); ++i )
        {
            LocaleGlobal::Location loc = locations[i];
            QPoint locPos = getLocationPosition( loc.longitude, loc.latitude );

            if ( ( abs( mX - locPos.x() ) + abs( mY - locPos.y() )  <  abs( mX - nX ) + abs( mY - nY ) ) )
            {
                currentLocation = loc;
                nX = locPos.x();
                nY = locPos.y();
            }
        }

        ++iter;
    }

    // Set zone image and repaint widget
    setCurrentLocation( currentLocation );

    // Emit signal
    emit locationChanged( currentLocation );
}