/*
    SPDX-FileCopyrightText: 2003-2005 Max Howell <max.howell@methylblue.com>
    SPDX-FileCopyrightText: 2005 Mark Kretschmann <kretschmann@kde.org>

    SPDX-License-Identifier: GPL-2.0-or-later
*/

#include "blockAnalyzer.h"

#include <cmath>

#include <QPainter>        //paletteChange()

static inline uint myMax( uint v1, uint v2 ) { return v1 > v2 ? v1 : v2; }

BlockAnalyzer::BlockAnalyzer( QWidget *parent )
    : Analyzer::Base2D( parent, 9 )
    , m_columns( 0 )         //uint
    , m_rows( 0 )            //uint
    , m_y( 0 )               //uint
    , m_barPixmap( 1, 1 )    //null qpixmaps cause crashes
    , m_topBarPixmap( WIDTH, HEIGHT )
    , m_scope( MIN_COLUMNS ) //Scope
    , m_store( 1 << 8, 0 )   //vector<uint>
    , m_fade_bars( FADE_SIZE ) //vector<QPixmap>
    , m_fade_pos( 1 << 8, 50 ) //vector<uint>
    , m_fade_intensity( 1 << 8, 32 ) //vector<uint>
{
    setMinimumSize( MIN_COLUMNS*(WIDTH+1) -1, MIN_ROWS*(HEIGHT+1) -1 ); //-1 is padding, no drawing takes place there
    setMaximumWidth( MAX_COLUMNS*(WIDTH+1) -1 );
    setMaximumHeight( MIN_ROWS*(HEIGHT+1) -1 );

    // mxcl says null pixmaps cause crashes, so let's play it safe
    for (int i = 0; i < FADE_SIZE; ++i)
        m_fade_bars[i] = QPixmap( 1, 1 );
}

BlockAnalyzer::~BlockAnalyzer()
{
}

void
BlockAnalyzer::resizeEvent( QResizeEvent *e )
{
    Analyzer::Base2D::resizeEvent( e );

    const uint oldRows = m_rows;

    //all is explained in analyze()..
    //+1 to counter -1 in maxSizes, trust me we need this!
    m_columns = qMin<uint>( uint(double(width()+1) / (WIDTH+1)), MAX_COLUMNS );
    m_rows    = uint(double(height()+1) / (HEIGHT+1));

    //this is the y-offset for drawing from the top of the widget
    m_y = (height() - (m_rows * (HEIGHT+1)) + 2) / 2;

    m_scope.resize( m_columns );

    if( m_rows != oldRows ) {
        m_barPixmap = QPixmap( WIDTH, m_rows*(HEIGHT+1) );

        for (int i = 0; i < FADE_SIZE; ++i)
            m_fade_bars[i] = QPixmap( WIDTH, m_rows*(HEIGHT+1) );

        m_yscale.resize( m_rows + 1 );

        const float PRE = 1, PRO = 1; //PRE and PRO allow us to restrict the range somewhat

        for( uint z = 0; z < m_rows; ++z )
            m_yscale[z] = 1 - (log10( PRE+z ) / log10( PRE+m_rows+PRO ));

        m_yscale[m_rows] = 0;

        determineStep();
        paletteChange( palette() );
    }
    else if( width() > e->oldSize().width() || height() > e->oldSize().height() )
        drawBackground();

    analyze( m_scope );
}

void
BlockAnalyzer::determineStep()
{
    // falltime is dependent on rowcount due to our digital resolution (ie we have boxes/blocks of pixels)
    // I calculated the value 30 based on some trial and error

    const double fallTime = 30 * m_rows;
    m_step = double(m_rows * 80) / fallTime; //80 = ~milliseconds between signals with audio data
}

void
BlockAnalyzer::transform( QVector<float> &s ) //pure virtual
{
    for(int x = 0; x < s.size(); ++x)
        s[x] *= 2;

    float *front = static_cast<float*>( &s.front() );

    m_fht->spectrum( front );
    m_fht->scale( front, 1.0 / 20 );

    //the second half is pretty dull, so only show it if the user has a large analyzer
    //by setting to m_scope.size() if large we prevent interpolation of large analyzers, this is good!
    s.resize( m_scope.size() <= MAX_COLUMNS/2 ? MAX_COLUMNS/2 : m_scope.size() );
}

void
BlockAnalyzer::analyze( const QVector<float> &s )
{
    Analyzer::interpolate( s, m_scope );
    update();
}

void
BlockAnalyzer::paintEvent(QPaintEvent*)
{
    // y = 2 3 2 1 0 2
    //     . . . . # .
    //     . . . # # .
    //     # . # # # #
    //     # # # # # #
    //
    // visual aid for how this analyzer works.
    // y represents the number of blanks
    // y starts from the top and increases in units of blocks

    // m_yscale looks similar to: { 0.7, 0.5, 0.25, 0.15, 0.1, 0 }
    // if it contains 6 elements there are 5 rows in the analyzer


    QPainter p( this );

    // Paint the background
    p.drawPixmap(0, 0, m_background);
    //   p.fillRect(rect(), palette().color( QPalette::Active, QPalette::Window ));

    uint y;

    for(int x = 0; x < m_scope.size(); ++x)
    {
        // determine y
        for( y = 0; m_scope[x] < m_yscale[y]; ++y )
            ;

        // this is opposite to what you'd think, higher than y
        // means the bar is lower than y (physically)
        if( (float)y > m_store[x] )
            y = uint(m_store[x] += m_step);
        else
            m_store[x] = y;

        // if y is lower than m_fade_pos, then the bar has exceeded the height of the fadeout
        // if the fadeout is quite faded now, then display the new one
        if(y <= m_fade_pos[x] /*|| m_fade_intensity[x] < FADE_SIZE / 3*/) {
            m_fade_pos[x] = y;
            m_fade_intensity[x] = FADE_SIZE;
        }

        if( m_fade_intensity[x] > 0 ) {
            const uint offset = --m_fade_intensity[x];
            const uint y = m_y + (m_fade_pos[x] * (HEIGHT+1));
            p.drawPixmap( x*(WIDTH+1), y, m_fade_bars[offset], 0, 0, WIDTH, height() - y );
        }

        if( m_fade_intensity[x] == 0 )
            m_fade_pos[x] = m_rows;

        //REMEMBER: y is a number from 0 to m_rows, 0 means all blocks are glowing, m_rows means none are
        p.drawPixmap( x*(WIDTH+1), y*(HEIGHT+1) + m_y, *bar(), 0, y*(HEIGHT+1), -1, -1 );
    }

    for( uint x = 0; x < m_store.size(); ++x )
        p.drawPixmap( x*(WIDTH+1), int(m_store[x])*(HEIGHT+1) + m_y, m_topBarPixmap );
}





static inline void
adjustToLimits( int &b, int &f, uint &amount )
{
    // with a range of 0-255 and maximum adjustment of amount,
    // maximise the difference between f and b

    if( b < f ) {
        if( b > 255 - f ) {
            amount -= f;
            f = 0;
        } else {
            amount -= (255 - f);
            f = 255;
        }
    }
    else {
        if( f > 255 - b ) {
            amount -= f;
            f = 0;
        } else {
            amount -= (255 - f);
            f = 255;
        }
    }
}

/**
 * Clever contrast function
 *
 * It will try to adjust the foreground color such that it contrasts well with the background
 * It won't modify the hue of fg unless absolutely necessary
 * @return the adjusted form of fg
 */
QColor
ensureContrast( const QColor &bg, const QColor &fg, uint _amount = 150 )
{
    class OutputOnExit {
    public:
        OutputOnExit( const QColor &color ) : c( color ) {}
        ~OutputOnExit() { int h,s,v; c.getHsv( &h, &s, &v ); }
    private:
        const QColor &c;
    };

    // hack so I don't have to cast everywhere
#define amount static_cast<int>(_amount)
    //     #define STAMP debug() << (QValueList<int>() << fh << fs << fv);
    //     #define STAMP1( string ) debug() << string << ": " << (QValueList<int>() << fh << fs << fv);
    //     #define STAMP2( string, value ) debug() << string << "=" << value << ": " << (QValueList<int>() << fh << fs << fv);

    OutputOnExit allocateOnTheStack( fg );

    int bh, bs, bv;
    int fh, fs, fv;

    bg.getHsv( &bh, &bs, &bv );
    fg.getHsv( &fh, &fs, &fv );

    int dv = abs( bv - fv );

    //     STAMP2( "DV", dv );

    // value is the best measure of contrast
    // if there is enough difference in value already, return fg unchanged
    if( dv > amount )
        return fg;

    int ds = abs( bs - fs );

    //     STAMP2( "DS", ds );

    // saturation is good enough too. But not as good. TODO adapt this a little
    if( ds > amount )
        return fg;

    int dh = abs( bh - fh );

    //     STAMP2( "DH", dh );

    if( dh > 120 ) {
        // a third of the colour wheel automatically guarentees contrast
        // but only if the values are high enough and saturations significant enough
        // to allow the colours to be visible and not be shades of grey or black

        // check the saturation for the two colours is sufficient that hue alone can
        // provide sufficient contrast
        if( ds > amount / 2 && (bs > 125 && fs > 125) )
            //             STAMP1( "Sufficient saturation difference, and hues are compliemtary" );
            return fg;
        else if( dv > amount / 2 && (bv > 125 && fv > 125) )
            //             STAMP1( "Sufficient value difference, and hues are compliemtary" );
            return fg;

        //         STAMP1( "Hues are complimentary but we must modify the value or saturation of the contrasting colour" );

        //but either the colours are two desaturated, or too dark
        //so we need to adjust the system, although not as much
        ///_amount /= 2;
    }

    if( fs < 50 && ds < 40 ) {
        // low saturation on a low saturation is sad
        const int tmp = 50 - fs;
        fs = 50;
        if( amount > tmp )
            _amount -= tmp;
        else
            _amount = 0;
    }

    // test that there is available value to honor our contrast requirement
    if( 255 - dv < amount )
    {
        // we have to modify the value and saturation of fg
        //adjustToLimits( bv, fv, amount );

        //         STAMP

        // see if we need to adjust the saturation
        if( amount > 0 )
            adjustToLimits( bs, fs, _amount );

        //         STAMP

        // see if we need to adjust the hue
        if( amount > 0 )
            fh += amount; // cycles around;

        //         STAMP

        return QColor::fromHsv( fh, fs, fv );
    }

    //     STAMP

    if( fv > bv && bv > amount )
        return QColor::fromHsv( fh, fs, bv - amount );

    //     STAMP

    if( fv < bv && fv > amount )
        return QColor::fromHsv( fh, fs, fv - amount );

    //     STAMP

    if( fv > bv && (255 - fv > amount) )
        return QColor::fromHsv( fh, fs, fv + amount );

    //     STAMP

    if( fv < bv && (255 - bv > amount ) )
        return QColor::fromHsv( fh, fs, bv + amount );

    //     STAMP
    //     debug() << "Something went wrong!\n";

    return Qt::blue;

#undef amount
    //     #undef STAMP
}

void
BlockAnalyzer::paletteChange( const QPalette& )
{
    const QColor bg = palette().color(QPalette::Active, QPalette::Window);
    const QColor fg = ensureContrast(bg, palette().color(QPalette::Active, QPalette::WindowText));

    m_topBarPixmap.fill( fg );

    const double dr = 15*double(bg.red()   - fg.red())   / (m_rows*16);
    const double dg = 15*double(bg.green() - fg.green()) / (m_rows*16);
    const double db = 15*double(bg.blue()  - fg.blue())  / (m_rows*16);
    const int r = fg.red(), g = fg.green(), b = fg.blue();

    bar()->fill( bg );

    QPainter p( bar() );
    for( int y = 0; (uint)y < m_rows; ++y )
        //graduate the fg color
        p.fillRect( 0, y*(HEIGHT+1), WIDTH, HEIGHT, QColor( r+int(dr*y), g+int(dg*y), b+int(db*y) ) );

    {
        const QColor bg = palette().color( QPalette::Active, QPalette::Window ).darker(112);

        //make a complimentary fadebar colour
        //TODO dark is not always correct, dumbo!
        int h,s,v; palette().color( QPalette::Active, QPalette::Window ).darker(150).getHsv( &h, &s, &v );
        const QColor fg = QColor::fromHsv( h + 60, s, v );

        const double dr = fg.red() - bg.red();
        const double dg = fg.green() - bg.green();
        const double db = fg.blue() - bg.blue();
        const int r = bg.red(), g = bg.green(), b = bg.blue();

        // Precalculate all fade-bar pixmaps
        for(int y = 0; y < FADE_SIZE; ++y) {
            m_fade_bars[y].fill( palette().color( QPalette::Active, QPalette::Window ) );
            QPainter f( &m_fade_bars[y] );
            for( int z = 0; (uint)z < m_rows; ++z ) {
                const double Y = 1.0 - (log10( static_cast<float>(FADE_SIZE) - y ) / log10( static_cast<float>(FADE_SIZE) ));
                f.fillRect( 0, z*(HEIGHT+1), WIDTH, HEIGHT, QColor( r+int(dr*Y), g+int(dg*Y), b+int(db*Y) ) );
            }
        }
    }

    drawBackground();
}

void
BlockAnalyzer::drawBackground()
{
    const QColor bg = palette().color( QPalette::Active, QPalette::Window);
    const QColor bgdark = bg.darker(112);

    m_background.fill( bg );

    QPainter p( &m_background );
    for( int x = 0; (uint)x < m_columns; ++x )
        for( int y = 0; (uint)y < m_rows; ++y )
            p.fillRect( x*(WIDTH+1), y*(HEIGHT+1) + m_y, WIDTH, HEIGHT, bgdark );

}
