/*
    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>
    , m_step(0)
{
    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);
}
