/* color_utils.cpp
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.org>
 * Copyright 1998 Gerald Combs
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 */

#include <ui/qt/utils/color_utils.h>
#include <ui/qt/utils/tango_colors.h>

#include <QApplication>
#include <QPalette>

// Colors we use in various parts of the UI.
//
// New colors should be chosen from tango_colors.h. The expert and hidden
// colors come from the GTK+ UI and are grandfathered in.
//
// At some point we should probably make these configurable along with the
// graph and sequence colors.

const QColor ColorUtils::expert_color_comment    = QColor (0xb7, 0xf7, 0x74);        /* Green */
const QColor ColorUtils::expert_color_chat       = QColor (0x80, 0xb7, 0xf7);        /* Light blue */
const QColor ColorUtils::expert_color_note       = QColor (0xa0, 0xff, 0xff);        /* Bright turquoise */
const QColor ColorUtils::expert_color_warn       = QColor (0xf7, 0xf2, 0x53);        /* Yellow */
const QColor ColorUtils::expert_color_error      = QColor (0xff, 0x5c, 0x5c);        /* Pale red */
const QColor ColorUtils::expert_color_foreground = QColor (0x00, 0x00, 0x00);        /* Black */
const QColor ColorUtils::hidden_proto_item       = QColor (0x44, 0x44, 0x44);        /* Gray */

ColorUtils::ColorUtils(QObject *parent) :
    QObject(parent)
{
}

//
// A color_t has RGB values in [0,65535].
// Qt RGB colors have RGB values in [0,255].
//
// 65535/255 = 257 = 0x0101, so converting from [0,255] to
// [0,65535] involves just shifting the 8-bit value left 8 bits
// and ORing them together.
//
// Converting from [0,65535] to [0,255] without rounding involves
// just shifting the 16-bit value right 8 bits; I guess you could
// round them by adding 0x80 to the value before shifting.
//
QColor ColorUtils::fromColorT (const color_t *color) {
    if (!color) return QColor();
    // Convert [0,65535] values to [0,255] values
    return QColor(color->red >> 8, color->green >> 8, color->blue >> 8);
}

QColor ColorUtils::fromColorT(color_t color)
{
    return fromColorT(&color);
}

const color_t ColorUtils::toColorT(const QColor color)
{
    color_t colort;

    // Convert [0,255] values to [0,65535] values
    colort.red = (color.red() << 8) | color.red();
    colort.green = (color.green() << 8) | color.green();
    colort.blue = (color.blue() << 8) | color.blue();

    return colort;
}

QRgb ColorUtils::alphaBlend(const QColor &color1, const QColor &color2, qreal alpha)
{
    alpha = qBound(qreal(0.0), alpha, qreal(1.0));

    int r1 = color1.red() * alpha;
    int g1 = color1.green() * alpha;
    int b1 = color1.blue() * alpha;
    int r2 = color2.red() * (1 - alpha);
    int g2 = color2.green() * (1 - alpha);
    int b2 = color2.blue() * (1 - alpha);

    QColor alpha_color(r1 + r2, g1 + g2, b1 + b2);
    return alpha_color.rgb();
}

QRgb ColorUtils::alphaBlend(const QBrush &brush1, const QBrush &brush2, qreal alpha)
{
    return alphaBlend(brush1.color(), brush2.color(), alpha);
}

QList<QRgb> ColorUtils::graph_colors_;
const QList<QRgb> ColorUtils::graphColors()
{
    if (graph_colors_.isEmpty()) {
        // Available graph colors
        // XXX - Add custom
        graph_colors_ = QList<QRgb>()
                << tango_aluminium_6 // Bar outline (use black instead)?
                << tango_sky_blue_5
                << tango_butter_6
                << tango_chameleon_5
                << tango_scarlet_red_5
                << tango_plum_5
                << tango_orange_6
                << tango_aluminium_3
                << tango_sky_blue_3
                << tango_butter_3
                << tango_chameleon_3
                << tango_scarlet_red_3
                << tango_plum_3
                << tango_orange_3;
    }
    return graph_colors_;
}

QRgb ColorUtils::graphColor(int item)
{
    if (graph_colors_.isEmpty()) graphColors(); // Init list.
    return graph_colors_[item % graph_colors_.size()];
}

QList<QRgb> ColorUtils::sequence_colors_;
QRgb ColorUtils::sequenceColor(int item)
{
    if (sequence_colors_.isEmpty()) {
        // Available sequence colors. Copied from gtk/graph_analysis.c.
        // XXX - Add custom?
        sequence_colors_ = QList<QRgb>()
                << qRgb(144, 238, 144)
                << qRgb(255, 160, 123)
                << qRgb(255, 182, 193)
                << qRgb(250, 250, 210)
                << qRgb(255, 255, 52)
                << qRgb(103, 205, 170)
                << qRgb(224, 255, 255)
                << qRgb(176, 196, 222)
                << qRgb(135, 206, 254)
                << qRgb(211, 211, 211);
    }
    return sequence_colors_[item % sequence_colors_.size()];
}

bool ColorUtils::themeIsDark()
{
    return qApp->palette().windowText().color().lightness() > qApp->palette().window().color().lightness();
}

// Qt < 5.12.6 on macOS always uses Qt::blue for the link color, which is
// unreadable when using a dark theme. Changing the application palette
// via ...Application::setPalette is problematic, since QGuiApplication
// sets a flag (ApplicationPaletteExplicitlySet) which keeps us from
// catching theme changes.
//
// themeLinkBrush and themeLinkStyle provide convenience routines for
// fetching the link brush and style.
//
// We could also override MainApplication::palette, but keeping the
// routines together here seemed to make more sense.
QBrush ColorUtils::themeLinkBrush()
{
#if QT_VERSION < QT_VERSION_CHECK(5, 12, 6)
    // https://bugreports.qt.io/browse/QTBUG-71740
    if (themeIsDark()) {
        return QBrush(tango_sky_blue_2);
    }
#endif
    return qApp->palette().link();
}

QString ColorUtils::themeLinkStyle()
{
    QString link_style;

    if (themeIsDark()) {
        link_style = QString("<style>a:link { color: %1; }</style>")
                .arg(themeLinkBrush().color().name());
    }
    return link_style;
}

const QColor ColorUtils::contrastingTextColor(const QColor color)
{
    bool background_is_light = color.lightness() > 127;
    if ( (background_is_light && !ColorUtils::themeIsDark()) || (!background_is_light && ColorUtils::themeIsDark()) ) {
        return QApplication::palette().text().color();
    }
    return QApplication::palette().base().color();
}

const QColor ColorUtils::hoverBackground()
{
    QPalette hover_palette = QApplication::palette();
#if defined(Q_OS_MAC)
    hover_palette.setCurrentColorGroup(QPalette::Active);
    return hover_palette.highlight().color();
#else
    return ColorUtils::alphaBlend(hover_palette.window(), hover_palette.highlight(), 0.5);
#endif
}

const QColor ColorUtils::warningBackground()
{
    if (themeIsDark()) {
        return QColor(tango_butter_6);
    }
    return QColor(tango_butter_2);
}
