/* Bespin widget style for Qt4
   Copyright (C) 2007 Thomas Luebking <thomas.luebking@web.de>

   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public
   License version 2 as published by the Free Software Foundation.

   This library 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
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public License
   along with this library; see the file COPYING.LIB.  If not, write to
   the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
   Boston, MA 02110-1301, USA.
 */

#include "colors.h"
#define CLAMP(x,l,u) (x) < (l) ? (l) :\
(x) > (u) ? (u) :\
(x)
#include <QWidget>
#include <QApplication>

using namespace Bespin;

const QColor &
Colors::bg(const QPalette &pal, const QWidget *w)
{
    QPalette::ColorRole role;
    if (!w)
        role = QPalette::Window;
    else if (w->parentWidget())
        role = w->parentWidget()->backgroundRole();
    else
        role = w->backgroundRole();

//     if (pal.brush(role).style() > 1)
        return pal.color(role);
//     return QApplication::palette().color(role);
}

int
Colors::contrast(const QColor &a, const QColor &b)
{
    int ar,ag,ab,br,bg,bb;
    a.getRgb(&ar,&ag,&ab);
    b.getRgb(&br,&bg,&bb);

    int diff = 299*(ar-br) + 587*(ag-bg) + 114*(ab-bb);
    diff = (diff < 0) ? -diff : 90*diff/100;
    int perc = diff / 2550;

    diff = qMax(ar,br) + qMax(ag,bg) + qMax(ab,bb)
        - (qMin(ar,br) + qMin(ag,bg) + qMin(ab,bb));

    perc += diff/765;
    perc /= 2;

    return perc;
}

QPalette::ColorRole
Colors::counterRole(QPalette::ColorRole role)
{
    switch (role) {
    case QPalette::ButtonText: //8
        return QPalette::Button;
    case QPalette::WindowText: //0
        return QPalette::Window;
    case QPalette::HighlightedText: //13
        return QPalette::Highlight;
    case QPalette::Window: //10
        return QPalette::WindowText;
    case QPalette::Base: //9
        return QPalette::Text;
    case QPalette::Text: //6
        return QPalette::Base;
    case QPalette::Highlight: //12
        return QPalette::HighlightedText;
    case QPalette::Button: //1
        return QPalette::ButtonText;
    default:
        return QPalette::Window;
    }
}

bool
Colors::counterRole(QPalette::ColorRole &from, QPalette::ColorRole &to, QPalette::ColorRole defFrom,
                                                                        QPalette::ColorRole defTo)
{
    switch (from) {
    case QPalette::WindowText: //0
        to = QPalette::Window; break;
    case QPalette::Window: //10
        to = QPalette::WindowText; break;
    case QPalette::Base: //9
        to = QPalette::Text; break;
    case QPalette::Text: //6
        to = QPalette::Base; break;
    case QPalette::Button: //1
        to = QPalette::ButtonText; break;
    case QPalette::ButtonText: //8
        to = QPalette::Button; break;
    case QPalette::Highlight: //12
        to = QPalette::HighlightedText; break;
    case QPalette::HighlightedText: //13
        to = QPalette::Highlight; break;
    default:
        from = defFrom;
        to = defTo;
        return false;
    }
    return true;
}

QColor
Colors::emphasize(const QColor &c, int value)
{
    int h,s,v,a;
    QColor ret;
    c.getHsv(&h,&s,&v,&a);
    if (v < 75+value) {
        ret.setHsv(h,s,CLAMP(85+value,85,255),a);
        return ret;
    }
    if (v > 200) {
        if (s > 30) {
            h -= 5; if (h < 0) h = 360 + h;
            s = (s<<3)/9;
            v += value;
            ret.setHsv(h,CLAMP(s,30,255),CLAMP(v,0,255),a);
            return ret;
        }
        if (v > 230) {
            ret.setHsv(h,s,CLAMP(v-value,0,255),a);
            return ret;
        }
    }
    if (v > 128)
        ret.setHsv(h,s,CLAMP(v+value,0,255),a);
    else
        ret.setHsv(h,s,CLAMP(v-value,0,255),a);
    return ret;
}

bool
Colors::haveContrast(const QColor &a, const QColor &b)
{
    int ar,ag,ab,br,bg,bb;
    a.getRgb(&ar,&ag,&ab);
    b.getRgb(&br,&bg,&bb);

    int diff = (299*(ar-br) + 587*(ag-bg) + 114*(ab-bb));

    if (qAbs(diff) < 91001)
        return false;

    diff = qMax(ar,br) + qMax(ag,bg) + qMax(ab,bb)
        - (qMin(ar,br) + qMin(ag,bg) + qMin(ab,bb));

    return (diff > 300);
}

QColor
Colors::light(const QColor &c, int value)
{
    int h,s,v, a;
    c.getHsv(&h,&s,&v,&a);
    QColor ret;
    if (v < 255-value)
    {
        ret.setHsv(h,s,CLAMP(v+value,0,255),a); //value could be negative
        return ret;
    }
    // psychovisual uplightning, i.e. shift hue and lower saturation
    if (s > 30)
    {
        h -= (value*5/20); if (h < 0) h = 400 + h;
        s = CLAMP((s<<3)/9,30,255);
        ret.setHsv(h,s,255,a);
        return ret;
    }
    else // hue shifting has no sense, half saturation (btw, white won't get brighter :)
        ret.setHsv(h,s>>1,255,a);
    return ret;
}

QColor
Colors::mid(const QColor &c1, const QColor &c2, int w1, int w2)
{
    int sum = (w1+w2);
    if (!sum)
       return Qt::black;

    int r,g,b,a;
#if 0
    QColor c1 = oc1;
    b = value(c1);
    if (b < 70)
    {
        c1.getHsv(&r,&g,&b,&a);
        c1.setHsv(r,g,70,a);
    }
#endif
    r = (w1*c1.red() + w2*c2.red())/sum; r = CLAMP(r,0,255);
    g = (w1*c1.green() + w2*c2.green())/sum; g = CLAMP(g,0,255);
    b = (w1*c1.blue() + w2*c2.blue())/sum; b = CLAMP(b,0,255);
    a = (w1*c1.alpha() + w2*c2.alpha())/sum; a = CLAMP(a,0,255);
    return QColor(r,g,b,a);
}

int
Colors::value(const QColor &c)
{
    int v = c.red();
    if (c.green() > v) v = c.green();
    if (c.blue() > v) v = c.blue();
    return v;
}
