#include "elescroll.h"
#include "playwin.h"
#include <QOpenGLWidget>
#include <QPainter>
#include <QPaintEvent>
#include <QDebug>

EleScroll::EleScroll(QWidget *parent, QList<QPixmap> imgs, char direct, double speed) : QWidget{parent}, imgs(imgs), direct(direct) {
    auto img0 = imgs[0];
    qDebug().nospace()<<"  SrcScroll img cnt "<<imgs.size()<<", "<<img0.width()<<"x"<<img0.height()<<" direct "<<direct<<" speed "<<speed;
    if(speed==0) return;
    int width = 0, height = 0;
    for(auto &img : imgs) {
        width += img.width();
        height += img.height();
    }
    if(direct=='l') end = -(width-step);
    else if(direct=='r') end = width-step;
    else if(direct=='t') end = -(height-step);
    else if(direct=='b') end = height-step;
    else direct = 0;
    if(direct==0) return;

    interval = step = 1;
    if(speed > 60) step = (int) round(speed/60);
    else if(speed < 60) interval = (int) round(60/speed);
}

void EleScroll::paintEvent(QPaintEvent *e) {
    if(imgs.isEmpty()) return;
    auto rect = e->rect();
    QPainter painter(this);
    painter.setRenderHints(QPainter::Antialiasing|QPainter::SmoothPixmapTransform);
    if(direct=='l') {
        int ii = 0, x = cur;
        do {
            if(x > rect.left()-imgs[ii].width() && x < rect.right()+1) painter.drawPixmap(x, 0, imgs[ii]);
            x += imgs[ii].width();
            if(++ii >= imgs.size()) ii = 0;
        } while(x < rect.right()+1);
    } else if(direct=='r') {
        int ii = imgs.size()-1, x = cur + width();
        bool con1;
        do {
            x -= imgs[ii].width();
            con1 = x > rect.left()-imgs[ii].width();
            if(con1 && x < rect.right()+1) painter.drawPixmap(x, 0, imgs[ii]);
            if(--ii < 0) ii = imgs.size()-1;
        } while(con1);
    } else if(direct=='t') {
        int ii = 0, y = cur;
        do {
            if(y > rect.top()-imgs[ii].height() && y < rect.bottom()+1) painter.drawPixmap(0, y, imgs[ii]);
            y += imgs[ii].height();
            if(++ii >= imgs.size()) ii = 0;
        } while(y < rect.bottom()+1);
    } else if(direct=='b') {
        int ii = imgs.size()-1, y = cur + height();
        bool con1;
        do {
            y -= imgs[ii].height();
            con1 = y > rect.top()-imgs[ii].height();
            if(con1 && y < rect.bottom()+1) painter.drawPixmap(0, y, imgs[ii]);
            if(--ii < 0) ii = imgs.size()-1;
        } while(con1);
    } else painter.drawPixmap(0, 0, imgs[0]);
    if(freshCnt==0 && direct!=0 && interval!=0) connect(PlayWin::self->gl, &QOpenGLWidget::frameSwapped, this, &EleScroll::doFrame, Qt::UniqueConnection);
}

void EleScroll::doFrame() {
    if(! isVisible()) {
        freshCnt = cur = 0;
        disconnect(PlayWin::self->gl, &QOpenGLWidget::frameSwapped, this, &EleScroll::doFrame);
        return;
    }
    if(freshCnt < interval) freshCnt++;
    else {
        freshCnt = 1;
        if(direct=='t' || direct=='l') {
            if(cur <= end) cur -= end;
            else cur -= step;
        } else if(direct=='b' || direct=='r') {
            if(cur >= end) cur -= end;
            else cur += step;
        }
        update();
    }
}