/*
  This program is free software; you can redistribute it and/or
  modify it under the terms of the GNU General Public License
  as published by the Free Software Foundation; either version
  2 of the License, or (at your option) any later version.
*/

#include <QTabWidget>
#include <QPainter>
#include <QVBoxLayout>
#include <QHBoxLayout>
#include <QSqlQuery>
#include <QVariant>
#include <QFontMetrics>
#include <QApplication>
#include <QPainter>
#include <QPen>
#include <QBrush>
#include <QLinearGradient>
#include <QPushButton>
#include <QSqlError>

#include "statisticsdialog.h"

StatisticsDialog::StatisticsDialog(QWidget *parent, Qt::WindowFlags f) : QDialog(parent, f){
	QVBoxLayout *mainLayout = new QVBoxLayout;
	mTab = new QTabWidget;
	QualityStats * qs = new QualityStats;
	mTab->addTab(qs, tr("Quality Distribution"));
	mainLayout->addWidget(mTab);
	QHBoxLayout *buttonLayout = new QHBoxLayout;
	buttonLayout->setAlignment(Qt::AlignHCenter);
	mOk = new QPushButton(tr("Ok"));
	connect(mOk, SIGNAL(clicked()), this, SLOT(accept()));
	buttonLayout->addWidget(mOk);
	mainLayout->addLayout(buttonLayout);
	QString title = QString(tr("%1 - Statistics")).arg(qApp->applicationName());
	setLayout(mainLayout);
	setWindowTitle(title);
}

QualityStats::QualityStats(QWidget *parent) : QWidget(parent), mMargin(10), mMaxValue(0) {
	QSqlQuery q("SELECT DISTINCT(iquality), COUNT(iquality) FROM movies GROUP BY iquality");
	while(q.next()){
		mQualityDistrib[q.value(0).toInt()] = q.value(1).toInt();
		if(q.value(1).toInt() > mMaxValue){
			mMaxValue = q.value(1).toInt();
		}
	}
	QFontMetrics fm(qApp->font());
	mBarHeight = fm.height();
}

void QualityStats::paintEvent(QPaintEvent *){
	QPainter p(this);
	QMap<int, qreal> length;
	QMap<int, int>::const_iterator it;
	QMap<int, qreal>::const_iterator itr;

	//draw background
	QPen pen(Qt::red, 2);
	p.setPen(pen);
	QLinearGradient bgGradient(QPointF(0.0, height() / 2), QPointF(width(), height() / 2));
	bgGradient.setColorAt(0, QColor(221, 107, 80));
	bgGradient.setColorAt(1, QColor(251, 179, 150));
	QBrush brush(bgGradient);
	p.setBrush(brush);
	p.drawRect(contentsRect());

	//draw caption
	QFont f = qApp->font();
	f.setUnderline(true);
	f.setBold(true);
	p.setFont(f);
	QString caption(tr("Quality Distribution"));
	QFontMetrics fm(f);
	int captionStartx = (width() - fm.width(caption)) / 2;
	int captionStarty = fm.height();
	p.drawText(captionStartx, captionStarty, caption);

	//prepare drawing data
	int barsStarty = fm.height() +  2 * mMargin;
	f.setUnderline(false);
	f.setBold(true);
	p.setFont(f);
	int maxKey = (--mQualityDistrib.end()).key();
	int barsStartx = p.fontMetrics().width(QString::number(maxKey)) + 2 * mMargin;
	int marginRight = p.fontMetrics().width(QString(tr("(%1")).arg(QString::number(mMaxValue))) + 2 * mMargin;
	int maxWidth = width() - barsStartx - marginRight;
	p.setRenderHints(QPainter::Antialiasing);
	p.setPen(QPen(Qt::red, 1));

	//calculate real lengths based on widget width 
	for(it = mQualityDistrib.constBegin(); it != mQualityDistrib.constEnd(); ++it){
		qreal value = it.value();
		value = static_cast<qreal>(value) / mMaxValue * maxWidth;
		length[it.key()] = value;
	}

	//draw the bars and numbers
	int ctr(0);
	for(itr = length.constBegin(); itr != length.constEnd(); ++itr, ++ctr){
		int starty = barsStarty + ctr * p.fontMetrics().height() + ctr * mMargin;
		p.drawText(mMargin, starty, QString::number(itr.key()));
		QLinearGradient barGradient(QPointF(barsStartx, starty), QPointF(width(), starty)); 
		barGradient.setColorAt(0, QColor(0, 128, 170));
		barGradient.setColorAt(1, QColor(131, 205, 214));
		QBrush b(barGradient);
		p.setBrush(b);
		QRect bar(barsStartx, starty - p.fontMetrics().height() + p.fontMetrics().descent(), itr.value(), p.fontMetrics().height());
		p.drawRect(bar);
		int nStartx = barsStartx + itr.value() + mMargin;
		p.drawText(nStartx, starty, QString(tr("(%1)")).arg(QString::number(mQualityDistrib[itr.key()])));
	}
}

QSize QualityStats::sizeHint() const {
	int height = mQualityDistrib.count() * mBarHeight;
	height += mQualityDistrib.count() * mMargin;
	height += mBarHeight + mMargin;
	return QSize(400, height);
}