//HEADER FILE
#ifndef DOWNLOADMANAGER_H
#define DOWNLOADMANAGER_H

#include <QFile>
#include <QObject>
#include <QQueue>
#include <QTime>
#include <QUrl>
#include <QtNetwork/QNetworkAccessManager>
#include <QtNetwork/QNetworkReply>
#include <QtNetwork/QSslError>
#include <QtNetwork/QAuthenticator>

class DownloadManager: public QObject
{
    Q_OBJECT

public:

    DownloadManager(QObject *parent = 0);

    void appendToQueue(const QUrl &url);
    void appendToQueue(const QStringList &urlList,const QString &sTargetFolder);
    QString getTargetFolder();
    void setTargetFolder(const QString &strTargetFolder);

Q_SIGNALS:

    void finished();
    void downloadComplete(bool,QString);

private slots:

    void startNextDownload();
    void downloadProgress(qint64 bytesReceived, qint64 bytesTotal);
    void downloadFinished();
    void downloadReadyRead();

    void errorNetworkReply(QNetworkReply::NetworkError);

    void authenticationRequired(QNetworkReply*,QAuthenticator*);

    void sslErrors(QNetworkReply*,QList<QSslError>);

    bool isDownloadDone();

    QString saveFileName(const QUrl &url);

private:

    QString        m_sTargetFolder;

    QNetworkAccessManager manager;
    QQueue<QUrl>          downloadQueue;
    QNetworkReply         *currentDownload;

    QFile output;
    QTime downloadTime;

    int downloadedCount;
    int totalCount;
};

#endif


//CPP FILE

#include "downloadmanager.h"

#include <QFileInfo>
#include <QtNetwork/QNetworkRequest>
#include <QtNetwork/QNetworkReply>
#include <QString>
#include <QStringList>
#include <QTimer>
#include <QDebug>
#include <QDir>
DownloadManager::DownloadManager(QObject *parent)
    : QObject(parent), downloadedCount(0), totalCount(0)
{
}

void DownloadManager::sslErrors(QNetworkReply*,QList<QSslError>)
{
	//FIXME: implement this
}

void DownloadManager::appendToQueue(const QStringList &urlList,const QString &sTargetFolder)
{
    setTargetFolder(sTargetFolder);

    foreach (QString url, urlList)
    {
        if(!url.isEmpty())
            appendToQueue(QUrl::fromEncoded(url.toLocal8Bit(),QUrl::StrictMode));
    }

    if (downloadQueue.isEmpty())
        QTimer::singleShot(0, this, SIGNAL(finished()));
}

void DownloadManager::appendToQueue(const QUrl &url)
{
    if (downloadQueue.isEmpty())
        QTimer::singleShot(0, this, SLOT(startNextDownload()));

    downloadQueue.enqueue(url);
    ++totalCount;
}


QString DownloadManager::saveFileName(const QUrl &url)
{
    QString path = url.path();    
    path.replace('/','_');
    return m_sTargetFolder + "/" + path;
}

void DownloadManager::startNextDownload()
{
    if (downloadQueue.isEmpty()) {

        qDebug() << QString("%1/%2 files downloaded successfully\n").arg(downloadedCount).arg(totalCount);
        emit finished();
        return;
    }

    QUrl url = downloadQueue.dequeue();

    QString filename = saveFileName(url);
    output.setFileName(filename);
    if (!output.open(QIODevice::WriteOnly)) {
        fprintf(stderr, "Problem opening save file '%s' for download '%s': %s\n",
                qPrintable(filename), url.toEncoded().constData(),
                qPrintable(output.errorString()));

        startNextDownload();
        return;                 // skip this download
    }


    QNetworkRequest request(url);
    currentDownload = manager.get(request);

    connect(currentDownload,SIGNAL(error(QNetworkReply::NetworkError)),this,
                            SLOT(errorNetworkReply(QNetworkReply::NetworkError)));

    connect(currentDownload, SIGNAL(downloadProgress(qint64,qint64)),
                             SLOT(downloadProgress(qint64,qint64)));

    connect(currentDownload, SIGNAL(finished()),
                             SLOT(downloadFinished()));

    connect(currentDownload, SIGNAL(readyRead()),
                             SLOT(downloadReadyRead()));

//    connect(&manager,SIGNAL(authenticationRequired(QNetworkReply*,QAuthenticator*)),
//            SLOT(authenticationRequired(QNetworkReply*,QAuthenticator*)));


    connect(&manager,SIGNAL(sslErrors(QNetworkReply*,QList<QSslError>)),SLOT(sslErrors(QNetworkReply*,QList<QSslError>)));
    // prepare the output
    printf("Downloading %s...\n", url.toEncoded().constData());
    downloadTime.start();
}

void DownloadManager::downloadProgress(qint64 bytesReceived, qint64 bytesTotal)
{

    qDebug() << QString("\n%1 data of %2 downloaded").arg(QString::number(bytesReceived)).arg(QString::number(bytesTotal));

}

void DownloadManager::downloadFinished()
{
    output.close();

    if (currentDownload->error()) {
        // download failed
        qDebug() << L"Download Status : Failed. \t Error Msg : " << currentDownload->errorString();


        emit downloadComplete(false,QFileInfo(output).absoluteFilePath());

    } else {

        ++downloadedCount;
        qDebug() << L"Download Status : Succeeded." ;

        emit downloadComplete(true,QFileInfo(output).absoluteFilePath());

    }

    currentDownload->deleteLater();
    startNextDownload();
}

void DownloadManager::downloadReadyRead()
{
    output.write(currentDownload->readAll());
}

//void DownloadManager::networkAccessibleChangedSlot(QNetworkAccessManager::NetworkAccessibility access)
//{
//
//    if(access == QNetworkAccessManager::NotAccessible)
//        qDebug() << "\n Net gone...................:)";
//}

void DownloadManager::errorNetworkReply(QNetworkReply::NetworkError code)
{
    qDebug() << "\nNetwork Error : " + QString::number(code);
}

void DownloadManager::setTargetFolder(const QString &strTargetFolder)
{
    m_sTargetFolder = strTargetFolder;

    QDir dirTarget;

	if(!dirTarget.exists())
		dirTarget.mkpath(sTargetFolder);

}

QString DownloadManager::getTargetFolder()
{
    return m_sTargetFolder;
}

bool DownloadManager::isDownloadDone()
{
    return totalCount == downloadedCount;
}

void DownloadManager::authenticationRequired(QNetworkReply *reply,QAuthenticator *auth)
{
    if(reply && reply->isRunning())
    {
        auth->setUser(reply->url().userName());
        auth->setPassword(reply->url().password());
    }
}