/* Copyright (C) 2014 by Bundesamt für Sicherheit in der Informationstechnik
 * Software engineering by Intevation GmbH
 *
 * This file is Free Software under the GNU GPL (v>=2)
 * and comes with ABSOLUTELY NO WARRANTY!
 * See LICENSE.txt for details.
 */
#ifndef SSLCONNECTION_H
#define SSLCONNECTION_H

/**
 * @file sslconnection.h
 * @brief Qt wrapper around polarssl ssl api
 */

#include <QDebug>
#include <QUrl>
#include <QString>
#include <QByteArray>

class SSLConnection
{
public:
    enum ErrorCode {
        NoError,
        NoConnection,
        SSLHandshakeFailed,
        InvalidCertificate,
        InvalidPinnedCertificate,
        InvalidResponse,
        ConnectionLost,
        Timeout,
        ErrUnknown
    };

    /**
     * @brief Construct a pinned SSL Connection
     *
     * @param[in] url the Url to connect to
     * @param[in] certificate optional certificate to validate https connection
     */
    SSLConnection(const QString& url,
                  const QByteArray& certificate = QByteArray()) :
        mUrl(url),
        mPinnedCert(certificate),
        mInitialized(false),
        mConnected(false),
        mNeedsReset(false),
        mServerFD(-1),
        mErrorState(NoError) {};

    virtual ~SSLConnection() {};

    bool initialized() { return mInitialized; }
    bool connected() { return mConnected; }

    ErrorCode getLastError() { return mErrorState; }

    /** @brief: Establish the connection
     *
     * @returns 0 on success otherwise an error or -1 is returned
     */
    virtual int connect() = 0;

    /** @brief get the last modified header of a resource.
     *
     * Connection should be established beforehand.
     * Modifies the error state.
     *
     * @param[in] resource The resource to check
     *
     * @returns the last modified date or a null datetime in case of errors
     */
    virtual QDateTime getLastModifiedHeader(const QString &resource) = 0;

    /** @brief Download resource
     *
     * Download a resource with the established connection.
     * Modifies the error state.
     *
     * @param[in] resource the resource to download
     * @param[in] filename where the file should be saved.
     * @param[in] maxSize maximum amount of bytes to download
     *
     * @returns True if the download was successful.
     */
    virtual bool downloadFile(const QString &resource, const QString &filename,
                              size_t maxSize) = 0;
protected:
    QUrl mUrl;
    QByteArray mPinnedCert;
    bool mInitialized;
    bool mConnected; /* A connection was established */
    bool mNeedsReset; /* The connection needs to be reset before the next
                         write */
    int mServerFD;
    SSLConnection::ErrorCode mErrorState;
};

#endif