/*
 * This program source code file is part of KiCad, a free EDA CAD application.
 *
 * Copyright (C) 2015 Mark Roszko <mark.roszko@gmail.com>
 * Copyright (C) 2015, 2021 KiCad Developers, see AUTHORS.txt for contributors.
 *
 * 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 3
 * of the License, or (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, you may find one here:
 * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 * or you may search the http://www.gnu.org website for the version 2 license,
 * or you may write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
 */
#ifndef KICAD_CURL_EASY_H_
#define KICAD_CURL_EASY_H_

/*
 * curl.h, and therefore kicad_curl.h must be included before wxWidgets headers because on Windows,
 * wxWidgets ends up including windows.h before winsocks2.h
 * curl and curl.h causes build warnings if included before any wxxxx.h
 *
 * So kicad_curl_easy.h does not include curl.h to avoid constraints,
 * and including kicad_curl.h could be needed in a few sources
 */

#include <kicommon.h>
#include <functional>
#include <memory>
#include <ostream>
#include <string>

typedef void CURL;
struct curl_slist;

/**
 * Wrapper interface around the curl_easy API/
 *
 * Handling of using the curl_easy API to make a request and save the response to
 * a memory buffer
 *
 * Here is a small example usage:
 * @code
 *   KICAD_CURL_EASY curl;
 *
 *   curl.SetURL( "http://github.com" );
 *   curl.SetUserAgent( <http-client-identifier> );
 *   curl.SetHeader( "Accept", "application/json" );
 *   curl.Perform();
 * @endcode
 */


typedef std::function<int( size_t, size_t, size_t, size_t )> TRANSFER_CALLBACK;
struct CURL_PROGRESS;


class KICOMMON_API KICAD_CURL_EASY
{
public:
    KICAD_CURL_EASY();
    ~KICAD_CURL_EASY();

    /**
     * Equivalent to curl_easy_perform. Executes the request that was previously setup.
     */
    int Perform();

    /**
     * Set an arbitrary header for the HTTP(s) request.
     *
     * @param aName is the left hand side of the header, i.e. Accept without the colon.
     * @param aValue is the right hand side of the header, i.e. application/json.
     */
    void SetHeader( const std::string& aName, const std::string& aValue );

    /**
     * Set the request user agent.
     *
     * @param aAgent is the string to set for the user agent.
     * @return True if successful, false if not.
     */
    bool SetUserAgent( const std::string& aAgent );

    /**
     * Set fields for application/x-www-form-urlencoded POST request.
     *
     * @param aFields is the vector of fields (key-value pairs).
     * @return True if successful, false if not.
     */
    bool SetPostFields( const std::vector<std::pair<std::string, std::string>>& aFields );

    /**
     * Set the request URL.
     *
     * @param aURL is the URL.
     * @return True if successful, false if not.
     */
    bool SetURL( const std::string& aURL );

    /**
     * Enable the following of HTTP(s) and other redirects, by default curl
     * does not follow redirects.
     *
     * @param aFollow is a boolean where true will enable following redirects.
     * @return True if successful, false if not.
     */
    bool SetFollowRedirects( bool aFollow );

    /**
     * Fetch CURL's "friendly" error string for a given error code.
     *
     * @param aCode is CURL error code.
     * @return The corresponding error string for the given code.
     */
    const std::string GetErrorText( int aCode );

    int GetTransferTotal( uint64_t& aDownloadedBytes ) const;

    /**
     * Return a reference to the received data buffer.
     */
    const std::string& GetBuffer() { return m_buffer; }

    /// Escapes a string for use as a URL
    std::string Escape( const std::string& aUrl );

    bool SetTransferCallback( const TRANSFER_CALLBACK& aCallback, size_t aInterval );

    bool SetOutputStream( const std::ostream* aOutput );

    CURL* GetCurl() { return m_CURL; }


private:
    /**
     * Set a curl option, only supports single parameter curl options.
     *
     * @param aOption is CURL option, see CURL manual for options.
     * @param aArg is the argument being passed to CURL, ensure it is the right type per manual.
     * @return A CURL error code, will return CURLE_OK unless a problem was encountered.
     */
    template <typename T>
    int setOption( int aOption, T aArg );

    CURL*                          m_CURL;
    curl_slist*                    m_headers;
    std::string                    m_buffer;
    std::unique_ptr<CURL_PROGRESS> progress;
};


#endif // KICAD_CURL_EASY_H_