/****************************************************************************
 *
 * (c) 2009-2020 QGROUNDCONTROL PROJECT <http://www.qgroundcontrol.org>
 *
 * QGroundControl is licensed according to the terms in the file
 * COPYING.md in the root of the source code directory.
 *
 ****************************************************************************/


#pragma once

#include "QGCMAVLink.h"

#include <QStringList>
#include <QFile>

class MockLink;

/// Mock implementation of Mavlink FTP server.
class MockLinkFTP : public QObject
{
    Q_OBJECT
    
public:
    MockLinkFTP(uint8_t systemIdServer, uint8_t componentIdServer, MockLink* mockLink);
    
    /// @brief Sets the list of files returned by the List command. Prepend names with F or D
    /// to indicate (F)ile or (D)irectory.
    void setFileList(QStringList& fileList) { _fileList = fileList; }
    
    /// @brief By calling setErrorMode with one of these modes you can cause the server to simulate an error.
    typedef enum {
        errModeNone,                ///< No error, respond correctly
        errModeNoResponse,          ///< No response to any request, client should eventually time out with no Ack
        errModeNakResponse,         ///< Nak all requests
        errModeNoSecondResponse,    ///< No response to subsequent request to initial command
        errModeNakSecondResponse,   ///< Nak subsequent request to initial command
        errModeBadSequence          ///< Return response with bad sequence number
    } ErrorMode_t;
    
    /// @brief Sets the error mode for command responses. This allows you to simulate various server errors.
    void setErrorMode(ErrorMode_t errMode) { _errMode = errMode; };
    
    /// @brief Array of failure modes you can cycle through for testing. By looping through this array you can avoid
    /// hardcoding the specific error modes in your unit test. This way when new error modes are added your unit test
    /// code may not need to be modified.
    static const ErrorMode_t rgFailureModes[];
    
    /// @brief The number of ErrorModes in the rgFailureModes array.
    static const size_t cFailureModes;
    
    /// Called to handle an FTP message
    void mavlinkMessageReceived(const mavlink_message_t& message);

    void enableRandromDrops(bool enable) { _randomDropsEnabled = enable; }

    static const char* sizeFilenamePrefix;

signals:
    /// You can connect to this signal to be notified when the server receives a Terminate command.
    void terminateCommandReceived(void);
    
    /// You can connect to this signal to be notified when the server receives a Reset command.
    void resetCommandReceived(void);
    
private:
    void        _sendAck                (uint8_t targetSystemId, uint8_t targetComponentId, uint16_t seqNumber, MavlinkFTP::OpCode_t reqOpCode);
    void        _sendNak                (uint8_t targetSystemId, uint8_t targetComponentId, MavlinkFTP::ErrorCode_t error, uint16_t seqNumber, MavlinkFTP::OpCode_t reqOpCode);
    void        _sendNakErrno           (uint8_t targetSystemId, uint8_t targetComponentId, uint8_t nakErrno, uint16_t seqNumber, MavlinkFTP::OpCode_t reqOpCode);
    void        _sendResponse           (uint8_t targetSystemId, uint8_t targetComponentId, MavlinkFTP::Request* request, uint16_t seqNumber);
    void        _listCommand            (uint8_t senderSystemId, uint8_t senderComponentId, MavlinkFTP::Request* request, uint16_t seqNumber);
    void        _openCommand            (uint8_t senderSystemId, uint8_t senderComponentId, MavlinkFTP::Request* request, uint16_t seqNumber);
    void        _readCommand            (uint8_t senderSystemId, uint8_t senderComponentId, MavlinkFTP::Request* request, uint16_t seqNumber);
    void        _burstReadCommand          (uint8_t senderSystemId, uint8_t senderComponentId, MavlinkFTP::Request* request, uint16_t seqNumber);
    void        _terminateCommand       (uint8_t senderSystemId, uint8_t senderComponentId, MavlinkFTP::Request* request, uint16_t seqNumber);
    void        _resetCommand           (uint8_t senderSystemId, uint8_t senderComponentId, uint16_t seqNumber);
    uint16_t    _nextSeqNumber          (uint16_t seqNumber);
    QString     _createTestTempFile     (int size);
    
    /// if request is a string, this ensures it's null-terminated
    static void ensureNullTemination(MavlinkFTP::Request* request);

    QStringList _fileList;  ///< List of files returned by List command
    
    QFile                   _currentFile;
    ErrorMode_t             _errMode            = errModeNone;  ///< Currently set error mode, as specified by setErrorMode
    const uint8_t           _systemIdServer;                    ///< System ID for server
    const uint8_t           _componentIdServer;                 ///< Component ID for server
    MockLink*               _mockLink;                          ///< MockLink to communicate through
    bool                    _lastReplyValid     = false;
    uint16_t                _lastReplySequence  = 0;
    mavlink_message_t       _lastReply;
    bool                    _randomDropsEnabled = false;

    static const uint8_t    _sessionId          = 1;    ///< We only support a single fixed session
};