/****************************************************************************
 *
 *   (c) 2009-2016 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.
 *
 ****************************************************************************/


#ifndef MissionManager_H
#define MissionManager_H

#include <QObject>
#include <QLoggingCategory>
#include <QThread>
#include <QMutex>
#include <QTimer>

#include "MissionItem.h"
#include "QGCMAVLink.h"
#include "QGCLoggingCategory.h"
#include "LinkInterface.h"

class Vehicle;

Q_DECLARE_LOGGING_CATEGORY(MissionManagerLog)

class MissionManager : public QObject
{
    Q_OBJECT
    
public:
    MissionManager(Vehicle* vehicle);
    ~MissionManager();
    
    bool inProgress(void);
    const QList<MissionItem*>& missionItems(void) { return _missionItems; }
    int currentItem(void) { return _currentMissionItem; }
    
    void requestMissionItems(void);
    
    /// Writes the specified set of mission items to the vehicle
    ///     @param missionItems Items to send to vehicle
    void writeMissionItems(const QList<MissionItem*>& missionItems);
    
    /// Writes the specified set mission items to the vehicle as an ArduPilot guided mode mission item.
    ///     @param gotoCoord Coordinate to move to
    ///     @param altChangeOnly true: only altitude change, false: lat/lon/alt change
    void writeArduPilotGuidedMissionItem(const QGeoCoordinate& gotoCoord, bool altChangeOnly);

    /// Removes all mission items from vehicle
    void removeAll(void);

    /// Error codes returned in error signal
    typedef enum {
        InternalError,
        AckTimeoutError,        ///< Timed out waiting for response from vehicle
        ProtocolOrderError,     ///< Incorrect protocol sequence from vehicle
        RequestRangeError,      ///< Vehicle requested item out of range
        ItemMismatchError,      ///< Vehicle returned item with seq # different than requested
        VehicleError,           ///< Vehicle returned error
        MissingRequestsError,   ///< Vehicle did not request all items during write sequence
        MaxRetryExceeded,       ///< Retry failed
    } ErrorCode_t;

    // These values are public so the unit test can set appropriate signal wait times
    static const int _ackTimeoutMilliseconds = 1000;
    static const int _maxRetryCount = 5;
    
signals:
    void newMissionItemsAvailable(bool removeAllRequested);
    void inProgressChanged(bool inProgress);
    void error(int errorCode, const QString& errorMsg);
    void currentItemChanged(int currentItem);
    
private slots:
    void _mavlinkMessageReceived(const mavlink_message_t& message);
    void _ackTimeout(void);
    
private:
    typedef enum {
        AckNone,            ///< State machine is idle
        AckMissionCount,    ///< MISSION_COUNT message expected
        AckMissionItem,     ///< MISSION_ITEM expected
        AckMissionRequest,  ///< MISSION_REQUEST is expected, or MISSION_ACK to end sequence
        AckGuidedItem,      ///< MISSION_ACK expected in response to ArduPilot guided mode single item send
    } AckType_t;
    
    void _startAckTimeout(AckType_t ack);
    bool _checkForExpectedAck(AckType_t receivedAck);
    void _readTransactionComplete(void);
    void _handleMissionCount(const mavlink_message_t& message);
    void _handleMissionItem(const mavlink_message_t& message, bool missionItemInt);
    void _handleMissionRequest(const mavlink_message_t& message, bool missionItemInt);
    void _handleMissionAck(const mavlink_message_t& message);
    void _handleMissionCurrent(const mavlink_message_t& message);
    void _requestNextMissionItem(void);
    void _clearMissionItems(void);
    void _sendError(ErrorCode_t errorCode, const QString& errorMsg);
    QString _ackTypeToString(AckType_t ackType);
    QString _missionResultToString(MAV_MISSION_RESULT result);
    void _finishTransaction(bool success);
    void _requestList(void);
    void _writeMissionCount(void);

private:
    Vehicle*            _vehicle;
    LinkInterface*      _dedicatedLink;
    
    QTimer*             _ackTimeoutTimer;
    AckType_t           _expectedAck;
    int                 _retryCount;
    
    bool        _readTransactionInProgress;
    bool        _writeTransactionInProgress;
    QList<int>  _itemIndicesToWrite;    ///< List of mission items which still need to be written to vehicle
    QList<int>  _itemIndicesToRead;     ///< List of mission items which still need to be requested from vehicle
    
    QMutex _dataMutex;
    
    QList<MissionItem*> _missionItems;
    int                 _currentMissionItem;
};

#endif