/***************************************************************************
    qgsadvanceddigitizingdock.h  -  dock for CAD tools
    ----------------------
    begin                : October 2014
    copyright            : (C) Denis Rouzaud
    email                : denis.rouzaud@gmail.com
 ***************************************************************************
 *                                                                         *
 *   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 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/

#ifndef QGSADVANCEDDIGITIZINGDOCK
#define QGSADVANCEDDIGITIZINGDOCK

#include <QDockWidget>

#include "qgsmapmouseevent.h"
#include "qgsmessagebaritem.h"

#include <ui_qgsadvanceddigitizingdockwidgetbase.h>


class QgsAdvancedDigitizingCanvasItem;
class QgsMapCanvas;
class QgsMapTool;
class QgsMapToolAdvancedDigitizing;
class QgsPoint;

// tolerances for soft constraints (last values, and common angles)
// for angles, both tolerance in pixels and degrees are used for better performance
static const double SoftConstraintTolerancePixel = 15;
static const double SoftConstraintToleranceDegrees = 10;

/**
 * @brief The QgsAdvancedDigitizingDock class is a dockable widget
 * used to handle the CAD tools on top of a selection of map tools.
 * It handles both the UI and the constraints. Constraints are applied
 * by implemeting filters called from QgsMapToolAdvancedDigitizing.
 */
class GUI_EXPORT QgsAdvancedDigitizingDockWidget : public QDockWidget, private Ui::QgsAdvancedDigitizingDockWidgetBase
{
    Q_OBJECT
    Q_FLAGS( CadCapacities )

  public:

    /**
     * The CadCapacity enum defines the possible constraints to be set
     * depending on the number of points in the CAD point list (the list of points
     * currently digitized)
     */
    enum CadCapacity
    {
      AbsoluteAngle = 1, //!< Azimuth
      RelativeAngle = 2, //!< also for parallel and perpendicular
      RelativeCoordinates = 4, //!< this corresponds to distance and relative coordinates
    };
    Q_DECLARE_FLAGS( CadCapacities, CadCapacity )

    /**
     * Additional constraints which can be enabled
     */
    enum AdditionalConstraint
    {
      NoConstraint,  //!< No additional constraint
      Perpendicular, //!< Perpendicular
      Parallel       //!< Parallel
    };

    /**
     * @brief The CadConstraint is an abstract class for all basic constraints (angle/distance/x/y).
     * It contains all values (locked, value, relative) and pointers to corresponding widgets.
     * @note Relative is not mandatory since it is not used for distance.
     */
    class GUI_EXPORT CadConstraint
    {
      public:
        /**
         * The lock mode
         */
        enum LockMode
        {
          NoLock,
          SoftLock,
          HardLock
        };

        CadConstraint( QLineEdit* lineEdit, QToolButton* lockerButton, QToolButton* relativeButton = nullptr )
            : mLineEdit( lineEdit )
            , mLockerButton( lockerButton )
            , mRelativeButton( relativeButton )
            , mLockMode( NoLock )
            , mRelative( false )
            , mValue( 0.0 )
        {}

        /**
         * The current lock mode of this constraint
         * @return Lock mode
         */
        LockMode lockMode() const { return mLockMode; }
        /**
         * Is any kind of lock mode enabled
         */
        bool isLocked() const { return mLockMode != NoLock; }
        /**
         * Is the constraint in relative mode
         */
        bool relative() const { return mRelative; }
        /**
         * The value of the constraint
         */
        double value() const { return mValue; }

        /**
         * The line edit that manages the value of the constraint
         */
        QLineEdit* lineEdit() const { return mLineEdit; }

        /**
         * Set the lock mode
         */
        void setLockMode( LockMode mode );

        /**
         * Set if the constraint should be treated relative
         */
        void setRelative( bool relative );

        /**
         * Set the value of the constraint
         */
        void setValue( double value );

        /**
         * Toggle lock mode
         */
        void toggleLocked();

        /**
         * Toggle relative mode
         */
        void toggleRelative();

      private:
        QLineEdit* mLineEdit;
        QToolButton* mLockerButton;
        QToolButton* mRelativeButton;
        LockMode mLockMode;
        bool mRelative;
        double mValue;
    };

    //! performs the intersection of a circle and a line
    //! @note from the two solutions, the intersection will be set to the closest point
    static bool lineCircleIntersection( const QgsPoint& center, const double radius, const QList<QgsPoint>& segment, QgsPoint& intersection );

    /**
     * Create an advanced digitizing dock widget
     * @param canvas The map canvas on which the widget operates
     * @param parent The parent
     */
    explicit QgsAdvancedDigitizingDockWidget( QgsMapCanvas* canvas, QWidget *parent = nullptr );

    /**
     * Disables the CAD tools when hiding the dock
     */
    void hideEvent( QHideEvent* ) override;

    /**
     * Will react on a canvas press event
     *
     * @param e A mouse event (may be modified)
     * @return  If the event is hidden (construction mode hides events from the maptool)
     */
    bool canvasPressEvent( QgsMapMouseEvent* e );
    /**
     * Will react on a canvas release event
     *
     * @param e A mouse event (may be modified)
     * @param captureSegment Capture segments?
     * @return  If the event is hidden (construction mode hides events from the maptool)
     */
    bool canvasReleaseEvent( QgsMapMouseEvent* e , bool captureSegment );
    /**
     * Will react on a canvas move event
     *
     * @param e A mouse event (may be modified)
     * @return  If the event is hidden (construction mode hides events from the maptool)
     */
    bool canvasMoveEvent( QgsMapMouseEvent* e );
    /**
     * Filter key events to e.g. toggle construction mode or adapt constraints
     *
     * @param e A mouse event (may be modified)
     * @return  If the event is hidden (construction mode hides events from the maptool)
     */
    bool canvasKeyPressEventFilter( QKeyEvent *e );

    //! apply the CAD constraints. The will modify the position of the map event in map coordinates by applying the CAD constraints.
    //! @return false if no solution was found (invalid constraints)
    virtual bool applyConstraints( QgsMapMouseEvent* e );

    /**
     * Clear any cached previous clicks and helper lines
     */
    void clear();

    /**
     * The snapping mode
     * @return Snapping mode
     */
    QgsMapMouseEvent::SnappingMode snappingMode() { return mSnappingMode; }

    //! key press event on the dock
    void keyPressEvent( QKeyEvent* e ) override;

    //! determines if CAD tools are enabled or if map tools behaves "nomally"
    bool cadEnabled() const { return mCadEnabled; }

    //! construction mode is used to draw intermediate points. These points won't be given any further (i.e. to the map tools)
    bool constructionMode() const { return mConstructionMode; }

    //! Additional constraints are used to place perpendicular/parallel segments to snapped segments on the canvas
    AdditionalConstraint additionalConstraint() const  { return mAdditionalConstraint; }
    //! Constraint on the angle
    const CadConstraint* constraintAngle() const  { return mAngleConstraint; }
    //! Constraint on the distance
    const CadConstraint* constraintDistance() const { return mDistanceConstraint; }
    //! Constraint on the X coordinate
    const CadConstraint* constraintX() const { return mXConstraint; }
    //! Constraint on the Y coordinate
    const CadConstraint* constraintY() const { return mYConstraint; }
    //! Constraint on a common angle
    bool commonAngleConstraint() const { return mCommonAngleConstraint; }

    /**
     * The last point.
     * Helper for the CAD point list. The CAD point list is the list of points
     * currently digitized. It contains both  "normal" points and intermediate points (construction mode).
     */
    QgsPoint currentPoint( bool* exists  = nullptr ) const;

    /**
     * The previous point.
     * Helper for the CAD point list. The CAD point list is the list of points
     * currently digitized. It contains both  "normal" points and intermediate points (construction mode).
     */
    QgsPoint previousPoint( bool* exists = nullptr ) const;

    /**
     * The penultimate point.
     * Helper for the CAD point list. The CAD point list is the list of points
     * currently digitized. It contains both  "normal" points and intermediate points (construction mode).
     */
    QgsPoint penultimatePoint( bool* exists = nullptr ) const;

    /**
     * The number of points in the CAD point helper list
     */
    inline int pointsCount() const { return mCadPointList.count(); }

    /**
     * Is it snapped to a vertex
     */
    inline bool snappedToVertex() const { return mSnappedToVertex; }

    /**
     * Snapped to a segment
     */
    const QList<QgsPoint>& snappedSegment() const { return mSnappedSegment; }

    //! return the action used to enable/disable the tools
    QAction* enableAction() { return mEnableAction; }

    /**
     * Enables the tool (call this when an appropriate map tool is set and in the condition to make use of
     * cad digitizing)
     * Normally done automatically from QgsMapToolAdvancedDigitizing::activate() but may need to be fine tuned
     * if the map tool depends on preconditions like a feature selection.
     */
    void enable();

    /**
     * Disable the widget. Normally done automatically from QgsMapToolAdvancedDigitizing::deactivate().
     */
    void disable();

  signals:
    /**
     * Push a warning
     *
     * @param message An informative message
     */
    void pushWarning( const QString& message );

    /**
     * Remove any previously emitted warnings (if any)
     */
    void popWarning();

    /**
     * Sometimes a constraint may change the current point out of a mouse event. This happens normally
     * when a constraint is toggled.
     *
     * @param point The last known digitizing point. Can be used to emulate a mouse event.
     */
    void pointChanged( const QgsPoint& point );

  private slots:
    //! set the additiona constraint by clicking on the perpendicular/parallel buttons
    void addtionalConstraintClicked( bool activated );

    //! lock/unlock a constraint and set its value
    void lockConstraint( bool activate = true );

    //! unlock all constraints
    void releaseLocks();

    //! set the relative properties of constraints
    void setConstraintRelative( bool activate );

    //! activate/deactivate tools. It is called when tools are activated manually (from the GUI)
    //! it will call setCadEnabled to properly update the UI.
    void activateCad( bool enabled );

    //! enable/disable construction mode (events are not forwarded to the map tool)
    void setConstructionMode( bool enabled );

    //! settings button triggered
    void settingsButtonTriggered( QAction* action );

  private:
    //! updates the UI depending on activation of the tools and clear points / release locks.
    void setCadEnabled( bool enabled );

    /**
     * @brief updateCapacity updates the cad capacities depending on the point list and update the UI according to the capabilities.
     * @param updateUIwithoutChange if true, it will update the UI even if new capacities are not different from previous ones.
     */
    void updateCapacity( bool updateUIwithoutChange = false );

    //! defines the additional constraint to be used (no/parallel/perpendicular)
    void lockAdditionalConstraint( AdditionalConstraint constraint );

    QList<QgsPoint> snapSegment( const QgsPointLocator::Match& snapMatch );

    //! align to segment for additional constraint.
    //! If additional constraints are used, this will determine the angle to be locked depending on the snapped segment.
    bool alignToSegment( QgsMapMouseEvent* e, CadConstraint::LockMode lockMode = CadConstraint::HardLock );

    //! add point to the CAD point list
    void addPoint( const QgsPoint& point );
    //! update the current point in the CAD point list
    void updateCurrentPoint( const QgsPoint& point );
    //! remove previous point in the CAD point list
    void removePreviousPoint();
    //! remove all points from the CAD point list
    void clearPoints();

    //! filters key press
    //! @note called by eventFilter (fitler on line edits), canvasKeyPressEvent (filter on map tool) and keyPressEvent (filter on dock)
    bool filterKeyPress( QKeyEvent* e );

    //! event filter for line edits in the dock UI (angle/distance/x/y line edits)
    bool eventFilter( QObject *obj, QEvent *event ) override;

    //! trigger fake mouse move event to update map tool rubber band and/or show new constraints
    void triggerMouseMoveEvent();



    QgsMapCanvas* mMapCanvas;
    QgsAdvancedDigitizingCanvasItem* mCadPaintItem;

    CadCapacities mCapacities;

    bool mCurrentMapToolSupportsCad;

    // CAD properties
    //! is CAD currently enabled for current map tool
    bool mCadEnabled;
    bool mConstructionMode;
    QgsMapMouseEvent::SnappingMode mSnappingMode;

    // constraints
    CadConstraint* mAngleConstraint;
    CadConstraint* mDistanceConstraint;
    CadConstraint* mXConstraint;
    CadConstraint* mYConstraint;
    AdditionalConstraint mAdditionalConstraint;
    int mCommonAngleConstraint; // if 0: do not snap to common angles

    // point list and current snap point / segment
    QList<QgsPoint> mCadPointList;
    QList<QgsPoint> mSnappedSegment;
    bool mSnappedToVertex;

    bool mSessionActive;

    // error message
    QScopedPointer<QgsMessageBarItem> mErrorMessage;

    // UI
    QAction* mEnableAction;
    QMap< QAction*, int > mCommonAngleActions; // map the common angle actions with their angle values
    QMap< QAction*, QgsMapMouseEvent::SnappingMode > mSnappingActions; // map the snapping mode actions with their values
};

Q_DECLARE_OPERATORS_FOR_FLAGS( QgsAdvancedDigitizingDockWidget::CadCapacities )

#endif // QGSADVANCEDDIGITIZINGDOCK_H
