/*
 * KiRouter - a push-and-(sometimes-)shove PCB router
 *
 * Copyright (C) 2013-2017 CERN
 * Copyright (C) 2017 KiCad Developers, see AUTHORS.txt for contributors.
 * Author: Tomasz Wlostowski <tomasz.wlostowski@cern.ch>
 *
 * 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, see <http://www.gnu.org/licenses/>.
 */

#include <wx/numdlg.h>
#include <core/optional.h>
#include <functional>
using namespace std::placeholders;
#include "class_board.h"
#include <pcb_edit_frame.h>
#include <id.h>
#include <macros.h>
#include <pcbnew_id.h>
#include <view/view_controls.h>
#include <pcb_layer_widget.h>
#include <pcb_painter.h>
#include <dialogs/dialog_pns_settings.h>
#include <dialogs/dialog_pns_diff_pair_dimensions.h>
#include <dialogs/dialog_track_via_size.h>
#include <base_units.h>
#include <confirm.h>
#include <bitmaps.h>
#include <collectors.h>
#include <tool/action_menu.h>
#include <tool/tool_manager.h>
#include <tool/grid_menu.h>
#include <tool/zoom_menu.h>
#include <tools/pcb_actions.h>
#include <tools/selection_tool.h>
#include <tools/grid_helper.h>

#include "router_tool.h"
#include "pns_segment.h"
#include "pns_router.h"

using namespace KIGFX;

/**
 * Flags used by via tool actions
 */
enum VIA_ACTION_FLAGS
{
    // Via type
    VIA_MASK     = 0x03,
    VIA          = 0x00,     ///> Normal via
    BLIND_VIA    = 0x01,     ///> blind/buried via
    MICROVIA     = 0x02,     ///> Microvia

    // Select layer
    SELECT_LAYER = VIA_MASK + 1,    ///> Ask user to select layer before adding via
};


// Actions, being statically-defined, require specialized I18N handling.  We continue to
// use the _() macro so that string harvesting by the I18N framework doesn't have to be
// specialized, but we don't translate on initialization and instead do it in the getters.

#undef _
#define _(s) s

static const TOOL_ACTION ACT_EndTrack( "pcbnew.InteractiveRouter.EndTrack",
        AS_CONTEXT, 
        WXK_END, "",
        _( "Finish Track" ),  _( "Stops laying the current track." ),
        checked_ok_xpm );

static const TOOL_ACTION ACT_AutoEndRoute( "pcbnew.InteractiveRouter.AutoEndRoute", 
        AS_CONTEXT, 
        'F', "",
        _( "Auto-finish Track" ),  _( "Automagically finishes laying the current track." ) );

static const TOOL_ACTION ACT_PlaceThroughVia( "pcbnew.InteractiveRouter.PlaceVia",
        AS_CONTEXT, 
        'V', LEGACY_HK_NAME( "Add Through Via" ),
        _( "Place Through Via" ),
        _( "Adds a through-hole via at the end of currently routed track." ),
        via_xpm, AF_NONE, (void*) VIA_ACTION_FLAGS::VIA );

static const TOOL_ACTION ACT_PlaceBlindVia( "pcbnew.InteractiveRouter.PlaceBlindVia",
        AS_CONTEXT, 
        MD_ALT + MD_SHIFT + 'V', LEGACY_HK_NAME( "Add Blind/Buried Via" ),
        _( "Place Blind/Buried Via" ),
        _( "Adds a blind or buried via at the end of currently routed track."),
        via_buried_xpm, AF_NONE, (void*) VIA_ACTION_FLAGS::BLIND_VIA );

static const TOOL_ACTION ACT_PlaceMicroVia( "pcbnew.InteractiveRouter.PlaceMicroVia",
        AS_CONTEXT, 
        MD_CTRL + 'V', LEGACY_HK_NAME( "Add MicroVia" ),
        _( "Place Microvia" ), _( "Adds a microvia at the end of currently routed track." ),
        via_microvia_xpm, AF_NONE, (void*) VIA_ACTION_FLAGS::MICROVIA );

static const TOOL_ACTION ACT_SelLayerAndPlaceThroughVia( "pcbnew.InteractiveRouter.SelLayerAndPlaceVia",
        AS_CONTEXT,
        '<', LEGACY_HK_NAME( "Select Layer and Add Through Via" ),
        _( "Select Layer and Place Through Via..." ),
        _( "Select a layer, then add a through-hole via at the end of currently routed track." ),
        select_w_layer_xpm, AF_NONE,
        (void*) ( VIA_ACTION_FLAGS::VIA | VIA_ACTION_FLAGS::SELECT_LAYER ) );

static const TOOL_ACTION ACT_SelLayerAndPlaceBlindVia( "pcbnew.InteractiveRouter.SelLayerAndPlaceBlindVia",
        AS_CONTEXT, 
        MD_ALT + '<', LEGACY_HK_NAME( "Select Layer and Add Blind/Buried Via" ),
        _( "Select Layer and Place Blind/Buried Via..." ),
        _( "Select a layer, then add a blind or buried via at the end of currently routed track."),
        select_w_layer_xpm, AF_NONE,
        (void*) ( VIA_ACTION_FLAGS::BLIND_VIA | VIA_ACTION_FLAGS::SELECT_LAYER ) );

static const TOOL_ACTION ACT_CustomTrackWidth( "pcbnew.InteractiveRouter.CustomTrackViaSize",
        AS_CONTEXT, 
        'Q', LEGACY_HK_NAME( "Custom Track/Via Size" ),
        _( "Custom Track/Via Size..." ),
        _( "Shows a dialog for changing the track width and via size." ),
        width_track_xpm );

static const TOOL_ACTION ACT_SwitchPosture( "pcbnew.InteractiveRouter.SwitchPosture", 
        AS_CONTEXT,
        '/', LEGACY_HK_NAME( "Switch Track Posture" ),
        _( "Switch Track Posture" ),
        _( "Switches posture of the currently routed track." ),
        change_entry_orient_xpm );

#undef _
#define _(s) wxGetTranslation((s))


ROUTER_TOOL::ROUTER_TOOL() :
    TOOL_BASE( "pcbnew.InteractiveRouter" )
{
}


class TRACK_WIDTH_MENU : public ACTION_MENU
{
public:
    TRACK_WIDTH_MENU( PCB_EDIT_FRAME& aFrame ) :
        ACTION_MENU( true ),
        m_frame( aFrame )
    {
        SetIcon( width_track_via_xpm );
        SetTitle( _( "Select Track/Via Width" ) );
    }

protected:
    ACTION_MENU* create() const override
    {
        return new TRACK_WIDTH_MENU( m_frame );
    }

    void update() override
    {
        EDA_UNITS_T            units = m_frame.GetUserUnits();
        BOARD_DESIGN_SETTINGS& bds = m_frame.GetBoard()->GetDesignSettings();
        bool                   useIndex = !bds.m_UseConnectedTrackWidth &&
                                          !bds.UseCustomTrackViaSize();
        wxString               msg;

        Clear();

        Append( ID_POPUP_PCB_SELECT_AUTO_WIDTH, _( "Use Starting Track Width" ),
                _( "Route using the width of the starting track." ), wxITEM_CHECK );
        Check( ID_POPUP_PCB_SELECT_AUTO_WIDTH,
               bds.m_UseConnectedTrackWidth && !bds.UseCustomTrackViaSize() );

        Append( ID_POPUP_PCB_SELECT_USE_NETCLASS_VALUES, _( "Use Net Class Values" ),
                _( "Use track and via sizes from the net class" ), wxITEM_CHECK );
        Check( ID_POPUP_PCB_SELECT_USE_NETCLASS_VALUES,
               useIndex && bds.GetTrackWidthIndex() == 0 && bds.GetViaSizeIndex() == 0 );

        Append( ID_POPUP_PCB_SELECT_CUSTOM_WIDTH, _( "Use Custom Values..." ),
                _( "Specify custom track and via sizes" ), wxITEM_CHECK );
        Check( ID_POPUP_PCB_SELECT_CUSTOM_WIDTH, bds.UseCustomTrackViaSize() );

        AppendSeparator();

        // Append the list of tracks & via sizes
        for( unsigned i = 0; i < bds.m_TrackWidthList.size(); i++ )
        {
            int width = bds.m_TrackWidthList[i];

            if( i == 0 )
                msg = _( "Track netclass width" );
            else
                msg.Printf( _( "Track %s" ), MessageTextFromValue( units, width, true ) );

            int menuIdx = ID_POPUP_PCB_SELECT_WIDTH1 + i;
            Append( menuIdx, msg, wxEmptyString, wxITEM_CHECK );
            Check( menuIdx, useIndex && bds.GetTrackWidthIndex() == i );
        }

        AppendSeparator();

        for( unsigned i = 0; i < bds.m_ViasDimensionsList.size(); i++ )
        {
            VIA_DIMENSION via = bds.m_ViasDimensionsList[i];

            if( i == 0 )
                msg = _( "Via netclass values" );
            else
            {
                if( via.m_Drill > 0 )
                    msg.Printf( _("Via %s, drill %s" ),
                                MessageTextFromValue( units, via.m_Diameter, true ),
                                MessageTextFromValue( units, via.m_Drill, true ) );
                else
                    msg.Printf( _( "Via %s" ), MessageTextFromValue( units, via.m_Diameter, true ) );
            }

            int menuIdx = ID_POPUP_PCB_SELECT_VIASIZE1 + i;
            Append( menuIdx, msg, wxEmptyString, wxITEM_CHECK );
            Check( menuIdx, useIndex && bds.GetViaSizeIndex() == i );
        }
    }

    OPT_TOOL_EVENT eventHandler( const wxMenuEvent& aEvent ) override
    {
        BOARD_DESIGN_SETTINGS &bds = m_frame.GetBoard()->GetDesignSettings();
        int id = aEvent.GetId();

        // On Windows, this handler can be called with an event ID not existing in any
        // menuitem, so only set flags when we have an ID match.

        if( id == ID_POPUP_PCB_SELECT_CUSTOM_WIDTH )
        {
            bds.UseCustomTrackViaSize( true );
            bds.m_UseConnectedTrackWidth = false;
            m_frame.GetToolManager()->RunAction( ACT_CustomTrackWidth, true );
        }
        else if( id == ID_POPUP_PCB_SELECT_AUTO_WIDTH )
        {
            bds.UseCustomTrackViaSize( false );
            bds.m_UseConnectedTrackWidth = true;
        }
        else if( id == ID_POPUP_PCB_SELECT_USE_NETCLASS_VALUES )
        {
            bds.UseCustomTrackViaSize( false );
            bds.m_UseConnectedTrackWidth = false;
            bds.SetViaSizeIndex( 0 );
            bds.SetTrackWidthIndex( 0 );
        }
        else if( id >= ID_POPUP_PCB_SELECT_VIASIZE1 && id <= ID_POPUP_PCB_SELECT_VIASIZE16 )
        {
            bds.UseCustomTrackViaSize( false );
            bds.m_UseConnectedTrackWidth = false;
            bds.SetViaSizeIndex( id - ID_POPUP_PCB_SELECT_VIASIZE1 );
        }
        else if( id >= ID_POPUP_PCB_SELECT_WIDTH1 && id <= ID_POPUP_PCB_SELECT_WIDTH16 )
        {
            bds.UseCustomTrackViaSize( false );
            bds.m_UseConnectedTrackWidth = false;
            bds.SetTrackWidthIndex( id - ID_POPUP_PCB_SELECT_WIDTH1 );
        }

        return OPT_TOOL_EVENT( PCB_ACTIONS::trackViaSizeChanged.MakeEvent() );
    }

private:
    PCB_EDIT_FRAME& m_frame;
};


class DIFF_PAIR_MENU : public ACTION_MENU
{
public:
    DIFF_PAIR_MENU( PCB_EDIT_FRAME& aFrame ) :
        ACTION_MENU( true ),
        m_frame( aFrame )
    {
        SetIcon( width_track_via_xpm );
        SetTitle( _( "Select Differential Pair Dimensions" ) );
    }

protected:
    ACTION_MENU* create() const override
    {
        return new DIFF_PAIR_MENU( m_frame );
    }

    void update() override
    {
        EDA_UNITS_T                   units = m_frame.GetUserUnits();
        const BOARD_DESIGN_SETTINGS&  bds = m_frame.GetBoard()->GetDesignSettings();

        Clear();

        Append( ID_POPUP_PCB_SELECT_USE_NETCLASS_DIFFPAIR, _( "Use Net Class Values" ),
                _( "Use differential pair dimensions from the net class" ), wxITEM_CHECK );
        Check( ID_POPUP_PCB_SELECT_USE_NETCLASS_DIFFPAIR,
               !bds.UseCustomDiffPairDimensions() && bds.GetDiffPairIndex() == 0 );

        Append( ID_POPUP_PCB_SELECT_CUSTOM_DIFFPAIR, _( "Use Custom Values..." ),
                _( "Specify custom differential pair dimensions" ), wxITEM_CHECK );
        Check( ID_POPUP_PCB_SELECT_CUSTOM_DIFFPAIR, bds.UseCustomDiffPairDimensions() );

        AppendSeparator();

        // Append the list of differential pair dimensions

        // Drop index 0 which is the current netclass dimensions (which are handled above)
        for( unsigned i = 1; i < bds.m_DiffPairDimensionsList.size(); ++i )
        {
            DIFF_PAIR_DIMENSION diffPair = bds.m_DiffPairDimensionsList[i];
            wxString            msg;

            msg << _( "Width " ) << MessageTextFromValue( units, diffPair.m_Width, true );

            if( diffPair.m_Gap > 0 )
                msg << _( ", gap " ) << MessageTextFromValue( units, diffPair.m_Gap, true );

            if( diffPair.m_ViaGap > 0 )
                msg << _( ", via gap " ) << MessageTextFromValue( units, diffPair.m_ViaGap, true );

            int menuIdx = ID_POPUP_PCB_SELECT_DIFFPAIR1 + i - 1;
            Append( menuIdx, msg, wxEmptyString, wxITEM_CHECK );
            Check( menuIdx, !bds.UseCustomDiffPairDimensions() && bds.GetDiffPairIndex() == i );
        }
    }

    OPT_TOOL_EVENT eventHandler( const wxMenuEvent& aEvent ) override
    {
        BOARD_DESIGN_SETTINGS &bds = m_frame.GetBoard()->GetDesignSettings();
        int id = aEvent.GetId();

        // On Windows, this handler can be called with an event ID not existing in any
        // menuitem, so only set flags when we have an ID match.

        if( id == ID_POPUP_PCB_SELECT_CUSTOM_DIFFPAIR )
        {
            bds.UseCustomDiffPairDimensions( true );
            TOOL_MANAGER* toolManager = m_frame.GetToolManager();
            toolManager->RunAction( PCB_ACTIONS::routerDiffPairDialog, true );
        }
        else if( id == ID_POPUP_PCB_SELECT_USE_NETCLASS_DIFFPAIR )
        {
            bds.UseCustomDiffPairDimensions( false );
            bds.SetDiffPairIndex( 0 );
        }
        else if( id >= ID_POPUP_PCB_SELECT_DIFFPAIR1 && id <= ID_POPUP_PCB_SELECT_DIFFPAIR16 )
        {
            bds.UseCustomDiffPairDimensions( false );
            // remember that the menu doesn't contain index 0 (which is the netclass values)
            bds.SetDiffPairIndex( id - ID_POPUP_PCB_SELECT_DIFFPAIR1 + 1 );
        }

        return OPT_TOOL_EVENT( PCB_ACTIONS::trackViaSizeChanged.MakeEvent() );
    }

private:
    PCB_EDIT_FRAME& m_frame;
};


class ROUTER_TOOL_MENU : public ACTION_MENU
{
public:
    ROUTER_TOOL_MENU( PCB_EDIT_FRAME& aFrame, PNS::ROUTER_MODE aMode ) :
        ACTION_MENU( true ),
        m_frame( aFrame ), m_mode( aMode ), m_trackViaMenu( aFrame ), m_diffPairMenu( aFrame ),
        m_zoomMenu( &aFrame ), m_gridMenu( &aFrame )
    {
        SetTitle( _( "Interactive Router" ) );

        Add( ACTIONS::cancelInteractive );

        AppendSeparator();

        Add( PCB_ACTIONS::routeSingleTrack );
        Add( PCB_ACTIONS::routeDiffPair );
        Add( ACT_EndTrack );
        Add( PCB_ACTIONS::breakTrack );

        Add( PCB_ACTIONS::drag45Degree );
        Add( PCB_ACTIONS::dragFreeAngle );

//        Add( ACT_AutoEndRoute );  // fixme: not implemented yet. Sorry.
        Add( ACT_PlaceThroughVia );
        Add( ACT_PlaceBlindVia );
        Add( ACT_PlaceMicroVia );
        Add( ACT_SelLayerAndPlaceThroughVia );
        Add( ACT_SelLayerAndPlaceBlindVia );
        Add( ACT_SwitchPosture );

        AppendSeparator();

        Add( &m_trackViaMenu );

        if( m_mode == PNS::PNS_MODE_ROUTE_DIFF_PAIR )
            Add( &m_diffPairMenu );

        Add( PCB_ACTIONS::routerSettingsDialog );

        AppendSeparator();

        Add( &m_zoomMenu );
        Add( &m_gridMenu );
    }

private:
    ACTION_MENU* create() const override
    {
        return new ROUTER_TOOL_MENU( m_frame, m_mode );
    }

    PCB_EDIT_FRAME&  m_frame;
    PNS::ROUTER_MODE m_mode;
    TRACK_WIDTH_MENU m_trackViaMenu;
    DIFF_PAIR_MENU   m_diffPairMenu;
    ZOOM_MENU        m_zoomMenu;
    GRID_MENU        m_gridMenu;
};


ROUTER_TOOL::~ROUTER_TOOL()
{
    m_savedSettings.Save( GetSettings() );
}


bool ROUTER_TOOL::Init()
{
    m_savedSettings.Load( GetSettings() );
    return true;
}


void ROUTER_TOOL::Reset( RESET_REASON aReason )
{
    if( aReason == RUN )
        TOOL_BASE::Reset( aReason );
}


void ROUTER_TOOL::handleCommonEvents( const TOOL_EVENT& aEvent )
{
#ifdef DEBUG
    if( aEvent.IsKeyPressed() )
    {
        switch( aEvent.KeyCode() )
        {
        case '0':
            wxLogTrace( "PNS", "saving drag/route log...\n" );
            m_router->DumpLog();
            break;
        }
    }
#endif
}


int ROUTER_TOOL::getStartLayer( const PNS::ITEM* aItem )
{
    int tl = getView()->GetTopLayer();

    if( m_startItem )
    {
        const LAYER_RANGE& ls = m_startItem->Layers();

        if( ls.Overlaps( tl ) )
            return tl;
        else
            return ls.Start();
    }

    return tl;
}


void ROUTER_TOOL::switchLayerOnViaPlacement()
{
    int al = frame()->GetActiveLayer();
    int cl = m_router->GetCurrentLayer();

    if( cl != al )
    {
        m_router->SwitchLayer( al );
    }

    OPT<int> newLayer = m_router->Sizes().PairedLayer( cl );

    if( !newLayer )
        newLayer = m_router->Sizes().GetLayerTop();

    m_router->SwitchLayer( *newLayer );
    frame()->SetActiveLayer( ToLAYER_ID( *newLayer ) );
}


static VIATYPE_T getViaTypeFromFlags( int aFlags )
{
    switch( aFlags & VIA_ACTION_FLAGS::VIA_MASK )
    {
    case VIA_ACTION_FLAGS::VIA:       return VIA_THROUGH;
    case VIA_ACTION_FLAGS::BLIND_VIA: return VIA_BLIND_BURIED;
    case VIA_ACTION_FLAGS::MICROVIA:  return VIA_MICROVIA;
    default:
        wxASSERT_MSG( false, "Unhandled via type" );
        return VIA_THROUGH;
    }
}


int ROUTER_TOOL::onViaCommand( const TOOL_EVENT& aEvent )
{
    const int actViaFlags = aEvent.Parameter<intptr_t>();

    VIATYPE_T viaType = getViaTypeFromFlags( actViaFlags );
    const bool selectLayer = actViaFlags & VIA_ACTION_FLAGS::SELECT_LAYER;

    BOARD_DESIGN_SETTINGS& bds = board()->GetDesignSettings();

    const int layerCount = bds.GetCopperLayerCount();
    int currentLayer = m_router->GetCurrentLayer();
    PCB_LAYER_ID pairTop = frame()->GetScreen()->m_Route_Layer_TOP;
    PCB_LAYER_ID pairBottom = frame()->GetScreen()->m_Route_Layer_BOTTOM;

    PNS::SIZES_SETTINGS sizes = m_router->Sizes();

    // ask the user for a target layer
    PCB_LAYER_ID targetLayer = UNDEFINED_LAYER;

    if( selectLayer )
    {
        wxPoint dlgPosition = wxGetMousePosition();

        targetLayer = frame()->SelectLayer( static_cast<PCB_LAYER_ID>( currentLayer ),
                LSET::AllNonCuMask(), dlgPosition );
    }

    // fixme: P&S supports more than one fixed layer pair. Update the dialog?
    sizes.ClearLayerPairs();

    if( !m_router->IsPlacingVia() )
    {
        // Cannot place microvias or blind vias if not allowed (obvious)
        if( ( viaType == VIA_BLIND_BURIED ) && ( !bds.m_BlindBuriedViaAllowed ) )
        {
            DisplayError( frame(), _( "Blind/buried vias have to be enabled in the design settings." ) );
            return false;
        }

        if( ( viaType == VIA_MICROVIA ) && ( !bds.m_MicroViasAllowed ) )
        {
            DisplayError( frame(), _( "Microvias have to be enabled in the design settings." ) );
            return false;
        }

        // Can only place through vias on 2-layer boards
        if( ( viaType != VIA_THROUGH ) && ( layerCount <= 2 ) )
        {
            DisplayError( frame(), _( "Only through vias are allowed on 2 layer boards." ) );
            return false;
        }

        // Can only place microvias if we're on an outer layer, or directly adjacent to one
        if( ( viaType == VIA_MICROVIA ) && ( currentLayer > In1_Cu ) && ( currentLayer < layerCount - 2 ) )
        {
            DisplayError( frame(), _( "Microvias can be placed only between the outer layers " \
                                      "(F.Cu/B.Cu) and the ones directly adjacent to them." ) );
            return false;
        }
    }

    // Convert blind/buried via to a through hole one, if it goes through all layers
    if( viaType == VIA_BLIND_BURIED && ( ( currentLayer == B_Cu ) || ( currentLayer == F_Cu ) )
                                    && ( ( pairTop == B_Cu && pairBottom == F_Cu )
                                      || ( pairTop == F_Cu && pairBottom == B_Cu ) ) )
    {
        viaType = VIA_THROUGH;
    }

    switch( viaType )
    {
    case VIA_THROUGH:
        sizes.SetViaDiameter( bds.GetCurrentViaSize() );
        sizes.SetViaDrill( bds.GetCurrentViaDrill() );

        if( targetLayer != UNDEFINED_LAYER )
        {
            // go from the current layer to the chosen layer
            sizes.AddLayerPair( currentLayer, targetLayer );
        }
        else
        {
            // use the default layer pair
            sizes.AddLayerPair( pairTop, pairBottom );
        }
        break;

    case VIA_MICROVIA:
        sizes.SetViaDiameter( bds.GetCurrentMicroViaSize() );
        sizes.SetViaDrill( bds.GetCurrentMicroViaDrill() );

        wxASSERT_MSG( !selectLayer, "Unexpected select layer for microvia (microvia layers are implicit)" );

        if( currentLayer == F_Cu || currentLayer == In1_Cu )
        {
            // front-side microvia
            sizes.AddLayerPair( F_Cu, In1_Cu );
        }
        else if( currentLayer == B_Cu || currentLayer == layerCount - 2 )
        {
            // back-side microvia
            sizes.AddLayerPair( B_Cu, layerCount - 2 );
        }
        else
        {
            wxASSERT_MSG( false, "Invalid layer pair for microvia (must be on or adjacent to an outer layer)" );
        }
        break;

    case VIA_BLIND_BURIED:
        sizes.SetViaDiameter( bds.GetCurrentViaSize() );
        sizes.SetViaDrill( bds.GetCurrentViaDrill() );

        if( targetLayer != UNDEFINED_LAYER )
        {
            // go directly to the user specified layer
            sizes.AddLayerPair( currentLayer, targetLayer );
        }
        else
        {
            if( currentLayer == pairTop || currentLayer == pairBottom )
            {
                // the current layer is on the defined layer pair,
                // swap to the other side
                sizes.AddLayerPair( pairTop, pairBottom );
            }
            else
            {
                // the current layer is not part of the current layer pair,
                // so fallback and swap to the top layer of the pair by default
                sizes.AddLayerPair( pairTop, currentLayer );
            }
        }
        break;

    default:
        wxASSERT( false );
        break;
    }

    sizes.SetViaType( viaType );

    m_router->UpdateSizes( sizes );
    m_router->ToggleViaPlacement();

    if( m_router->RoutingInProgress() )
        updateEndItem( aEvent );
    else
        updateStartItem( aEvent );

    m_router->Move( m_endSnapPoint, m_endItem );        // refresh

    return 0;
}


bool ROUTER_TOOL::prepareInteractive()
{
    int routingLayer = getStartLayer( m_startItem );

    if( !IsCopperLayer( routingLayer ) )
    {
        DisplayError( frame(), _( "Tracks on Copper layers only" ) );
        return false;
    }

    PCB_EDIT_FRAME* editFrame = getEditFrame<PCB_EDIT_FRAME>();

    editFrame->SetActiveLayer( ToLAYER_ID( routingLayer ) );

    // Force layer visible
    editFrame->GetLayerManager()->SetLayerVisible( routingLayer, true );

    // for some reason I don't understand, GetNetclass() may return null sometimes...
    if( m_startItem && m_startItem->Net() >= 0 &&
        m_startItem->Parent() && m_startItem->Parent()->GetNetClass() )
    {
        highlightNet( true, m_startItem->Net() );
        // Update track width and via size shown in main toolbar comboboxes
        editFrame->SetCurrentNetClass( m_startItem->Parent()->GetNetClass()->GetName() );
    }
    else
        editFrame->SetCurrentNetClass( NETCLASS::Default );

    controls()->ForceCursorPosition( false );
    controls()->SetAutoPan( true );

    PNS::SIZES_SETTINGS sizes( m_router->Sizes() );

    sizes.Init( board(), m_startItem );
    sizes.AddLayerPair( frame()->GetScreen()->m_Route_Layer_TOP,
                        frame()->GetScreen()->m_Route_Layer_BOTTOM );
    m_router->UpdateSizes( sizes );

    if( !m_router->StartRouting( m_startSnapPoint, m_startItem, routingLayer ) )
    {
        DisplayError( frame(), m_router->FailureReason() );
        highlightNet( false );
        controls()->SetAutoPan( false );
        return false;
    }

    m_endItem = nullptr;
    m_endSnapPoint = m_startSnapPoint;

    frame()->UndoRedoBlock( true );

    return true;
}


bool ROUTER_TOOL::finishInteractive()
{
    m_router->StopRouting();

    controls()->SetAutoPan( false );
    controls()->ForceCursorPosition( false );
    frame()->UndoRedoBlock( false );
    highlightNet( false );

    return true;
}


void ROUTER_TOOL::performRouting()
{
    if( !prepareInteractive() )
        return;

    while( TOOL_EVENT* evt = Wait() )
    {
        frame()->GetCanvas()->SetCurrentCursor( wxCURSOR_PENCIL );

        // Don't crash if we missed an operation that cancelled routing.
        wxCHECK2( m_router->RoutingInProgress(), break );

        handleCommonEvents( *evt );

        if( evt->IsMotion() )
        {
            m_router->SetOrthoMode( evt->Modifier( MD_CTRL ) );
            updateEndItem( *evt );
            m_router->Move( m_endSnapPoint, m_endItem );
        }
        else if( evt->IsClick( BUT_LEFT ) || evt->IsAction( &PCB_ACTIONS::routeSingleTrack ) )
        {
            updateEndItem( *evt );
            bool needLayerSwitch = m_router->IsPlacingVia();
            bool forceFinish = evt->Modifier( MD_SHIFT );


            if( m_router->FixRoute( m_endSnapPoint, m_endItem, forceFinish ) )
                break;

            if( needLayerSwitch )
                switchLayerOnViaPlacement();

            // Synchronize the indicated layer
            frame()->SetActiveLayer( ToLAYER_ID( m_router->GetCurrentLayer() ) );
            updateEndItem( *evt );
            m_router->Move( m_endSnapPoint, m_endItem );
            m_startItem = nullptr;
        }
        else if( evt->IsAction( &ACT_SwitchPosture ) )
        {
            m_router->FlipPosture();
            updateEndItem( *evt );
            m_router->Move( m_endSnapPoint, m_endItem );        // refresh
        }
        else if( evt->IsAction( &PCB_ACTIONS::layerChanged ) )
        {
            m_router->SwitchLayer( frame()->GetActiveLayer() );
            updateEndItem( *evt );
            m_router->Move( m_endSnapPoint, m_endItem );        // refresh
        }
        else if( evt->IsAction( &ACT_EndTrack ) )
        {
            bool still_routing = true;
            while( still_routing )
                still_routing = m_router->FixRoute( m_endSnapPoint, m_endItem );
            break;
        }
        else if( evt->IsCancelInteractive() || evt->IsActivate()
                 || evt->IsUndoRedo()
                 || evt->IsAction( &PCB_ACTIONS::routerInlineDrag ) )
        {
            if( evt->IsCancelInteractive() && !m_router->RoutingInProgress() )
                m_cancelled = true;

            if( evt->IsActivate() && !evt->IsMoveTool() )
                m_cancelled = true;

            break;
        }
    }

    finishInteractive();
}


int ROUTER_TOOL::DpDimensionsDialog( const TOOL_EVENT& aEvent )
{
    PNS::SIZES_SETTINGS sizes = m_router->Sizes();
    DIALOG_PNS_DIFF_PAIR_DIMENSIONS settingsDlg( frame(), sizes );

    if( settingsDlg.ShowModal() == wxID_OK )
    {
        m_router->UpdateSizes( sizes );
        m_savedSizes = sizes;

        BOARD_DESIGN_SETTINGS& bds = frame()->GetBoard()->GetDesignSettings();
        bds.SetCustomDiffPairWidth( sizes.DiffPairWidth() );
        bds.SetCustomDiffPairGap( sizes.DiffPairGap() );
        bds.SetCustomDiffPairViaGap( sizes.DiffPairViaGap() );
    }

    return 0;
}


int ROUTER_TOOL::SettingsDialog( const TOOL_EVENT& aEvent )
{
    DIALOG_PNS_SETTINGS settingsDlg( frame(), m_router->Settings() );

    if( settingsDlg.ShowModal() == wxID_OK )
        m_savedSettings = m_router->Settings();

    return 0;
}


void ROUTER_TOOL::breakTrack()
{
    if( m_startItem && m_startItem->OfKind( PNS::ITEM::SEGMENT_T ) )
        m_router->BreakSegment( m_startItem, m_startSnapPoint );
}


int ROUTER_TOOL::MainLoop( const TOOL_EVENT& aEvent )
{
    PNS::ROUTER_MODE mode = aEvent.Parameter<PNS::ROUTER_MODE>();
    PCB_EDIT_FRAME*  frame = getEditFrame<PCB_EDIT_FRAME>();

    // Deselect all items
    m_toolMgr->RunAction( PCB_ACTIONS::selectionClear, true );

    std::string tool = aEvent.GetCommandStr().get();
    frame->PushTool( tool );
    Activate();

    m_router->SetMode( mode );

    VIEW_CONTROLS* ctls = getViewControls();
    ctls->ShowCursor( true );
    ctls->ForceCursorPosition( false );
    m_cancelled = false;
    m_startSnapPoint = ctls->GetCursorPosition();

    std::unique_ptr<ROUTER_TOOL_MENU> ctxMenu( new ROUTER_TOOL_MENU( *frame, mode ) );
    SetContextMenu( ctxMenu.get() );

    // Prime the pump
    if( aEvent.HasPosition() )
        m_toolMgr->RunAction( ACTIONS::cursorClick );

    // Main loop: keep receiving events
    while( TOOL_EVENT* evt = Wait() )
    {
        frame->GetCanvas()->SetCurrentCursor( wxCURSOR_PENCIL );

        if( evt->IsCancelInteractive() )
        {
            frame->PopTool( tool );
            break;
        }
        else if( evt->IsActivate() )
        {
            if( evt->IsMoveTool() )
            {
                // leave ourselves on the stack so we come back after the move
                break;
            }
            else
            {
                frame->PopTool( tool );
                break;
            }
        }
        else if( evt->Action() == TA_UNDO_REDO_PRE )
        {
            m_router->ClearWorld();
        }
        else if( evt->Action() == TA_UNDO_REDO_POST || evt->Action() == TA_MODEL_CHANGE )
        {
            m_router->SyncWorld();
        }
        else if( evt->IsMotion() )
        {
            updateStartItem( *evt );
        }
        else if( evt->IsAction( &PCB_ACTIONS::dragFreeAngle ) )
        {
            updateStartItem( *evt, true );
            performDragging( PNS::DM_ANY | PNS::DM_FREE_ANGLE );
        }
        else if( evt->IsAction( &PCB_ACTIONS::drag45Degree ) )
        {
            updateStartItem( *evt, true );
            performDragging( PNS::DM_ANY );
        }
        else if( evt->IsAction( &PCB_ACTIONS::breakTrack ) )
        {
            updateStartItem( *evt, true );
            breakTrack( );
        }
        else if( evt->IsClick( BUT_LEFT )
              || evt->IsAction( &PCB_ACTIONS::routeSingleTrack )
              || evt->IsAction( &PCB_ACTIONS::routeDiffPair ) )
        {
            if( evt->IsAction( &PCB_ACTIONS::routeSingleTrack )
             || evt->IsAction( &PCB_ACTIONS::routeDiffPair ) )
            {
                mode = evt->Parameter<PNS::ROUTER_MODE>();
            }

            updateStartItem( *evt );

            if( evt->HasPosition() )
            {
                if( evt->Modifier( MD_CTRL ) )
                    performDragging( PNS::DM_ANY );
                else
                    performRouting();
            }
        }
        else if( evt->IsAction( &ACT_PlaceThroughVia ) )
        {
            m_toolMgr->RunAction( PCB_ACTIONS::layerToggle, true );
        }

        if( m_cancelled )
        {
            frame->PopTool( tool );
            break;
        }
    }

    SetContextMenu( nullptr );

    // Store routing settings till the next invocation
    m_savedSettings = m_router->Settings();
    m_savedSizes = m_router->Sizes();

    return 0;
}


void ROUTER_TOOL::performDragging( int aMode )
{
    VIEW_CONTROLS* ctls = getViewControls();

    if( m_startItem && m_startItem->IsLocked() )
    {
        KIDIALOG dlg( frame(), _( "The selected item is locked." ), _( "Confirmation" ),
                      wxOK | wxCANCEL | wxICON_WARNING );
        dlg.SetOKLabel( _( "Drag Anyway" ) );
        dlg.DoNotShowCheckbox( __FILE__, __LINE__ );

        if( dlg.ShowModal() == wxID_CANCEL )
            return;
    }

    bool dragStarted = m_router->StartDragging( m_startSnapPoint, m_startItem, aMode );

    if( !dragStarted )
        return;

    if( m_startItem && m_startItem->Net() >= 0 )
        highlightNet( true, m_startItem->Net() );

    ctls->SetAutoPan( true );
    m_gridHelper->SetAuxAxes( true, m_startSnapPoint );
    frame()->UndoRedoBlock( true );

    while( TOOL_EVENT* evt = Wait() )
    {
        ctls->ForceCursorPosition( false );

        if( evt->IsMotion() )
        {
            updateEndItem( *evt );
            m_router->Move( m_endSnapPoint, m_endItem );
        }
        else if( evt->IsClick( BUT_LEFT ) )
        {
            if( m_router->FixRoute( m_endSnapPoint, m_endItem ) )
                break;
        }
        else if( evt->IsCancelInteractive() || evt->IsActivate() || evt->IsUndoRedo() )
        {
            if( evt->IsCancelInteractive() && !m_startItem )
                m_cancelled = true;

            if( evt->IsActivate() && !evt->IsMoveTool() )
                m_cancelled = true;

            break;
        }

        handleCommonEvents( *evt );
    }

    if( m_router->RoutingInProgress() )
        m_router->StopRouting();

    m_startItem = nullptr;

    m_gridHelper->SetAuxAxes( false );
    frame()->UndoRedoBlock( false );
    ctls->SetAutoPan( false );
    ctls->ForceCursorPosition( false );
    highlightNet( false );
}


void ROUTER_TOOL::NeighboringSegmentFilter( const VECTOR2I& aPt, GENERAL_COLLECTOR& aCollector )
{
    /*
     * If the collection contains a trivial line corner (two connected segments)
     * or a non-fanout-via (a via with no more than two connected segments), then
     * trim the collection down to a single item (which one won't matter since
     * they're all connected).
     */

    // First make sure we've got something that *might* match.
    int vias = aCollector.CountType( PCB_VIA_T );
    int traces = aCollector.CountType( PCB_TRACE_T );

    if( vias > 1 || traces > 2 || vias + traces < 1 )
        return;

    // Fetch first TRACK (via or trace) as our reference
    TRACK* reference = nullptr;

    for( int i = 0; !reference && i < aCollector.GetCount(); i++ )
        reference = dynamic_cast<TRACK*>( aCollector[i] );

    int refNet = reference->GetNetCode();

    wxPoint refPoint( aPt.x, aPt.y );
    STATUS_FLAGS flags = reference->IsPointOnEnds( refPoint, -1 );

    if( flags & STARTPOINT )
        refPoint = reference->GetStart();
    else if( flags & ENDPOINT )
        refPoint = reference->GetEnd();

    // Check all items to ensure that any TRACKs are co-terminus with the reference and on
    // the same net.
    for( int i = 0; i < aCollector.GetCount(); i++ )
    {
        TRACK* neighbor = dynamic_cast<TRACK*>( aCollector[i] );

        if( neighbor && neighbor != reference )
        {
            if( neighbor->GetNetCode() != refNet )
                return;

            if( neighbor->GetStart() != refPoint && neighbor->GetEnd() != refPoint )
                return;
        }
    }

    // Selection meets criteria; trim it to the reference item.
    aCollector.Empty();
    aCollector.Append( reference );
}


bool ROUTER_TOOL::CanInlineDrag()
{
    m_toolMgr->RunAction( PCB_ACTIONS::selectionCursor, true, NeighboringSegmentFilter );
    const auto& selection = m_toolMgr->GetTool<SELECTION_TOOL>()->GetSelection();

    if( selection.Size() == 1 )
    {
        const BOARD_CONNECTED_ITEM* item = static_cast<const BOARD_CONNECTED_ITEM*>( selection.Front() );

        if( item->Type() == PCB_TRACE_T || item->Type() == PCB_VIA_T )
            return true;
    }

    return false;
}


int ROUTER_TOOL::InlineDrag( const TOOL_EVENT& aEvent )
{
    const auto& selection = m_toolMgr->GetTool<SELECTION_TOOL>()->GetSelection();

    if( selection.Empty() )
        m_toolMgr->RunAction( PCB_ACTIONS::selectionCursor, true, NeighboringSegmentFilter );

    if( selection.Size() != 1 )
        return 0;

    const BOARD_CONNECTED_ITEM* item = static_cast<const BOARD_CONNECTED_ITEM*>( selection.Front() );

    if( item->Type() != PCB_TRACE_T && item->Type() != PCB_VIA_T )
        return 0;

    Activate();

    m_toolMgr->RunAction( PCB_ACTIONS::selectionClear, true );
    m_router->SyncWorld();
    m_startItem = m_router->GetWorld()->FindItemByParent( item );

    if( m_startItem && m_startItem->IsLocked() )
    {
        KIDIALOG dlg( frame(), _( "The selected item is locked." ), _( "Confirmation" ),
                      wxOK | wxCANCEL | wxICON_WARNING );
        dlg.SetOKLabel( _( "Drag Anyway" ) );
        dlg.DoNotShowCheckbox( __FILE__, __LINE__ );

        if( dlg.ShowModal() == wxID_CANCEL )
            return 0;
    }

    VECTOR2I p0 = controls()->GetCursorPosition( false );
    auto p = snapToItem( true, m_startItem, p0 );
    int dragMode = aEvent.Parameter<int64_t> ();

    bool dragStarted = m_router->StartDragging( p, m_startItem, dragMode );

    if( !dragStarted )
        return 0;

    m_gridHelper->SetAuxAxes( true, p );
    controls()->ShowCursor( true );
    controls()->ForceCursorPosition( false );
    controls()->SetAutoPan( true );
    frame()->UndoRedoBlock( true );

    while( TOOL_EVENT* evt = Wait() )
    {
        frame()->GetCanvas()->SetCurrentCursor( wxCURSOR_ARROW );

        if( evt->IsCancelInteractive() )
        {
            break;
        }
        else if( evt->IsMotion() || evt->IsDrag( BUT_LEFT ) )
        {
            updateEndItem( *evt );
            m_router->Move( m_endSnapPoint, m_endItem );
        }
        else if( evt->IsMouseUp( BUT_LEFT ) || evt->IsClick( BUT_LEFT ) )
        {
            updateEndItem( *evt );
            m_router->FixRoute( m_endSnapPoint, m_endItem );
            break;
        }
    }

    if( m_router->RoutingInProgress() )
        m_router->StopRouting();

    m_gridHelper->SetAuxAxes( false );
    controls()->SetAutoPan( false );
    controls()->ForceCursorPosition( false );
    frame()->UndoRedoBlock( false );

    return 0;
}


int ROUTER_TOOL::InlineBreakTrack( const TOOL_EVENT& aEvent )
{
    const auto& selection = m_toolMgr->GetTool<SELECTION_TOOL>()->GetSelection();

    if( selection.Size() != 1 )
        return 0;

    const BOARD_CONNECTED_ITEM* item = static_cast<const BOARD_CONNECTED_ITEM*>( selection.Front() );

    if( item->Type() != PCB_TRACE_T )
        return 0;

    Init();
    Activate();

    m_toolMgr->RunAction( PCB_ACTIONS::selectionClear, true );
    m_router->SyncWorld();
    m_startItem = m_router->GetWorld()->FindItemByParent( item );
    m_startSnapPoint = snapToItem( true, m_startItem, controls()->GetCursorPosition() );


    if( m_startItem && m_startItem->IsLocked() )
    {
        KIDIALOG dlg( frame(), _( "The selected item is locked." ), _( "Confirmation" ),
                      wxOK | wxCANCEL | wxICON_WARNING );
        dlg.SetOKLabel( _( "Break Track" ) );
        dlg.DoNotShowCheckbox( __FILE__, __LINE__ );

        if( dlg.ShowModal() == wxID_CANCEL )
            return 0;
    }

    frame()->UndoRedoBlock( true );
    breakTrack();

    if( m_router->RoutingInProgress() )
        m_router->StopRouting();

    frame()->UndoRedoBlock( false );

    return 0;
}


int ROUTER_TOOL::CustomTrackWidthDialog( const TOOL_EVENT& aEvent )
{
    BOARD_DESIGN_SETTINGS& bds = board()->GetDesignSettings();
    DIALOG_TRACK_VIA_SIZE sizeDlg( frame(), bds );

    if( sizeDlg.ShowModal() )
    {
        bds.UseCustomTrackViaSize( true );
        m_toolMgr->RunAction( PCB_ACTIONS::trackViaSizeChanged, true );
    }

    return 0;
}


int ROUTER_TOOL::onTrackViaSizeChanged( const TOOL_EVENT& aEvent )
{
    PNS::SIZES_SETTINGS sizes( m_router->Sizes() );
    sizes.ImportCurrent( board()->GetDesignSettings() );
    m_router->UpdateSizes( sizes );

    // Changing the track width can affect the placement, so call the
    // move routine without changing the destination
    m_router->Move( m_endSnapPoint, m_endItem );

    return 0;
}


void ROUTER_TOOL::setTransitions()
{
    Go( &ROUTER_TOOL::SelectCopperLayerPair,  PCB_ACTIONS::selectLayerPair.MakeEvent() );

    Go( &ROUTER_TOOL::MainLoop,               PCB_ACTIONS::routeSingleTrack.MakeEvent() );
    Go( &ROUTER_TOOL::MainLoop,               PCB_ACTIONS::routeDiffPair.MakeEvent() );
    Go( &ROUTER_TOOL::DpDimensionsDialog,     PCB_ACTIONS::routerDiffPairDialog.MakeEvent() );
    Go( &ROUTER_TOOL::SettingsDialog,         PCB_ACTIONS::routerSettingsDialog.MakeEvent() );
    Go( &ROUTER_TOOL::InlineDrag,             PCB_ACTIONS::routerInlineDrag.MakeEvent() );
    Go( &ROUTER_TOOL::InlineBreakTrack,       PCB_ACTIONS::inlineBreakTrack.MakeEvent() );

    Go( &ROUTER_TOOL::onViaCommand,           ACT_PlaceThroughVia.MakeEvent() );
    Go( &ROUTER_TOOL::onViaCommand,           ACT_PlaceBlindVia.MakeEvent() );
    Go( &ROUTER_TOOL::onViaCommand,           ACT_PlaceMicroVia.MakeEvent() );
    Go( &ROUTER_TOOL::onViaCommand,           ACT_SelLayerAndPlaceThroughVia.MakeEvent() );
    Go( &ROUTER_TOOL::onViaCommand,           ACT_SelLayerAndPlaceBlindVia.MakeEvent() );

    Go( &ROUTER_TOOL::CustomTrackWidthDialog, ACT_CustomTrackWidth.MakeEvent() );
    Go( &ROUTER_TOOL::onTrackViaSizeChanged,  PCB_ACTIONS::trackViaSizeChanged.MakeEvent() );
}