/*
 * KiRouter - a push-and-(sometimes-)shove PCB router
 *
 * Copyright (C) 2013-2014 CERN
 * Copyright (C) 2016-2020 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 <core/optional.h>

#include <geometry/shape_line_chain.h>

#include "pns_walkaround.h"
#include "pns_optimizer.h"
#include "pns_utils.h"
#include "pns_router.h"
#include "pns_debug_decorator.h"

namespace PNS {

void WALKAROUND::start( const LINE& aInitialPath )
{
    m_iteration = 0;
    m_iterationLimit = 50;
}


NODE::OPT_OBSTACLE WALKAROUND::nearestObstacle( const LINE& aPath )
{
    NODE::OPT_OBSTACLE obs = m_world->NearestObstacle( &aPath, m_itemMask, m_restrictedSet.empty() ? NULL : &m_restrictedSet );

    if( m_restrictedSet.empty() )
        return obs;

    else if( obs && m_restrictedSet.find ( obs->m_item ) != m_restrictedSet.end() )
        return obs;

    return NODE::OPT_OBSTACLE();
}


WALKAROUND::WALKAROUND_STATUS WALKAROUND::singleStep( LINE& aPath,
                                                              bool aWindingDirection )
{
    OPT<OBSTACLE>& current_obs =
        aWindingDirection ? m_currentObstacle[0] : m_currentObstacle[1];

    if( !current_obs )
        return DONE;

    SHAPE_LINE_CHAIN path_pre[2], path_walk[2], path_post[2];

    if( aPath.PointCount() > 1 )
    {
        VECTOR2I last = aPath.CPoint( -1 );

        if( ( current_obs->m_hull ).PointInside( last ) || ( current_obs->m_hull ).PointOnEdge( last ) )
        {
            m_recursiveBlockageCount++;

            if( m_recursiveBlockageCount < 3 )
                aPath.Line().Append( current_obs->m_hull.NearestPoint( last ) );
            else
            {
                aPath = aPath.ClipToNearestObstacle( m_world );
                return DONE;
            }
        }
    }

    aPath.Walkaround( current_obs->m_hull, path_pre[0], path_walk[0],
                      path_post[0], aWindingDirection );
    aPath.Walkaround( current_obs->m_hull, path_pre[1], path_walk[1],
                      path_post[1], !aWindingDirection );

    if( !aPath.Walkaround( current_obs->m_hull, path_pre[1], path_walk[1],
                      path_post[1], !aWindingDirection ) )
        return STUCK;
    auto l =aPath.CLine();

#if 0
    if( m_logger )
    {
        m_logger->NewGroup( aWindingDirection ? "walk-cw" : "walk-ccw", m_iteration );
        m_logger->Log( &path_walk[0], 0, "path_walk" );
        m_logger->Log( &path_pre[0], 1, "path_pre" );
        m_logger->Log( &path_post[0], 4, "path_post" );
        m_logger->Log( &current_obs->m_hull, 2, "hull" );
        m_logger->Log( current_obs->m_item, 3, "item" );
    }
#endif

    if ( Dbg() )
    {
        char name[128];
        snprintf(name, sizeof(name), "hull-%s-%d", aWindingDirection ? "cw" : "ccw", m_iteration );
        Dbg()->AddLine( current_obs->m_hull, 0, 1, name);
        snprintf(name, sizeof(name), "path-%s-%d", aWindingDirection ? "cw" : "ccw", m_iteration );
        Dbg()->AddLine( aPath.CLine(), 1, 1, name );
    }

    int len_pre = path_walk[0].Length();
    int len_alt = path_walk[1].Length();

    LINE walk_path( aPath, path_walk[1] );

    bool alt_collides = static_cast<bool>( m_world->CheckColliding( &walk_path, m_itemMask ) );

    SHAPE_LINE_CHAIN pnew;

    /*if( !m_forceLongerPath && len_alt < len_pre && !alt_collides && !prev_recursive )
    {
        pnew = path_pre[1];
        pnew.Append( path_walk[1] );
        pnew.Append( path_post[1] );

        if( !path_post[1].PointCount() || !path_walk[1].PointCount() )
            current_obs = nearestObstacle( LINE( aPath, path_pre[1] ) );
        else
            current_obs = nearestObstacle( LINE( aPath, path_post[1] ) );
    }
    else*/
    {
        pnew = path_pre[0];
        pnew.Append( path_walk[0] );
        pnew.Append( path_post[0] );

        if( path_post[0].PointCount() == 0 || path_walk[0].PointCount() == 0 )
            current_obs = nearestObstacle( LINE( aPath, path_pre[0] ) );
        else
            current_obs = nearestObstacle( LINE( aPath, path_walk[0] ) );

        if( !current_obs )
        {
            current_obs = nearestObstacle( LINE( aPath, path_post[0] ) );
        }
    }

    pnew.Simplify();
    aPath.SetShape( pnew );

    return IN_PROGRESS;
}



bool clipToLoopStart( SHAPE_LINE_CHAIN& l )
{
    auto ip = l.SelfIntersecting();

    if(!ip)
        return false;
    else {
        int pidx = l.Split( ip->p );
        auto lead = l.Slice(0, pidx);
        auto tail = l.Slice(pidx + 1, -1);

        int pidx2 = tail.Split( ip->p );

        auto dbg = ROUTER::GetInstance()->GetInterface()->GetDebugDecorator();
        dbg->AddPoint( ip->p, 5 );

        l = lead;
        l.Append( tail.Slice( 0, pidx2 ) );
        //l = l.Slice(0, pidx);
        return true;
    }


}



const WALKAROUND::RESULT WALKAROUND::Route( const LINE& aInitialPath )
{
    LINE path_cw( aInitialPath ), path_ccw( aInitialPath );
    WALKAROUND_STATUS s_cw = IN_PROGRESS, s_ccw = IN_PROGRESS;
    SHAPE_LINE_CHAIN best_path;
    RESULT result;

    // special case for via-in-the-middle-of-track placement
    if( aInitialPath.PointCount() <= 1 )
    {
        if( aInitialPath.EndsWithVia() && m_world->CheckColliding( &aInitialPath.Via(), m_itemMask ) )
            return RESULT( STUCK, STUCK );

        return RESULT( DONE, DONE, aInitialPath, aInitialPath );
    }

    start( aInitialPath );

    m_currentObstacle[0] = m_currentObstacle[1] = nearestObstacle( aInitialPath );
    m_recursiveBlockageCount = 0;

    result.lineCw = aInitialPath;
    result.lineCcw = aInitialPath;

    if( m_forceWinding )
    {
        s_cw = m_forceCw ? IN_PROGRESS : STUCK;
        s_ccw = m_forceCw ? STUCK : IN_PROGRESS;
        m_forceSingleDirection = true;
    } else {
        m_forceSingleDirection = false;
    }

    while( m_iteration < m_iterationLimit )
    {
        if( s_cw != STUCK )
            s_cw = singleStep( path_cw, true );

        if( s_ccw != STUCK )
            s_ccw = singleStep( path_ccw, false );

        auto old = path_cw.CLine();

        if( clipToLoopStart( path_cw.Line() ))
        {
            s_cw = ALMOST_DONE;
        }

        if( clipToLoopStart( path_ccw.Line() ))
        {
            s_ccw = ALMOST_DONE;
        }


        if( s_cw != IN_PROGRESS )
        {
            result.lineCw = path_cw;
            result.statusCw = s_cw;
        }

        if( s_ccw != IN_PROGRESS )
        {
            result.lineCcw = path_ccw;
            result.statusCcw = s_ccw;
        }

        if( s_cw != IN_PROGRESS && s_ccw != IN_PROGRESS )
            break;

        m_iteration++;
    }

    if( s_cw == IN_PROGRESS )
    {
        result.lineCw = path_cw;
        result.statusCw = ALMOST_DONE;
    }

    if( s_ccw == IN_PROGRESS )
    {
        result.lineCcw = path_ccw;
        result.statusCcw = ALMOST_DONE;
    }

    result.lineCw.Line().Simplify();
    result.lineCcw.Line().Simplify();

    if( result.lineCw.SegmentCount() < 1 || result.lineCw.CPoint( 0 ) != aInitialPath.CPoint( 0 ) )
    {
        result.statusCw = STUCK;
    }

    if( result.lineCw.PointCount() > 0 && result.lineCw.CPoint( -1 ) != aInitialPath.CPoint( -1 ) )
    {
        result.statusCw = ALMOST_DONE;
    }

    if( result.lineCcw.SegmentCount() < 1 || result.lineCcw.CPoint( 0 ) != aInitialPath.CPoint( 0 ) )
    {
        result.statusCcw = STUCK;
    }

    if( result.lineCcw.PointCount() > 0 && result.lineCcw.CPoint( -1 ) != aInitialPath.CPoint( -1 ) )
    {
        result.statusCcw = ALMOST_DONE;
    }

    return result;
}



WALKAROUND::WALKAROUND_STATUS WALKAROUND::Route( const LINE& aInitialPath,
        LINE& aWalkPath, bool aOptimize )
{
    LINE path_cw( aInitialPath ), path_ccw( aInitialPath );
    WALKAROUND_STATUS s_cw = IN_PROGRESS, s_ccw = IN_PROGRESS;
    SHAPE_LINE_CHAIN best_path;

    // special case for via-in-the-middle-of-track placement
    if( aInitialPath.PointCount() <= 1 )
    {
        if( aInitialPath.EndsWithVia() && m_world->CheckColliding( &aInitialPath.Via(), m_itemMask ) )
            return STUCK;

        aWalkPath = aInitialPath;
        return DONE;
    }

    start( aInitialPath );

    m_currentObstacle[0] = m_currentObstacle[1] = nearestObstacle( aInitialPath );
    m_recursiveBlockageCount = 0;

    aWalkPath = aInitialPath;

    if( m_forceWinding )
    {
        s_cw = m_forceCw ? IN_PROGRESS : STUCK;
        s_ccw = m_forceCw ? STUCK : IN_PROGRESS;
        m_forceSingleDirection = true;
    } else {
        m_forceSingleDirection = false;
    }

    while( m_iteration < m_iterationLimit )
    {
        if( s_cw != STUCK )
            s_cw = singleStep( path_cw, true );

        if( s_ccw != STUCK )
            s_ccw = singleStep( path_ccw, false );

        if( ( s_cw == DONE && s_ccw == DONE ) || ( s_cw == STUCK && s_ccw == STUCK ) )
        {
            int len_cw  = path_cw.CLine().Length();
            int len_ccw = path_ccw.CLine().Length();

            if( m_forceLongerPath )
                aWalkPath = ( len_cw > len_ccw ? path_cw : path_ccw );
            else
                aWalkPath = ( len_cw < len_ccw ? path_cw : path_ccw );

            break;
        }
        else if( s_cw == DONE && !m_forceLongerPath )
        {
            aWalkPath = path_cw;
            break;
        }
        else if( s_ccw == DONE && !m_forceLongerPath )
        {
            aWalkPath = path_ccw;
            break;
        }

        m_iteration++;
    }

    if( m_iteration == m_iterationLimit )
    {
        int len_cw  = path_cw.CLine().Length();
        int len_ccw = path_ccw.CLine().Length();

        if( m_forceLongerPath )
            aWalkPath = ( len_cw > len_ccw ? path_cw : path_ccw );
        else
            aWalkPath = ( len_cw < len_ccw ? path_cw : path_ccw );
    }

    if( m_cursorApproachMode )
    {
        // int len_cw = path_cw.GetCLine().Length();
        // int len_ccw = path_ccw.GetCLine().Length();
        bool found = false;

        SHAPE_LINE_CHAIN l = aWalkPath.CLine();

        for( int i = 0; i < l.SegmentCount(); i++ )
        {
            const SEG s = l.Segment( i );

            VECTOR2I nearest = s.NearestPoint( m_cursorPos );
            VECTOR2I::extended_type dist_a = ( s.A - m_cursorPos ).SquaredEuclideanNorm();
            VECTOR2I::extended_type dist_b = ( s.B - m_cursorPos ).SquaredEuclideanNorm();
            VECTOR2I::extended_type dist_n = ( nearest - m_cursorPos ).SquaredEuclideanNorm();

            if( dist_n <= dist_a && dist_n < dist_b )
            {
                l.Remove( i + 1, -1 );
                l.Append( nearest );
                l.Simplify();
                found = true;
                break;
            }
        }

        if( found )
        {
            aWalkPath = aInitialPath;
            aWalkPath.SetShape( l );
        }
    }

    aWalkPath.Line().Simplify();

    if( aWalkPath.SegmentCount() < 1 )
        return STUCK;
    if( aWalkPath.CPoint( -1 ) != aInitialPath.CPoint( -1 ) )
        return ALMOST_DONE;
    if( aWalkPath.CPoint( 0 ) != aInitialPath.CPoint( 0 ) )
        return STUCK;

    WALKAROUND_STATUS st = s_ccw == DONE || s_cw == DONE ? DONE : STUCK;

    if( st == DONE )
    {
        if( aOptimize )
            OPTIMIZER::Optimize( &aWalkPath, OPTIMIZER::MERGE_OBTUSE, m_world );
    }

    return st;
}

}