/*
 * vim: ts=4 sw=4 et tw=0 wm=0
 *
 * libavoid - Fast, Incremental, Object-avoiding Line Router
 *
 * Copyright (C) 2011-2014  Monash University
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * See the file LICENSE.LGPL distributed with the library.
 *
 * Licensees holding a valid commercial license may use this file in
 * accordance with the commercial license agreement provided with the 
 * library.
 *
 * This library 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.  
 *
 * Author(s):  Michael Wybrow
*/

#include "libavoid/hyperedge.h"
#include "libavoid/hyperedgetree.h"
#include "libavoid/mtst.h"
#include "libavoid/junction.h"
#include "libavoid/connector.h"
#include "libavoid/vertices.h"
#include "libavoid/connend.h"
#include "libavoid/shape.h"
#include "libavoid/router.h"
#include "libavoid/assertions.h"
#include "libavoid/debughandler.h"
#include "libavoid/debug.h"


namespace Avoid {

HyperedgeRerouter::HyperedgeRerouter()
    : m_router(nullptr)
{
}

void HyperedgeRerouter::setRouter(Router *router)
{
    m_router = router;
}

size_t HyperedgeRerouter::registerHyperedgeForRerouting(
        ConnEndList terminals)
{
    m_terminals_vector.push_back(terminals);
    m_root_junction_vector.push_back(nullptr);

    return m_terminals_vector.size() - 1;
}

size_t HyperedgeRerouter::registerHyperedgeForRerouting(
        JunctionRef *junction)
{
    m_terminals_vector.push_back(ConnEndList());
    m_root_junction_vector.push_back(junction);

    return m_terminals_vector.size() - 1;
}

size_t HyperedgeRerouter::count(void) const
{
    return m_terminals_vector.size();
}

HyperedgeNewAndDeletedObjectLists HyperedgeRerouter::newAndDeletedObjectLists(
        size_t index) const
{
    COLA_ASSERT(index <= count());

    HyperedgeNewAndDeletedObjectLists result;

    result.newJunctionList = m_new_junctions_vector[index];
    result.deletedJunctionList = m_deleted_junctions_vector[index];
    result.newConnectorList = m_new_connectors_vector[index];
    result.deletedConnectorList = m_deleted_connectors_vector[index];

    return result;
}


void HyperedgeRerouter::outputInstanceToSVG(FILE *fp)
{
    if (count() == 0)
    {
        return;
    }

    fprintf(fp, "    HyperedgeRerouter *hyperedgeRerouter = router->hyperedgeRerouter();\n");
    const size_t num_hyperedges = count();
    for (size_t i = 0; i < num_hyperedges; ++i)
    {
        if (m_root_junction_vector[i])
        {
            fprintf(fp, "    hyperedgeRerouter->registerHyperedgeForRerouting(junctionRef%u);\n",
                    m_root_junction_vector[i]->id());
        }
        else
        {
            fprintf(fp, "    ConnEndList heConnList%u;\n", (unsigned int) i);
            for (ConnEndList::const_iterator it = m_terminals_vector[i].begin();
                    it != m_terminals_vector[i].end(); ++it)
            {
                (*it).outputCode(fp, "heEnd");
                fprintf(fp, "    heConnList%u.push_back(heEndPt);\n",
                        (unsigned int) i);
            }
            fprintf(fp, "    hyperedgeRerouter->registerHyperedgeForRerouting(heConnList%u);\n",
                    (unsigned int) i);

        }
    }
    fprintf(fp, "\n");
}


// Follow connected junctions and connectors from the given connector to
// determine the hyperedge topology, saving objects to the deleted-objects
// vectors as we go.
bool HyperedgeRerouter::findAttachedObjects(size_t index,
        ConnRef *connector, JunctionRef *ignore, ConnRefSet& hyperedgeConns)
{
    bool validHyperedge = false;

    connector->assignConnectionPinVisibility(true);

    m_deleted_connectors_vector[index].push_back(connector);
    hyperedgeConns.insert(connector);

    std::pair<Obstacle *, Obstacle *> anchors = connector->endpointAnchors();
    JunctionRef *jFirst = dynamic_cast<JunctionRef *> (anchors.first);
    JunctionRef *jSecond = dynamic_cast<JunctionRef *> (anchors.second);

    if (jFirst)
    {
        // If attached to a junction and not one we've explored, then continue.
        if (jFirst != ignore)
        {
            validHyperedge |= findAttachedObjects(index, jFirst, connector, hyperedgeConns);
        }
    }
    else
    {
        // If its an endpoint, then record the vertex for this endpoint.
        COLA_ASSERT(connector->m_src_vert);
        m_terminal_vertices_vector[index].insert(connector->m_src_vert);
    }

    if (jSecond)
    {
        // If attached to a junction and not one we've explored, then continue.
        if (jSecond != ignore)
        {
            validHyperedge |= findAttachedObjects(index, jSecond, connector, hyperedgeConns);
        }
    }
    else
    {
        // If its an endpoint, then record the vertex for this endpoint.
        COLA_ASSERT(connector->m_dst_vert);
        m_terminal_vertices_vector[index].insert(connector->m_dst_vert);
    }
    return validHyperedge;
}


// Follow connected junctions and connectors from the given junction to
// determine the hyperedge topology, saving objects to the deleted-objects
// vectors as we go.
bool HyperedgeRerouter::findAttachedObjects(size_t index,
        JunctionRef *junction, ConnRef *ignore, ConnRefSet& hyperedgeConns)
{
    bool validHyperedge = false;

    m_deleted_junctions_vector[index].push_back(junction);

    ConnRefList connectors = junction->attachedConnectors();

    if (connectors.size() > 2)
    {
        // A valid hyperedge must have at least one junction with three
        // connectors attached, i.e., more than two endpoints.
        validHyperedge |= true;
    }

    for (ConnRefList::iterator curr  = connectors.begin();
            curr != connectors.end(); ++curr)
    {
        if (*curr == ignore)
        {
            continue;
        }

        COLA_ASSERT(*curr != nullptr);
        validHyperedge |= findAttachedObjects(index, (*curr), junction, hyperedgeConns);
    }
    return validHyperedge;
}


// Populate the deleted-object vectors with all the connectors and junctions
// that form the registered hyperedges.  Then return the set of all these
// connectors so they can be ignored for individual rerouting.
ConnRefSet HyperedgeRerouter::calcHyperedgeConnectors(void)
{
    COLA_ASSERT(m_router != nullptr);

    ConnRefSet allRegisteredHyperedgeConns;

    // Clear the deleted-object vectors.  We populate them here if necessary.
    m_deleted_junctions_vector.clear();
    m_deleted_junctions_vector.resize(count());
    m_deleted_connectors_vector.clear();
    m_deleted_connectors_vector.resize(count());

    m_terminal_vertices_vector.clear();
    m_terminal_vertices_vector.resize(count());
    m_added_vertices.clear();

    // Populate the deleted-object vectors.
    const size_t num_hyperedges = count();
    for (size_t i = 0; i < num_hyperedges; ++i)
    {
        if (m_root_junction_vector[i])
        {
            // Follow objects attached to junction to find the hyperedge.
            bool valid = findAttachedObjects(i, m_root_junction_vector[i], nullptr,
                    allRegisteredHyperedgeConns);
            if (!valid)
            {
                err_printf("Warning: Hyperedge %d registered with "
                           "HyperedgeRerouter is invalid and will be "
                           "ignored.\n", (int) i);
                // Hyperedge is invalid.  Clear the terminals and other info
                // so it will be ignored, and rerouted as a normal set of 
                // connectors.
                m_terminals_vector[i].clear();
                m_terminal_vertices_vector[i].clear();
                m_deleted_junctions_vector[i].clear();
                m_deleted_connectors_vector[i].clear();
            }
            continue;
        }

        // Alternatively, we have a set of ConnEnds, so store the
        // corresponding terminals
        std::pair<bool, VertInf *> maybeNewVertex;
        for (ConnEndList::const_iterator it = m_terminals_vector[i].begin();
                it != m_terminals_vector[i].end(); ++it)
        {
            maybeNewVertex = it->getHyperedgeVertex(m_router);
            COLA_ASSERT(maybeNewVertex.second != nullptr);
            m_terminal_vertices_vector[i].insert(maybeNewVertex.second);

            if (maybeNewVertex.first)
            {
                // This is a newly created vertex.  Remember it so we can
                // free it and it's visibility edges later.
                m_added_vertices.push_back(maybeNewVertex.second);
            }
        }
    }

    // Return these connectors that don't require rerouting.
    return allRegisteredHyperedgeConns;
}


void HyperedgeRerouter::performRerouting(void)
{
    COLA_ASSERT(m_router != nullptr);

    m_new_junctions_vector.clear();
    m_new_junctions_vector.resize(count());
    m_new_connectors_vector.clear();
    m_new_connectors_vector.resize(count());

#ifdef DEBUGHANDLER
    if (m_router->debugHandler())
    {
        std::vector<Box> obstacleBoxes;
        ObstacleList::iterator obstacleIt = m_router->m_obstacles.begin();
        while (obstacleIt != m_router->m_obstacles.end())
        {
            Obstacle *obstacle = *obstacleIt;
            JunctionRef *junction = dynamic_cast<JunctionRef *> (obstacle);
            if (junction && ! junction->positionFixed())
            {
                // Junctions that are free to move are not treated as obstacles.
                ++obstacleIt;
                continue;
            }
            Box bbox = obstacle->routingBox();
            obstacleBoxes.push_back(bbox);
            ++obstacleIt;
        }
        m_router->debugHandler()->updateObstacleBoxes(obstacleBoxes);
    }
#endif

    // For each hyperedge...
    const size_t num_hyperedges = count();
    for (size_t i = 0; i < num_hyperedges; ++i)
    {
        if (m_terminal_vertices_vector[i].empty())
        {
            // Invalid hyperedge, ignore.
            continue;
        }

        // Execute the MTST method to find good junction positions and an
        // initial path.  A hyperedge tree will be built for the new route.
        JunctionHyperedgeTreeNodeMap hyperedgeTreeJunctions;
        MinimumTerminalSpanningTree mtst(m_router, 
                m_terminal_vertices_vector[i], &hyperedgeTreeJunctions);

        // The older MTST construction method (faster, worse results).
        //mtst.constructSequential();
        
        // The preferred MTST construction method.
        // Slightly slower, better quality results.
        mtst.constructInterleaved();

        HyperedgeTreeNode *treeRoot = mtst.rootJunction();
        COLA_ASSERT(treeRoot);
        
        // Fill in connector information and join them to junctions of endpoints
        // of original connectors.
        treeRoot->addConns(nullptr, m_router, 
                m_deleted_connectors_vector[i], nullptr);

        // Output the list of new junctions and connectors from hyperedge tree.
        treeRoot->listJunctionsAndConnectors(nullptr, m_new_junctions_vector[i],
                m_new_connectors_vector[i]);

        // Write paths from the hyperedge tree back into individual
        // connector routes.
        for (size_t pass = 0; pass < 2; ++pass)
        {
            treeRoot->writeEdgesToConns(nullptr, pass);
        }

        // Tell the router that we are deleting the objects used for the
        // previous path for the hyperedge.
        for (ConnRefList::iterator curr = 
                m_deleted_connectors_vector[i].begin();
                curr != m_deleted_connectors_vector[i].end(); ++curr)
        {
            // Clear visibility assigned for connection pins.
            (*curr)->assignConnectionPinVisibility(false);

            m_router->deleteConnector(*curr);
        }
        for (JunctionRefList::iterator curr = 
                m_deleted_junctions_vector[i].begin();
                curr != m_deleted_junctions_vector[i].end(); ++curr)
        {
            m_router->deleteJunction(*curr);
        }
    }

    // Clear the input to this class, so that new objects can be registered
    // for rerouting for the next time that transaction that is processed.
    m_terminals_vector.clear();
    m_root_junction_vector.clear();

    // Free temporarily added vertices.
    for (VertexList::iterator curr = m_added_vertices.begin();
            curr != m_added_vertices.end(); ++curr)
    {
        (*curr)->removeFromGraph();
        m_router->vertices.removeVertex(*curr);
        delete *curr;
    }
    m_added_vertices.clear();
}


}