osrm-backend/Descriptors/JSONDescriptor.h

/*
    open source routing machine
    Copyright (C) Dennis Luxen, others 2010

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU AFFERO General Public License as published by
the Free Software Foundation; either version 3 of the License, or
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 Affero General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
or see http://www.gnu.org/licenses/agpl.txt.
 */

#ifndef JSON_DESCRIPTOR_H_
#define JSON_DESCRIPTOR_H_

#include <algorithm>

#include "BaseDescriptor.h"
#include "DescriptionFactory.h"
#include "../Algorithms/ObjectToBase64.h"
#include "../DataStructures/SegmentInformation.h"
#include "../DataStructures/TurnInstructions.h"
#include "../Util/Azimuth.h"
#include "../Util/StringUtil.h"

template<class SearchEngineT>
class JSONDescriptor : public BaseDescriptor<SearchEngineT>{
private:
    _DescriptorConfig config;
    DescriptionFactory descriptionFactory;
    DescriptionFactory alternateDescriptionFactory;
    _Coordinate current;
    unsigned numberOfEnteredRestrictedAreas;
    struct {
        int startIndex;
        int nameID;
        int leaveAtExit;
    } roundAbout;

public:
    JSONDescriptor() : numberOfEnteredRestrictedAreas(0) {}
    void SetConfig(const _DescriptorConfig & c) { config = c; }

    void Run(http::Reply & reply, const RawRouteData &rawRoute, PhantomNodes &phantomNodes, SearchEngineT &sEngine) {
        WriteHeaderToOutput(reply.content);
        if(rawRoute.lengthOfShortestPath != INT_MAX) {
            descriptionFactory.SetStartSegment(phantomNodes.startPhantom);
            reply.content += "0,"
                    "\"status_message\": \"Found route between points\",";

            //Get all the coordinates for the computed route
            BOOST_FOREACH(const _PathData & pathData, rawRoute.computedShortestPath) {
                sEngine.GetCoordinatesForNodeID(pathData.node, current);
                descriptionFactory.AppendSegment(current, pathData );
            }
            descriptionFactory.SetEndSegment(phantomNodes.targetPhantom);
        } else {
            //We do not need to do much, if there is no route ;-)
            reply.content += "207,"
                    "\"status_message\": \"Cannot find route between points\",";
        }

        descriptionFactory.Run(sEngine, config.z, rawRoute.lengthOfShortestPath);
        reply.content += "\"route_geometry\": ";
        if(config.geometry) {
            descriptionFactory.AppendEncodedPolylineString(reply.content, config.encodeGeometry);
        } else {
            reply.content += "[]";
        }

        reply.content += ","
                "\"route_instructions\": [";
        numberOfEnteredRestrictedAreas = 0;
        if(config.instructions) {
            BuildTextualDescription(descriptionFactory, reply, rawRoute.lengthOfShortestPath, sEngine);
        } else {
            BOOST_FOREACH(const SegmentInformation & segment, descriptionFactory.pathDescription) {
                short currentInstruction = segment.turnInstruction & TurnInstructions.InverseAccessRestrictionFlag;
                numberOfEnteredRestrictedAreas += (currentInstruction != segment.turnInstruction);
            }
        }
        reply.content += "],";
        descriptionFactory.BuildRouteSummary(descriptionFactory.entireLength, rawRoute.lengthOfShortestPath - ( numberOfEnteredRestrictedAreas*TurnInstructions.AccessRestrictionPenalty));

        reply.content += "\"route_summary\":";
        reply.content += "{";
        reply.content += "\"total_distance\":";
        reply.content += descriptionFactory.summary.lengthString;
        reply.content += ","
                "\"total_time\":";
        reply.content += descriptionFactory.summary.durationString;
        reply.content += ","
                "\"start_point\":\"";
        reply.content += sEngine.GetEscapedNameForNameID(descriptionFactory.summary.startName);
        reply.content += "\","
                "\"end_point\":\"";
        reply.content += sEngine.GetEscapedNameForNameID(descriptionFactory.summary.destName);
        reply.content += "\"";
        reply.content += "}";
        reply.content +=",";

        //only one alternative route is computed at this time, so this is hardcoded

        if(rawRoute.lengthOfAlternativePath != INT_MAX) {
            alternateDescriptionFactory.SetStartSegment(phantomNodes.startPhantom);
            //Get all the coordinates for the computed route
            BOOST_FOREACH(const _PathData & pathData, rawRoute.computedAlternativePath) {
                sEngine.GetCoordinatesForNodeID(pathData.node, current);
                alternateDescriptionFactory.AppendSegment(current, pathData );
            }
            alternateDescriptionFactory.SetEndSegment(phantomNodes.targetPhantom);
        }
        alternateDescriptionFactory.Run(sEngine, config.z, rawRoute.lengthOfAlternativePath);

        //give an array of alternative routes
        reply.content += "\"alternative_geometries\": [";
        if(config.geometry && INT_MAX != rawRoute.lengthOfAlternativePath) {
            //Generate the linestrings for each alternative
            alternateDescriptionFactory.AppendEncodedPolylineString(reply.content, config.encodeGeometry);
        }
        reply.content += "],";
        reply.content += "\"alternative_instructions\":[";
        if(config.instructions && INT_MAX != rawRoute.lengthOfAlternativePath) {
            reply.content += "[";
            //Generate instructions for each alternative
            BuildTextualDescription(alternateDescriptionFactory, reply, rawRoute.lengthOfAlternativePath, sEngine);
            reply.content += "]";
        }
        reply.content += "],";
        reply.content += "\"alternative_summaries\":[";
        if(INT_MAX != rawRoute.lengthOfAlternativePath) {
            //Generate route summary (length, duration) for each alternative
            alternateDescriptionFactory.BuildRouteSummary(alternateDescriptionFactory.entireLength, rawRoute.lengthOfAlternativePath - ( numberOfEnteredRestrictedAreas*TurnInstructions.AccessRestrictionPenalty));
            reply.content += "{";
            reply.content += "\"total_distance\":";
            reply.content += alternateDescriptionFactory.summary.lengthString;
            reply.content += ","
                    "\"total_time\":";
            reply.content += alternateDescriptionFactory.summary.durationString;
            reply.content += ","
                    "\"start_point\":\"";
            reply.content += sEngine.GetEscapedNameForNameID(descriptionFactory.summary.startName);
            reply.content += "\","
                    "\"end_point\":\"";
            reply.content += sEngine.GetEscapedNameForNameID(descriptionFactory.summary.destName);
            reply.content += "\"";
            reply.content += "}";
        }
        reply.content += "],";

        //list all viapoints so that the client may display it
        reply.content += "\"via_points\":[";
        std::string tmp;
        if(config.geometry && INT_MAX != rawRoute.lengthOfShortestPath) {
            for(unsigned i = 0; i < rawRoute.segmentEndCoordinates.size(); ++i) {
                reply.content += "[";
                if(rawRoute.segmentEndCoordinates[i].startPhantom.location.isSet())
                    convertInternalReversedCoordinateToString(rawRoute.segmentEndCoordinates[i].startPhantom.location, tmp);
                else
                    convertInternalReversedCoordinateToString(rawRoute.rawViaNodeCoordinates[i], tmp);

                reply.content += tmp;
                reply.content += "],";
            }
            reply.content += "[";
            if(rawRoute.segmentEndCoordinates.back().startPhantom.location.isSet())
                convertInternalReversedCoordinateToString(rawRoute.segmentEndCoordinates.back().targetPhantom.location, tmp);
            else
                convertInternalReversedCoordinateToString(rawRoute.rawViaNodeCoordinates.back(), tmp);
            reply.content += tmp;
            reply.content += "]";
        }
        reply.content += "],";
        reply.content += "\"hint_data\": {";
        reply.content += "\"checksum\":";
        intToString(rawRoute.checkSum, tmp);
        reply.content += tmp;
        reply.content += ", \"locations\": [";

        std::string hint;
        for(unsigned i = 0; i < rawRoute.segmentEndCoordinates.size(); ++i) {
            reply.content += "\"";
            EncodeObjectToBase64(rawRoute.segmentEndCoordinates[i].startPhantom, hint);
            reply.content += hint;
            reply.content += "\", ";
        }
        EncodeObjectToBase64(rawRoute.segmentEndCoordinates.back().targetPhantom, hint);
        reply.content += "\"";
        reply.content += hint;
        reply.content += "\"]";
        reply.content += "},";
        reply.content += "\"transactionId\": \"OSRM Routing Engine JSON Descriptor (v0.3)\"";
        reply.content += "}";
    }

    inline void WriteHeaderToOutput(std::string & output) {
        output += "{"
                "\"version\": 0.3,"
                "\"status\":";
    }

    inline void BuildTextualDescription(DescriptionFactory & descriptionFactory, http::Reply & reply, const int lengthOfRoute, const SearchEngineT &sEngine) {
        //Segment information has following format:
        //["instruction","streetname",length,position,time,"length","earth_direction",azimuth]
        //Example: ["Turn left","High Street",200,4,10,"200m","NE",22.5]
        //See also: http://developers.cloudmade.com/wiki/navengine/JSON_format
        unsigned prefixSumOfNecessarySegments = 0;
        roundAbout.leaveAtExit = 0;
        roundAbout.nameID = 0;
        std::string tmpDist, tmpLength, tmpDuration, tmpBearing, tmpInstruction;
        //Fetch data from Factory and generate a string from it.
        BOOST_FOREACH(const SegmentInformation & segment, descriptionFactory.pathDescription) {
            short currentInstruction = segment.turnInstruction & TurnInstructions.InverseAccessRestrictionFlag;
            numberOfEnteredRestrictedAreas += (currentInstruction != segment.turnInstruction);
            if(TurnInstructions.TurnIsNecessary( currentInstruction) ) {
                if(TurnInstructions.EnterRoundAbout == currentInstruction) {
                    roundAbout.nameID = segment.nameID;
                    roundAbout.startIndex = prefixSumOfNecessarySegments;
                } else {
                    if(0 != prefixSumOfNecessarySegments){
                        reply.content += ",";
                    }
                    reply.content += "[\"";
                    if(TurnInstructions.LeaveRoundAbout == currentInstruction) {
                        intToString(TurnInstructions.EnterRoundAbout, tmpInstruction);
                        reply.content += tmpInstruction;
                        reply.content += "-";
                        intToString(roundAbout.leaveAtExit+1, tmpInstruction);
                        reply.content += tmpInstruction;
                        roundAbout.leaveAtExit = 0;
                    } else {
                        intToString(currentInstruction, tmpInstruction);
                        reply.content += tmpInstruction;
                    }
                    reply.content += "\",\"";
                    reply.content += sEngine.GetEscapedNameForNameID(segment.nameID);
                    reply.content += "\",";
                    intToString(segment.length, tmpDist);
                    reply.content += tmpDist;
                    reply.content += ",";
                    intToString(prefixSumOfNecessarySegments, tmpLength);
                    reply.content += tmpLength;
                    reply.content += ",";
                    intToString(segment.duration, tmpDuration);
                    reply.content += tmpDuration;
                    reply.content += ",\"";
                    intToString(segment.length, tmpLength);
                    reply.content += tmpLength;
                    reply.content += "m\",\"";
                    reply.content += Azimuth::Get(segment.bearing);
                    reply.content += "\",";
                    intToString(round(segment.bearing), tmpBearing);
                    reply.content += tmpBearing;
                    reply.content += "]";
                }
            } else if(TurnInstructions.StayOnRoundAbout == currentInstruction) {
                ++roundAbout.leaveAtExit;
            }
            if(segment.necessary)
                ++prefixSumOfNecessarySegments;
        }
        if(INT_MAX != lengthOfRoute) {
            reply.content += ",[\"";
            intToString(TurnInstructions.ReachedYourDestination, tmpInstruction);
            reply.content += tmpInstruction;
            reply.content += "\",\"";
            reply.content += "\",";
            reply.content += "0";
            reply.content += ",";
            intToString(prefixSumOfNecessarySegments-1, tmpLength);
            reply.content += tmpLength;
            reply.content += ",";
            reply.content += "0";
            reply.content += ",\"";
            reply.content += "\",\"";
            reply.content += Azimuth::Get(0.0);
            reply.content += "\",";
            reply.content += "0.0";
            reply.content += "]";
        }

    }

};
#endif /* JSON_DESCRIPTOR_H_ */