// runwayprefs.cxx - class implementations corresponding to runwayprefs.hxx
// assignments by the AI code
//
// Written by Durk Talsma, started January 2005.
//
// Copyright (C) 2004 Durk Talsma.
//
// 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.
//
// 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, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
//
// $Id$

#include <config.h>

#include <algorithm>
#include <cmath>
#include <cstdlib>
#include <cstring>

#include <simgear/compiler.h>
#include <simgear/debug/logstream.hxx>
#include <simgear/misc/strutils.hxx>
#include <simgear/structure/exception.hxx>

#include <Main/globals.hxx>
#include <Airports/runways.hxx>

#include "runwayprefs.hxx"
#include "airport.hxx"

using namespace simgear;

/******************************************************************************
 * ScheduleTime
 ***************e*************************************************************/
void ScheduleTime::clear()
{
    start.clear();
    end.clear();
    scheduleNames.clear();
}


ScheduleTime::ScheduleTime(const ScheduleTime & other)
{
    //timeVec   start;
    timeVecConstIterator i;
    for (i = other.start.begin(); i != other.start.end(); i++)
        start.push_back(*i);
    for (i = other.end.begin(); i != other.end.end(); i++)
        end.push_back(*i);
    stringVecConstIterator k;
    for (k = other.scheduleNames.begin(); k != other.scheduleNames.end();
         k++)
        scheduleNames.push_back(*k);

    //timeVec   end;
    //stringVec scheduleNames;
    tailWind = other.tailWind;
    crssWind = other.tailWind;
}


ScheduleTime & ScheduleTime::operator=(const ScheduleTime & other)
{
    //timeVec   start;
    clear();
    timeVecConstIterator i;
    for (i = other.start.begin(); i != other.start.end(); i++)
        start.push_back(*i);
    for (i = other.end.begin(); i != other.end.end(); i++)
        end.push_back(*i);
    stringVecConstIterator k;
    for (k = other.scheduleNames.begin(); k != other.scheduleNames.end();
         k++)
        scheduleNames.push_back(*k);

    //timeVec   end;
    //stringVec scheduleNames;
    tailWind = other.tailWind;
    crssWind = other.tailWind;
    return *this;
}

std::string ScheduleTime::getName(time_t dayStart)
{
    if ((start.size() != end.size())
        || (start.size() != scheduleNames.size())) {
        SG_LOG(SG_GENERAL, SG_INFO, "Unable to parse schedule times");
        throw sg_exception("Unable to parse schedule times");
    } else {
        int nrItems = start.size();
        //cerr << "Nr of items to process: " << nrItems << endl;
        if (nrItems > 0) {
            for (unsigned int i = 0; i < start.size(); i++) {
                //cerr << i << endl;
                if ((dayStart >= start[i]) && (dayStart <= end[i]))
                    return scheduleNames[i];
            }
        }
        //couldn't find one so return 0;
        //cerr << "Returning 0 " << endl;
    }
    return std::string("");
}

/******************************************************************************
 * RunwayList
 *****************************************************************************/

RunwayList::RunwayList(const RunwayList & other)
{
    type = other.type;
    stringVecConstIterator i;
    for (i = other.preferredRunways.begin();
         i != other.preferredRunways.end(); i++)
        preferredRunways.push_back(*i);
}

RunwayList & RunwayList::operator=(const RunwayList & other)
{
    type = other.type;
    preferredRunways.clear();
    stringVecConstIterator i;
    for (i = other.preferredRunways.begin();
         i != other.preferredRunways.end(); i++)
        preferredRunways.push_back(*i);
    return *this;
}

void RunwayList::set(const std::string & tp, const std::string & lst)
{
    //weekday          = atoi(timeCopy.substr(0,1).c_str());
    //    timeOffsetInDays = weekday - currTimeDate->getGmt()->tm_wday;
    //    timeCopy = timeCopy.substr(2,timeCopy.length());
    type = tp;
    for (const auto& s : strutils::split(lst, ",")) {
        auto ident = strutils::strip(s);
        // http://code.google.com/p/flightgear-bugs/issues/detail?id=1137
        if ((ident.size() < 2) || !isdigit(ident[1])) {
            ident = "0" + ident;
        }

        preferredRunways.push_back(ident);
    }
}

void RunwayList::clear()
{
    type = "";
    preferredRunways.clear();
}

/****************************************************************************
 *
 ***************************************************************************/

RunwayGroup::RunwayGroup(const RunwayGroup & other)
{
    name = other.name;
    RunwayListVecConstIterator i;
    for (i = other.rwyList.begin(); i != other.rwyList.end(); i++)
        rwyList.push_back(*i);
    choice[0] = other.choice[0];
    choice[1] = other.choice[1];
    nrActive = other.nrActive;
}

RunwayGroup & RunwayGroup::operator=(const RunwayGroup & other)
{
    rwyList.clear();
    name = other.name;
    RunwayListVecConstIterator i;
    for (i = other.rwyList.begin(); i != other.rwyList.end(); i++)
        rwyList.push_back(*i);
    choice[0] = other.choice[0];
    choice[1] = other.choice[1];
    nrActive = other.nrActive;
    return *this;
}

void RunwayGroup::setActive(const FGAirport * airport,
                            double windSpeed,
                            double windHeading,
                            double maxTail,
                            double maxCross, stringVec * currentlyActive)
{
    FGRunway *rwy;
    int activeRwys = rwyList.size();    // get the number of runways active
    int nrOfPreferences;
    // bool found = true;
    // double heading;
    double hdgDiff;
    double crossWind;
    double tailWind;
    std::string name;
    //stringVec names;
    int bestMatch = 0, bestChoice = 0;

    if (activeRwys == 0) {
        active = -1;
        nrActive = 0;
        return;
    }

    // Now downward iterate across all the possible preferences
    // starting by the least preferred choice working toward the most preferred choice

    nrOfPreferences = rwyList[0].getPreferredRunways().size();
    bool validSelection = true;
    bool foundValidSelection = false;
    for (int i = nrOfPreferences - 1; i >= 0; i--) {
        int match = 0;


        // Test each runway listed in the preference to see if it's possible to use
        // If one runway of the selection isn't allowed, we need to exclude this
        // preference, however, we don't want to stop right there, because we also
        // don't want to randomly swap runway preferences, unless there is a need to.
        //
        validSelection = true;

        for (int j = 0; j < activeRwys; j++) {
            const auto& currentRunwayPrefs = rwyList.at(j).getPreferredRunways();

            // if this rwyList has shorter preferences vec than the first one,
            // don't crash accesing an invalid index.
            // see https://sourceforge.net/p/flightgear/codetickets/2439/
            if (currentRunwayPrefs.size() <= i) {
                validSelection = false;
                continue;
            }

            const auto& ident(currentRunwayPrefs.at(i));
            if (!airport->hasRunwayWithIdent(ident)) {
                SG_LOG(SG_GENERAL, SG_WARN,
                       "no such runway:" << ident << " at " << airport->ident());
                validSelection = false;
                continue;
            }

            rwy = airport->getRunwayByIdent(ident);

            //cerr << "Succes" << endl;
            hdgDiff = fabs(windHeading - rwy->headingDeg());
            name = rwy->name();


            if (hdgDiff > 180)
                hdgDiff = 360 - hdgDiff;
            //cerr << "Heading diff: " << hdgDiff << endl;
            hdgDiff *= ((2 * M_PI) / 360.0); // convert to radians
            crossWind = windSpeed * sin(hdgDiff);
            tailWind = -windSpeed * cos(hdgDiff);
            //cerr << "Runway : " << rwy->name() << ": " << rwy->headingDeg() << endl;
            //cerr << ". Tailwind : " << tailWind;
            //cerr << ". Crosswnd : " << crossWind;
            if ((tailWind > maxTail) || (crossWind > maxCross)) {
                //cerr << ". [Invalid] " << endl;
                validSelection = false;
            } else {
                //cerr << ". [Valid] ";
            }
            //cerr << endl;
            for (stringVecIterator it = currentlyActive->begin();
                 it != currentlyActive->end(); it++) {
                //cerr << "Checking : \"" << (*it) << "\". vs \"" << name << "\"" << endl;
                if ((*it) == name) {
                    match++;
                }
            }
        } // of active runways iteration

        if (validSelection) {
            //cerr << "Valid selection  : " << i << endl;;
            foundValidSelection = true;
            if (match >= bestMatch) {
                bestMatch = match;
                bestChoice = i;
            }
        }
        //cerr << "Preference " << i << "Match " << match << " bestMatch " << bestMatch << " choice " << bestChoice << " valid selection " << validSelection << endl;
    }

    if (foundValidSelection) {
        //cerr << "Valid runay selection : " << bestChoice << endl;
        nrActive = activeRwys;
        active = bestChoice;
        return;
    }

    // If this didn't work, due to heavy winds, try again
    // but select only one landing and one takeoff runway.
    choice[0] = 0;
    choice[1] = 0;
    for (int i = activeRwys - 1; i; i--) {
        if (rwyList[i].getType() == std::string("landing"))
            choice[0] = i;
        if (rwyList[i].getType() == std::string("takeoff"))
            choice[1] = i;
    }
    //cerr << "Choosing " << choice[0] << " for landing and " << choice[1] << "for takeoff" << endl;
    nrOfPreferences = rwyList[0].getPreferredRunways().size();
    for (int i = 0; i < nrOfPreferences; i++) {
        bool validSelection = true;
        for (int j = 0; j < 2; j++) {
            const auto& currentRunwayPrefs = rwyList.at(choice[j]).getPreferredRunways();
            if (i >= currentRunwayPrefs.size()) {
                validSelection = false;
                continue;
            }

            const auto& name = currentRunwayPrefs.at(i);
            if (!airport->hasRunwayWithIdent(name)) {
                validSelection = false;
                continue;
            }

            rwy = airport->getRunwayByIdent(name);
            //cerr << "Succes" << endl;
            hdgDiff = fabs(windHeading - rwy->headingDeg());
            if (hdgDiff > 180)
                hdgDiff = 360 - hdgDiff;
            hdgDiff *= ((2 * M_PI) / 360.0); // convert to radians
            crossWind = windSpeed * sin(hdgDiff);
            tailWind = -windSpeed * cos(hdgDiff);
            if ((tailWind > maxTail) || (crossWind > maxCross)) {
                validSelection = false;
            }
        }

        if (validSelection) {
            //cerr << "Valid runay selection : " << i << endl;
            active = i;
            nrActive = 2;
            return;
        }
    }

    // failed to find any valid runways
    active = -1;
    nrActive = 0;
}

void RunwayGroup::getActive(int i, std::string & name, std::string & type)
{
    if (i == -1) {
        return;
    }

    if (i >= nrActive) {
        SG_LOG(SG_AI, SG_DEV_ALERT, "RunwayGroup::getActive: invalid index " << i);
        return;
    }

    // nrActive is either the full size of the list *or* two, if we
    // fell back due to heavy winds
    const bool usingFullList = nrActive == (int)rwyList.size();
    if (usingFullList) {
        const auto& runways = rwyList.at(i).getPreferredRunways();
        name = runways.at(active);
        type = rwyList[i].getType();
    } else {
        const auto& runways = rwyList.at(choice[i]).getPreferredRunways();
        name = runways.at(active);
        type = rwyList[choice[i]].getType();
    }
}

/*****************************************************************************
 * FGRunway preference
 ****************************************************************************/
FGRunwayPreference::FGRunwayPreference(FGAirport * ap):
_ap(ap)
{
    //cerr << "Running default Constructor" << endl;
    initialized = false;
}

FGRunwayPreference::FGRunwayPreference(const FGRunwayPreference & other)
{
    initialized = other.initialized;

    comTimes = other.comTimes;  // Commercial Traffic;
    genTimes = other.genTimes;  // General Aviation;
    milTimes = other.milTimes;  // Military Traffic;

    PreferenceListConstIterator i;
    for (i = other.preferences.begin(); i != other.preferences.end(); i++)
        preferences.push_back(*i);
}

FGRunwayPreference & FGRunwayPreference::operator=(const FGRunwayPreference
                                                   & other)
{
    initialized = other.initialized;

    comTimes = other.comTimes;  // Commercial Traffic;
    genTimes = other.genTimes;  // General Aviation;
    milTimes = other.milTimes;  // Military Traffic;

    PreferenceListConstIterator i;
    preferences.clear();
    for (i = other.preferences.begin(); i != other.preferences.end(); i++)
        preferences.push_back(*i);
    return *this;
}

ScheduleTime *FGRunwayPreference::getSchedule(const char *trafficType)
{
    if (!(strcmp(trafficType, "com"))) {
        return &comTimes;
    }
    if (!(strcmp(trafficType, "gen"))) {
        return &genTimes;
    }
    if (!(strcmp(trafficType, "mil"))) {
        return &milTimes;
    }
    return 0;
}

RunwayGroup *FGRunwayPreference::getGroup(const std::string & groupName)
{
    auto it = std::find_if(preferences.begin(), preferences.end(),
                           [&groupName](const RunwayGroup& g) {
                               return g.getName() == groupName;
                           });

    if (it == preferences.end())
        return nullptr;

    return &(*it); // not thrilled about this, but ok
}

std::string FGRunwayPreference::getId()
{
    return _ap->getId();
};
