#ifdef HAVE_CONFIG_H
  #include "config.h"
#endif

#include "performancedb.hxx"

#include <simgear/sg_inlines.h>
#include <simgear/misc/sg_path.hxx>
#include <simgear/props/props.hxx>
#include <simgear/props/props_io.hxx>
#include <simgear/structure/exception.hxx>

#include <Main/globals.hxx>
#include <cstring>
#include <iostream>

#include "performancedata.hxx"

using std::string;

void PerformanceDB::init()
{
    SGPath dbpath( globals->get_fg_root() );
    dbpath.append( "/AI/Aircraft/" );
    dbpath.append( "performancedb.xml");
    load(dbpath);

    if (getDefaultPerformance() == 0) {
        SG_LOG(SG_AI, SG_WARN, "PerformanceDB: no default performance data found/loaded");
    }
}

void PerformanceDB::shutdown()
{
    PerformanceDataDict::iterator it;
    for (it = _db.begin(); it != _db.end(); ++it) {
        delete it->second;
    }

    _db.clear();
    _aliases.clear();
}

void PerformanceDB::update(double dt)
{
    SG_UNUSED(dt);
    suspend();
}

void PerformanceDB::registerPerformanceData(const std::string& id, PerformanceData* data) {
    // TODO: if key exists already replace data "inplace", i.e. copy to existing PerfData instance
    // this updates all aircraft currently using the PerfData instance.
    _db[id] = data;
}

PerformanceData* PerformanceDB::getDataFor(const string& acType, const string& acClass) const
{
  // first, try with the specific aircraft type, such as 738 or A322
    PerformanceDataDict::const_iterator it;
    it = _db.find(acType);
    if (it != _db.end()) {
        return it->second;
    }

    const string& alias = findAlias(acType);
    it = _db.find(alias);
    if (it != _db.end()) {
        return it->second;
    }

    it = _db.find(acClass);
    if (it == _db.end()) {
        return getDefaultPerformance();
    }

    return it->second;
}

PerformanceData* PerformanceDB::getDefaultPerformance() const
{
    PerformanceDataDict::const_iterator it = _db.find("jet_transport");
    if (it == _db.end())
        return NULL;

    return it->second;
}

bool PerformanceDB::havePerformanceDataForAircraftType(const std::string& acType) const
{
    PerformanceDataDict::const_iterator it = _db.find(acType);
    if (it != _db.end())
        return true;

    const std::string alias(findAlias(acType));
    return (_db.find(alias) != _db.end());
}

void PerformanceDB::load(const SGPath& filename)
{
    SGPropertyNode root;
    try {
        readProperties(filename, &root);
    } catch (const sg_exception &) {
        SG_LOG(SG_AI, SG_ALERT,
            "Error reading AI aircraft performance database: " << filename);
        return;
    }

    SGPropertyNode * node = root.getNode("performancedb");
    for (int i = 0; i < node->nChildren(); i++) {
        SGPropertyNode * db_node = node->getChild(i);
        if (db_node->getNameString() == "aircraft") {
            PerformanceData* data = NULL;
            if (db_node->hasChild("base")) {
              std::string baseName = db_node->getStringValue("base");
              PerformanceData* baseData = _db[baseName];
              if (!baseData) {
                SG_LOG(SG_AI, SG_ALERT,
                       "Error reading AI aircraft performance database: unknown base type " << baseName);
                return;
              }

              // clone base data to 'inherit' from it
              data = new PerformanceData(baseData);
            } else {
              data = new PerformanceData;
            }

            data->initFromProps(db_node);
            std::string name = db_node->getStringValue("type", "heavy_jet");
            registerPerformanceData(name, data);
        } else if (db_node->getNameString() == "alias") {
            std::string alias = db_node->getStringValue("alias");
            if (alias.empty()) {
                SG_LOG(SG_AI, SG_ALERT, "performance DB alias entry with no <alias> definition");
                continue;
            }

            for (auto matchNode : db_node->getChildren("match")) {
                std::string match = matchNode->getStringValue();
                _aliases.push_back(StringPair(match, alias));
            }
        } else {
            SG_LOG(SG_AI, SG_ALERT, "unrecognized performance DB entry:" << db_node->getNameString());
        }
    } // of nodes iteration
}

const string& PerformanceDB::findAlias(const string& acType) const
{
    for (const auto& alias : _aliases) {
        if (acType.find(alias.first) == 0) { // matched!
            return alias.second;
        }
    } // of alias iteration

    static const string empty;
    return empty;
}


// Register the subsystem.
SGSubsystemMgr::Registrant<PerformanceDB> registrantPerformanceDB(
    SGSubsystemMgr::POST_FDM);
