#include "calculate_price.h"
#include "configuration.h"
#include "calculator_functions.h"
#include "payment_option.h"
#include "utilities.h"

#include <QFile>
#include <QFileInfo>
#include <QDateTime>
#include <QDebug>

static Calculator calculator;

int CALCULATE_LIBRARY_API get_zone_nr(int zone)
{
    if(zone > -1) return zone;
    else
    {
        QFile zone("/etc/zone_nr");
        if (zone.exists()) {
            QFileInfo finfo(zone);
            if (finfo.size() <= 4) { // decimal 000\n
                if (zone.open(QIODevice::ReadOnly | QIODevice::Text)) {
                    QTextStream in(&zone);
                    return in.readLine(100).toInt();
                }
            }
        }
        return -1;
    }
}

CalcState CALCULATE_LIBRARY_API init_tariff(parking_tariff_t **tariff, char const *config_file) {
    *tariff = new Configuration();

    CalcState calcState;
#if __linux__

    int const zone = get_zone_nr();

    // DEBUG
    qCritical() << "init_tariff:";
    qCritical() << "      ... zone = " << zone;

    if (zone <= 0) {
        delete *tariff;
        *tariff = nullptr;
        return calcState.set(CalcState::State::ERROR_PARSING_ZONE_NR);
    }

    QString confFile(config_file);
    if (!confFile.endsWith(QChar('/'))) {
        confFile += "/";
    }

    char buffer[32];
    memset(buffer, 0x00, sizeof(buffer));
    snprintf(buffer, sizeof(buffer)-1, "tariff%02d.json", zone);
    confFile += buffer;
#else // windows
    QString confFile(config_file);
#endif

    // DEBUG
    qCritical() << "      ... confFile = " << confFile;

    QFile fname(confFile);
    if (fname.exists() &&
            fname.open(QIODevice::ReadOnly | QIODevice::Text)) {
        // DEBUG
        qCritical() << "      ... confFile is open";

        QString json = fname.readAll();
        if (! (*tariff)->ParseJson(*tariff, json.toStdString().c_str())) {
            delete *tariff;
            *tariff = nullptr;
            return calcState.set(CalcState::State::ERROR_PARSING_TARIFF);
        }
    } else {
        delete *tariff;
        *tariff = nullptr;
        return calcState.set(CalcState::State::ERROR_LOADING_TARIFF);
    }

    qCritical() << "init_tariff: Parsing tariff config (" << confFile << ")";

    return calcState;
}

void CALCULATE_LIBRARY_API free_tariff(parking_tariff_t *tariff) {
    if (tariff != nullptr) {
        delete tariff;
    }
}

//
// UpDown 1 -> up; 0 -> down
int CALCULATE_LIBRARY_API compute_next_timestep(parking_tariff_t *tariff, int currentTimeMinutes, int UpDown)
{
    // use tariff with structure as for instance Schnau, Koenigsee:
    // without given YearPeriod, SpecialDays and SpecialDaysWorktime
    if (tariff->YearPeriod.size() == 0
        && tariff->SpecialDays.size() == 0
        && tariff->SpecialDaysWorktime.size() == 0)
    {
        static const QList<int> stepList = calculator.GetTimeSteps(tariff);

        int currentStepIndex = stepList.indexOf(currentTimeMinutes);

        if (currentStepIndex == -1) {
            qCritical() << "compute_next_timestep() *NO STEP* for currentTimeMinutes (" << currentTimeMinutes << ")";
            return  currentTimeMinutes;
        }

        if (UpDown == 1) { // UP
            if (stepList[currentStepIndex] == stepList.last()) {
                qCritical() << "compute_next_timestep() *NO NEXT STEP* for currentTimeMinutes (" << currentTimeMinutes << ")";
                return  currentTimeMinutes;
            }
            else {
                return stepList[currentStepIndex + 1];
            }
        }
        if (UpDown == 0) { // DOWN
            if (stepList[currentStepIndex] == stepList.first()) {
                qCritical() << "compute_next_timestep() *NO PREVIOUS STEP* for currentTimeMinutes (" << currentTimeMinutes << ")";
                return  currentTimeMinutes;
            }
            else {
                return stepList[currentStepIndex - 1];
            }
        }
    } else {
        Configuration const *cfg = tariff;

        // currentTimeMinutes is the number of minutes actually used. This
        // value is an offset from the start time and cannot be used as a
        // QDateTime.

        qCritical() << "compute_next_timestep() currentTimeMinutes:" << currentTimeMinutes;

        // compute payment method id (e.g. Linear=3, Steps=4)
        PaymentMethod paymentMethodId = Utilities::getPaymentMethodId(cfg);
        qCritical() << "   compute_next_timestep() paymentMethodId:" << paymentMethodId;

        // get minimal and maximal parking times
        int const minParkingTime = Utilities::getMinimalParkingTime(cfg, paymentMethodId);
        int const maxParkingTime = Utilities::getMaximalParkingTime(cfg, paymentMethodId);

        qCritical() << "    compute_next_timestep() maxParkingTime:" << paymentMethodId;
        qCritical() << "    compute_next_timestep() minParkingTime:" << paymentMethodId;

        // use the first (i.e. main duration step contained in the tariff json-file)
        int firstDurationStep = Utilities::getFirstDurationStep(cfg, paymentMethodId);
        qCritical() << " compute_next_timestep() firstDurationStep:" << paymentMethodId;

        int nextTimeStep = currentTimeMinutes + firstDurationStep;
        if (currentTimeMinutes >= minParkingTime && nextTimeStep <= maxParkingTime) {
            qCritical() << "  compute_next_timestep() nextTimeStep:" << nextTimeStep;
            return nextTimeStep;
        }
    }

    qCritical() << "compute_next_timestep() *CAN NOT COMPUTE* for currentTimeMinutes (" << currentTimeMinutes << ")";
    return  currentTimeMinutes;
}

// this is currently not used
CalcState CALCULATE_LIBRARY_API compute_price_for_parking_ticket(
        parking_tariff_t *tariff,
        time_t start_parking_time, // in minutes
        time_t end_parking_time,   // netto time in minutes
        struct price_t *price) {
    CalcState calcState;
    double minMin = tariff->PaymentOption.find(tariff->getPaymentOptions().pop_payment_method_id)->second.pop_min_time;
    double maxMin = tariff->PaymentOption.find(tariff->getPaymentOptions().pop_payment_method_id)->second.pop_max_time;

    if (minMin < 0 || maxMin < 0 || maxMin < minMin) {
        calcState.setDesc(QString("minMin=%1, maxMin=%2").arg(minMin).arg(maxMin));
        return calcState.set(CalcState::State::WRONG_PARAM_VALUES);
    }

    int const duration = end_parking_time - start_parking_time;
    if (duration < 0) {
        calcState.setDesc(QString("end=%1, start=%2")
                          .arg(end_parking_time, start_parking_time));
        return calcState.set(CalcState::State::NEGATIVE_PARING_TIME);
    }
    if (duration > maxMin) {
        calcState.setDesc(QString("duration=%1, maxMin=%2").arg(duration).arg(maxMin));
        return calcState.set(CalcState::State::ABOVE_MAX_PARKING_TIME);
    }
    if (duration < minMin) {
        calcState.setDesc(QString("duration=%1, minMin=%2").arg(duration).arg(minMin));
        return calcState.set(CalcState::State::BELOW_MIN_PARKING_TIME);
    }
    if (duration == 0) {
        memset(price, 0x00, sizeof(*price));
        return calcState.set(CalcState::State::SUCCESS);
    }

    QDate const d(1970, 1, 1);
    QTime const t(0, 0, 0);
    QDateTime start(d, t, Qt::UTC);
    start = start.toLocalTime().addSecs(start_parking_time * 60);
    QDateTime end(start);
    if (start.isValid()) {
        double cost = calculator.GetCostFromDuration(
                    tariff,
                    tariff->getPaymentOptions().pop_payment_method_id,
                    start,
                    end,
                    duration, false, true);
        double minCost = tariff->PaymentOption.find(tariff->getPaymentOptions().pop_payment_method_id)->second.pop_min_price;
        if (cost < minCost) {
            calcState.setDesc(QString("minCost=%1, cost=%2").arg(minCost).arg(cost));
            return calcState.set(CalcState::State::BELOW_MIN_PARKING_PRICE);
        }
        price->units = cost;
        price->netto = cost;
    } else {
        return calcState.set(CalcState::State::INVALID_START_DATE);
    }

    return calcState.set(CalcState::State::SUCCESS);
}

CalcState CALCULATE_LIBRARY_API compute_price_for_parking_ticket(
        parking_tariff_t *tariff,
        QDateTime const &start_parking_time,
        int netto_parking_time,
        QDateTime &end_parking_time,
        struct price_t *price)
{
    CalcState calcState;
    double minMin = tariff->getPaymentOptions().pop_min_time;
    double maxMin = tariff->getPaymentOptions().pop_max_time;

    // DEBUG
    qCritical() << "compute_price_for_parking_ticket() " << endl
                << "          start_parking_time: " << start_parking_time << endl
                << "          netto_parking_time: " << netto_parking_time << endl
                << "                      minMin: " << minMin << endl
                << "                      maxMin: " << maxMin;


    if (netto_parking_time < 0) {
        calcState.setDesc(QString("end=%1, start=%2")
                          .arg(end_parking_time.toString(Qt::ISODate),
                               start_parking_time.toString(Qt::ISODate)));
        return calcState.set(CalcState::State::NEGATIVE_PARING_TIME);
    }
    if (netto_parking_time > maxMin) {
        calcState.setDesc(QString("duration=%1, maxMin=%2").arg(netto_parking_time).arg(maxMin));
        return calcState.set(CalcState::State::ABOVE_MAX_PARKING_TIME);
    }
    if (netto_parking_time < minMin) {
        calcState.setDesc(QString("duration=%1, minMin=%2").arg(netto_parking_time).arg(minMin));
        return calcState.set(CalcState::State::BELOW_MIN_PARKING_TIME);
    }
    if (netto_parking_time == 0) {
        memset(price, 0x00, sizeof(*price));
        return calcState.set(CalcState::State::SUCCESS);
    }

    if (start_parking_time.isValid()) {
        double cost = calculator.GetCostFromDuration(
                        tariff,
                        tariff->getPaymentOptions().pop_payment_method_id,
                        start_parking_time,         // starting time
                        end_parking_time,           // return value: end time
                        netto_parking_time,         // minutes, netto
                        false, true);
        double minCost = tariff->getPaymentOptions().pop_min_price;
        if (cost < minCost) {
            calcState.setDesc(QString("minCost=%1, cost=%2").arg(minCost, cost));
            return calcState.set(CalcState::State::BELOW_MIN_PARKING_PRICE);
        }

        // DEBUG
        qCritical() << "               -> calculated cost (price->netto) =  " << cost;

        price->units = cost;
        price->netto = cost;
    } else {
        return calcState.set(CalcState::State::INVALID_START_DATE);
    }

    return calcState.set(CalcState::State::SUCCESS);
}

CalcState CALCULATE_LIBRARY_API compute_duration_for_parking_ticket(
        parking_tariff_t *tariff,
        time_t start_parking_time,
        double price,
        QString &duration) {
    CalcState calcState;
    QDate const d(1970, 1, 1);
    QTime const t(0, 0, 0);
    QDateTime start(d, t, Qt::UTC);
    start = start.toLocalTime().addSecs(start_parking_time * 60);
    if (start.isValid()) {
        QString cs = start.toString(Qt::ISODate);

        // DEBUG
        qCritical() << "compute_duration_for_parking_ticket(): ";
        qCritical() << "      start (cs): " << cs;
        qCritical() << "           price: " << price;

        duration = calculator.GetDurationFromCost(tariff,
                                                  tariff->getPaymentOptions().pop_payment_method_id,
                                                  cs.toLocal8Bit().constData(),
                                                  price, false, true).c_str();
        QDateTime d = QDateTime::fromString(duration, Qt::ISODate);
        if (!d.isValid()) {
            calcState.setDesc(QString("ticketEndTime=%1").arg(duration));
            return calcState.set(CalcState::State::WRONG_ISO_TIME_FORMAT);
        }
    } else {
        return calcState.set(CalcState::State::INVALID_START_DATE);
    }

    return calcState.set(CalcState::State::SUCCESS);
}

CalcState CALCULATE_LIBRARY_API compute_duration_for_parking_ticket(
        parking_tariff_t *tariff,
        QDateTime const &start_parking_time,
        double price,
        QDateTime &ticketEndTime)
{
    CalcState calcState;
    if (start_parking_time.isValid()) {
        QString cs = start_parking_time.toString(Qt::ISODate);
        QString endTime = calculator.GetDurationFromCost(
                    tariff,
                    tariff->getPaymentOptions().pop_payment_method_id,
                    cs.toLocal8Bit().constData(),
                    price, false, true).c_str();
        ticketEndTime = QDateTime::fromString(endTime,Qt::ISODate);

        // DEBUG
        qCritical() << "compute_duration_for_parking_ticket(): ";
        qCritical() << "                 endTime: " << endTime;
        qCritical() << "           ticketEndTime: " << ticketEndTime;

        if (!ticketEndTime.isValid()) {
            calcState.setDesc(QString("ticketEndTime=%1").arg(endTime));
            return calcState.set(CalcState::State::WRONG_ISO_TIME_FORMAT);
        }
    } else {
        return calcState.set(CalcState::State::INVALID_START_DATE);
    }

    return calcState.set(CalcState::State::SUCCESS);
}

CalcState CALCULATE_LIBRARY_API compute_duration_for_daily_ticket(parking_tariff_t *tariff, QDateTime const &start_parking_time, QDateTime &ticketEndTime)
{
    CalcState calcState;
    if (start_parking_time.isValid()) {

        ticketEndTime = calculator.GetDailyTicketDuration(tariff,
                                                            start_parking_time,
                                                            tariff->getPaymentOptions().pop_payment_method_id,
                                                            false);    // carry over

        // DEBUG
        qCritical() << "compute_duration_for_daily_ticket(): ";
        qCritical() << "           ticketEndTime: " << ticketEndTime;

        if (!ticketEndTime.isValid()) {
            calcState.setDesc(QString("ticketEndTime=%1").arg(ticketEndTime.toString(Qt::ISODate)));
            return calcState.set(CalcState::State::WRONG_ISO_TIME_FORMAT);
        }

    } else {
        return calcState.set(CalcState::State::INVALID_START_DATE);
    }

    return calcState.set(CalcState::State::SUCCESS);
}