#include "tariff_utils.h"
#include <assert.h>
#include <ctime>


/// <inheritdoc/>
time_t TariffUtils::GetCurrentLocalTime() {
    time_t epoch = time(NULL);
    struct tm *local_time = localtime(&epoch);
    if (local_time) {
        // local_time->tm_isdst > 0: DST is in effect
        // local_time->tm_isdst = 0: DST is not in effect
        // and a negative value means that mktime() should use timezone
        // information to attempt to determine whether DST is in effect
        // at the specified time.
        local_time->tm_isdst = -1;
        return mktime(local_time);
    }
    return -1;
}

/// <inheritdoc/>
bool TariffUtils::DateToStructTm(const char* dateStr, struct tm *t) {
    return (strptime(dateStr, "%Y-%m-%d", t) != 0);
}

static time_t DateTimeStrToTime(std::string const &dateTimeStr) {
    struct tm t = {};
    if (strptime(dateTimeStr.c_str(), "%Y-%m-%dT%H:%M:%S", &t) != 0) {
        t.tm_isdst = -1;
        return mktime(&t);
    }
    return -1;
}

/// <inheritdoc/>
bool TariffUtils::TimeToStructTm(const char* timeStr, struct tm *t) {
    return (strptime(timeStr, "%H:%M:%S", t) != 0);
}

/// <inheritdoc/>ateTimeToStructTm(char const* dateTimeStr) {
bool TariffUtils::DateTimeToStructTm(char const* dateTimeStr, struct tm *t) {
    return (strptime(dateTimeStr, "%Y-%m-%dT%H:%M:%S", t) != 0);
}

/// <inheritdoc/>
DayOfWeek TariffUtils::GetDayOfWeek(struct tm const *t) {
    return (DayOfWeek)t->tm_wday;
}

/// <inheritdoc/>
bool TariffUtils::IsSpecialDay(TariffConfiguration const* tariff_cfg,
                               const char* datetime, int& specialDayId) {
    for (size_t i = 0; i < tariff_cfg->SpecialDays.size(); i++) {
        TariffSpecialDays const &sd = tariff_cfg->SpecialDays[i];
        char const *sdt = sd.ped_date_start.c_str();
        char const *edt = sd.ped_date_end.c_str();

        // format datetime: 2022-12-04T22:30:30
        // format sdt resp. edt: 2022-12-25
        // comparing the strings gives the result
        if (strncmp(datetime, sdt, strlen(sdt)) >= 0
         && strncmp(datetime, edt, strlen(edt)) <= 0) {
            specialDayId = sd.ped_id;
            return true;
        }
    }
    return false;
}

bool TariffUtils::PriceForSpecialDay(TariffConfiguration const* tariff_cfg,
                                     int specialDayId, double *price) {
    for (size_t j = 0; j <= tariff_cfg->SpecialDaysWorktime.size(); j++) {
        int wt_id = tariff_cfg->SpecialDaysWorktime.at(j).pedwt_period_exc_day_id;
        if (specialDayId == wt_id) {
            *price = tariff_cfg->SpecialDaysWorktime.at(j).pedwt_price;
            return true;
        }
    }
    return false;
}

/// <inheritdoc/>
bool TariffUtils::ValidateParkingTicket(TariffConfiguration const */*tariff_cfg*/,
                                        time_t /*initial*/,
                                        int /*durationMin*/,
                                        double /*price*/,
                                        TariffTimeRange /*time_range*/,
                                        bool /*isSpecialDay*/,
                                        int /*spec_day_id*/) {
    // TODO
    return true;
}

static ActiveTimeRange computeActiveTimeRange(std::string const &currentDayDate,
                                              std::string const &currentDayTime,
                                              std::string const &time_from,
                                              std::string const &time_to) {
    ActiveTimeRange result;

    if (currentDayTime.compare(time_from) >= 0
     && currentDayTime.compare(time_to) <= 0) {
        std::string timeFrom = currentDayDate + "T" + time_from;
        std::string timeTo = currentDayDate + "T" + time_to;
        time_t const from = DateTimeStrToTime(timeFrom);
        time_t const to = DateTimeStrToTime(timeTo);
        if (from != -1 && to != -1) {
            result.timeRange.time_from = from;
            result.timeRange.time_to = to;
            result.isActive = true;
        }
    }

    return result;
}

/// <inheritdoc/>
ActiveTimeRange
TariffUtils::isParkingTimeRangeActive(TariffConfiguration* tariff_cfg,
                                      std::string datetimeStr,
                                      bool isSpecialDay = false,
                                      int spec_day_id = -1) {
    size_t const pos = datetimeStr.find_first_of('T');
    if (pos == std::string::npos || pos == 0 || pos >= datetimeStr.size()-1) {
        return ActiveTimeRange();
    }

    // split dateTime at 'T'
    std::string const currentDayDate = datetimeStr.substr(0, pos - 1);
    std::string const currentDayTime = datetimeStr.substr(pos + 1);

    // return (strptime(dateStr, "%Y-%m-%d", t) != 0);

    if (isSpecialDay) {
        for (size_t i = 0; i < tariff_cfg->SpecialDaysWorktime.size(); i++) {
            TariffSpecialDaysWorktime const &sdwt = tariff_cfg->SpecialDaysWorktime[i];
            if (sdwt.pedwt_period_exc_day_id == spec_day_id) {
                std::string const &time_from = sdwt.pedwt_time_from;
                std::string const &time_to = sdwt.pedwt_time_to;
                return computeActiveTimeRange(currentDayDate, currentDayTime,
                                              time_from, time_to);
            }
        }
    } else {
        struct tm current_time_tm = {};
        if (!TariffUtils::DateTimeToStructTm(datetimeStr.c_str(), &current_time_tm)) {
            return ActiveTimeRange();
        }
        auto const dayOfWeek = TariffUtils::GetDayOfWeek(&current_time_tm);
        for (size_t i = 0; i < tariff_cfg->WeekDaysWorktime.size(); i++) {
            TariffWeekDaysWorktime const &wdwt = tariff_cfg->WeekDaysWorktime[i];
            if (wdwt.pwd_period_day_in_week_id == dayOfWeek) {
                std::string const &time_from = wdwt.pwd_time_from;
                std::string const &time_to = wdwt.pwd_time_to;
                return computeActiveTimeRange(currentDayDate, currentDayTime,
                                              time_from, time_to);
            }
        }
    }
    return ActiveTimeRange();
}