day_of_week_field.cpp

#include "day_of_week_field.h"

namespace geheb {

day_of_week_field::day_of_week_field() {
    _allowBackwardRange = true;
    _literals = {
        { "SUN", 0 },
        { "MON", 1 },
        { "TUE", 2 },
        { "WED", 3 },
        { "THU", 4 },
        { "FRI", 5 },
        { "SAT", 6 }
    };
}

bool day_of_week_field::validate(const std::string &value) const {
    if (value == "?") return true;
    std::string lastDayOfWeek = parse_last_day_of_week(value);
    if (!lastDayOfWeek.empty()) {
        return cron_field::validate(lastDayOfWeek);
    }
    auto nthDayOfWeek = parse_nth_day_of_week(value);
    if (nthDayOfWeek.has_values()) {
        if (!cron_field::validate(nthDayOfWeek.day)) return false;
        int count = std::stoi(nthDayOfWeek.count);
        return count >= 1 && count <= 5;
    }
    return cron_field::validate(value);
}

bool day_of_week_field::match(const std::string &value, const date_time &time) const {
    if (value == "?") return true;
    // allows to specify constructs such as "the last Friday" 5L of a given month
    std::string lastDayOfWeek = parse_last_day_of_week(value);
    if (!lastDayOfWeek.empty()) {
        int targetDayOfWeek = std::stoi(lastDayOfWeek);
        date_time targetTime(time.year(), time.month(), time.last_day_of_month());
        while (targetTime.day_of_week() != targetDayOfWeek) {
            targetTime -= days(1);
        }
        return time.day() == targetTime.day();
    }
    // allows to specify constructs such as "the second Friday" 5#2 of a given month
    auto nthDayOfWeek = parse_nth_day_of_week(value);
    if (nthDayOfWeek.has_values()) {
        int targetDay = std::stoi(nthDayOfWeek.day);
        int targetDayCount = std::stoi(nthDayOfWeek.count);
        // current day of week must match the targeted day of week
        if (time.day_of_week() != targetDay) return false;
        date_time targetTime(time.year(), time.month(), 1);
        int lastDayOfMonth = targetTime.last_day_of_month();
        int count = 0;
        do {
            if (targetTime.day_of_week() == targetDay && ++count >= targetDayCount) break;
            targetTime += days(1);
        } while (targetTime.day() < lastDayOfMonth + 1);
        return time.day() == targetTime.day();
    }
    return cron_field::match(value, time.day_of_week());
}

date_time day_of_week_field::increment(const std::string &value, const date_time &time) const {
    date_time nextTime(time);
    nextTime -= minutes(nextTime.minute()); // reset minutes to 0
    nextTime -= hours(nextTime.hour()); // reset hour to 0
    nextTime += days(1);
    return nextTime;
}

day_of_week_field::nth_day_of_week day_of_week_field::parse_nth_day_of_week(const std::string &value) const {
    size_t pos = value.find_first_of("#");
    if (pos != std::string::npos) {
        return { value.substr(0, pos), value.substr(pos + 1) };
    }
    return nth_day_of_week();
}

std::string day_of_week_field::parse_last_day_of_week(const std::string &value) const {
    size_t pos = value.find_first_of("L");
    return pos != std::string::npos ? value.substr(0, pos) : std::string();
}

} // namespace geheb