package net.knarcraft.dynmapcitizens.util;

import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import static net.knarcraft.dynmapcitizens.formatting.StringFormatter.replacePlaceholder;

/**
 * A helper class for time formatting
 */
public class TimeFormatter {

    /**
     * Gets a datetime string for the given timestamp
     *
     * @param timestamp <p>A timestamp in milliseconds</p>
     * @return <p>A datetime string</p>
     */
    public static String formatTimestamp(long timestamp) {
        DateFormat format = new SimpleDateFormat("dd MM yyyy HH:mm:ss");
        Date date = new Date(timestamp);
        return format.format(date);
    }

    /**
     * Gets the string used for displaying this sign's duration
     *
     * @return <p>The string used for displaying this sign's duration</p>
     */
    public static String getDurationString(long duration) {
        if (duration == 0) {
            return "immediately";
        } else {
            double minute = 60;
            double hour = minute * 60;
            double day = hour * 24;
            double week = day * 7;
            double month = day * 30;
            double year = day * 365;
            double decade = year * 10;

            Map<Double, String[]> timeUnits = new HashMap<>();
            timeUnits.put(decade, new String[]{"decade", "decades"});
            timeUnits.put(year, new String[]{"year", "years"});
            timeUnits.put(month, new String[]{"month", "months"});
            timeUnits.put(week, new String[]{"week", "weeks"});
            timeUnits.put(day, new String[]{"day", "days"});
            timeUnits.put(hour, new String[]{"hour", "hours"});
            timeUnits.put(minute, new String[]{"minute", "minutes"});
            timeUnits.put(1D, new String[]{"second", "seconds"});

            List<Double> sortedUnits = new ArrayList<>(timeUnits.keySet());
            Collections.sort(sortedUnits);
            Collections.reverse(sortedUnits);

            for (Double unit : sortedUnits) {
                if (duration / unit >= 1) {
                    double units = round(duration / unit);
                    return formatDurationString(units, timeUnits.get(unit)[units == 1 ? 0 : 1],
                            (units * 10) % 10 == 0);
                }
            }
            return formatDurationString(duration, "seconds", false);
        }
    }

    /**
     * Rounds a number to its last two digits
     *
     * @param number <p>The number to round</p>
     * @return <p>The rounded number</p>
     */
    private static double round(double number) {
        return Math.round(number * 100.0) / 100.0;
    }

    /**
     * Formats a duration string
     *
     * @param duration            <p>The duration to display</p>
     * @param translatableMessage <p>The time unit to display</p>
     * @param castToInt           <p>Whether to cast the duration to an int</p>
     * @return <p>The formatted duration string</p>
     */
    private static String formatDurationString(double duration, String translatableMessage, boolean castToInt) {
        String durationFormat = "{duration} {unit}";
        durationFormat = replacePlaceholder(durationFormat, "{unit}", translatableMessage);
        return replacePlaceholder(durationFormat, "{duration}", castToInt ? String.valueOf((int) duration) :
                String.valueOf(duration));
    }

}