package de.szimnau;

import de.szimnau.tools.CommonTools;
import de.szimnau.tools.FormatTools;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.IOException;
import java.math.BigDecimal;
import java.math.MathContext;
import java.math.RoundingMode;
import java.nio.charset.StandardCharsets;
import java.text.DecimalFormat;
import java.time.LocalTime;
import java.time.temporal.ChronoUnit;

import static de.szimnau.tools.CommonTools.print;


public class DrinkingBar extends AbstractLoadingBar {

   private static final int MINS_PER_HALF_HOUR = CommonTools.MINS_PER_HOUR / 2;
   private static final int MINUTES_BEFORE_PAUSE = 4 * CommonTools.MINS_PER_HOUR + MINS_PER_HALF_HOUR;
   private static final int MINUTES_WITH_PAUSE = 6 * CommonTools.MINS_PER_HOUR;
   private static final int DEFAULT_TOTAL_TIME = 8 * CommonTools.MINS_PER_HOUR + MINS_PER_HALF_HOUR;
   private static final BigDecimal DEFAULT_TOTAL_TIME_BD = BigDecimal.valueOf(DEFAULT_TOTAL_TIME);
   private static final BigDecimal DEFAULT_TOTAL_LITRES = BigDecimal.valueOf(2.0);
   private static final BigDecimal QUARTER_LITRE = BigDecimal.valueOf(0.25);
   private static final DecimalFormat LITRE_FORMAT = new DecimalFormat("0.00");

   private BigDecimal totalLitres;


   public static void main(String[] args) throws IOException {
      var br = new BufferedReader(new InputStreamReader(System.in, StandardCharsets.UTF_8));
      print("Ankunftszeit: ");
      var startTime = LocalTime.parse(br.readLine(), FormatTools.TIME_FORMATTER).truncatedTo(ChronoUnit.MINUTES);
      var db = new DrinkingBar(startTime);
      db.showLoadingBar();
   }


   protected DrinkingBar(LocalTime startTime) {
      super(startTime, DEFAULT_TOTAL_TIME);
      this.totalLitres = DEFAULT_TOTAL_LITRES;
   }


   @Override
   protected void extraInitEndTimeTotalMinutes() {
      // correct necessary litres to drink based on the end time.
      // lower the volume in quarter litre steps
      BigDecimal calcTotalLitres = DEFAULT_TOTAL_LITRES;
      BigDecimal totalLitresFromMinutes = DEFAULT_TOTAL_LITRES
         .multiply(getTotalMinutesBD()) // reverse dreisatz
         .divide(DEFAULT_TOTAL_TIME_BD, MathContext.DECIMAL64);
      do {
         calcTotalLitres = calcTotalLitres.subtract(QUARTER_LITRE);
      } while (calcTotalLitres.compareTo(totalLitresFromMinutes) >= 0);
      // add quarter since we always did a step "too many", due to the do ... while loop
      this.totalLitres = calcTotalLitres.add(QUARTER_LITRE);
   }


   @Override
   protected String fillLoadingBar(long passedMinutes, boolean progressive) {
      long effectivePassedMinutes = passedMinutes < 0 ? 0 : passedMinutes;
      if (getTotalMinutes() > MINUTES_WITH_PAUSE && passedMinutes > MINUTES_BEFORE_PAUSE && passedMinutes <= MINUTES_WITH_PAUSE) {
         effectivePassedMinutes = MINUTES_BEFORE_PAUSE;
      }
      var effectivePassedMinutesBD = BigDecimal.valueOf(effectivePassedMinutes);
      BigDecimal currentLitres = totalLitres
         .multiply(effectivePassedMinutesBD) // reverse dreisatz
         .divide(getTotalMinutesBD(), MathContext.DECIMAL64)
         .add(QUARTER_LITRE);
      BigDecimal printedLitres = currentLitres.subtract(currentLitres.remainder(QUARTER_LITRE, MathContext.DECIMAL64));
      /* BigDecimal currentProgressToNextStep = ONE_HUNDRED_PERCENT
         .multiply(currentLitres.subtract(printedLitres)) // reverse dreisatz
         .divide(QUARTER_LITRE, MathContext.DECIMAL64); */
      BigDecimal minutesToNextStep = getMinutesToNextStep(currentLitres);
      String progressivePart = progressive ? "\r" : "";
      return progressivePart + "Aktuelles Volumen: " + LITRE_FORMAT.format(printedLitres) + "L - "
         // + FormatTools.PERCENTAGE_FORMAT.format(currentProgressToNextStep) + "% - "
         + FormatTools.minutesToTimeString(minutesToNextStep);
   }


   private BigDecimal getMinutesToNextStep(BigDecimal currentLitres) {
      // berechne Liter benötigt bis zum nächsten 0.25er Schritt
      BigDecimal litresToNextStep = QUARTER_LITRE.subtract(currentLitres.remainder(QUARTER_LITRE));
      // berechne Minuten benötigt für 1 Liter
      BigDecimal minutesPerLitre = getTotalMinutesBD().divide(totalLitres, MathContext.DECIMAL64);
      // berechne Minuten benötigt bis zum nächsten 0.25er Schritt
      return minutesPerLitre.multiply(litresToNextStep).setScale(0, RoundingMode.HALF_EVEN);
   }
}