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.nio.charset.StandardCharsets;
import java.time.LocalTime;
import java.time.temporal.ChronoUnit;
import java.util.*;
import java.util.regex.Pattern;
import java.util.stream.Collectors;

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


public class LoadingBar extends AbstractProgressBar {

   private static final Pattern LUNCH_DURATION_PATTERN = Pattern.compile("\\d+");
   private static final Pattern OFFSET_PATTERN = Pattern.compile("[+-]\\d+");
   private static final int MIN_LUNCH_DURATION = 30;
   private static final LocalTime LATEST_LUNCH_TIME = LocalTime.of(13, 30);
   private static final long DEFAULT_NUMBER_WORK_MINS_BEFORE_LUNCH = 5L * CommonTools.MINS_PER_HOUR;
   private static final int MAX_NUMBER_WORK_MINS_WITHOUT_LUNCH = 6 * CommonTools.MINS_PER_HOUR;
   private static final long MAX_NUMBER_WORK_MINS = 8L * CommonTools.MINS_PER_HOUR;


   private enum DaySection {
      MITTAG("-m", "Mittag"),
      ZAPFENSTREICH("-z", "Zapfenstreich");

      private final String param;
      private final String description;


      DaySection(String param, String description) {
         this.param = param;
         this.description = description;
      }


      public static DaySection byParam(String param) {
         return Arrays.stream(DaySection.values()).filter((DaySection section) -> section.getParam().equals(param)).findFirst().orElse(null);
      }


      public String getParam() {
         return param;
      }


      public String getDescription() {
         return description;
      }
   }


   protected LoadingBar(LocalTime startTime) {
      super(startTime);
   }


   public static void main(String[] args) throws IOException {
      if (args.length == 0) {
         askParametersAndRun();
      } else {
         parseParametersAndRun(args);
      }
   }


   private static void askParametersAndRun() 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 lb = new LoadingBar(startTime);
      boolean passedMinutesZero = true;
      if (lb.hasMittagspauseArrived()) {
      // if (lb.hasMittagspauseArrived(passedMinutesZero)) { // DEBUG
         handleMittagspause(br, lb);
         lb.showLoadingBar();
         // lb.showLoadingBarDebug(passedMinutesZero); // DEBUG
      }
      handleZapfenstreich(br, lb);
      lb.showLoadingBar();
      // lb.showLoadingBarDebug(passedMinutesZero); // DEBUG
   }


   protected static void handleMittagspause(BufferedReader br, LoadingBar lb) throws IOException {
      print("Mittagspause verschieben um (optional): ");
      String mittagspauseOffsetRaw = br.readLine();
      if (mittagspauseOffsetRaw != null && !mittagspauseOffsetRaw.isBlank()) {
         var mittagspauseOffset = Integer.parseInt(mittagspauseOffsetRaw);
         lb.initMittagspause(mittagspauseOffset);
         return;
      }
      print("Mittagspause um (optional): ");
      String manualMittagspauseRaw = br.readLine();
      if (manualMittagspauseRaw != null && !manualMittagspauseRaw.isBlank()) {
         var manualMittagspause = LocalTime.parse(manualMittagspauseRaw, FormatTools.TIME_FORMATTER).truncatedTo(ChronoUnit.MINUTES);
         lb.initMittagspause(manualMittagspause);
      } else {
         lb.initMittagspause();
      }
   }


   protected static void handleZapfenstreich(BufferedReader br, LoadingBar lb) throws IOException {
      print("Mittagspause hat gedauert (optional): ");
      String mittagspauseDurationRaw = br.readLine();
      Integer mittagspauseDuration = null;
      if (mittagspauseDurationRaw != null && !mittagspauseDurationRaw.isBlank()) {
         mittagspauseDuration = Integer.valueOf(mittagspauseDurationRaw);
      }
      LocalTime vorlaeufigeEndzeit = lb.getStartTime().plusMinutes(MAX_NUMBER_WORK_MINS)
         .plusMinutes(mittagspauseDuration != null ? mittagspauseDuration : MIN_LUNCH_DURATION);
      println("Endzeit: " + FormatTools.TIME_FORMATTER.format(vorlaeufigeEndzeit));
      print("Feierabend verschieben um (optional): ");
      String zapfenstreichOffsetRaw = br.readLine();
      Integer zapfenstreichOffset = null;
      if (zapfenstreichOffsetRaw != null && !zapfenstreichOffsetRaw.isBlank()) {
         zapfenstreichOffset = Integer.valueOf(zapfenstreichOffsetRaw);
         lb.initZapfenstreich(mittagspauseDuration, zapfenstreichOffset);
         return;
      }
      print("Manuelle Uhrzeit Feierabend (optional): ");
      String manualZapfenstreichRaw = br.readLine();
      LocalTime manualZapfenstreich = null;
      if (manualZapfenstreichRaw != null && !manualZapfenstreichRaw.isBlank()) {
         manualZapfenstreich = LocalTime.parse(manualZapfenstreichRaw, FormatTools.TIME_FORMATTER).truncatedTo(ChronoUnit.MINUTES);
         lb.initZapfenstreich(mittagspauseDuration, manualZapfenstreich);
      } else {
         lb.initZapfenstreich(mittagspauseDuration);
      }
   }


   private static void parseParametersAndRun(String[] args) {
      LoadingBar lb = getLoadingBarFromCLI(args);
      lb.showLoadingBar();
      // wlb.showLoadingBarDebug(true); // DEBUG
   }


   protected static LoadingBar getLoadingBarFromCLI(String[] args) {
      String nextArg = args[0];
      if ("--help".equals(nextArg)) {
         printHelp();
         System.exit(1);
      }
      verifyMinimumNumberOfArgs(args);
      verifyTimeFormat(nextArg, "Erstes Argument");
      var startTime = LocalTime.parse(nextArg, FormatTools.TIME_FORMATTER).truncatedTo(ChronoUnit.MINUTES);
      nextArg = args[1];
      var section = DaySection.byParam(nextArg);
      verifyDaySection(section, nextArg);
      return section == DaySection.MITTAG ? getLoadingBarMittagspause(args, startTime) : getLoadingBarZapfenstreich(args, startTime);
   }


   private static LoadingBar getLoadingBarMittagspause(String[] args, LocalTime startTime) {
      var lb = new LoadingBar(startTime);
      if (args.length == 2) {
         lb.initMittagspause();
         return lb;
      }
      String nextArg = args[2];
      if (OFFSET_PATTERN.matcher(nextArg).matches()) {
         lb.initMittagspause(Integer.parseInt(nextArg));
         return lb;
      }
      verifyTimeFormat(nextArg, "Argument nach " + DaySection.MITTAG.getParam());
      var manualMittagspause = LocalTime.parse(nextArg, FormatTools.TIME_FORMATTER).truncatedTo(ChronoUnit.MINUTES);
      lb.initMittagspause(manualMittagspause);
      return lb;
   }


   private static LoadingBar getLoadingBarZapfenstreich(String[] args, LocalTime startTime) {
      var lb = new LoadingBar(startTime);
      if (args.length == 2) {
         lb.initZapfenstreich();
         return lb;
      }
      String nextArg = args[2];
      LocalTime maxZapfenstreich = null;
      int endTimeOffset = 0;
      Integer lunchDuration = null;
      if (FormatTools.TIME_PATTERN.matcher(nextArg).matches()) {
         maxZapfenstreich = LocalTime.parse(nextArg, FormatTools.TIME_FORMATTER).truncatedTo(ChronoUnit.MINUTES);
      } else if (OFFSET_PATTERN.matcher(nextArg).matches()) {
         endTimeOffset = Integer.parseInt(nextArg);
      } else {
         verifyDurationFormat(nextArg, "Argument nach " + DaySection.ZAPFENSTREICH.getParam());
         lunchDuration = Integer.parseInt(nextArg);
      }
      if (args.length == 3) {
         if (maxZapfenstreich == null && endTimeOffset == 0) {
            lb.initZapfenstreich(lunchDuration);
         } else if (maxZapfenstreich == null) {
            lb.initZapfenstreich(lunchDuration, endTimeOffset);
         } else {
            lb.initZapfenstreich(lunchDuration, maxZapfenstreich);
         }
         return lb;
      }
      nextArg = args[3];
      if (lunchDuration == null) {
         println("Letztes Argument darf nur auf Mittagspausendauer folgen.");
         System.exit(1);
      }
      if (maxZapfenstreich == null && !OFFSET_PATTERN.matcher(nextArg).matches()) {
         verifyTimeFormat(nextArg, "Letztes Argument nach " + DaySection.ZAPFENSTREICH.getParam() + " und Mittagspausendauer");
         maxZapfenstreich = LocalTime.parse(nextArg, FormatTools.TIME_FORMATTER).truncatedTo(ChronoUnit.MINUTES);
         lb.initZapfenstreich(lunchDuration, maxZapfenstreich);
         return lb;
      }
      verifyOffsetFormat(nextArg, "Letztes Argument nach " + DaySection.ZAPFENSTREICH.getParam() + " und Enduhrzeit");
      endTimeOffset = Integer.parseInt(nextArg);
      lb.initZapfenstreich(lunchDuration, endTimeOffset);
      return lb;
   }


   private static void verifyMinimumNumberOfArgs(String[] args) {
      if (args.length >= 2) {
         return;
      }
      println("Mindestens 2 Argumente müssen gegeben sein.");
      printHelp();
      System.exit(1);
   }


   private static void verifyTimeFormat(String param, String errMsgPrefix) {
      verifyInputFormat(FormatTools.TIME_PATTERN, param, errMsgPrefix, "Uhrzeitformat (" + FormatTools.TIME_FORMAT + ")", false);
   }


   private static void verifyDurationFormat(String param, String errMsgPrefix) {
      verifyInputFormat(LUNCH_DURATION_PATTERN, param, errMsgPrefix, "Minutenanzahl (ganze Zahl)", true);
   }


   private static void verifyOffsetFormat(String param, String errMsgPrefix) {
      verifyInputFormat(OFFSET_PATTERN, param, errMsgPrefix, "Minutendifferenz (ganze Zahl mit Vorzeichen)", false);
   }


   private static void verifyInputFormat(Pattern pattern, String param, String errMsgPrefix, String firstInputPart, boolean timeInputPossible) {
      if (pattern.matcher(param).matches()) {
         return;
      }
      var possibleTimeInputPart = timeInputPossible ? " oder Uhrzeitformat (" + FormatTools.TIME_FORMAT + ")" : "";
      println(errMsgPrefix + " \"" + param + "\" muss " + firstInputPart + possibleTimeInputPart + " entsprechen.");
      System.exit(1);
   }


   private static void verifyDaySection(DaySection section, String param) {
      if (section != null) {
         return;
      }
      List<String> sectionDescs = Arrays.stream(DaySection.values()).map((DaySection ds) -> ds.getDescription() + " (" + ds.getParam() + ")")
          .collect(Collectors.toList());
      String sectionDescsJoined = String.join(" oder ", sectionDescs);
      println("Argument nach Startzeit \"" + param + "\" muss Angabe für " + sectionDescsJoined + " sein.");
      System.exit(1);
   }


   private static void printHelp() {
      println("Mögliche Argumente für LoadingBar:\n"
          + "Normalfall Vormittag (Mittagspause <= " + LATEST_LUNCH_TIME + ")\n"
          + FormatTools.TIME_FORMAT + " " + DaySection.MITTAG.getParam() + "\n"
          + "Vormittag mit expliziter Mittagspause (<= " + LATEST_LUNCH_TIME + ")\n"
          + FormatTools.TIME_FORMAT + " " + DaySection.MITTAG.getParam() + " " + FormatTools.TIME_FORMAT + "\n"
          + "Vormittag mit abweichender Minutenanzahl Arbeitszeit\n"
          + FormatTools.TIME_FORMAT + " " + DaySection.MITTAG.getParam() + " -+mm\n"
          + "Normalfall Nachmittag (Mittagspause " + MIN_LUNCH_DURATION + " min)\n"
          + FormatTools.TIME_FORMAT + " " + DaySection.ZAPFENSTREICH.getParam() + "\n"
          + "Nachmittag mit expliziter Länge Mittagspause (Mittagspause unter " + MIN_LUNCH_DURATION + " min wird auf " + MIN_LUNCH_DURATION + " min korrigiert)\n"
          + FormatTools.TIME_FORMAT + " " + DaySection.ZAPFENSTREICH.getParam() + " mm\n"
          + "Nachmittag mit explizitem Feierabend (Mittagspause je nach Minimum (s.u.))\n"
          + FormatTools.TIME_FORMAT + " " + DaySection.ZAPFENSTREICH.getParam() + " " + FormatTools.TIME_FORMAT + "\n"
          + "Nachmittag mit abweichender Minutenanzahl Arbeitszeit\n"
          + FormatTools.TIME_FORMAT + " " + DaySection.ZAPFENSTREICH.getParam() + " -+mm\n"
          + "Nachmittag mit explizitem Feierabend u. expliziter Länge Mittagspause (Mittagspause unter Minimum (s.u.) wird auf Minimum korrigiert)\n"
          + FormatTools.TIME_FORMAT + " " + DaySection.ZAPFENSTREICH.getParam() + " mm " + FormatTools.TIME_FORMAT + "\n"
          + "Nachmittag mit explizitem Feierabend u. abweichender Minutenanzahl Arbeitszeit\n"
          + FormatTools.TIME_FORMAT + " " + DaySection.ZAPFENSTREICH.getParam() + " " + FormatTools.TIME_FORMAT + " -+mm\n\n"
          + "Mittagspause minimum in Minuten:\n"
          + " - bis " + MAX_NUMBER_WORK_MINS_WITHOUT_LUNCH + " min ("
          + MAX_NUMBER_WORK_MINS_WITHOUT_LUNCH / CommonTools.MINS_PER_HOUR + " std):  0\n"
          + " - bis " + MAX_NUMBER_WORK_MINS_WITHOUT_LUNCH + " min + "
          + MIN_LUNCH_DURATION + " min: Arbeitszeit - " + MAX_NUMBER_WORK_MINS_WITHOUT_LUNCH + " min\n"
          + " - ab  " + MAX_NUMBER_WORK_MINS_WITHOUT_LUNCH + " min + " + MIN_LUNCH_DURATION + " min: "
          + MIN_LUNCH_DURATION + " min\n"
      );
   }


   protected boolean hasMittagspauseArrived() {
      return hasMittagspauseArrived(false);
   }


   protected boolean hasMittagspauseArrived(boolean debugWithPassedMinutesZero) {
      return getPassedMinutes(debugWithPassedMinutesZero) < DEFAULT_NUMBER_WORK_MINS_BEFORE_LUNCH;
   }


   private void initMittagspause() {
      LocalTime defaultEndTime = getStartTime().plusMinutes(DEFAULT_NUMBER_WORK_MINS_BEFORE_LUNCH);
      realInitMittagspause(defaultEndTime);
   }


   private void initMittagspause(int endTimeOffset) {
      LocalTime offsetEndTime = getStartTime().plusMinutes(DEFAULT_NUMBER_WORK_MINS_BEFORE_LUNCH + endTimeOffset);
      realInitMittagspause(offsetEndTime);
   }


   private void initMittagspause(LocalTime manualEndTime) {
      LocalTime effectiveEndTime = manualEndTime != null ? manualEndTime : getStartTime().plusMinutes(DEFAULT_NUMBER_WORK_MINS_BEFORE_LUNCH);
      realInitMittagspause(effectiveEndTime);
   }


   private void realInitMittagspause(LocalTime theoreticalEndTime) {
      setEndTime(theoreticalEndTime.isAfter(LATEST_LUNCH_TIME) ? LATEST_LUNCH_TIME : theoreticalEndTime);
   }


   private void initZapfenstreich() {
      LocalTime trueEndTime = getStartTime().plusMinutes(MAX_NUMBER_WORK_MINS + MIN_LUNCH_DURATION);
      realInitZapfenstreich(MIN_LUNCH_DURATION, trueEndTime);
   }


   private void initZapfenstreich(Integer manualLunchDuration) {
      initZapfenstreich(manualLunchDuration, 0);
   }


   private void initZapfenstreich(Integer manualLunchDuration, int endTimeOffset) {
      long minLunchDuration = getMinLunchDuration(endTimeOffset);
      long realLunchDuration = getRealLunchDuration(manualLunchDuration, minLunchDuration);
      LocalTime trueEndTime = getStartTime().plusMinutes(MAX_NUMBER_WORK_MINS + realLunchDuration + endTimeOffset);
      realInitZapfenstreich(realLunchDuration, trueEndTime);
   }


   private void initZapfenstreich(Integer manualLunchDuration, LocalTime manualEndTime) {
      LocalTime trueEndTime = manualEndTime;
      long minLunchDuration = getMinLunchDuration(trueEndTime);
      long realLunchDuration = getRealLunchDuration(manualLunchDuration, minLunchDuration);
      if (trueEndTime == null) {
         trueEndTime = getStartTime().plusMinutes(MAX_NUMBER_WORK_MINS + realLunchDuration);
      }
      realInitZapfenstreich(realLunchDuration, trueEndTime);
   }


   private long getMinLunchDuration(int endTimeOffset) {
      if (endTimeOffset == 0) {
         return MIN_LUNCH_DURATION;
      }
      long totalDuration = MAX_NUMBER_WORK_MINS + endTimeOffset;
      long effectiveLunchDuration = totalDuration - MAX_NUMBER_WORK_MINS_WITHOUT_LUNCH;
      return getMinLunchDuration(effectiveLunchDuration);
   }


   private long getMinLunchDuration(LocalTime manualEndTime) {
      if (manualEndTime == null) {
         return MIN_LUNCH_DURATION;
      }
      long totalDuration = getStartTime().until(manualEndTime, ChronoUnit.MINUTES);
      long effectiveLunchDuration = totalDuration - MAX_NUMBER_WORK_MINS_WITHOUT_LUNCH;
      return getMinLunchDuration(effectiveLunchDuration);
   }


   private long getMinLunchDuration(long effectiveLunchDuration) {
      if (effectiveLunchDuration < 0) {
         effectiveLunchDuration = 0;
      }
      return Math.min(effectiveLunchDuration, MIN_LUNCH_DURATION);
   }


   private long getRealLunchDuration(Integer manualLunchDuration, long minLunchDuration) {
      return manualLunchDuration != null && manualLunchDuration >= minLunchDuration ? manualLunchDuration : minLunchDuration;
   }


   private void realInitZapfenstreich(long effectiveLunchDuration, LocalTime effectiveEndTime) {
      if (effectiveLunchDuration > 0) {
         var totalWorkTime = LocalTime.MIDNIGHT.plusMinutes(getStartTime().until(effectiveEndTime, ChronoUnit.MINUTES) - effectiveLunchDuration);
         print("Arbeitszeit: " + FormatTools.TIME_FORMATTER.format(totalWorkTime) + "; ");
      }
      setEndTime(effectiveEndTime);
   }
}