package de.szimnau.tools;

import de.szimnau.LoadingBar;
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.function.Function;
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 LoadingBarCliTools {

   private static final Pattern OFFSET_PATTERN = Pattern.compile("[+-]\\d+");
   private static final Pattern LUNCH_DURATION_PATTERN = Pattern.compile("\\d+");


   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;
      }
   }


   private LoadingBarCliTools() {}


   public static void askParametersAndRun(Function<LocalTime, ? extends LoadingBar> constructor) 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);
      LoadingBar lb = constructor.apply(startTime);
      boolean debug = false;
      boolean passedMinutesZero = false;
      if (lb.hasMittagspauseArrived(debug && passedMinutesZero)) {
         handleMittagspause(br, lb);
         lb.showLoadingBar(debug, passedMinutesZero);
      }
      handleZapfenstreich(br, lb);
      lb.showLoadingBar(debug, passedMinutesZero);
   }


   private 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();
      }
   }


   private 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(LoadingBar.MAX_NUMBER_WORK_MINS)
         .plusMinutes(mittagspauseDuration != null ? mittagspauseDuration : LoadingBar.MIN_LUNCH_DURATION);
      println("Endzeit: " + FormatTools.TIME_FORMATTER.format(vorlaeufigeEndzeit));
      print("Feierabend verschieben um (optional): ");
      String zapfenstreichOffsetRaw = br.readLine();
      if (zapfenstreichOffsetRaw != null && !zapfenstreichOffsetRaw.isBlank()) {
         int zapfenstreichOffset = Integer.parseInt(zapfenstreichOffsetRaw);
         lb.initZapfenstreich(mittagspauseDuration, zapfenstreichOffset);
         return;
      }
      print("Manuelle Uhrzeit Feierabend (optional): ");
      String manualZapfenstreichRaw = br.readLine();
      if (manualZapfenstreichRaw != null && !manualZapfenstreichRaw.isBlank()) {
         LocalTime manualZapfenstreich = LocalTime.parse(manualZapfenstreichRaw, FormatTools.TIME_FORMATTER).truncatedTo(ChronoUnit.MINUTES);
         lb.initZapfenstreich(mittagspauseDuration, manualZapfenstreich);
      } else {
         lb.initZapfenstreich(mittagspauseDuration);
      }
   }


   public static void parseParametersAndRun(String[] args, Function<LocalTime, ? extends LoadingBar> constructor) {
      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);
      LoadingBar lb = constructor.apply(startTime);
      if (section == DaySection.MITTAG) {
         initLoadingBarMittagspause(args, lb);
      } else {
         initLoadingBarZapfenstreich(args, lb);
      }
      boolean debug = false;
      boolean passedMinutesZero = false;
      lb.showLoadingBar(debug, passedMinutesZero);
   }


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


   private static void initLoadingBarZapfenstreich(String[] args, LoadingBar lb) {
      if (args.length == 2) {
         lb.initZapfenstreich();
         return;
      }
      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;
      }
      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;
      }
      verifyOffsetFormat(nextArg, "Letztes Argument nach " + DaySection.ZAPFENSTREICH.getParam() + " und Enduhrzeit");
      endTimeOffset = Integer.parseInt(nextArg);
      lb.initZapfenstreich(lunchDuration, endTimeOffset);
   }


   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 <= " + LoadingBar.LATEST_LUNCH_TIME + ")\n"
          + FormatTools.TIME_FORMAT + " " + DaySection.MITTAG.getParam() + "\n"
          + "Vormittag mit expliziter Mittagspause (<= " + LoadingBar.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 " + LoadingBar.MIN_LUNCH_DURATION + " min)\n"
          + FormatTools.TIME_FORMAT + " " + DaySection.ZAPFENSTREICH.getParam() + "\n"
          + "Nachmittag mit expliziter Länge Mittagspause (Mittagspause unter " + LoadingBar.MIN_LUNCH_DURATION + " min wird auf "
          + LoadingBar.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 " + LoadingBar.MAX_NUMBER_WORK_MINS_WITHOUT_LUNCH + " min ("
          + LoadingBar.MAX_NUMBER_WORK_MINS_WITHOUT_LUNCH / CommonTools.MINS_PER_HOUR + " std):  0\n"
          + " - bis " + LoadingBar.MAX_NUMBER_WORK_MINS_WITHOUT_LUNCH + " min + "
          + LoadingBar.MIN_LUNCH_DURATION + " min: Arbeitszeit - " + LoadingBar.MAX_NUMBER_WORK_MINS_WITHOUT_LUNCH + " min\n"
          + " - ab  " + LoadingBar.MAX_NUMBER_WORK_MINS_WITHOUT_LUNCH + " min + " + LoadingBar.MIN_LUNCH_DURATION + " min: "
          + LoadingBar.MIN_LUNCH_DURATION + " min\n"
      );
   }
}