content: package emu.grasscutter.utils;
  
  import java.io.*;
  import java.nio.charset.StandardCharsets;
  import java.nio.file.Files;
  import java.nio.file.StandardCopyOption;
  import java.time.*;
  import java.time.temporal.TemporalAdjusters;
  import java.util.*;
  import java.util.concurrent.ThreadLocalRandom;
  
  import emu.grasscutter.Grasscutter;
  import emu.grasscutter.config.ConfigContainer;
  import emu.grasscutter.data.DataLoader;
  import io.netty.buffer.ByteBuf;
  import io.netty.buffer.ByteBufUtil;
  import io.netty.buffer.Unpooled;
  import it.unimi.dsi.fastutil.ints.IntArrayList;
  import it.unimi.dsi.fastutil.ints.IntList;
  
  import org.slf4j.Logger;
  
  import javax.annotation.Nullable;
  
  import static emu.grasscutter.utils.FileUtils.getResourcePath;
  import static emu.grasscutter.utils.Language.translate;
  
  @SuppressWarnings({"UnusedReturnValue", "BooleanMethodIsAlwaysInverted"})
  public final class Utils {
      public static final Random random = new Random();
  
      public static int randomRange(int min, int max) {
          return random.nextInt(max - min + 1) + min;
      }
  
      public static float randomFloatRange(float min, float max) {
          return random.nextFloat() * (max - min) + min;
      }
  
      public static double getDist(Position pos1, Position pos2) {
          double xs = pos1.getX() - pos2.getX();
          xs = xs * xs;
  
          double ys = pos1.getY() - pos2.getY();
          ys = ys * ys;
  
          double zs = pos1.getZ() - pos2.getZ();
          zs = zs * zs;
  
          return Math.sqrt(xs + zs + ys);
      }
  
      public static int getCurrentSeconds() {
          return (int) (System.currentTimeMillis() / 1000.0);
      }
  
      public static String lowerCaseFirstChar(String s) {
          StringBuilder sb = new StringBuilder(s);
          sb.setCharAt(0, Character.toLowerCase(sb.charAt(0)));
          return sb.toString();
      }
  
      public static String toString(InputStream inputStream) throws IOException {
          BufferedInputStream bis = new BufferedInputStream(inputStream);
          ByteArrayOutputStream buf = new ByteArrayOutputStream();
          for (int result = bis.read(); result != -1; result = bis.read()) {
              buf.write((byte) result);
          }
          return buf.toString();
      }
  
      public static void logByteArray(byte[] array) {
          ByteBuf b = Unpooled.wrappedBuffer(array);
          Grasscutter.getLogger().info("\n" + ByteBufUtil.prettyHexDump(b));
          b.release();
      }
  
      private static final char[] HEX_ARRAY = "0123456789abcdef".toCharArray();
      public static String bytesToHex(byte[] bytes) {
          if (bytes == null) return "";
          char[] hexChars = new char[bytes.length * 2];
          for (int j = 0; j < bytes.length; j++) {
              int v = bytes[j] & 0xFF;
              hexChars[j * 2] = HEX_ARRAY[v >>> 4];
              hexChars[j * 2 + 1] = HEX_ARRAY[v & 0x0F];
          }
          return new String(hexChars);
      }
  
      public static String bytesToHex(ByteBuf buf) {
          return bytesToHex(byteBufToArray(buf));
      }
  
      public static byte[] byteBufToArray(ByteBuf buf) {
          byte[] bytes = new byte[buf.capacity()];
          buf.getBytes(0, bytes);
          return bytes;
      }
  
      public static int abilityHash(String str) {
          int v7 = 0;
          int v8 = 0;
          while (v8 < str.length()) {
              v7 = str.charAt(v8++) + 131 * v7;
          }
          return v7;
      }
  
      /**
       * Creates a string with the path to a file.
       * @param path The path to the file.
       * @return A path using the operating system's file separator.
       */
      public static String toFilePath(String path) {
          return path.replace("/", File.separator);
      }
  
      /**
       * Checks if a file exists on the file system.
       * @param path The path to the file.
       * @return True if the file exists, false otherwise.
       */
      public static boolean fileExists(String path) {
          return new File(path).exists();
      }
  
      /**
       * Creates a folder on the file system.
       * @param path The path to the folder.
       * @return True if the folder was created, false otherwise.
       */
      public static boolean createFolder(String path) {
          return new File(path).mkdirs();
      }
  
      /**
       * Copies a file from the archive's resources to the file system.
       * @param resource The path to the resource.
       * @param destination The path to copy the resource to.
       * @return True if the file was copied, false otherwise.
       */
      public static boolean copyFromResources(String resource, String destination) {
          try (InputStream stream = Grasscutter.class.getResourceAsStream(resource)) {
              if (stream == null) {
                  Grasscutter.getLogger().warn("Could not find resource: " + resource);
                  return false;
              }
  
              Files.copy(stream, new File(destination).toPath(), StandardCopyOption.REPLACE_EXISTING);
              return true;
          } catch (Exception exception) {
              Grasscutter.getLogger().warn("Unable to copy resource " + resource + " to " + destination, exception);
              return false;
          }
      }
  
      /**
       * Logs an object to the console.
       * @param object The object to log.
       */
      public static void logObject(Object object) {
          Grasscutter.getLogger().info(JsonUtils.encode(object));
      }
  
      /**
       * Checks for required files and folders before startup.
       */
      public static void startupCheck() {
          ConfigContainer config = Grasscutter.getConfig();
          Logger logger = Grasscutter.getLogger();
          boolean exit = false;
  
          String dataFolder = config.folderStructure.data;
  
          // Check for resources folder.
          if (!Files.exists(getResourcePath(""))) {
              logger.info(translate("messages.status.create_resources"));
              logger.info(translate("messages.status.resources_error"));
              createFolder(config.folderStructure.resources); exit = true;
          }
  
          // Check for BinOutput + ExcelBinOutput.
          if (!Files.exists(getResourcePath("BinOutput")) ||
              !Files.exists(getResourcePath("ExcelBinOutput"))) {
              logger.info(translate("messages.status.resources_error"));
              exit = true;
          }
  
          // Check for game data.
          if (!fileExists(dataFolder))
              createFolder(dataFolder);
  
          // Make sure the data folder is populated, if there are any missing files copy them from resources
          DataLoader.checkAllFiles();
  
          if (exit) System.exit(1);
      }
  
      /**
       * Gets the timestamp of the next hour.
       * @return The timestamp in UNIX seconds.
       */
      public static int getNextTimestampOfThisHour(int hour, String timeZone, int param) {
          ZonedDateTime zonedDateTime = ZonedDateTime.now(ZoneId.of(timeZone));
          for (int i = 0; i < param; i ++) {
              if (zonedDateTime.getHour() < hour) {
                  zonedDateTime = zonedDateTime.withHour(hour).withMinute(0).withSecond(0);
              } else {
                  zonedDateTime = zonedDateTime.plusDays(1).withHour(hour).withMinute(0).withSecond(0);
              }
          }
          return (int) zonedDateTime.toInstant().atZone(ZoneOffset.UTC).toEpochSecond();
      }
  
      /**
       * Gets the timestamp of the next hour in a week.
       * @return The timestamp in UNIX seconds.
       */
      public static int getNextTimestampOfThisHourInNextWeek(int hour, String timeZone, int param) {
          ZonedDateTime zonedDateTime = ZonedDateTime.now(ZoneId.of(timeZone));
          for (int i = 0; i < param; i++) {
              if (zonedDateTime.getDayOfWeek() == DayOfWeek.MONDAY && zonedDateTime.getHour() < hour) {
                  zonedDateTime = ZonedDateTime.now(ZoneId.of(timeZone)).withHour(hour).withMinute(0).withSecond(0);
              } else {
                  zonedDateTime = zonedDateTime.with(TemporalAdjusters.next(DayOfWeek.MONDAY)).withHour(hour).withMinute(0).withSecond(0);
              }
          }
          return (int) zonedDateTime.toInstant().atZone(ZoneOffset.UTC).toEpochSecond();
      }
  
      /**
       * Gets the timestamp of the next hour in a month.
       * @return The timestamp in UNIX seconds.
       */
      public static int getNextTimestampOfThisHourInNextMonth(int hour, String timeZone, int param) {
          ZonedDateTime zonedDateTime = ZonedDateTime.now(ZoneId.of(timeZone));
          for (int i = 0; i < param; i++) {
              if (zonedDateTime.getDayOfMonth() == 1 && zonedDateTime.getHour() < hour) {
                  zonedDateTime = ZonedDateTime.now(ZoneId.of(timeZone)).withHour(hour).withMinute(0).withSecond(0);
              } else {
                  zonedDateTime = zonedDateTime.with(TemporalAdjusters.firstDayOfNextMonth()).withHour(hour).withMinute(0).withSecond(0);
              }
          }
          return (int) zonedDateTime.toInstant().atZone(ZoneOffset.UTC).toEpochSecond();
      }
  
      /**
       * Retrieves a string from an input stream.
       * @param stream The input stream.
       * @return The string.
       */
      public static String readFromInputStream(@Nullable InputStream stream) {
          if (stream == null) return "empty";
  
          StringBuilder stringBuilder = new StringBuilder();
          try (BufferedReader reader = new BufferedReader(new InputStreamReader(stream, StandardCharsets.UTF_8))) {
              String line; while ((line = reader.readLine()) != null) {
                  stringBuilder.append(line);
              } stream.close();
          } catch (IOException e) {
              Grasscutter.getLogger().warn("Failed to read from input stream.");
          } catch (NullPointerException ignored) {
              return "empty";
          } return stringBuilder.toString();
      }
  
      /**
       * Performs a linear interpolation using a table of fixed points to create an effective piecewise f(x) = y function.
       * @param x The x value.
       * @param xyArray Array of points in [[x0,y0], ... [xN, yN]] format
       * @return f(x) = y
       */
      public static int lerp(int x, int[][] xyArray) {
          try {
              if (x <= xyArray[0][0]) {  // Clamp to first point
                  return xyArray[0][1];
              } else if (x >= xyArray[xyArray.length-1][0]) {  // Clamp to last point
                  return xyArray[xyArray.length-1][1];
              }
              // At this point we're guaranteed to have two lerp points, and pity be somewhere between them.
              for (int i=0; i < xyArray.length-1; i++) {
                  if (x == xyArray[i+1][0]) {
                      return xyArray[i+1][1];
                  }
                  if (x < xyArray[i+1][0]) {
                      // We are between [i] and [i+1], interpolation time!
                      // Using floats would be slightly cleaner but we can just as easily use ints if we're careful with order of operations.
                      int position = x - xyArray[i][0];
                      int fullDist = xyArray[i+1][0] - xyArray[i][0];
                      int prevValue = xyArray[i][1];
                      int fullDelta = xyArray[i+1][1] - prevValue;
                      return prevValue + ( (position * fullDelta) / fullDist );
                  }
              }
          } catch (IndexOutOfBoundsException e) {
              Grasscutter.getLogger().error("Malformed lerp point array. Must be of form [[x0, y0], ..., [xN, yN]].");
          }
          return 0;
      }
  
      /**
       * Checks if an int is in an int[]
       * @param key int to look for
       * @param array int[] to look in
       * @return key in array
       */
      public static boolean intInArray(int key, int[] array) {
          for (int i : array) {
              if (i == key) {
                  return true;
              }
          }
          return false;
      }
  
      /**
       * Return a copy of minuend without any elements found in subtrahend.
       * @param minuend The array we want elements from
       * @param subtrahend The array whose elements we don't want
       * @return The array with only the elements we want, in the order that minuend had them
       */
      public static int[] setSubtract(int[] minuend, int[] subtrahend) {
          IntList temp = new IntArrayList();
          for (int i : minuend) {
              if (!intInArray(i, subtrahend)) {
                  temp.add(i);
              }
          }
          return temp.toIntArray();
      }
  
      /**
       * Gets the language code from a given locale.
       * @param locale A locale.
       * @return A string in the format of 'XX-XX'.
       */
      public static String getLanguageCode(Locale locale) {
          return String.format("%s-%s", locale.getLanguage(), locale.getCountry());
      }
  
      /**
       * Base64 encodes a given byte array.
       * @param toEncode An array of bytes.
       * @return A base64 encoded string.
       */
      public static String base64Encode(byte[] toEncode) {
          return Base64.getEncoder().encodeToString(toEncode);
      }
  
      /**
       * Base64 decodes a given string.
       * @param toDecode A base64 encoded string.
       * @return An array of bytes.
       */
      public static byte[] base64Decode(String toDecode) {
          return Base64.getDecoder().decode(toDecode);
      }
  
      /***
       * Draws a random element from the given list, following the given probability distribution, if given.
       * @param list The list from which to draw the element.
       * @param probabilities The probability distribution. This is given as a list of probabilities of the same length it `list`.
       * @return A randomly drawn element from the given list.
       */
      public static <T> T drawRandomListElement(List<T> list, List<Integer> probabilities) {
          // If we don't have a probability distribution, or the size of the distribution does not match
          // the size of the list, we assume uniform distribution.
          if (probabilities == null || probabilities.size() <= 1 || probabilities.size() != list.size()) {
              int index = ThreadLocalRandom.current().nextInt(0, list.size());
              return list.get(index);
          }
  
          // Otherwise, we roll with the given distribution.
          int totalProbabilityMass = probabilities.stream().reduce(Integer::sum).get();
          int roll = ThreadLocalRandom.current().nextInt(1, totalProbabilityMass + 1);
  
          int currentTotalChance = 0;
          for (int i = 0; i < list.size(); i++) {
              currentTotalChance += probabilities.get(i);
  
              if (roll <= currentTotalChance) {
                  return list.get(i);
              }
          }
  
          // Should never happen.
          return list.get(0);
      }
  
      /***
       * Draws a random element from the given list, following a uniform probability distribution.
       * @param list The list from which to draw the element.
       * @return A randomly drawn element from the given list.
       */
      public static <T> T drawRandomListElement(List<T> list) {
          return drawRandomListElement(list, null);
      }
  
      /***
       * Splits a string by a character, into a list
       * @param input The string to split
       * @param separator The character to use as the split points
       * @return A list of all the substrings
       */
      public static List<String> nonRegexSplit(String input, int separator) {
          var output = new ArrayList<String>();
          int start = 0;
          for (int next = input.indexOf(separator); next > 0; next = input.indexOf(separator, start)) {
              output.add(input.substring(start, next));
              start = next + 1;
          }
          if (start < input.length())
              output.add(input.substring(start));
          return output;
      }
  }
  