package com.openrsc.data;

import java.io.BufferedInputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.Random;

public final class DataConversions {

	private static Random rand = new Random();
	private static char[] characters = {' ', 'e', 't', 'a', 'o', 'i', 'h',
		'n', 's', 'r', 'd', 'l', 'u', 'm', 'w', 'c', 'y', 'f', 'g', 'p',
		'b', 'v', 'k', 'x', 'j', 'q', 'z', '0', '1', '2', '3', '4', '5',
		'6', '7', '8', '9', ' ', '!', '?', '.', ',', ':', ';', '(', ')',
		'-', '&', '*', '\\', '\'', '@', '#', '+', '=', '\243', '$', '%',
		'"', '[', ']'};


	/**
	 * Returns a ByteBuffer containing everything available from the given
	 * InputStream
	 */
	public static ByteBuffer streamToBuffer(BufferedInputStream in)
		throws IOException {
		byte[] buffer = new byte[in.available()];
		in.read(buffer, 0, buffer.length);
		return ByteBuffer.wrap(buffer);
	}

	/**
	 * Calculates the average of all values in the array
	 */
	public static int average(int[] values) {
		int total = 0;
		for (int value : values) {
			total += value;
		}
		return (int) (total / values.length);
	}

	/**
	 * returns the code used to represent the given character in our byte array
	 * encoding methods
	 */
	private static int getCharCode(char c) {
		for (int x = 0; x < characters.length; x++) {
			if (c == characters[x]) {
				return x;
			}
		}
		return 0;
	}

	/**
	 * Encodes a string into a byte array
	 */
	public static byte[] stringToByteArray(String message) {
		byte[] buffer = new byte[100];
		if (message.length() > 80) {
			message = message.substring(0, 80);
		}
		message = message.toLowerCase();
		int length = 0;
		int j = -1;
		for (int k = 0; k < message.length(); k++) {
			int code = getCharCode(message.charAt(k));
			if (code > 12) {
				code += 195;
			}
			if (j == -1) {
				if (code < 13)
					j = code;
				else
					buffer[length++] = (byte) code;
			} else if (code < 13) {
				buffer[length++] = (byte) ((j << 4) + code);
				j = -1;
			} else {
				buffer[length++] = (byte) ((j << 4) + (code >> 4));
				j = code & 0xf;
			}
		}
		if (j != -1) {
			buffer[length++] = (byte) (j << 4);
		}
		byte[] string = new byte[length];
		System.arraycopy(buffer, 0, string, 0, length);
		return string;
	}

	/**
	 * Decodes a byte array back into a string
	 */
	public static String byteToString(byte[] data, int offset, int length) {
		char[] buffer = new char[100];
		try {
			int k = 0;
			int l = -1;
			for (int i1 = 0; i1 < length; i1++) {
				int j1 = data[offset++] & 0xff;
				int k1 = j1 >> 4 & 0xf;
				if (l == -1) {
					if (k1 < 13) {
						buffer[k++] = characters[k1];
					} else {
						l = k1;
					}
				} else {
					buffer[k++] = characters[((l << 4) + k1) - 195];
					l = -1;
				}
				k1 = j1 & 0xf;
				if (l == -1) {
					if (k1 < 13) {
						buffer[k++] = characters[k1];
					} else {
						l = k1;
					}
				} else {
					buffer[k++] = characters[((l << 4) + k1) - 195];
					l = -1;
				}
			}
			boolean flag = true;
			for (int l1 = 0; l1 < k; l1++) {
				char c = buffer[l1];
				if (l1 > 4 && c == '@') {
					buffer[l1] = ' ';
				}
				if (c == '%') {
					buffer[l1] = ' ';
				}
				if (flag && c >= 'a' && c <= 'z') {
					buffer[l1] += '\uFFE0';
					flag = false;
				}
				if (c == '.' || c == '!' || c == ':') {
					flag = true;
				}
			}
			return new String(buffer, 0, k);
		} catch (Exception e) {
			e.printStackTrace();
			return ".";
		}
	}

	/**
	 * Checks if the given int is in the array
	 */
	public static boolean inArray(int[] haystack, int needle) {
		for (int i : haystack) {
			if (needle == i) {
				return true;
			}
		}
		return false;
	}

	/**
	 * returns the max of the 2 values
	 */
	public static int max(int i1, int i2) {
		return i1 > i2 ? i1 : i2;
	}

	/**
	 * returns a random number within the given bounds
	 */
	public static int random(int low, int high) {
		return low + rand.nextInt(high - low + 1);
	}

	/**
	 * returns a random number within the given bounds, but allows for certain
	 * values to be weighted
	 */
	public static int randomWeighted(int low, int dip, int peak, int max) {
		int total = 0;
		int probability = 100;
		int[] probArray = new int[max + 1];
		for (int x = 0; x < probArray.length; x++) {
			total += probArray[x] = probability;
			if (x < dip || x > peak) {
				probability -= 3;
			} else {
				probability += 3;
			}
		}
		int hit = random(0, total);
		total = 0;
		for (int x = 0; x < probArray.length; x++) {
			if (hit >= total && hit < (total + probArray[x])) {
				return x;
			}
			total += probArray[x];
		}
		return 0;
	}

	/**
	 * Converts a username to a unique hash
	 */
	public static long usernameToHash(String s) {
		s = s.toLowerCase();
		String s1 = "";
		for (int i = 0; i < s.length(); i++) {
			char c = s.charAt(i);
			if (c >= 'a' && c <= 'z')
				s1 = s1 + c;
			else if (c >= '0' && c <= '9')
				s1 = s1 + c;
			else
				s1 = s1 + ' ';
		}

		s1 = s1.trim();
		if (s1.length() > 12)
			s1 = s1.substring(0, 12);
		long l = 0L;
		for (int j = 0; j < s1.length(); j++) {
			char c1 = s1.charAt(j);
			l *= 37L;
			if (c1 >= 'a' && c1 <= 'z')
				l += (1 + c1) - 97;
			else if (c1 >= '0' && c1 <= '9')
				l += (27 + c1) - 48;
		}
		return l;
	}

	/**
	 * Converts a usernames hash back to the username
	 */
	public static String hashToUsername(long l) {
		if (l < 0L)
			return "invalid_name";
		String s = "";
		while (l != 0L) {
			int i = (int) (l % 37L);
			l /= 37L;
			if (i == 0)
				s = " " + s;
			else if (i < 27) {
				if (l % 37L == 0L)
					s = (char) ((i + 65) - 1) + s;
				else
					s = (char) ((i + 97) - 1) + s;
			} else {
				s = (char) ((i + 48) - 27) + s;
			}
		}
		return s;
	}
}