package luan.modules;

import java.security.NoSuchAlgorithmException;
import java.util.Arrays;
import goodjava.util.GoodUtils;
import luan.Luan;
import luan.LuanTable;
import luan.LuanFunction;
import luan.LuanException;


public final class StringLuan {

	static int start(String s,int i) {
		int len = s.length();
		return i==0 ? 0 : i > 0 ? Math.min(i-1,len) : Math.max(len+i,0);
	}

	static int start(String s,Integer i,int dflt) {
		return i==null ? dflt : start(s,i);
	}

	static int end(String s,int i) {
		int len = s.length();
		return i==0 ? 0 : i > 0 ? Math.min(i,len) : Math.max(len+i+1,0);
	}

	static int end(String s,Integer i,int dflt) {
		return i==null ? dflt : end(s,i);
	}

	public static Integer[] unicode(String s,Integer i,Integer j) throws LuanException {
		Utils.checkNotNull(s);
		int start = start(s,i,0);
		int end = end(s,j,start+1);
		Integer[] chars = new Integer[end-start];
		for( int k=0; k<chars.length; k++ ) {
			chars[k] = (int)s.charAt(start+k);
		}
		return chars;
	}

	public static String char_(int... chars) {
		char[] a = new char[chars.length];
		for( int i=0; i<chars.length; i++ ) {
			a[i] = (char)chars[i];
		}
		return new String(a);
	}

	public static byte[] to_binary(String s) {
		return s.getBytes();
	}

	public static String lower(String s) throws LuanException {
		Utils.checkNotNull(s);
		return s.toLowerCase();
	}

	public static String upper(String s) throws LuanException {
		Utils.checkNotNull(s);
		return s.toUpperCase();
	}

	public static String trim(String s) throws LuanException {
		Utils.checkNotNull(s);
		return s.trim();
	}

	public static String reverse(String s) throws LuanException {
		Utils.checkNotNull(s);
		return new StringBuilder(s).reverse().toString();
	}

	public static String repeated(String s,int n,String sep) {
		if( n < 1 )
			return "";
		StringBuilder buf = new StringBuilder(s);
		while( --n > 0 ) {
			if( sep != null )
				buf.append(sep);
			buf.append(s);
		}
		return buf.toString();
	}

	public static String sub(String s,int i,Integer j) throws LuanException {
		Utils.checkNotNull(s);
		int start = start(s,i);
		int end = end(s,j,s.length());
		return s.substring(start,end);
	}

	public static Object[] find(String s,String s2,Integer init) {
		int start = start(s,init,0);
		int i = s.indexOf(s2,start);
		return i == -1 ? null : new Integer[]{i+1,i+s2.length()};
	}

	// note - String.format() is too stupid to convert between ints and floats.
	public static String format(String format,Object... args) {
		return String.format(format,args);
	}

	public static String encode(String s) {
		return Luan.stringEncode(s);
	}

	public static Number to_number(String s,Integer base) throws LuanException {
		Utils.checkNotNull(s);
		try {
			if( base == null ) {
				return Double.valueOf(s);
			} else {
				return Long.valueOf(s,base);
			}
		} catch(NumberFormatException e) {}
		return null;
	}

	public static String[] split(String s,String s2,Integer limit) throws LuanException {
		Utils.checkNotNull(s);
		Utils.checkNotNull(s2,2);
		int n = limit==null ? -1 : limit;
		return GoodUtils.split(s,s2,n);
	}

	public static String digest_message(String algorithm,String input) throws LuanException, NoSuchAlgorithmException {
		Utils.checkNotNull(algorithm,1);
		Utils.checkNotNull(input,2);
		return BinaryLuan.to_hex( BinaryLuan.digest_message( algorithm, input.getBytes() ) );
	}

	public static boolean contains(String s,String s2) throws LuanException {
		Utils.checkNotNull(s);
		Utils.checkNotNull(s2,2);
		return s.contains(s2);
	}

	public static boolean starts_with(String s,String s2) throws LuanException {
		Utils.checkNotNull(s);
		Utils.checkNotNull(s2,2);
		return s.startsWith(s2);
	}

	public static boolean ends_with(String s,String s2) throws LuanException {
		Utils.checkNotNull(s);
		Utils.checkNotNull(s2,2);
		return s.endsWith(s2);
	}

	public static String replace(String s,String target,String replacement) throws LuanException {
		Utils.checkNotNull(s);
		Utils.checkNotNull(target,2);
		Utils.checkNotNull(replacement,3);
		return GoodUtils.replace(s,target,replacement);
	}

}