/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * Copyright (c) 2008, Red Hat Middleware LLC or third-party contributors as
 * indicated by the @author tags or express copyright attribution
 * statements applied by the authors.  All third-party contributions are
 * distributed under license by Red Hat Middleware LLC.
 *
 * This copyrighted material is made available to anyone wishing to use, modify,
 * copy, or redistribute it subject to the terms and conditions of the GNU
 * Lesser General Public License, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this distribution; if not, write to:
 * Free Software Foundation, Inc.
 * 51 Franklin Street, Fifth Floor
 * Boston, MA  02110-1301  USA
 *
 */
package org.hibernate.util;

import java.util.Iterator;
import java.util.StringTokenizer;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.regex.Pattern;

import org.hibernate.dialect.Dialect;

public final class StringHelper {

	private static final int ALIAS_TRUNCATE_LENGTH = 10;
	public static final String WHITESPACE = " \n\r\f\t";

	private StringHelper() { /* static methods only - hide constructor */
	}
	
	/*public static boolean containsDigits(String string) {
		for ( int i=0; i<string.length(); i++ ) {
			if ( Character.isDigit( string.charAt(i) ) ) return true;
		}
		return false;
	}*/

	public static int lastIndexOfLetter(String string) {
		for ( int i=0; i<string.length(); i++ ) {
			char character = string.charAt(i);
			if ( !Character.isLetter(character) /*&& !('_'==character)*/ ) return i-1;
		}
		return string.length()-1;
	}

	public static String join(String seperator, String[] strings) {
		int length = strings.length;
		if ( length == 0 ) return "";
		StringBuffer buf = new StringBuffer( length * strings[0].length() )
				.append( strings[0] );
		for ( int i = 1; i < length; i++ ) {
			buf.append( seperator ).append( strings[i] );
		}
		return buf.toString();
	}

	public static String join(String seperator, Iterator objects) {
		StringBuffer buf = new StringBuffer();
		if ( objects.hasNext() ) buf.append( objects.next() );
		while ( objects.hasNext() ) {
			buf.append( seperator ).append( objects.next() );
		}
		return buf.toString();
	}

	public static String[] add(String[] x, String sep, String[] y) {
		String[] result = new String[x.length];
		for ( int i = 0; i < x.length; i++ ) {
			result[i] = x[i] + sep + y[i];
		}
		return result;
	}

	public static String repeat(String string, int times) {
		StringBuffer buf = new StringBuffer( string.length() * times );
		for ( int i = 0; i < times; i++ ) buf.append( string );
		return buf.toString();
	}

	public static String repeat(char character, int times) {
		char[] buffer = new char[times];
		Arrays.fill( buffer, character );
		return new String( buffer );
	}


	public static String replace(String template, String placeholder, String replacement) {
		return replace( template, placeholder, replacement, false );
	}

	public static String[] replace(String templates[], String placeholder, String replacement) {
		String[] result = new String[templates.length];
		for ( int i =0; i<templates.length; i++ ) {
			result[i] = replace( templates[i], placeholder, replacement );
		}
		return result;
	}

	public static String replace(String template, String placeholder, String replacement, boolean wholeWords) {
		return replace( template, placeholder, replacement, wholeWords, false );
	}

	public static String replace(String template,
								 String placeholder,
								 String replacement,
								 boolean wholeWords,
								 boolean encloseInParensIfNecessary) {
		if ( template == null ) {
			return template;
		}
		int loc = template.indexOf( placeholder );
		if ( loc < 0 ) {
			return template;
		}
		else {
			String beforePlaceholder = template.substring( 0, loc );
			String afterPlaceholder = template.substring( loc + placeholder.length() );
			return replace( beforePlaceholder, afterPlaceholder, placeholder, replacement, wholeWords, encloseInParensIfNecessary );
		}
	}


	public static String replace(String beforePlaceholder,
								 String afterPlaceholder,
								 String placeholder,
								 String replacement,
								 boolean wholeWords,
								 boolean encloseInParensIfNecessary) {
		final boolean actuallyReplace =
				! wholeWords ||
				afterPlaceholder.length() == 0 ||
				! Character.isJavaIdentifierPart( afterPlaceholder.charAt( 0 ) );
		boolean encloseInParens =
				actuallyReplace &&
				encloseInParensIfNecessary &&
				! ( getLastNonWhitespaceCharacter( beforePlaceholder ) == '(' ) &&
				! ( getFirstNonWhitespaceCharacter( afterPlaceholder ) == ')' );		
		StringBuilder buf = new StringBuilder( beforePlaceholder );
		if ( encloseInParens ) {
			buf.append( '(' );
		}
		buf.append( actuallyReplace ? replacement : placeholder );
		if ( encloseInParens ) {
			buf.append( ')' );
		}
		buf.append(
				replace(
						afterPlaceholder,
						placeholder,
						replacement,
						wholeWords,
						encloseInParensIfNecessary
				)
		);
		return buf.toString();
	}

	public static char getLastNonWhitespaceCharacter(String str) {
		if ( str != null && str.length() > 0 ) {
			for ( int i = str.length() - 1 ; i >= 0 ; i-- ) {
				char ch = str.charAt( i );
				if ( ! Character.isWhitespace( ch ) ) {
					return ch;
				}
			}
		}
		return '\0';
	}

	public static char getFirstNonWhitespaceCharacter(String str) {
		if ( str != null && str.length() > 0 ) {
			for ( int i = 0 ; i < str.length() ; i++ ) {
				char ch = str.charAt( i );
				if ( ! Character.isWhitespace( ch ) ) {
					return ch;
				}
			}
		}
		return '\0';
	}

	public static String replaceOnce(String template, String placeholder, String replacement) {
		if ( template == null ) {
			return template; // returnign null!
		}
        int loc = template.indexOf( placeholder );
		if ( loc < 0 ) {
			return template;
		}
		else {
			return new StringBuffer( template.substring( 0, loc ) )
					.append( replacement )
					.append( template.substring( loc + placeholder.length() ) )
					.toString();
		}
	}


	public static String[] split(String seperators, String list) {
		return split( seperators, list, false );
	}

	public static String[] split(String seperators, String list, boolean include) {
		StringTokenizer tokens = new StringTokenizer( list, seperators, include );
		String[] result = new String[ tokens.countTokens() ];
		int i = 0;
		while ( tokens.hasMoreTokens() ) {
			result[i++] = tokens.nextToken();
		}
		return result;
	}

	public static String unqualify(String qualifiedName) {
		int loc = qualifiedName.lastIndexOf(".");
		return ( loc < 0 ) ? qualifiedName : qualifiedName.substring( qualifiedName.lastIndexOf(".") + 1 );
	}

	public static String qualifier(String qualifiedName) {
		int loc = qualifiedName.lastIndexOf(".");
		return ( loc < 0 ) ? "" : qualifiedName.substring( 0, loc );
	}

	/**
	 * Collapses a name.  Mainly intended for use with classnames, where an example might serve best to explain.
	 * Imagine you have a class named <samp>'org.hibernate.util.StringHelper'</samp>; calling collapse on that
	 * classname will result in <samp>'o.h.u.StringHelper'<samp>.
	 *
	 * @param name The name to collapse.
	 * @return The collapsed name.
	 */
	public static String collapse(String name) {
		if ( name == null ) {
			return null;
		}
		int breakPoint = name.lastIndexOf( '.' );
		if ( breakPoint < 0 ) {
			return name;
		}
		return collapseQualifier( name.substring( 0, breakPoint ), true ) + name.substring( breakPoint ); // includes last '.'
	}

	/**
	 * Given a qualifier, collapse it.
	 *
	 * @param qualifier The qualifier to collapse.
	 * @param includeDots Should we include the dots in the collapsed form?
	 *
	 * @return The collapsed form.
	 */
	public static String collapseQualifier(String qualifier, boolean includeDots) {
		StringTokenizer tokenizer = new StringTokenizer( qualifier, "." );
		String collapsed = Character.toString( tokenizer.nextToken().charAt( 0 ) );
		while ( tokenizer.hasMoreTokens() ) {
			if ( includeDots ) {
				collapsed += '.';
			}
			collapsed += tokenizer.nextToken().charAt( 0 );
		}
		return collapsed;
	}

	/**
	 * Partially unqualifies a qualified name.  For example, with a base of 'org.hibernate' the name
	 * 'org.hibernate.util.StringHelper' would become 'util.StringHelper'.
	 *
	 * @param name The (potentially) qualified name.
	 * @param qualifierBase The qualifier base.
	 *
	 * @return The name itself, or the partially unqualified form if it begins with the qualifier base.
	 */
	public static String partiallyUnqualify(String name, String qualifierBase) {
		if ( name == null || ! name.startsWith( qualifierBase ) ) {
			return name;
		}
		return name.substring( qualifierBase.length() + 1 ); // +1 to start after the following '.'
	}

	/**
	 * Cross between {@link #collapse} and {@link #partiallyUnqualify}.  Functions much like {@link #collapse}
	 * except that only the qualifierBase is collapsed.  For example, with a base of 'org.hibernate' the name
	 * 'org.hibernate.util.StringHelper' would become 'o.h.util.StringHelper'.
	 *
	 * @param name The (potentially) qualified name.
	 * @param qualifierBase The qualifier base.
	 *
	 * @return The name itself if it does not begin with the qualifierBase, or the properly collapsed form otherwise.
	 */
	public static String collapseQualifierBase(String name, String qualifierBase) {
		if ( name == null || ! name.startsWith( qualifierBase ) ) {
			return collapse( name );
		}
		return collapseQualifier( qualifierBase, true ) + name.substring( qualifierBase.length() );
	}

	public static String[] suffix(String[] columns, String suffix) {
		if ( suffix == null ) return columns;
		String[] qualified = new String[columns.length];
		for ( int i = 0; i < columns.length; i++ ) {
			qualified[i] = suffix( columns[i], suffix );
		}
		return qualified;
	}

	private static String suffix(String name, String suffix) {
		return ( suffix == null ) ? name : name + suffix;
	}

	public static String root(String qualifiedName) {
		int loc = qualifiedName.indexOf( "." );
		return ( loc < 0 ) ? qualifiedName : qualifiedName.substring( 0, loc );
	}

	public static String unroot(String qualifiedName) {
		int loc = qualifiedName.indexOf( "." );
		return ( loc < 0 ) ? qualifiedName : qualifiedName.substring( loc+1, qualifiedName.length() );
	}

	public static boolean booleanValue(String tfString) {
		String trimmed = tfString.trim().toLowerCase();
		return trimmed.equals( "true" ) || trimmed.equals( "t" );
	}

	public static String toString(Object[] array) {
		int len = array.length;
		if ( len == 0 ) return "";
		StringBuffer buf = new StringBuffer( len * 12 );
		for ( int i = 0; i < len - 1; i++ ) {
			buf.append( array[i] ).append(", ");
		}
		return buf.append( array[len - 1] ).toString();
	}

	public static String[] multiply(String string, Iterator placeholders, Iterator replacements) {
		String[] result = new String[]{string};
		while ( placeholders.hasNext() ) {
			result = multiply( result, ( String ) placeholders.next(), ( String[] ) replacements.next() );
		}
		return result;
	}

	private static String[] multiply(String[] strings, String placeholder, String[] replacements) {
		String[] results = new String[replacements.length * strings.length];
		int n = 0;
		for ( int i = 0; i < replacements.length; i++ ) {
			for ( int j = 0; j < strings.length; j++ ) {
				results[n++] = replaceOnce( strings[j], placeholder, replacements[i] );
			}
		}
		return results;
	}

	public static int countUnquoted(String string, char character) {
		if ( '\'' == character ) {
			throw new IllegalArgumentException( "Unquoted count of quotes is invalid" );
		}
		if (string == null)
			return 0;
		// Impl note: takes advantage of the fact that an escpaed single quote
		// embedded within a quote-block can really be handled as two seperate
		// quote-blocks for the purposes of this method...
		int count = 0;
		int stringLength = string.length();
		boolean inQuote = false;
		for ( int indx = 0; indx < stringLength; indx++ ) {
			char c = string.charAt( indx );
			if ( inQuote ) {
				if ( '\'' == c ) {
					inQuote = false;
				}
			}
			else if ( '\'' == c ) {
				inQuote = true;
			}
			else if ( c == character ) {
				count++;
			}
		}
		return count;
	}

	public static int[] locateUnquoted(String string, char character) {
		if ( '\'' == character ) {
			throw new IllegalArgumentException( "Unquoted count of quotes is invalid" );
		}
		if (string == null) {
			return new int[0];
		}

		ArrayList locations = new ArrayList( 20 );

		// Impl note: takes advantage of the fact that an escpaed single quote
		// embedded within a quote-block can really be handled as two seperate
		// quote-blocks for the purposes of this method...
		int stringLength = string.length();
		boolean inQuote = false;
		for ( int indx = 0; indx < stringLength; indx++ ) {
			char c = string.charAt( indx );
			if ( inQuote ) {
				if ( '\'' == c ) {
					inQuote = false;
				}
			}
			else if ( '\'' == c ) {
				inQuote = true;
			}
			else if ( c == character ) {
				locations.add( new Integer( indx ) );
			}
		}
		return ArrayHelper.toIntArray( locations );
	}

	public static boolean isNotEmpty(String string) {
		return string != null && string.length() > 0;
	}

	public static boolean isEmpty(String string) {
		return string == null || string.length() == 0;
	}

	public static String qualify(String prefix, String name) {
		if ( name == null || prefix == null ) {
			throw new NullPointerException();
		}
		return new StringBuffer( prefix.length() + name.length() + 1 )
				.append(prefix)
				.append('.')
				.append(name)
				.toString();
	}

	public static String[] qualify(String prefix, String[] names) {
		if ( prefix == null ) return names;
		int len = names.length;
		String[] qualified = new String[len];
		for ( int i = 0; i < len; i++ ) {
			qualified[i] = qualify( prefix, names[i] );
		}
		return qualified;
	}

	public static int firstIndexOfChar(String sqlString, String string, int startindex) {
		int matchAt = -1;
		for ( int i = 0; i < string.length(); i++ ) {
			int curMatch = sqlString.indexOf( string.charAt( i ), startindex );
			if ( curMatch >= 0 ) {
				if ( matchAt == -1 ) { // first time we find match!
					matchAt = curMatch;
				}
				else {
					matchAt = Math.min( matchAt, curMatch );
				}
			}
		}
		return matchAt;
	}

	public static String truncate(String string, int length) {
		if ( string.length() <= length ) {
			return string;
		}
		else {
			return string.substring( 0, length );
		}
	}

	public static String generateAlias(String description) {
		return generateAliasRoot(description) + '_';
	}

	/**
	 * Generate a nice alias for the given class name or collection role name and unique integer. Subclasses of
	 * Loader do <em>not</em> have to use aliases of this form.
	 *
	 * @param description The base name (usually an entity-name or collection-role)
	 * @param unique A uniquing value
	 *
	 * @return an alias of the form <samp>foo1_</samp>
	 */
	public static String generateAlias(String description, int unique) {
		return generateAliasRoot(description) +
			Integer.toString(unique) +
			'_';
	}

	/**
	 * Generates a root alias by truncating the "root name" defined by
	 * the incoming decription and removing/modifying any non-valid
	 * alias characters.
	 *
	 * @param description The root name from which to generate a root alias.
	 * @return The generated root alias.
	 */
	private static String generateAliasRoot(String description) {
		String result = truncate( unqualifyEntityName(description), ALIAS_TRUNCATE_LENGTH )
				.toLowerCase()
		        .replace( '/', '_' ) // entityNames may now include slashes for the representations
				.replace( '$', '_' ); //classname may be an inner class
		result = cleanAlias( result );
		if ( Character.isDigit( result.charAt(result.length()-1) ) ) {
			return result + "x"; //ick!
		}
		else {
			return result;
		}
	}

	/**
	 * Clean the generated alias by removing any non-alpha characters from the
	 * beginning.
	 *
	 * @param alias The generated alias to be cleaned.
	 * @return The cleaned alias, stripped of any leading non-alpha characters.
	 */
	private static String cleanAlias(String alias) {
		char[] chars = alias.toCharArray();
		// short cut check...
		if ( !Character.isLetter( chars[0] ) ) {
			for ( int i = 1; i < chars.length; i++ ) {
				// as soon as we encounter our first letter, return the substring
				// from that position
				if ( Character.isLetter( chars[i] ) ) {
					return alias.substring( i );
				}
			}
		}
		return alias;
	}

	public static String unqualifyEntityName(String entityName) {
		String result = unqualify(entityName);
		int slashPos = result.indexOf( '/' );
		if ( slashPos > 0 ) {
			result = result.substring( 0, slashPos - 1 );
		}
		return result;
	}
	
	public static String toUpperCase(String str) {
		return str==null ? null : str.toUpperCase();
	}
	
	public static String toLowerCase(String str) {
		return str==null ? null : str.toLowerCase();
	}

	public static String moveAndToBeginning(String filter) {
		if ( filter.trim().length()>0 ){
			filter += " and ";
			if ( filter.startsWith(" and ") ) filter = filter.substring(4);
		}
		return filter;
	}

	/**
	 * Determine if the given string is quoted (wrapped by '`' characters at beginning and end).
	 *
	 * @param name The name to check.
	 * @return True if the given string starts and ends with '`'; false otherwise.
	 */
	public static boolean isQuoted(String name) {
		return name != null && name.length() != 0 && name.charAt( 0 ) == '`' && name.charAt( name.length() - 1 ) == '`';
	}

	/**
	 * Return a representation of the given name ensuring quoting (wrapped with '`' characters).  If already wrapped
	 * return name.
	 *
	 * @param name The name to quote.
	 * @return The quoted version.
	 */
	public static String quote(String name) {
		if ( name == null || name.length() == 0 || isQuoted( name ) ) {
			return name;
		}
		else {
			return new StringBuffer( name.length() + 2 ).append('`').append( name ).append( '`' ).toString();
		}
	}

	/**
	 * Return the unquoted version of name (stripping the start and end '`' characters if present).
	 *
	 * @param name The name to be unquoted.
	 * @return The unquoted version.
	 */
	public static String unquote(String name) {
		if ( isQuoted( name ) ) {
			return name.substring( 1, name.length() - 1 );
		}
		else {
			return name;
		}
	}

	/**
	 * Determine if the given name is quoted.  It is considered quoted if either:
	 * <ol>
	 * <li>starts AND ends with backticks (`)</li>
	 * <li>starts with dialect-specified {@link org.hibernate.dialect.Dialect#openQuote() open-quote}
	 * 		AND ends with dialect-specified {@link org.hibernate.dialect.Dialect#closeQuote() close-quote}</li>
	 * </ol>
	 *
	 * @param name The name to check
	 * @param dialect The dialect (to determine the "real" quoting chars).
	 *
	 * @return True if quoted, false otherwise
	 */
	public static boolean isQuoted(String name, Dialect dialect) {
		return name != null && name.length() != 0
				&& ( name.charAt( 0 ) == '`' && name.charAt( name.length() - 1 ) == '`'
				|| name.charAt( 0 ) == dialect.openQuote() && name.charAt( name.length() - 1 ) == dialect.closeQuote() );
	}

	/**
	 * Return the unquoted version of name stripping the start and end quote characters.
	 *
	 * @param name The name to be unquoted.
	 * @param dialect The dialect (to determine the "real" quoting chars).
	 *
	 * @return The unquoted version.
	 */
	public static String unquote(String name, Dialect dialect) {
		if ( isQuoted( name, dialect ) ) {
			return name.substring( 1, name.length() - 1 );
		}
		else {
			return name;
		}
	}

	/**
	 * Return the unquoted version of name stripping the start and end quote characters.
	 *
	 * @param names The names to be unquoted.
	 * @param dialect The dialect (to determine the "real" quoting chars).
	 *
	 * @return The unquoted versions.
	 */
	public static String[] unquote(String[] names, Dialect dialect) {
		if ( names == null ) {
			return null;
		}
		String[] unquoted = new String[ names.length ];
		for ( int i = 0; i < names.length; i++ ) {
			unquoted[i] = unquote( names[i], dialect );
		}
		return unquoted;
	}
}
