/*
 * [ScriptItem.java]
 *
 * Summary: base class for user-written search/replace Script.
 *
 * Copyright: (c) 2014-2017 Roedy Green, Canadian Mind Products, http://mindprod.com
 *
 * Licence: This software may be copied and used freely for any purpose but military.
 *          http://mindprod.com/contact/nonmil.html
 *
 * Requires: JDK 1.8+
 *
 * Created with: JetBrains IntelliJ IDEA IDE http://www.jetbrains.com/idea/
 *
 * Version History:
 *  1.0 2014-12-29 initial version
 */
package com.mindprod.rep;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

import static java.lang.System.*;

/**
 * base class for user-written search/replace Script.
 *
 * @author Roedy Green, Canadian Mind Products
 * @version 1.0 2014-12-29 initial version
 * @since 2014-12-29
 */
public class ScriptItem
    {
    // declarations

    /**
     * string to replace found text, plain or with $ to copy group
     */
    private final String replaceString;

    /**
     * plain search string
     */
    private final String searchString;

    /**
     * regex search pattern
     */
    private final Pattern searchPattern;

    /**
     * did this script item result in any file changes
     */
    private boolean used = false;
    // /declarations

    /**
     * constructor for plain string search/replace
     *
     * @param search  plain search string
     * @param replace string to replace found text
     */
    public ScriptItem( String search, String replace )
        {
        this.searchString = search;
        this.searchPattern = null;
        this.replaceString = replace;
        }

    /**
     * constructor for plain string search/replace
     *
     * @param search  plain regex search pattern
     * @param replace string to replace found text with $ to copy group
     */
    public ScriptItem( Pattern search, String replace )
        {
        this.searchPattern = search;
        this.searchString = null;
        this.replaceString = replace;
        }
    // methods

    /**
     * do all replacements in one file for one ScriptItem replacement.
     *
     * @param prev the file contents as modified so far.
     *
     * @return modified string
     */
    String doReplacements( String prev )
        {
        if ( searchString != null )
            {
            final String modified = prev.replace( searchString, replaceString );
            if ( modified.equals( prev ) )
                {
                return prev;
                }
            else
                {
                used = true;
                return modified;
                }
            }
        else
            {
            try
                {
                // where we collect the replacement. Must be a StringBuffer, not a StringBuilder. Regex has a legacy problem.
                final StringBuffer sb = new StringBuffer( prev.length() );
                final Matcher m = searchPattern.matcher( prev );
                boolean changed = false;
                while ( m.find() )
                    {
                    m.appendReplacement( sb, replaceString );
                    changed = true;
                    used = true;
                    }
                if ( changed )
                    {
                    // we have now processed the replacements.
                    m.appendTail( sb );
                    return sb.toString();
                    }
                else
                    {
                    return prev;
                    }
                }
            catch ( IndexOutOfBoundsException e )
                {
                err.println( e.getMessage() );
                err.println( searchPattern );
                err.println( replaceString );
                System.exit( 1 );
                return prev;
                }
            }
        }// /method

    /**
     * did this script item result in any replacements?
     *
     * @return true if were replacements.
     */
    public boolean isUsed()
        {
        return used;
        }// /method

    /**
     * display ScriptItem as a String
     *
     * @return representation of ScriptItem
     */
    public String toString()
        {
        if ( searchString != null )
            {
            return searchString + " : " + replaceString;
            }
        else
            {
            return searchPattern.toString() + " : " + replaceString;
            }
        }// /method
    // /methods
    }