package org.jabref.logic.layout.format;

import java.util.List;

import org.jabref.logic.layout.AbstractParamLayoutFormatter;

/// Formatter that does regexp replacement.
/// To use this formatter, a two-part argument must be given. The parts are
/// separated by a comma. To indicate the comma character, use an escape
/// sequence: \,
/// For inserting newlines and tabs in arguments, use \n and \t, respectively.
/// The first part is the regular expression to search for. Remember that any commma
/// character must be preceded by a backslash, and consequently a literal backslash must
/// be written as a pair of backslashes. A description of Java regular expressions can be
/// found at:
///   http://java.sun.com/j2se/1.4.2/docs/api/java/util/regex/Pattern.html
/// The second part is the text to replace all matches with.
/// For instance:
///
/// `\format[Replace(and,&)]{\author}`
///      will output the "author" field after replacing all occurences of "and"
///      by "&"
///
///  `\format[Replace(\s,_)]{\author}`
///      will output the "author" field after replacing all whitespace
///      by underscores.
///
///  `\format[Replace(\,,;)]{\author}`
///      will output the "author" field after replacing all commas by semicolons.
public class Replace extends AbstractParamLayoutFormatter {

    private String regex;
    private String replaceWith;

    @Override
    public void setArgument(String arg) {
        List<String> parts = AbstractParamLayoutFormatter.parseArgument(arg);

        if (parts.size() < 2) {
            return; // TODO: too few arguments. Print an error message here?
        }
        regex = parts.getFirst();
        replaceWith = parts.get(1);
    }

    @Override
    public String format(String fieldText) {
        if ((fieldText == null) || (regex == null)) {
            return fieldText; // TODO: argument missing or invalid. Print an error message here?
        }
        return fieldText.replaceAll(regex, replaceWith);
    }
}
