package Torello.Java;

import Torello.Java.Function.IntTFunction;

class StrArrToReplFunc
{
    static String replace(
            final boolean                       ignoreCase,
            final String                        s,
            final String[]                      matchStrs,
            final IntTFunction<String, String>  replaceFunction
        )
    {
        // Loop simply checks for null pointers.
        for (int i=0; i < matchStrs.length; i++)

            if (matchStrs[i] == null) throw new NullPointerException(
                "The " + i + StrPrint.ordinalIndicator(i) + " of array parameter " +
                "'matchStrs' is null."
            );


        // Use a StringBuilder to build the return String.  It is precisely what it was
        // it was designed for.

        StringBuilder sb = new StringBuilder();

        int last = 0;


        // Main Loop: Builds a replacement StringBuilder.  Looks for matches between the input
        // String 's', and the matchStrs in array String[] matchStrs.

        TOP:
        for (int i=0; i < s.length(); i++)

            for (int j=0; j < matchStrs.length; j++)

                if (s.regionMatches(ignoreCase, i, matchStrs[j], 0, matchStrs[j].length()))
                {
                    // A match was found, so begin
                    String nonMatchStr  = s.substring(last, i);
                    String oldStr       = s.substring(i, i + matchStrs[j].length());
                    String newStr       = replaceFunction.apply(i, oldStr);

                    // Append them to the StringBuilder.
                    if (nonMatchStr.length() > 0) sb.append(nonMatchStr);
                    sb.append(newStr);

                    // Update the pointers
                    last    = i + oldStr.length();
                    i       = last - 1; // use -1 because of the loop-incrementer at top

                    continue TOP;
                }

        if (last == 0) return s; // There were no matches, return original String.


        // This happens when there are remaining characters after the last match that occurred.
        // Same as the HTML Parser - trailing READ/PARSE.

        if (last < s.length()) sb.append(s.substring(last));

        return sb.toString();
    }
}