addLinks($text);

class ScriptureUtils {

    private $booksAbbreviated = array(
        "Gen", "Exo", "Lev", "Num", "Deu", "Jos", "Jud", "Rut", "1 Sam", "2 Sam", "1 Kin", 
        "2 Kin", "1 Chr", "2 Chr", "Ezr", "Neh", "Est", "Job", "Psa", "Pro", "Ecc", "Son", 
        "Isa", "Jer", "Lam", "Eze", "Dan", "Hos", "Joe", "Amo", "Oba", "Jon", "Mic", 
        "Nah", "Hab", "Zep", "Hag", "Zec", "Mal", "Mat", "Mar", "Luk", "Joh", "Act", 
        "Rom", "1 Cor", "2 Cor", "Gal", "Eph", "Phi", "Col", "1 The", "2 The", "1 Tim", 
        "2 Tim", "Tit", "Phi", "Heb", "Jam", "1 Pet", "2 Pet", "1 Joh", "2 Joh", "3 Joh", 
        "Jud", "Rev"
    );

    private $booksFullnames = array(
        "Genesis", "Exodus", "Leviticus", "Numbers", "Deuteronomy", "Joshua", "Judges", 
        "Ruth", "1 Samuel", "2 Samuel", "1 Kings", "2 Kings", "1 Chronicles", 
        "2 Chronicles", "Ezra", "Nehemiah", "Esther", "Job", "Psalms", "Proverbs", 
        "Ecclesiastes", "Song of Solomon", "Isaiah", "Jeremiah", "Lamentations", "Ezekiel", 
        "Daniel", "Hosea", "Joel", "Amos", "Obadiah", "Jonah", "Micah", "Nahum", 
        "Habakkuk", "Zephaniah", "Haggai", "Zechariah", "Malachi", "Matthew", "Mark", 
        "Luke", "John", "Acts", "Romans", "1 Corinthians", "2 Corinthians", "Galatians", 
        "Ephesians", "Philippians", "Colossians", "1 Thessalonians", "2 Thessalonians", 
        "1 Timothy", "2 Timothy", "Titus", "Philemon", "Hebrews", "James", "1 Peter", 
        "2 Peter", "1 John", "2 John", "3 John", "Jude", "Revelation"
    );

    private $addLinkPattern;

    public function __construct() {
        $this->defineLinkPattern();
    }

    public function addLinks($text) {
        $returnString = preg_replace_callback(
            $this->addLinkPattern,
            array($this, "addLinkCallback"),
            $text
        );
        return $returnString;
    }

    private function addLinkCallback($matches) {
        $returnString = "";
        foreach($matches as $match) {
            $returnString .= "$match";
        }
        return $returnString;
    }

    private function defineLinkPattern() {
        // It is important that the full names appear before the abbreviated ones.
        $bookList = implode("|", array_merge($this->booksFullnames, $this->booksAbbreviated));
        $this->addLinkPattern = "/\\b(?:$bookList)(?:\\s+\\d+)?(?::\\d+(?:–\\d+)?(?:,\\s*\\d+(?:–\\d+)?)*)?/";
    }

}