<?php
/**
 * Class Minify_Lines  
 * @package Minify
 */

/**
 * Add line numbers in C-style comments for easier debugging of combined content
 *
 * @package Minify
 * @author Stephen Clay <steve@mrclay.org>
 */
class Minify_Lines {

    /**
     * Add line numbers in C-style comments
     *
     * This uses a very basic parser easily fooled by comment tokens inside
     * strings or regexes, but, otherwise, generally clean code will not be 
     * mangled.
     * 
     * @param string $content
     * 
     * @param array $options available options:
     * 
     * 'id': (optional) string to identify file. E.g. file name/path
     * 
     * @return string 
     */
    public static function minify($content, $options = array()) 
    {
        $id = (isset($options['id']) && $options['id'])
            ? $options['id']
            : '';
        if (! $eol = self::_getEol($content)) {
            return $content;
        }
        $lines = explode($eol, $content);
        $numLines = count($lines);
        // determine left padding
        $padTo = strlen($numLines);
        $inComment = false;
        $i = 0;
        $newLines = array();
        while (null !== ($line = array_shift($lines))) {
            if (('' !== $id) && (0 == $i % 50)) {
                array_push($newLines, '', "/* {$id} */", '');
            }
            ++$i;
            $newLines[] = self::_addNote($line, $i, $inComment, $padTo);
            $inComment = self::_eolInComment($line, $inComment);
        }
        return implode($eol, $newLines) . $eol;
    }
    
    /**
     * Determine EOL character sequence
     *
     * @param string $str file content
     * 
     * @return string EOL char(s) or '' if no EOL could be found
     */
    private static function _getEol($str)
    {
        $r = strpos($str, "\r");
        $n = strpos($str, "\n");
        if (false === $r && false === $n) {
            return '';
        }
        return ($r !== false)
            ? ($n == ($r + 1) 
                ? "\r\n"
                : "\r")
            : "\n";
    }
    
    /**
     * Is the parser within a C-style comment at the end of this line?
     *
     * @param string $line current line of code
     * 
     * @param bool $inComment was the parser in a comment at the
     * beginning of the line?
     * 
     * @return bool
     */
    private static function _eolInComment($line, $inComment)
    {
        while (strlen($line)) {
            $search = $inComment
                ? '*/'
                : '/*';
            $pos = strpos($line, $search);
            if (false === $pos) {
                return $inComment;
            } else {
                $inComment = ! $inComment;
                $line = substr($line, $pos + 2);
            }
        }
        return $inComment;
    }
    
    /**
     * Prepend a comment (or note) to the given line
     *
     * @param string $line current line of code
     *
     * @param string $note content of note/comment
     * 
     * @param bool $inComment was the parser in a comment at the
     * beginning of the line?
     *
     * @param int $padTo minimum width of comment
     * 
     * @return string
     */
    private static function _addNote($line, $note, $inComment, $padTo)
    {
        return $inComment
            ? '/* ' . str_pad($note, $padTo, ' ', STR_PAD_RIGHT) . ' *| ' . $line
            : '/* ' . str_pad($note, $padTo, ' ', STR_PAD_RIGHT) . ' */ ' . $line;
    }
}