/t2tx.php

#!/usr/bin/php
<?php
/**
 * t2tx - split XHTML pages created with txt2tags into multi-page "books"
 * 
 * @author Peeter P. Mõtsküla <peeterpaul@motskula.net>
 * @copyright (c) 2010 Peeter P. Mõtsküla
 * @version 1.1
 * @license New BSD license (http://opensource.org/licenses/bsd-license.php)
 *
 * Usage: see main block below or just call t2tx without parameters
 * 
 * Notes / to do:
 *   * internal hyperlinks are not recalculated.
 *
 * The script contains two classes (Book and Chapter), a simple error-handling
 * routine (error) and a main block that takes the arguments from the command
 * line, creates a new Book from the input file, and saves the Book.
 */

error_reporting(E_ALL | E_STRICT);

/*
 * global constants
 */
define('t2tx_PROGID',
    't2tx 1.1 by Peeter P. Mõtsküla <peeterpaul@motskula.net>');
define('t2tx_FNFORNOHTML',      'not html or file not found');
define('t2tx_NOT2TXHTML',       'not txt2tags-generated xhtml');
define('t2tx_NOBODY',           'empty document body');
define('t2tx_BADSPLITLEVEL',    'invalid splitLevel');
define('t2tx_BADTOCLEVEL',      'invalid tocLevel');
define('t2tx_BADCHAPTER',       'invalid chapter content');
define('t2tx_NOCHAPTERS',       'no chapters found');
define('t2tx_BADSECTION',       'invalid section specified');

/**
 * Chapter of a book
 */
class Chapter {
    protected $_body;
    protected $_level;
    protected $_title;
    protected $_anchor;

    /**
     * @param string $body HTML snippet containing the chapter body
     */
    public function __construct($body) {
        $this->_body = $body;
    }

    /**
     * @return string HTML snippet containing the chapter body
     */
    public function body() {
        return $this->_body;
    }

    /**
     * return int chapter level -- the level of the first heading
     */
    public function level() {
        if (! isset($this->_level)) {
            if (preg_match('#<h([1-6])#s', $this->_body, $matches)) {
                $this->_level = $matches[1];
            } else {
                $this->_level = 0;
            }
        }
        return $this->_level;
    }

    /**
     * return string chapter title -- the content of the first heading
     */
    public function title() {
        if (! isset($this->_title)) {
            if (preg_match('#<h[1-6].*?>(.*?)</h[1-6]>#s',
                    $this->_body, $matches)) {
                $this->_title = $matches[1];
            } else {
                $this->_title = '';
            }
        }
        return $this->_title;
    }

    /**
     * return string the anchor string immediately preceding the first heading
     */
    public function anchor() {
        if (! $this->_anchor) {
            if (preg_match('#^<a.*? name="(.*?)".*?></a>#s',
                    $this->_body, $matches)) {
                $this->_anchor = $matches[1];
            } else {
                $this->_anchor = '';
            }
        }
        return $this->_anchor;
    }

}

/**
 * Book containing the chapters
 */
class Book {
    protected $_html;
    protected $_filename;
    protected $_splitLevel;
    protected $_tocLevel;
    protected $_bookPath;
    protected $_bookName;
    protected $_htmlHead;
    protected $_title;
    protected $_header;
    protected $_body;
    protected $_toc;
    protected $_chapters;

    /*
     * @property string $content input filename or contents thereof
     * @property int $splitLevel
     *           deepest heading to break document into chapters (default 1)
     * @property int $tocLevel
     *           how many sublevels to include into table of contents
     *           (default 1; 0 means all)
     */
    public function __construct($content = NULL, $splitLevel = 1,
            $tocLevel = 1) {
        // check $splitLevel
        if ($splitLevel < 1 || $splitLevel > 6 ||
                intval($splitLevel) != $splitLevel) {
            throw new Exception(t2tx_BADSPLITLEVEL);
        } else {
            $this->_splitLevel = $splitLevel;
        }

        // check $tocLevel
        if ($tocLevel < 0 || intval($tocLevel) != $tocLevel) {
            throw new Exception(t2tx_BADTOCLEVEL);
        } else {
            $this->_tocLevel = ($tocLevel > 0 ? $tocLevel : 6);
        }
        // do we have a file?
        if (file_exists($content)) {
            $this->_filename = $content;
            $html = file_get_contents($this->_filename);
        } else {
            $html = $content;
        }

        // do we have HTML content?
        if (preg_match('#<html.*?>.*</html>#s', $html)) {
            $this->_html = $html;
        } else {
            throw new Exception(t2tx_FNFORNOHTML);
        }

        // do we have something in document body?
        if (! $body = trim($this->body())) {
            throw new Exception(t2tx_NOBODY);
        }
        
        // extract chapters
        $this->chapters();
    }

    /**
     * @return string full path to input file without .html extension
     */
    public function bookPath() {
        if (! $this->_bookPath) {
            $this->_bookPath = preg_replace('#\.html$#', '', $this->_filename);
        }
        return $this->_bookPath;
    }

    /**
     * @return string name of input file without .html extension
     */
    public function bookName() {
        if (! $this->_bookName) {
            $this->_bookName = preg_replace('#.*/#', '', $this->bookPath());
        }
        return $this->_bookName;
    }

    /**
     * @return string start of input file until the end of <head> tag
     *         with an extra <meta name="generator"... added
     */
    public function htmlHead() {
        if (! $this->_htmlHead) {
            if (preg_match('#(^.*?</head>)#s', $this->_html, $matches)) {
                $this->_htmlHead = preg_replace(
                    "#</title>\n#",
                    "</title>\n" .
                    '<meta name="generator" content="' .
                    t2tx_PROGID .
                    "\" />\n",
                    $matches[0]);
            } else {
                throw new Exception(t2tx_NOT2TXHTML);
            }
        }
        return $this->_htmlHead;
    }

    /**
     * @return string book title taken from the <title> of input file
     */
    public function title() {
        if (! $this->_title) {
            if (preg_match('#<title>(.*?)</title>#s', $this->htmlHead(),
                    $matches)) {
                $this->_title = $matches[1];
            } else {
                throw new Exception(t2tx_NOT2TXHTML);
            }
        }
        return $this->_title;
    }

    /**
     * @return string content of input file's div#header
     */
    public function header() {
        if (! $this->_header) {
            if (preg_match('#<div class="header" id="header">(.*?)</div>#s',
                    $this->_html, $matches)) {
                $this->_header = $matches[1];
            } else {
                throw new Exception(t2tx_NOT2TXHTML);
            }
        }
        return $this->_header;
    }

    /**
     * @return string content of input file's div#body
     */
    public function body() {
        if (! $this->_body) {
            if (preg_match('#<div\ class="body"\ id="body">' . "\n" .
                    '(.*?)</div>' . "\n\n" .
                    '<!-- xhtml code generated by txt2tags#s',
                    $this->_html, $matches)) {
                $this->_body = $matches[1];
            } else {
                throw new Exception(t2tx_NOT2TXHTML);
            }
        }
        return $this->_body;
    }

    /**
     * @return array list of chapters in the book
     */
    public function chapters() {
        if (! is_array($this->_chapters)) {
            $this->_getSections($this->body(), $this->_chapters,
                $this->_splitLevel);
        }
        return $this->_chapters;
    }        

    /**
     * Break input file into chapters
     * 
     * @param string $body content of input file's div#body
     * @param array $chapters chapter list to be populated
     * @param int $splitLevel smallest heading to split input into chapters at
     * @return void
     */
    protected function _getSections($body, &$chapters, $splitLevel = NULL) {
        // set up nextHead;
        if (! $splitLevel) {
            $splitLevel = $this->_splitLevel;
        }
        $nextHead = '(<a[^>]+></a>\n)?<h';
        if ($splitLevel == 1) {
            $nextHead .= '1';
        } else {
            $nextHead .= "[1-$splitLevel]";
        }

        // extract chapter 0
        $chapters = array();
        preg_match("#^(.*?)(?=$nextHead|$)#s", $body, $matches);
        $chapters[] = new Chapter($matches[0]);
        $body = trim(str_replace($matches[0], '', $body));

        // extract chapters 1..n
        while ($body) {
            if (preg_match("#^($nextHead.*?)(?=$nextHead)#s",
                    $body, $matches)) {
                $chapters[] = new Chapter($matches[0]);
                $body = trim(str_replace($matches[0], '', $body));
            } else {
                $chapters[] = new Chapter($body);
                $body = '';
            }
        }
    }

    /**
     * Create table of contents
     *
     * @return string HTML-formatted table of contents
     */
    public function toc() {
        if (! $this->_toc) {
            // bail out if no chapters found
            if (! count($this->_chapters)) {
                throw new Exception(t2tx_NOCHAPTERS);
            }

            // build table of contents
            $level = 1;
            $toc = '<div class="toc" id="toc">' . "\n<ul>\n";
            $chapNum = 0;
            foreach ($this->_chapters as $chapter) {
                if ($chapter->level() == 0) {
                    continue;
                }
                $chapNum++;
                $this->_getSections($chapter->body(), $_chapters,
                    $this->_splitLevel + $this->_tocLevel);
                foreach ($_chapters as $_chapter) {
                    if ($_chapter->level() == 0) {
                        continue;
                    }
                    while ($_chapter->level() > $level) {
                        $toc .= str_repeat("  ", $level++) . "<li><ul>\n";
                    }
                    while ($_chapter->level() < $level) {
                        $toc .= str_repeat("  ", --$level) . "</ul></li>\n";
                    }
                    $toc .= str_repeat("  ", $level) .
                        '<li><a href="' . $this->bookName() . "-$chapNum.html" .
                        ($_chapter->anchor() ? "#{$_chapter->anchor()}" : '') .
                        "\">{$_chapter->title()}</a></li>\n";
                }
                // close last open ul-s
                while ($level > 1) {
                    $toc .= str_repeat("  ", --$level) . "</ul></li>\n";
                }
            }
            $toc .= "</ul>\n</div>\n";

            // remove unnecessary li-s around ul-s
            $toc = preg_replace('#</li>(\n +)<li><ul>#s', '$1<ul>', $toc);
            $toc = preg_replace('#(\n +)</ul></li>#s', '$1</ul>$1</li>', $toc);
            
            $this->_toc = $toc;
        }
        return $this->_toc;
    }

    /**
     * Create chapter-specific navigation bars
     *
     * @param int $section section number (0 - TOC/preamble, 1..n - chapters)
     * @return string HTML-formatted navigation bar for given chapter
     */
    public function navbar($section) {
        // do we have a valid section?
        if ($section < 1 || $section >= count($this->_chapters) ||
                $section != intval($section)) {
            throw new Exception(t2tx_BADSECTION);
        }

        // build navbar
        $navbar = '<div class="navbar" id="navbar">' . "\n" .
            '<table width="100%"><tr>' . "\n" .
            '  <td align="left" width="5%">';
        if ($section > 1) { # link to previous if exists
            $navbar .= '<a href="' .
                $this->bookName() . '-' . ($section - 1) . '.html">' .
                '&lt;&lt;</a>';
        }
        $navbar .= "</td>\n" . '  <td align="center" width="90%"><a href="' .
            $this->bookName() . '-0.html">' . $this->title() . "</a></td>\n" .
            '  <td align="right" width="5%">';
        if ($section < count($this->_chapters) -1) { # link to next if exists
            $navbar .= '<a href="' .
                $this->bookName() . '-' . ($section + 1) . '.html">' .
                '&gt;&gt;</a>';
        }
        $navbar .= "</td>\n</tr></table>\n</div>\n";
        
        return $navbar;
    }

    /**
     * Save the current book into set of files
     *
     * @return void
     */
    public function save() {
        $chapNum = 0;
        foreach ($this->_chapters as $chapter) {
            if ($chapNum == 0) {
                $content = $this->htmlHead() . "<body>\n" .
                    $this->header() . $this->toc() .
                    '<div class="body" id="body">' . "\n" .
                    $chapter->body() .
                    "</div>\n</body>\n</html>\n";
            } else {
                $content = $this->htmlHead() . "<body>\n" .
                    $this->navbar($chapNum) .
                    '<div class="body" id="body">' . "\n" .
                    $chapter->body() .
                    "</div>\n" .
                    $this->navbar($chapNum) .
                    "</body>\n</html>\n";
            }
            file_put_contents($this->bookPath() . "-$chapNum.html", $content);
            $chapNum++;
        }
    }
    
}

/**
 * main block
 */
if ($argc < 2 || $argc > 4) {
    echo <<<END
t2tx - split XHTML pages created with txt2tags into multi-page "books"

Usage:
    t2tx docName.html [splitLevel [tocLevel]]
        docName.html    - to be converted into docName-0.html .. docName-n.html
        splitLevel      - deepest heading level to split into chapters
        tocLevel        - how many levels of subchapters to include in TOC

See README.txt for more details.

END;
    exit;
}

$input = $argv[1];
$splitLevel = ($argc > 2 ? $argv[2] : 1);
$tocLevel = ($argc > 3 ? $argv[3] : 1);
$book = new Book($input, $splitLevel, $tocLevel);
$book->save();
echo "Done, ", count($book->chapters()) - 1, " chapters.\n";