<?php
/* Reminder: always indent with 4 spaces (no tabs). */
// +---------------------------------------------------------------------------+
// | Copyright (c) 2008, Demian Turner                                         |
// | All rights reserved.                                                      |
// |                                                                           |
// | Redistribution and use in source and binary forms, with or without        |
// | modification, are permitted provided that the following conditions        |
// | are met:                                                                  |
// |                                                                           |
// | o Redistributions of source code must retain the above copyright          |
// |   notice, this list of conditions and the following disclaimer.           |
// | o Redistributions in binary form must reproduce the above copyright       |
// |   notice, this list of conditions and the following disclaimer in the     |
// |   documentation and/or other materials provided with the distribution.    |
// | o The names of the authors may not be used to endorse or promote          |
// |   products derived from this software without specific prior written      |
// |   permission.                                                             |
// |                                                                           |
// | THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS       |
// | "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT         |
// | LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR     |
// | A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT      |
// | OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,     |
// | SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT          |
// | LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,     |
// | DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY     |
// | THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT       |
// | (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE     |
// | OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.      |
// |                                                                           |
// +---------------------------------------------------------------------------+
// | Seagull 0.6                                                               |
// +---------------------------------------------------------------------------+
// | BlockLoader.php                                                           |
// +---------------------------------------------------------------------------+
// | Author:   Demian Turner <demian@phpkitchen.com>                           |
// +---------------------------------------------------------------------------+
// $Id$

/**
 * BlockLoader manages units of content that can be dynamically positioned in a
 * page's left or right columns.
 *
 * @package SGL
 * @author  Demian Turner <demian@phpkitchen.com>
 * @version $Revision: 1.7 $
 * @access  public
 */
class SGL_BlockLoader
{
    /**
     * Temporary container for processing blocks.
     *
     * @access  private
     * @var     array
     */
    var $_aData = array();

    /**
     * Array of processed blocks
     *
     * Left/right blocks stored as $this->aBlocks['left'],
     * $this->aBlocks['right'].
     *
     * @access  public
     * @var     array
     */
    var $aBlocks = array();

    /**
     * The role id, used so blocks can be cached per role.
     *
     * @access  private
     * @var     int
     */
    var $_rid = 0;

    /**
     * SectionId is currently roughtly equivalent to page id.
     *
     * @access  private
     * @var     int
     * @todo    change to pageId, also rename section table
     */
    var $_currentSectionId = 0;

    /**
     * Constructor - sets the sectionId.
     *
     * @access  public
     * @return  void
     */
    function SGL_BlockLoader($sectionId)
    {
        $this->_rid = (int)SGL_Session::get('rid');
        if (isset($sectionId)) {
            $this->_currentSectionId = $sectionId;
        }
    }

    /**
     * Initialises Block Mgr, loads blocks into temporary array
     * $_aData for later processing.
     *
     * @author  Andy Crain <apcrain@fuse.net>>
     * @access  private
     * @return  array   array of block objects
     */
    function render(&$output)
    {
        //  put data generated so far into class scope
        $this->output = &$output;
        $cache = & SGL_Cache::singleton();
        $currLang = (isset($output->currLang))
            ? $output->currLang
            : '';
        $charset = (isset($output->charset))
            ? $output->charset
            : '';
        $cacheId = $this->_currentSectionId . $this->_rid
            . $currLang . $charset;
        if ($data = $cache->get($cacheId, 'blocks')) {
            $this->aBlocks = unserialize($data);

            //  update uncached blocks
            $this->_loadBlocks(false);
            SGL::logMessage('blocks from cache', PEAR_LOG_DEBUG);
        } else {
            $this->_loadBlocks();
            $data = serialize($this->aBlocks);
            $cache->save($data, $cacheId, 'blocks');
            SGL::logMessage('blocks from db', PEAR_LOG_DEBUG);
        }
        return $this->aBlocks;
    }

    /**
     * Loads blocks from DB.
     *
     * @access  private
     * @return  void
     */
    function _loadBlocks($getAll = true)
    {
        $dbh = & SGL_DB::singleton();
        $addWhere = $getAll ? '' : "AND b.is_cached = 0 ";

        $b  = SGL_Config::get('table.block');
        $ba = SGL_Config::get('table.block_assignment');
        $br = SGL_Config::get('table.block_role');
        $query = "
            SELECT
                b.block_id, b.name, b.title, b.title_class,
                b.body_class, b.position, b.params, b.is_cached
            FROM    $b b, $ba ba, $br br
            WHERE   b.is_enabled = 1 " . $addWhere .
            "AND     (br.block_id = b.block_id AND
                      (br.role_id = '" . SGL_Session::getRoleId() . "' OR br.role_id = '" . SGL_ANY_ROLE . "')
                    )
            AND     b.block_id = ba.block_id
            AND     ( ba.section_id = ".SGL_ANY_SECTION." OR ba.section_id = " . $this->_currentSectionId . ' )
            ORDER BY b.blk_order
        ';
        $aResult = $dbh->getAll($query);

        if (!PEAR::isError($aResult)) {
            $this->_aData = $aResult;

            //  render content from each class
            $this->_buildBlocks();
        } else {
            SGL::raiseError('section ID not found', SGL_ERROR_NODATA);
        }
    }

    /**
     * With block structures in place, block contents are built.
     *
     * Each block is a class in the modules/block/classes/blocks directory,
     * containing static HTML or dynamic content
     *
     * @access  private
     * @return  void
     */
    function _buildBlocks()
    {
        //  render content
        if (count($this->_aData) > 0 ) {
            foreach ($this->_aData as $index => $oBlock) {
                $blockClass = $oBlock->name;
                preg_match('/^(.*)_.*_(.*)$/', $blockClass, $aMatches);
                @$blockPath = strtolower($aMatches[1]) . '/blocks/' . $aMatches[2];

                //  load CMS blocks if installed
                if (SGL::moduleIsEnabled('cms') && $blockPath == 'navigation/blocks/Navigation') {
                    $blockPath = 'cms/blocks/Navigation';
                    $blockClass = 'Cms_Block_Navigation';
                }
                if (file_exists( SGL_MOD_DIR . '/' . $blockPath . '.php')) {
                    require_once SGL_MOD_DIR . '/' . $blockPath . '.php';
                } else {
                    unset($this->_aData[$index]);
                    SGL::raiseError('cannot load ' . $blockClass . '; '
                        . $blockPath . '.php does not exist', SGL_ERROR_NOFILE);
                }
                if (!class_exists($blockClass)) {
                    unset($this->_aData[$index]);
                    SGL::raiseError($blockClass . ' is not a valid block classname',
                        SGL_ERROR_NOCLASS);
                } else {
                    if (is_scalar($aParams = @unserialize($oBlock->params))) {
                        $aParams = array();
                    }
                    @$obj = & new $blockClass();
                    if ($data = $obj->init($this->output, $oBlock->block_id, $aParams)) {
                        $this->_aData[$index]->content = $data;
                    } else {
                        //  remove the whole block if a false is captured
                        unset($this->_aData[$index]);
                    }
                }
            }
            $this->_sort();
        }
    }

    /**
     * Sorts tmp array $_aData into order within block positions.
     *
     * easier to manage in Controller
     *
     * @access  private
     * @return  void
     */
    function _sort()
    {
        if (count($this->_aData) > 0) {
            foreach ($this->_aData as $oBlock) {
                $this->aBlocks[$oBlock->position][$oBlock->block_id] = $oBlock;
            }
        }
        unset($this->_aData);
    }
}
?>