<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**
 * @package    tool
 * @subpackage xmldb
 * @copyright  2003 onwards Eloy Lafuente (stronk7) {@link http://stronk7.com}
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */

/**
 * This class will delete completely one field
 *
 * @package    tool
 * @subpackage xmldb
 * @copyright  2003 onwards Eloy Lafuente (stronk7) {@link http://stronk7.com}
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */
class delete_field extends XMLDBAction {

    /**
     * Init method, every subclass will have its own
     */
    function init() {
        parent::init();

        // Set own custom attributes

        // Get needed strings
        $this->loadStrings(array(
            'confirmdeletefield' => 'tool_xmldb',
            'yes' => '',
            'no' => ''
        ));
    }

    /**
     * Invoke method, every class will have its own
     * returns true/false on completion, setting both
     * errormsg and output as necessary
     */
    function invoke() {
        parent::invoke();

        $result = true;

        // Set own core attributes
        $this->does_generate = ACTION_GENERATE_HTML;

        // These are always here
        global $CFG, $XMLDB;

        // Do the job, setting result as needed

        // Get the dir containing the file
        $dirpath = required_param('dir', PARAM_PATH);
        $dirpath = $CFG->dirroot . $dirpath;
        $tableparam = required_param('table', PARAM_CLEAN);
        $fieldparam = required_param('field', PARAM_CLEAN);

        $confirmed = optional_param('confirmed', false, PARAM_BOOL);

        // If  not confirmed, show confirmation box
        if (!$confirmed) {
            $o = '<table width="60" class="generalbox" border="0" cellpadding="5" cellspacing="0" id="notice">';
            $o.= '  <tr><td class="generalboxcontent">';
            $o.= '    <p class="centerpara">' . $this->str['confirmdeletefield'] . '<br /><br />' . $fieldparam . '</p>';
            $o.= '    <table class="boxaligncenter" cellpadding="20"><tr><td>';
            $o.= '      <div class="singlebutton">';
            $o.= '        <form action="index.php?action=delete_field&amp;sesskey=' . sesskey() . '&amp;confirmed=yes&amp;postaction=edit_table&amp;field=' . $fieldparam . '&amp;table=' . $tableparam . '&amp;dir=' . urlencode(str_replace($CFG->dirroot, '', $dirpath)) . '" method="post"><fieldset class="invisiblefieldset">';
            $o.= '          <input type="submit" value="'. $this->str['yes'] .'" /></fieldset></form></div>';
            $o.= '      </td><td>';
            $o.= '      <div class="singlebutton">';
            $o.= '        <form action="index.php?action=edit_table&amp;table=' . $tableparam . '&amp;dir=' . urlencode(str_replace($CFG->dirroot, '', $dirpath)) . '" method="post"><fieldset class="invisiblefieldset">';
            $o.= '          <input type="submit" value="'. $this->str['no'] .'" /></fieldset></form></div>';
            $o.= '      </td></tr>';
            $o.= '    </table>';
            $o.= '  </td></tr>';
            $o.= '</table>';

            $this->output = $o;
        } else {
            // Get the edited dir
            if (!empty($XMLDB->editeddirs)) {
                if (isset($XMLDB->editeddirs[$dirpath])) {
                    $dbdir =& $XMLDB->dbdirs[$dirpath];
                    $editeddir =& $XMLDB->editeddirs[$dirpath];
                    if ($editeddir) {
                        $structure =& $editeddir->xml_file->getStructure();
                        // Move adjacent fields prev and next attributes
                        $tables =& $structure->getTables();
                        $table =& $structure->getTable($tableparam);
                        $fields =& $table->getFields();
                        $field =& $table->getField($fieldparam);
                        if ($field->getPrevious()) {
                            $prev =& $table->getField($field->getPrevious());
                            $prev->setNext($field->getNext());
                        }
                        if ($field->getNext()) {
                            $next =& $table->getField($field->getNext());
                            $next->setPrevious($field->getPrevious());
                        }
                        // Remove the field
                        $table->deleteField($fieldparam);

                        // Recalculate the hash
                        $structure->calculateHash(true);

                        // If the hash has changed from the original one, change the version
                        // and mark the structure as changed
                        $origstructure =& $dbdir->xml_file->getStructure();
                        if ($structure->getHash() != $origstructure->getHash()) {
                            $structure->setVersion(userdate(time(), '%Y%m%d', 99, false));
                            $structure->setChanged(true);
                        }
                    }
                }
            }
        }

        // Launch postaction if exists (leave this here!)
        if ($this->getPostAction() && $result) {
            return $this->launch($this->getPostAction());
        }

        // Return ok if arrived here
        return $result;
    }
}

