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

/**
 * Main xmldb action clasee
 *
 * Main xmldb action class. It implements all the basic
 * functionalities to be shared by each action.
 *
 * @package    tool_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 XMLDBAction {

    /** @var bool Type of value returned by the invoke method, ACTION_GENERATE_HTML have contents to show, set by each specialized invoke*/
    protected $does_generate;

    /** @var string Title of the Action (class name, by default), set by parent init automatically*/
    protected $title;

    /** @var string Strings used by the action set by each specialized init, calling loadStrings*/
    protected $str;

    /** @var string  Output of the action, set by each specialized invoke, get with getOutput*/
    protected $output;

    /** @var string Last Error produced. Check when any invoke returns false, get with getError*/
    protected $errormsg;

    /** @var string Action to execute at the end of the invoke script*/
    protected $postaction;

    /** @var bool Actions must be protected by sesskey mechanism*/
    protected $sesskey_protected;

    /**
     * Constructor
     */
    function __construct() {
        $this->init();
    }

    /**
     * Init method, every subclass will have its own,
     * always calling the parent one
     */
    function init() {
        $this->does_generate = ACTION_NONE;
        $this->title     = strtolower(get_class($this));
        $this->str       = array();
        $this->output    = NULL;
        $this->errormsg  = NULL;
        $this->subaction = NULL;
        $this->sesskey_protected = true;
    }

    /**
     * Returns the type of output of the file
     * @return bool
     */
    function getDoesGenerate() {
        return $this->does_generate;
    }

    /**
     * getError method, returns the last error string.
     * Used if the invoke() methods returns false
     * @return string
     */
    function getError() {
        return $this->errormsg;
    }

    /**
     * getOutput method, returns the output generated by the action.
     * Used after execution of the invoke() methods if they return true
     * @return string
     */
    function getOutput() {
        return $this->output;
    }

    /**
     * getPostAction method, returns the action to launch after executing
     * another one
     * @return string
     */
    function getPostAction() {
        return $this->postaction;
    }

    /**
     * getTitle method returns the title of the action (that is part
     * of the $str array attribute
     * @return string
     */
    function getTitle() {
        return $this->str['title'];
    }

    /**
     * loadStrings method, loads the required strings specified in the
     * array parameter
     * @param string[] $strings
     */
    function loadStrings($strings) {
        // Load some commonly used strings
        if (get_string_manager()->string_exists($this->title, 'tool_xmldb')) {
            $this->str['title'] = get_string($this->title, 'tool_xmldb');
        } else {
            $this->str['title'] = $this->title;
        }

        // Now process the $strings array loading it in the $str atribute
        if ($strings) {
            foreach ($strings as $key => $module) {
                $this->str[$key] = get_string($key, $module);
            }
        }
    }

    /**
     * main invoke method, it sets the postaction attribute
     * if possible and checks sesskey_protected if needed
     */
    function invoke() {

        global $SESSION;

        // Sesskey protection
        if ($this->sesskey_protected) {
            require_sesskey();
        }

        // If we are used any dir, save it in the lastused session object
        // Some actions can use it to perform positioning
        if ($lastused = optional_param ('dir', NULL, PARAM_PATH)) {
            $SESSION->lastused = $lastused;
        }

        $this->postaction = optional_param ('postaction', NULL, PARAM_ALPHAEXT);
        // Avoid being recursive
        if ($this->title == $this->postaction) {
            $this->postaction = NULL;
        }
    }

    /**
     * launch method, used to easily call invoke methods between actions
     * @param string $action
     * @return mixed
     */
    function launch($action) {

        global $CFG;

        // Get the action path and invoke it
        $actionsroot = "$CFG->dirroot/$CFG->admin/tool/xmldb/actions";
        $actionclass = $action . '.class.php';
        $actionpath = "$actionsroot/$action/$actionclass";

        // Load and invoke the proper action
        $result = false;
        if (file_exists($actionpath) && is_readable($actionpath)) {
            require_once($actionpath);
            if ($xmldb_action = new $action) {
                $result = $xmldb_action->invoke();
                if ($result) {
                    if ($xmldb_action->does_generate != ACTION_NONE &&
                        $xmldb_action->getOutput()) {
                        $this->does_generate = $xmldb_action->does_generate;
                        $this->title = $xmldb_action->title;
                        $this->str = $xmldb_action->str;
                        $this->output .= $xmldb_action->getOutput();
                    }
                } else {
                    $this->errormsg = $xmldb_action->getError();
                }
            } else {
                $this->errormsg = "Error: cannot instantiate class (actions/$action/$actionclass)";
            }
        } else {
            $this->errormsg = "Error: wrong action specified ($action)";
        }
        return $result;
    }

    /**
     * This function will generate the PHP code needed to
     * implement the upgrade_xxxx_savepoint() php calls in
     * upgrade code generated from the editor. It's used by
     * the view_structure_php and view_table_php actions
     *
     * @param xmldb_structure structure object containing all the info
     * @return string PHP code to be used to mark a reached savepoint
     */
    function upgrade_savepoint_php($structure) {
        global $CFG;

        // NOTE: $CFG->admin !== 'admin' is not supported in XMLDB editor, sorry.

        $path = $structure->getPath();
        $plugintype = 'error';

        if ($path === 'lib/db') {
            $plugintype = 'lib';
            $pluginname = null;

        } else {
            $path = dirname($path);
            $pluginname = basename($path);
            $path = dirname($path);
            $plugintypes = core_component::get_plugin_types();
            foreach ($plugintypes as $type => $fulldir) {
                if ($CFG->dirroot.'/'.$path === $fulldir) {
                    $plugintype = $type;
                    break;
                }
            }
        }

        $result = '';

        switch ($plugintype ) {
            case 'lib': // has own savepoint function
                $result = XMLDB_LINEFEED .
                          '        // Main savepoint reached.' . XMLDB_LINEFEED .
                          '        upgrade_main_savepoint(true, XXXXXXXXXX);' . XMLDB_LINEFEED;
                break;
            case 'mod': // has own savepoint function
                $result = XMLDB_LINEFEED .
                          '        // ' . ucfirst($pluginname) . ' savepoint reached.' . XMLDB_LINEFEED .
                          '        upgrade_mod_savepoint(true, XXXXXXXXXX, ' . "'$pluginname'" . ');' . XMLDB_LINEFEED;
                break;
            case 'block': // has own savepoint function
                $result = XMLDB_LINEFEED .
                          '        // ' . ucfirst($pluginname) . ' savepoint reached.' . XMLDB_LINEFEED .
                          '        upgrade_block_savepoint(true, XXXXXXXXXX, ' . "'$pluginname'" . ');' . XMLDB_LINEFEED;
                break;
            default: // rest of plugins
                $result = XMLDB_LINEFEED .
                          '        // ' . ucfirst($pluginname) . ' savepoint reached.' . XMLDB_LINEFEED .
                          '        upgrade_plugin_savepoint(true, XXXXXXXXXX, ' . "'$plugintype'" . ', ' . "'$pluginname'" . ');' . XMLDB_LINEFEED;
        }
        return $result;
    }
}