converter.php

См. документацию.

<?
 
 
if($updater->CanUpdateDatabase())
{
    class CLearnInstall201203ConvertDBTimeOut extends Exception
    {
    }
 
 
    class CLearnInstall201203ConvertDBException extends Exception
    {
    }
 
 
    class CLearnInstall201203ConvertDB
    {
        const MODULE_ID = 'learning';
        const OPTION_ID = '~LearnInstall201203ConvertDB::_IsAlreadyConverted';     // don't change this constant, NEVER!
        const STATUS_INSTALL_COMPLETE    = '1';
        const STATUS_INSTALL_NEVER_START = '2';
        const STATUS_INSTALL_INCOMPLETE  = '3';
 
        const JOURNAL_STATUS_UNPROCESSED          = -1;
        const JOURNAL_STATUS_COURSE_LINKED        = 1;
        const JOURNAL_STATUS_CHAPTER_COPIED       = 2;
        const JOURNAL_STATUS_LESSON_EDGES_CREATED = 3;
 
 
        public static function run()
        {
            global $DB;
            $msg = $step = false;
            $errorMessage = '';
 
            // If data tables are not installed - nothing to do
            if ( ! $DB->TableExists('b_learn_lesson') )
                return ($errorMessage);
 
            try
            {
                if ( ! self::IsNewRightsModelInitialized($step, $msg) )
                {
                    self::InitializeNewRightsModel();
                    $step = false;
                    if ( ! self::IsNewRightsModelInitialized($step, $msg) )
                    {
                        $errorMessage .= 'FAILED on step ' . $step . '; msg = ' . $msg . '.';
                        return ($errorMessage);            // FATAL
                    }
                }
 
                self::StartTransaction();
                self::ReCreateTriggersForMSSQL();
                self::Commit();
 
                self::StartTransaction();
                self::ConvertDB($errorMessage);
                self::Commit();
            }
            catch (CLearnInstall201203ConvertDBException $e)
            {
                self::Rollback();
                $errorMessage .= "Cautch exception at line: " . $e->getLine()
                    . "; with message: " . $e->getMessage();
            }
            catch (CLearnInstall201203ConvertDBTimeOut $e)
            {
                self::Commit();
                /*
                $errorMessage .= "Timeout occured at line: " . $e->getLine() 
                    . ". Convertation is incomplete and should be executed another time.";
                */
                $errorMessage .= '';
            }
            catch (Exception $e)
            {
                self::Rollback();
                $errorMessage .= "Cautch general exception at line: " . $e->getLine() 
                    . "; with message: " . $e->getMessage();
            }
 
            return ($errorMessage);
        }
 
 
        protected static function StartTransaction()
        {
            global $DB;
 
            $DB->StartTransaction();
        }
 
 
        protected static function Rollback()
        {
            global $DB;
 
            $DB->Rollback();
        }
 
 
        protected static function Commit()
        {
            global $DB;
 
            $DB->Commit();
        }
 
 
        protected static function ReCreateTriggersForMSSQL()
        {
        }
 
 
        protected static function _RightsModelGetTasksWithOperations()
        {
            $arTasksOperations = array(
                'learning_lesson_access_denied'            => array(),
                'learning_lesson_access_read'              => array(
                    'lesson_read'
                    ),
                'learning_lesson_access_manage_basic'      => array(
                    'lesson_read', 
                    'lesson_create',
                    'lesson_write', 
                    'lesson_remove'
                    ),
                'learning_lesson_access_linkage_as_child'  => array(
                    'lesson_read', 
                    'lesson_link_to_parents', 
                    'lesson_unlink_from_parents'
                    ),
                'learning_lesson_access_linkage_as_parent' => array(
                    'lesson_read', 
                    'lesson_link_descendants',
                    'lesson_unlink_descendants'
                    ),
                'learning_lesson_access_linkage_any'       => array(
                    'lesson_read', 
                    'lesson_link_to_parents', 
                    'lesson_unlink_from_parents',
                    'lesson_link_descendants',
                    'lesson_unlink_descendants'
                    ),
                'learning_lesson_access_manage_as_child'   => array(
                    'lesson_read', 
                    'lesson_create',
                    'lesson_write', 
                    'lesson_remove',
                    'lesson_link_to_parents', 
                    'lesson_unlink_from_parents'
                    ),
                'learning_lesson_access_manage_as_parent'  => array(
                    'lesson_read', 
                    'lesson_create',
                    'lesson_write', 
                    'lesson_remove',
                    'lesson_link_descendants',
                    'lesson_unlink_descendants'
                    ),
                'learning_lesson_access_manage_dual'       => array(
                    'lesson_read', 
                    'lesson_create',
                    'lesson_write', 
                    'lesson_remove',
                    'lesson_link_to_parents', 
                    'lesson_unlink_from_parents',
                    'lesson_link_descendants',
                    'lesson_unlink_descendants'
                    ),
                'learning_lesson_access_manage_full'       => array(
                    'lesson_read', 
                    'lesson_create',
                    'lesson_write', 
                    'lesson_remove',
                    'lesson_link_to_parents', 
                    'lesson_unlink_from_parents',
                    'lesson_link_descendants',
                    'lesson_unlink_descendants',
                    'lesson_manage_rights'
                    )           
                );
 
            return ($arTasksOperations);
        }
 
 
        protected static function _RightsModelGetAllOperations()
        {
            $arAllOperations = array(
                'lesson_read',
                'lesson_create',
                'lesson_write',
                'lesson_remove',
                'lesson_link_to_parents',
                'lesson_unlink_from_parents',
                'lesson_link_descendants',
                'lesson_unlink_descendants',
                'lesson_manage_rights'
                );
 
            return ($arAllOperations);
        }
 

        protected static function _CheckOperationsInDB()
        {
            global $DB;
 
            $arAllOperations = self::_RightsModelGetAllOperations();
 
            $rc = $DB->Query ("SELECT ID, NAME, BINDING FROM b_operation WHERE MODULE_ID = 'learning'", true);
 
            if ($rc === false)
                throw new CLearnInstall201203ConvertDBException('EA_SQLERROR');
 
            $arOperationsInDB = array();
            while ($arOperation = $rc->Fetch())
            {
                if (mb_substr($arOperation['NAME'], 0, 7) === 'lesson_')
                    $binding = 'lesson';
                else
                    $binding = 'module';
 
                if ($arOperation['BINDING'] !== $binding)
                    throw new Exception();
 
                $arOperationsInDB[$arOperation['NAME']] = $arOperation['ID'];
            }
 
            if (count($arOperationsInDB) !== count($arAllOperations))
                throw new Exception();  // not all operations in DB
 
            foreach ($arAllOperations as $operationName)
            {
                if ( ! isset($arOperationsInDB[$operationName]) )
                    throw new Exception();  // not all operations in DB
            }
 
            return ($arOperationsInDB);
        }
 
 
        protected static function _CheckTasksInDB($arTasksOperations)
        {
            global $DB;
 
            $rc = $DB->Query ("SELECT ID, NAME, BINDING FROM b_task WHERE MODULE_ID = 'learning'", true);
 
            if ($rc === false)
                throw new CLearnInstall201203ConvertDBException('EA_SQLERROR');
 
            $arTasksInDB = array();
            while ($arTask = $rc->Fetch())
            {
                if (mb_substr($arTask['NAME'], 0, 16) === 'learning_lesson_')
                    $binding = 'lesson';
                else
                    $binding = 'module';
 
                if ($arTask['BINDING'] !== $binding)
                    throw new Exception();
 
                $arTasksInDB[$arTask['NAME']] = $arTask['ID'];
            }
 
            if (count($arTasksInDB) !== count($arTasksOperations))
            {
                throw new Exception('count($arTasksInDB) = ' 
                    . count($arTasksInDB) 
                    . '; count($arTasksOperations) = ' 
                    . count($arTasksOperations));  // not all tasks in DB
            }
 
            foreach (array_keys($arTasksOperations) as $taskName)
            {
                if ( ! isset($arTasksInDB[$taskName]) )
                    throw new Exception();  // not all tasks in DB
            }
 
            return ($arTasksInDB);
        }
 
 
        protected static function _CheckTasksOperationsRelations($arOperationsInDB, $arTasksInDB, $arTasksOperations)
        {
            global $DB;
 
            foreach ($arTasksInDB as $taskName => $taskId)
            {
                if ( ! isset($arTasksOperations[$taskName]) )
                    throw new Exception();
 
                $arCurTaskOperations = $arTasksOperations[$taskName];
                $arCurTaskOperationsIDs = array();
                foreach ($arCurTaskOperations as $operationName)
                {
                    if ( ! isset($arOperationsInDB[$operationName]) )
                        throw new Exception();
 
                    $operationId = $arOperationsInDB[$operationName];
 
                    $arCurTaskOperationsIDs[$operationId] = 'operation';
                }
 
                // Get list of task's operations reltaions
                $rc = $DB->Query ("SELECT OPERATION_ID FROM b_task_operation WHERE TASK_ID = " . ($taskId + 0), true);
 
                if ($rc === false)
                    throw new CLearnInstall201203ConvertDBException('EA_SQLERROR');
 
 
 
                while ($arRelation = $rc->Fetch())
                {
                    if ( ! isset($arCurTaskOperationsIDs[$arRelation['OPERATION_ID']]) )
                        throw new Exception();
 
                    unset ($arCurTaskOperationsIDs[$arRelation['OPERATION_ID']]);
                }
 
                if (count($arCurTaskOperationsIDs) > 0)
                    throw new Exception();
            }
        }
 
 
        protected static function IsNewRightsModelInitialized(&$step, &$msg)
        {
            try
            {
                $arTasksOperations = self::_RightsModelGetTasksWithOperations();
                // Compare list of operations in DB
                $arOperationsInDB = self::_CheckOperationsInDB();
 
                // Compare list of tasks in DB
                $arTasksInDB = self::_CheckTasksInDB($arTasksOperations);
 
                // Compare relations between tasks and operations
                self::_CheckTasksOperationsRelations($arOperationsInDB, $arTasksInDB, $arTasksOperations);
 
                return (true);  // new rights model correctly initialized
            }
            catch (Exception $e)
            {
                $step = $e->getLine();
                $msg = $e->getMessage();
                return (false); // new rights model not initialized
            }
        }
 
 
        protected static function _RightsModelCreateOperations()
        {
            global $DB;
 
            $arAllOperations = self::_RightsModelGetAllOperations();
 
            $arOperationsInDB = array();
 
            foreach ($arAllOperations as $operationName)
            {
                if (mb_substr($operationName, 0, 7) === 'lesson_')
                    $binding = 'lesson';
                else
                    $binding = 'module';
 
                $arFields = array(
                    'NAME'        => "'" . $DB->ForSql($operationName) . "'",
                    'MODULE_ID'   => "'learning'",
                    'DESCRIPTION' => 'NULL',
                    'BINDING'     => "'" . $binding . "'"
                    );
 
                $id = $DB->Insert(
                        'b_operation',
                        $arFields,
                        "",     // $error_position
                        false,  // $debug
                        "",     // $exist_id
                        false   // don't ignore errors, due to the bug in Database::Insert (it don't checks Query return status)
                    );
 
                if ($id === false)
                    throw new Exception();
 
                $arOperationsInDB[$operationName] = $id;
            }
 
            return ($arOperationsInDB);
        }
 
 
        protected static function _RightsModelCreateTasksAndRelation($arOperationsInDB)
        {
            global $DB, $APPLICATION;
 
            $arOld2NewRightsMatrix = array(
                'D' => 'learning_lesson_access_read',
                'W' => 'learning_lesson_access_manage_full'
                );
 
            $module_id = 'learning';
 
            $arDefaultRights = array (
                'learning_lesson_access_read'        => array(),
                'learning_lesson_access_manage_dual' => array('CR'),   // Author
                'learning_lesson_access_manage_full' => array('G1')        // Admins
                );
 
            $rc = CGroup::GetList('sort', 'asc', array('ACTIVE' => 'Y'));
            while($zr = $rc->Fetch())
            {
                $group_id = $zr['ID'];
                $oldSymbol = $APPLICATION->GetGroupRight(
                    $module_id, 
                    array($group_id), 
                    $use_default_level = "N", 
                    $max_right_for_super_admin = "N", 
                    $site_id = false);
 
                if (isset($arOld2NewRightsMatrix[$oldSymbol]))
                {
                    $newSymbol = $arOld2NewRightsMatrix[$oldSymbol];
                    if (isset($arDefaultRights[$newSymbol]))
                        $arDefaultRights[$newSymbol][] = 'G' . $group_id;
                }
            }
 
            $arTasksOperations = self::_RightsModelGetTasksWithOperations();
 
            foreach ($arTasksOperations as $taskName => $arOperationsForTask)
            {
                if (mb_substr($taskName, 0, 16) === 'learning_lesson_')
                    $binding = 'lesson';
                else
                    $binding = 'module';
 
                $arFields = array(
                    'NAME'        => "'" . $DB->ForSql($taskName) . "'",
                    'LETTER'      => 'NULL',
                    'MODULE_ID'   => "'learning'",
                    'SYS'         => "'Y'",
                    'DESCRIPTION' => 'NULL',
                    'BINDING'     => "'" . $binding . "'"
                    );
 
                $taskId = $DB->Insert(
                    'b_task',
                    $arFields,
                    "",     // $error_position
                    false,  // $debug
                    "",     // $exist_id
                    false   // don't ignore errors, due to the bug in Database::Insert (it don't checks Query return status)
                    );
 
                if ($taskId === false)
                    throw new Exception();
 
                // Create relation for every operation per task
                foreach ($arOperationsForTask as $operationName)
                {
                    if ( ! isset($arOperationsInDB[$operationName]) )
                        throw new Exception();
 
                    $operationId = (int) $arOperationsInDB[$operationName];
 
                    $rc = $DB->Query(
                        "INSERT INTO b_task_operation (TASK_ID, OPERATION_ID) 
                        VALUES (" . (int) $taskId . ", " . (int) $operationId . ")", true);
 
                    if ($rc === false)
                        throw new Exception();
                }
 
                // Add default rights for this task, if it exists
                if ( array_key_exists($taskName, $arDefaultRights) )
                {
                    $arDefaultRights[$taskName] = array_unique($arDefaultRights[$taskName]);
                    foreach ($arDefaultRights[$taskName] as $subject_id)
                    {
                        $rc = $DB->Query (
                            "INSERT INTO b_learn_rights_all (SUBJECT_ID, TASK_ID) 
                            VALUES ('" . $DB->ForSQL($subject_id) . "', " . (int) $taskId . ")",
                            true);
 
                        if ($rc === false)
                            throw new Exception();
                    }
                }
            }
        }
 
 
        protected static function _RightsModelPurge()
        {
            global $DB;
 
            $arQueries = array(
                "DELETE FROM b_task_operation 
                WHERE TASK_ID IN (SELECT ID FROM b_task WHERE MODULE_ID = 'learning')
                    OR OPERATION_ID IN (SELECT ID FROM b_operation WHERE MODULE_ID = 'learning')",
 
                "DELETE FROM b_operation
                WHERE MODULE_ID = 'learning'",
 
                "DELETE FROM b_task
                WHERE MODULE_ID = 'learning'"
                );
 
            foreach ($arQueries as $key => $query)
            {
                $rc = $DB->Query($query, true);        // ignore_errors = true
                if ($rc === false)
                    throw new Exception ('EA_SQLERROR in query #' . $key);
            }
        }
 
 
        protected static function InitializeNewRightsModel()
        {
            global $DB;
 
            // Clean up learning module operations and tasks (if exists)
            self::_RightsModelPurge();
 
            if ( ! $DB->TableExists('b_learn_rights_all') )
                self::_CreateTblRightsAll();
 
            $arOperationsInDB = self::_RightsModelCreateOperations();
 
            self::_RightsModelCreateTasksAndRelation($arOperationsInDB);
        }
 
 
        protected static function _CreateTblRightsAll ()
        {
            global $DB;
 
            if ( ! $DB->TableExists('b_learn_rights_all') )
            {
                // Prepare sql code for adding fields
                $sql_tbl_b_learn_rights_all = "
                    CREATE TABLE b_learn_rights_all (
                    SUBJECT_ID VARCHAR( 100 ) NOT NULL ,
                    TASK_ID INT NOT NULL ,
                    PRIMARY KEY ( SUBJECT_ID )
                    )";
 
                $rc = $DB->Query($sql_tbl_b_learn_rights_all);
                if ($rc === false)
                    throw new CLearnInstall201203ConvertDBException(__LINE__ . '/tbl: sql_tbl_b_learn_rights_all');
            }
        }
 

        public static function ConvertDB(&$errorMessage)
        {
            global $DB;
 
            // Check, was DB already converted?
            if (self::_IsAlreadyConverted() === true)
                return (true);
 
            // Mark that db convert process started
            $rc = COption::SetOptionString(self::MODULE_ID, self::OPTION_ID, self::STATUS_INSTALL_INCOMPLETE);
            if ($rc === false)
                throw new CLearnInstall201203ConvertDBException('SetOptionString() failed!');
 
            // Create fields `CODE`, `WAS_CHAPTER_ID` in `b_learn_lesson` (if they doesn't exists yet) 
            // and `JOURNAL_STATUS` in `b_learn_chapter`
            // and `LINKED_LESSON_ID` in `b_learn_course`
            self::_CreateFieldsInTbls();

 
            $items_processed = 0;
 
            // Process courses
            $items_processed += self::_processCourses();
 
            // Process chapters
            $items_processed += self::_processChapters();
 
            // Creates table for edges, if it doesn't exists yet.
            self::_CreateEdgesTbl();
 
            // Build edges for lessons and chapters (`WAS_COURSE_ID` === NULL)
            $items_processed += self::_buildEdges($errorMessage);
 
            // Convert old permissions to new
            self::ConvertPermissions();
 
            // Add new path: COURSE_ID=#COURSE_ID#
            // ?LESSON_PATH=#LESSON_PATH#
            self::AddPath();
 
            // Remove b_learn_course_permission, if exists
            self::_RemoveOrphanedTables();
 
            // Mark that db convert process complete
            $rc = COption::SetOptionString(self::MODULE_ID, self::OPTION_ID, self::STATUS_INSTALL_COMPLETE);
            if ($rc === false)
                throw new CLearnInstall201203ConvertDBException('SetOptionString() failed!');
        }
 
 
        protected static function ConvertPermissions()
        {
            global $DB;
 
            $arTaskIdByOldSymbol = array();
            $arTasks = array(
                'R' => 'learning_lesson_access_read', 
                'W' => 'learning_lesson_access_manage_basic', 
                'X' => 'learning_lesson_access_manage_full');
 
            foreach ($arTasks as $oldSymbol => $taskName)
            {
                $rc = $DB->Query (
                    "SELECT ID 
                    FROM b_task 
                    WHERE NAME = '" . $taskName . "'",
                    true);
 
                if ($rc === false)
                    throw new CLearnInstall201203ConvertDBException('EA_SQLERROR');
 
                $row = $rc->Fetch();
 
                if ( ! isset($row['ID']) )
                    throw new CLearnInstall201203ConvertDBException('EA_LOGIC');
 
                $arTaskIdByOldSymbol[$oldSymbol] = (int) $row['ID'];
            }
 
 
 
            $sql = 
            "SELECT TLL.ID, TLCP.PERMISSION, TLCP.USER_GROUP_ID 
            FROM b_learn_lesson TLL
            INNER JOIN b_learn_course_permission TLCP
                ON TLL.COURSE_ID = TLCP.COURSE_ID
            WHERE TLL.COURSE_ID > 0
            AND TLCP.PERMISSION != 'D'
 
            UNION 
 
            SELECT TLL.ID, TLCP.PERMISSION, TLCP.USER_GROUP_ID
            FROM b_learn_lesson TLL
            INNER JOIN b_learn_course_permission TLCP
                ON TLL.WAS_COURSE_ID = TLCP.COURSE_ID
            WHERE TLL.COURSE_ID = 0
            AND TLL.WAS_COURSE_ID > 0
            AND TLCP.PERMISSION != 'D'
            ";
 
            $res = $DB->Query($sql, true);
 
            if ($res === false)
                throw new CLearnInstall201203ConvertDBException('EA_SQLERROR');
 
            while ($row = $res->Fetch())
            {
                $lessonId      = $row['ID'];
                $permission    = $row['PERMISSION'];
                $user_group_id = $row['USER_GROUP_ID'];
 
                $group = 'G' . $user_group_id;
 
                // Determine task id
                if ( ! in_array($permission, array('R', 'W', 'X'), true) )
                    continue;       // skip elements with D
 
                $task_id = $arTaskIdByOldSymbol[$permission];
 
                $rc = $DB->Query (
                    "DELETE FROM b_learn_rights 
                    WHERE LESSON_ID = " . (int) $lessonId . "
                        AND SUBJECT_ID = '" . $DB->ForSql($group) . "'",
                    true);
                if ($rc === false)
                    throw new CLearnInstall201203ConvertDBException('EA_SQLERROR');
                    
 
                $rc = $DB->Query (
                    "INSERT INTO b_learn_rights (LESSON_ID, SUBJECT_ID, TASK_ID) 
                    VALUES (" . (int) $lessonId . ", '" . $DB->ForSql($group) . "', '" . $task_id . "')", true);
 
                if ($rc === false)
                    throw new CLearnInstall201203ConvertDBException('EA_SQLERROR');
            }
 
        }
 
 
        protected static function AddPath()
        {
            global $DB;
 
            $res = $DB->Query(
                "SELECT DISTINCT SITE_ID 
                FROM b_learn_site_path 
                WHERE 1=1", true);
 
            if ($res === false)
                throw new CLearnInstall201203ConvertDBException('EA_SQLERROR');
 
            $arSitesIds = array();
            while ($row = $res->Fetch())
                $arSitesIds[] = $row['SITE_ID'];
 
            foreach ($arSitesIds as $k => $siteId)
            {
                $res = $DB->Query (
                    "DELETE FROM b_learn_site_path 
                    WHERE SITE_ID = '" . $DB->ForSql($siteId) . "' 
                        AND TYPE = 'U'", true);
 
                if ($res === false)
                    throw new CLearnInstall201203ConvertDBException('EA_SQLERROR');
 
                $res = $DB->Query (
                    "SELECT TSP.PATH
                    FROM b_learn_site_path TSP
                    WHERE TYPE = 'C' AND SITE_ID = '" . $DB->ForSql($siteId) . "'", 
                    true);
                
                if ($res === false)
                    throw new CLearnInstall201203ConvertDBException('EA_SQLERROR');
 
                $row = $res->Fetch();
                if (isset($row['PATH']))
                {
                    $path = str_replace('COURSE_ID=#COURSE_ID#', 'LESSON_PATH=#LESSON_PATH#', $row['PATH']);
                    $path = str_replace('&INDEX=Y', '', $path);
                }
                else
                    $path = '/services/learning/course.php?LESSON_PATH=#LESSON_PATH#';
 
                $DB->Insert(
                    'b_learn_site_path',
                    array(
                        'SITE_ID' => "'" . $DB->ForSql($siteId) . "'",
                        'PATH'    => "'" . $DB->ForSql($path) . "'",
                        'TYPE'    => "'U'"
                        )
                    );
            }
        }

        public static function _buildEdges(&$errorMessage)
        {
            global $DB;
 
            $items_processed = 0;
 
            // For lessons, on which b_learn_course.LINKED_LESSON_ID linked we don't need edges, because they are tops nodes now.
            $res = $DB->Query (
                "SELECT ID, COURSE_ID, CHAPTER_ID, ACTIVE, SORT, WAS_CHAPTER_ID, 
                    WAS_PARENT_CHAPTER_ID, WAS_PARENT_COURSE_ID
                FROM b_learn_lesson 
                WHERE JOURNAL_STATUS != " . self::JOURNAL_STATUS_LESSON_EDGES_CREATED . "
                    AND WAS_COURSE_ID IS NULL", 
                $ignore_errors = true);
            
            if ($res === false)
                throw new CLearnInstall201203ConvertDBException('EA_SQLERROR');
 
            while ($arLesson = $res->Fetch())
            {
                $sort = $arLesson['SORT'];
 
                $childNodeId = $arLesson['ID'];
 
                // Determine, who is immediate parent of lesson - chapter or course
                if ($arLesson['WAS_CHAPTER_ID'] === NULL)   // current node wasn't a chapter
                {
                    if ($arLesson['CHAPTER_ID'] !== NULL)
                    {
                        // intermediate parent is chapter, get it id in new data model
                        $parentNodeId = self::_GetChapterIdInNewDataModel ($arLesson['CHAPTER_ID']);
                    }
                    elseif ($arLesson['COURSE_ID'] !== NULL)
                    {
                        // intermediate parent is course, get it id in new data model
                        $parentNodeId = self::_GetCourseIdInNewDataModel ($arLesson['COURSE_ID']);
                    }
                    else
                    {
                        // No parent? It's very strange for old data model, but it's OK for new data model.
                        // So, nothing to do here.
                        $parentNodeId = NULL;
                    }
                }
                else    // current node was a chapter
                {
                    if ($arLesson['WAS_PARENT_CHAPTER_ID'] !== NULL)
                    {
                        // intermediate parent is chapter, get it id in new data model
                        $parentNodeId = self::_GetChapterIdInNewDataModel ($arLesson['WAS_PARENT_CHAPTER_ID']);
                    }
                    elseif ($arLesson['WAS_PARENT_COURSE_ID'] !== NULL)
                    {
                        // intermediate parent is course, get it id in new data model
                        $parentNodeId = self::_GetCourseIdInNewDataModel ($arLesson['WAS_PARENT_COURSE_ID']);
                    }
                    else
                    {
                        // No parent? It's very strange for old data model, but it's OK for new data model.
                        // So, nothing to do here.
                        $parentNodeId = NULL;
                    }
                }           
 
                if ($parentNodeId === NULL)
                    ; //    nothing to do
                elseif ($parentNodeId === -1)
                {
                    $errorMessage .= "Problem occured with CHAPTER_ID = " . $arLesson['CHAPTER_ID'] 
                    . "; COURSE_ID = " . $arLesson['COURSE_ID'] . "<br>\n";
                }
                elseif ($parentNodeId <= 0)
                {
                    // This is invalid value
                    throw new CLearnInstall201203ConvertDBException('EA_OTHER: invalid parentNodeId for lesson_id = ' . $arLesson['ID']);
                }
                else
                {
                    // All is OK, so create edge for nodes
                    self::_CreateEdgeForNodes ($parentNodeId, $childNodeId, $sort);
                }
 
                // Mark lesson as processed
                self::_MarkLessonAsProcessed ($arLesson['ID']);
 
                ++$items_processed;
 
                // This function throws exception CLearnInstall201203ConvertDBTimeOut, if it's low time left.
                self::avoidTimeout();
            }
 
            return ($items_processed);
        }
 
        public static function _MarkLessonAsProcessed ($lessonId)
        {
            global $DB;
 
            // Mark this course as processed
            $rc = $DB->Update('b_learn_lesson', 
                array ('JOURNAL_STATUS' => self::JOURNAL_STATUS_LESSON_EDGES_CREATED), 
                "WHERE ID = '" . ($lessonId + 0) . "'",
                    $error_position = "",
                    $debug = false,
                    $ignore_errors = true
                );
 
            if ($rc === false)
                throw new CLearnInstall201203ConvertDBException('EA_SQLERROR');
 
        }
 
        public static function _CreateEdgeForNodes ($parentNodeId, $childNodeId, $sort)
        {
            global $DB;
 
            $parentNodeId += 0;
            $childNodeId  += 0;
 
            // Firstly, remove such edge, if exists
            $rc = $DB->Query (
                "DELETE FROM b_learn_lesson_edges 
                WHERE SOURCE_NODE = '" . $parentNodeId . "'
                   AND TARGET_NODE = '" . $childNodeId . "'", 
                $ignore_errors = true);
 
            if ($rc === false)
                throw new CLearnInstall201203ConvertDBException('EA_SQLERROR');
 
            // Now, create edge
            $rc = $DB->Query (
                "INSERT INTO b_learn_lesson_edges (SOURCE_NODE, TARGET_NODE, SORT)
                VALUES ('" . $parentNodeId . "', '" . $childNodeId . "', '" . $sort . "')", 
                $ignore_errors = true);
 
            if ($rc === false)
                throw new CLearnInstall201203ConvertDBException('EA_SQLERROR');
        }

        public static function _GetChapterIdInNewDataModel ($b_learn_chapter_ID)
        {
            global $DB;
 
            $res = $DB->Query (
                "SELECT ID FROM b_learn_lesson 
                WHERE WAS_CHAPTER_ID = '" . ($b_learn_chapter_ID + 0) . "'", 
                $ignore_errors = true);
            
            if ($res === false)
                throw new CLearnInstall201203ConvertDBException('EA_SQLERROR');
 
            if ($arLesson = $res->Fetch())
                return ($arLesson['ID'] + 0);
            else
                return (-1);
        }

        public static function _GetCourseIdInNewDataModel ($b_learn_course_ID)
        {
            global $DB;
 
            $res = $DB->Query (
                "SELECT ID FROM b_learn_lesson 
                WHERE WAS_COURSE_ID = '" . ($b_learn_course_ID + 0) . "'", 
                $ignore_errors = true);
            
            if ($res === false)
                throw new CLearnInstall201203ConvertDBException('EA_SQLERROR');
 
            if ($arLesson = $res->Fetch())
                return ($arLesson['ID'] + 0);
            else
                return (-1);
        }

        public static function _processCourses()
        {
            global $DB;
 
            $items_processed = 0;
 
            $res = $DB->Query ("SELECT * FROM b_learn_course WHERE JOURNAL_STATUS != " . self::JOURNAL_STATUS_COURSE_LINKED, 
                $ignore_errors = true);
            
            if ($res === false)
                throw new CLearnInstall201203ConvertDBException('EA_SQLERROR');
 
            while ($arCourses = $res->Fetch())
            {
                $arFields = array(
                    'ACTIVE'                => $arCourses['ACTIVE'],
                    'NAME'                  => ($arCourses['NAME'] === NULL) ? false : $arCourses['NAME'],
                    'CODE'                  => ($arCourses['CODE'] === NULL) ? false : $arCourses['CODE'],
                    'SORT'                  => $arCourses['SORT'],
                    'PREVIEW_PICTURE'       => ($arCourses['PREVIEW_PICTURE'] === NULL) ? false : $arCourses['PREVIEW_PICTURE'],
                    'DETAIL_PICTURE'        => ($arCourses['PREVIEW_PICTURE'] === NULL) ? false : $arCourses['PREVIEW_PICTURE'],
                    'PREVIEW_TEXT_TYPE'     => $arCourses['PREVIEW_TEXT_TYPE'],
                    'DETAIL_TEXT_TYPE'      => $arCourses['DESCRIPTION_TYPE'],
                    'LAUNCH'                => '',
                    'JOURNAL_STATUS'        => self::JOURNAL_STATUS_UNPROCESSED,
                    'WAS_CHAPTER_ID'        => false,
                    'WAS_PARENT_CHAPTER_ID' => false,
                    'WAS_PARENT_COURSE_ID'  => false,
                    'WAS_COURSE_ID'         => $arCourses['ID'],
                    'PREVIEW_TEXT'          => $arCourses['PREVIEW_TEXT'],
                    'DETAIL_TEXT'           => $arCourses['DESCRIPTION']
                    );
 
                // Creates new lesson (unprocessed duplicates will be removed first)
                $id_of_new_lesson = self::_UnrepeatableCreateLesson ($arFields);
 
                // Link course to this lesson
                $rc = $DB->Update ('b_learn_course', 
                    array ('LINKED_LESSON_ID' => $id_of_new_lesson), 
                    "WHERE ID = '" . ($arCourses['ID'] + 0) . "'",
                    $error_position = "",
                    $debug = false,
                    $ignore_errors = true
                );
 
                if ($rc === false)
                    throw new CLearnInstall201203ConvertDBException('EA_SQLERROR');
 
                // Mark this course as processed
                $rc = $DB->Update('b_learn_course', 
                    array ('JOURNAL_STATUS' => self::JOURNAL_STATUS_COURSE_LINKED), 
                    "WHERE ID = '" . ($arCourses['ID'] + 0) . "'",
                    $error_position = "",
                    $debug = false,
                    $ignore_errors = true
                );
 
                if ($rc === false)
                    throw new CLearnInstall201203ConvertDBException('EA_SQLERROR');
 
                ++$items_processed;
 
                // This function throws exception CLearnInstall201203ConvertDBTimeOut, if it's low time left.
                self::avoidTimeout();
            }
 
            return ($items_processed);
        }

        public static function avoidTimeout()
        {
            static $started_at = false;
            static $time_limit = false;
 
            if ($started_at === false)
            {
                $started_at = microtime (true);
 
                $rc = ini_get('max_execution_time');
                if (($rc === false) || ($rc === '') || ($rc < 0))
                {
                    // We fail to determine max_execution_time, try to set it
                    set_time_limit (28);
 
                    // Ensure, that max_execution_time was set
                    $rc = ini_get('max_execution_time');
                }
 
                if (($rc === false) || ($rc === '') || ($rc < 0))
                {
                    $time_limit = 25;
                }
                elseif ($rc == 0)
                {
                    $time_limit = 20;
                }
                else
                {
                    $time_limit = ($rc + 0);
                }
            }
 
            $time_executed = microtime(true) - $started_at;
            $time_left = $time_limit - $time_executed;
 
            if ($time_left < 4)
                throw new CLearnInstall201203ConvertDBTimeOut();
        }
 
 
        public static function _processChapters()
        {
            global $DB;
 
            $items_processed = 0;
 
            $res = $DB->Query ("SELECT * FROM b_learn_chapter WHERE JOURNAL_STATUS != " . self::JOURNAL_STATUS_CHAPTER_COPIED, 
                $ignore_errors = true);
            
            if ($res === false)
                throw new CLearnInstall201203ConvertDBException('EA_SQLERROR');
 
            while ($arChapter = $res->Fetch())
            {
                $arFields = array (
                    'ACTIVE'                => $arChapter['ACTIVE'],
                    'NAME'                  => ($arChapter['NAME'] === NULL) ? false : $arChapter['NAME'],
                    'CODE'                  => ($arChapter['CODE'] === NULL) ? false : $arChapter['CODE'],
                    'SORT'                  => (string) (1000000 + (int) $arChapter['SORT']),
                    'PREVIEW_PICTURE'       => ($arChapter['PREVIEW_PICTURE'] === NULL) ? false : $arChapter['PREVIEW_PICTURE'],
                    'PREVIEW_TEXT'          => $arChapter['PREVIEW_TEXT'],
                    'PREVIEW_TEXT_TYPE'     => $arChapter['PREVIEW_TEXT_TYPE'],
                    'DETAIL_PICTURE'        => ($arChapter['DETAIL_PICTURE'] === NULL) ? false : $arChapter['DETAIL_PICTURE'],
                    'DETAIL_TEXT'           => $arChapter['DETAIL_TEXT'],
                    'DETAIL_TEXT_TYPE'      => $arChapter['DETAIL_TEXT_TYPE'],
                    'LAUNCH'                => '',
                    'JOURNAL_STATUS'        => self::JOURNAL_STATUS_UNPROCESSED,
                    'WAS_CHAPTER_ID'        => ($arChapter['ID']),
                    'WAS_PARENT_CHAPTER_ID' => ($arChapter['CHAPTER_ID'] === NULL) ? false : $arChapter['CHAPTER_ID'],
                    'WAS_PARENT_COURSE_ID'  => ($arChapter['COURSE_ID'] === NULL) ? false : $arChapter['COURSE_ID'],
                    'WAS_COURSE_ID'         => false
                    );
 
                // Creates new lesson (unprocessed duplicates will be removed first)
                $id_of_new_lesson = self::_UnrepeatableCreateLesson ($arFields);
 
                // Now we must replace QUESTIONS_FROM_ID (where now is $arChapter['ID'])
                // in b_learn_test for QUESTIONS_FROM=='H'. Replace them to QUESTIONS_FROM=''
 
                // UPDATE b_learn_test SET QUESTIONS_FROM = 'R', QUESTIONS_FROM_ID = 150 WHERE QUESTIONS_FROM = 'H' AND QUESTIONS_FROM_ID = '1'
                $rc = $DB->Query(
                    "UPDATE b_learn_test 
                    SET TIMESTAMP_X = " . $DB->GetNowFunction()
                    . ", QUESTIONS_FROM = 'R', 
                    QUESTIONS_FROM_ID = " . ($id_of_new_lesson + 0)
                    . " WHERE QUESTIONS_FROM = 'H' 
                        AND QUESTIONS_FROM_ID = '" . ($arChapter['ID'] + 0) . "'",
                    $ignore_errors = true
                );
 
                if ($rc === false)
                    throw new CLearnInstall201203ConvertDBException('EA_SQLERROR');
 
                // Mark this chapter as processed
                $rc = $DB->Update('b_learn_chapter', 
                    array ('JOURNAL_STATUS' => self::JOURNAL_STATUS_CHAPTER_COPIED), 
                    "WHERE ID = '" . ($arChapter['ID'] + 0) . "'",
                    $error_position = "",
                    $debug = false,
                    $ignore_errors = true
                );
 
                if ($rc === false)
                    throw new CLearnInstall201203ConvertDBException('EA_SQLERROR');
 
                ++$items_processed;
 
                // This function throws exception CLearnInstall201203ConvertDBTimeOut, if it's low time left.
                self::avoidTimeout();
            }
 
            return ($items_processed);
        }

        public static function _UnrepeatableCreateLesson ($arFields)
        {
            global $DB;
 
            if ( ! is_array($arFields) )
                throw new CLearnInstall201203ConvertDBException('EA_PARAMS');
 
            if ( ! isset($arFields['COURSE_ID']) )
                $arFields['COURSE_ID'] = 0;
 
            // Determine, from what source import doing (Chapter or Course)
            if (array_key_exists('WAS_CHAPTER_ID', $arFields) 
                && ($arFields['WAS_CHAPTER_ID'] !== false)
            )
            {
                // new lesson will be created from chapter
                $sqlWhere = "WAS_CHAPTER_ID = '" . ($arFields['WAS_CHAPTER_ID'] + 0) . "'";
            }
            elseif (array_key_exists('WAS_COURSE_ID', $arFields) 
                && ($arFields['WAS_COURSE_ID'] !== false)
            )
            {
                // new lesson will be created from chapter
                $sqlWhere = "WAS_COURSE_ID = '" . ($arFields['WAS_COURSE_ID'] + 0) . "'";
            }
            else
            {
                throw new CLearnInstall201203ConvertDBException('EA_PARAMS');
            }
 
            // Firstly, remove such imported lesson, if exists
            $rc = $DB->Query ("DELETE FROM b_learn_lesson WHERE " . $sqlWhere, $ignore_errors = true);
            if ($rc === false)
                throw new CLearnInstall201203ConvertDBException('EA_SQLERROR');
 
            $arFields['~TIMESTAMP_X'] = $DB->GetNowFunction();
            $arFields['~DATE_CREATE'] = $DB->GetNowFunction();
            $arFields['~CREATED_BY'] = '1';
 
            $newLessonId = $DB->Add('b_learn_lesson', $arFields);
 
            return ($newLessonId);
        }

        public static function _IsAlreadyConverted()
        {
            $rc = COption::GetOptionString(self::MODULE_ID, self::OPTION_ID, self::STATUS_INSTALL_NEVER_START, $site = '');
 
            if ($rc === self::STATUS_INSTALL_NEVER_START)
            {
                global $DB;
 
                if ($DB->TableExists('b_learn_lesson_edges')
                    && $DB->TableExists('b_learn_rights_all')
                    && ( ! $DB->TableExists('b_learn_course_permission') )
                )
                {
                    return (true);
                }
                else
                    return (false);
            }
            elseif ($rc === self::STATUS_INSTALL_COMPLETE)
                return (true);
            elseif ($rc === self::STATUS_INSTALL_INCOMPLETE)
                return (false);
            else
                self::_GiveUp(__LINE__);
        }
 
 
        protected static function _RemoveOrphanedTables()
        {
            global $DB;
 
            if ( ! $DB->TableExists('b_learn_course_permission') )
                return;
 
            $rc = $DB->Query ("DROP TABLE b_learn_course_permission", true);
            if ($rc === false)
                throw new CLearnInstall201203ConvertDBException('Can\'t DROP `b_learn_course_permission` under database engine: mysql');
        }
 
        public static function _CreateEdgesTbl()
        {
            global $DB;
 
            if ($DB->TableExists('b_learn_lesson_edges'))
                return;
 
            $sql
                = "CREATE TABLE b_learn_lesson_edges (
                SOURCE_NODE INT NOT NULL ,
                TARGET_NODE INT NOT NULL ,
                SORT INT NOT NULL DEFAULT '500',
                PRIMARY KEY ( SOURCE_NODE , TARGET_NODE )
            )";
 
            $rc = $DB->Query ($sql, $ignore_errors = true);
            if ($rc === false)
                throw new CLearnInstall201203ConvertDBException('Can\'t create `b_learn_lesson_edges` under database engine: mysql');
        }
 
        public static function _CreateFieldsInTbls()
        {
            global $DB;
 
            $arTableFields = array(
                'b_learn_lesson'  => $DB->GetTableFieldsList ('b_learn_lesson'),
                'b_learn_chapter' => $DB->GetTableFieldsList ('b_learn_chapter'),
                'b_learn_course'  => $DB->GetTableFieldsList ('b_learn_course')
                );
 
            $sql_add = array();
            $other_sql_skip_errors = array();
            $other_sql = array();
 
            // Prepare sql code for adding fields
            $sql_add['b_learn_lesson'] = array (
                'KEYWORDS'              => "ALTER TABLE b_learn_lesson ADD KEYWORDS TEXT NOT NULL DEFAULT ''",
                'CODE'                  => "ALTER TABLE b_learn_lesson ADD CODE VARCHAR( 50 ) NULL DEFAULT NULL",
                'WAS_CHAPTER_ID'        => "ALTER TABLE b_learn_lesson ADD WAS_CHAPTER_ID INT NULL DEFAULT NULL",
                'WAS_PARENT_CHAPTER_ID' => "ALTER TABLE b_learn_lesson ADD WAS_PARENT_CHAPTER_ID INT NULL DEFAULT NULL",
                'WAS_PARENT_COURSE_ID'  => "ALTER TABLE b_learn_lesson ADD WAS_PARENT_COURSE_ID INT NULL DEFAULT NULL",
                'WAS_COURSE_ID'         => "ALTER TABLE b_learn_lesson ADD WAS_COURSE_ID INT NULL DEFAULT NULL",
                'JOURNAL_STATUS'        => "ALTER TABLE b_learn_lesson ADD JOURNAL_STATUS INT NOT NULL DEFAULT '0'"
                );
 
            $sql_add['b_learn_chapter'] = array (
                'JOURNAL_STATUS' => "ALTER TABLE b_learn_chapter ADD JOURNAL_STATUS INT NOT NULL DEFAULT '0'"
                );
 
            $sql_add['b_learn_course'] = array (
                'LINKED_LESSON_ID' => "ALTER TABLE b_learn_course ADD LINKED_LESSON_ID INT NULL DEFAULT NULL",
                'JOURNAL_STATUS'   => "ALTER TABLE b_learn_course ADD JOURNAL_STATUS INT NOT NULL DEFAULT '0'"
                );
 
            $sql_tbl_b_learn_rights = "
                CREATE TABLE b_learn_rights (
                LESSON_ID INT UNSIGNED NOT NULL ,
                SUBJECT_ID VARCHAR( 100 ) NOT NULL ,
                TASK_ID INT NOT NULL ,
                PRIMARY KEY ( LESSON_ID , SUBJECT_ID )
                )";
 
            $other_sql_skip_errors[] = "ALTER TABLE b_learn_course ALTER COLUMN NAME SET DEFAULT 'name'";
            $other_sql_skip_errors[] = "ALTER TABLE b_learn_lesson ALTER COLUMN NAME SET DEFAULT 'name'";
            $other_sql_skip_errors[] = "ALTER TABLE b_learn_lesson ALTER COLUMN COURSE_ID SET DEFAULT '0'";
 
            $other_sql_skip_errors[] = "
                CREATE TABLE b_learn_publish_prohibition
                (
                    COURSE_LESSON_ID INT UNSIGNED NOT NULL ,
                    PROHIBITED_LESSON_ID INT UNSIGNED NOT NULL ,
                    PRIMARY KEY ( COURSE_LESSON_ID , PROHIBITED_LESSON_ID )
                )";
 
            $other_sql_skip_errors[] = "
                CREATE TABLE b_learn_exceptions_log (
                  DATE_REGISTERED datetime NOT NULL,
                  CODE int(11) NOT NULL,
                  MESSAGE text NOT NULL,
                  FFILE text NOT NULL,
                  LINE int(11) NOT NULL,
                  BACKTRACE text NOT NULL
                )";
 
            if ( ! $DB->TableExists('b_learn_rights'))
            {
                $rc = $DB->Query($sql_tbl_b_learn_rights);
                if ($rc === false)
                    throw new CLearnInstall201203ConvertDBException(__LINE__ . '/tbl: sql_tbl_b_learn_rights');
            }
 
            foreach ($sql_add as $tableName => $sql_for_table)
            {
                // Add every field (if not exists yet) to table $tableName
                foreach ($sql_for_table as $fieldName => $sql)
                {
                    if ( ! in_array($fieldName, $arTableFields[$tableName], true) )
                    {
                        $rc = $DB->Query($sql, $ignore_erros = true);
 
                        if ($rc === false)
                            throw new CLearnInstall201203ConvertDBException(__LINE__.'/tbl:'.mb_strlen($fieldName));
                    }
                }
                /*
 
                !!! This does not work correctly (table's fields cache in Database class issue?)
                // Now, ensure, that fields was added really
                $arTableFields_after = $DB->GetTableFieldsList ($tableName);
                foreach ($sql_for_table as $fieldName => $sql)
                {
                    if ( ! in_array($fieldName, $arTableFields_after, true) )
                        self::_GiveUp(__LINE__ . '/tbl:' . strlen($fieldName));
                }
                */
            }
 
            foreach ($other_sql_skip_errors as $sql)
                $rc = $DB->Query($sql, $ignore_erros = true);
 
            foreach ($other_sql as $sql)
            {
                $rc = $DB->Query($sql, $ignore_erros = true);
                if ($rc === false)
                    throw new CLearnInstall201203ConvertDBException(__LINE__ . '/sql:' . htmlspecialcharsbx($sql));
            }
 
            // Drop cache
            $rc = $DB->DDL("SELECT * FROM b_learn_lesson WHERE 1=1", true);
            if ($rc === false)
                throw new CLearnInstall201203ConvertDBException(__LINE__ . ', on DDL\'s cache drop');
        }
 
        /*
        public static function _RemoveFieldsFromLesson()
        {
            //      ORACLE:
            //      ALTER TABLE `b_learn_lesson` DROP COLUMN `JOURNAL_ID` ???
 
            global $DB, $DBType;
 
            $arTableFields = $DB->GetTableFieldsList (`b_learn_lesson`);
 
            // Prepare sql code for removing fields
            $sql_add = array();
            if ($DBType === 'mysql')
            {
                $sql_add['JOURNAL_ID'] = "ALTER TABLE `b_learn_lesson` DROP `JOURNAL_ID`";
            }
            else
            {
                // TODO: do sql code for MSSQL and Oracle
 
                self::_GiveUp ('SQL code not ready for: ' . $DBType);
            }
 
            // Remove every field (if exists) from table b_learn_lesson
            foreach ($sql_add as $fieldName => $sql)
            {
                if ( in_array($fieldName, $arTableFields, true) )
                {
                    $rc = $DB->Query($sql, $ignore_erros = true);
 
                    if ($rc === false)
                        self::_GiveUp(__LINE__);
                }
            }
 
            // Don't ensure, that fields was really removed, because it's not critical for us
        }
        */
 
        public static function _GiveUp($msg = false)
        {
            if ($msg !== false)
                throw new Exception ('FATAL: ' . $msg);
            else
                throw new Exception ('Shit happens.');
        }
    }
 
 
    $rc = CLearnInstall201203ConvertDB::run();
    if ($rc <> '')
        $errorMessage = $rc;
}