<?php
/**
* @version	$Id: ChangeLogHelper.php 16824 2025-01-28 16:19:21Z alex $
* @package	In-Portal
* @copyright	Copyright (C) 1997 - 2009 Intechnic. All rights reserved.
* @license      GNU/GPL
* In-Portal is Open Source software.
* This means that this software may have been modified pursuant
* the GNU General Public License, and as distributed it includes
* or is derivative of works licensed under the GNU General Public License
* or other free or open source software licenses.
* See http://www.in-portal.org/license for copyright notices and details.
*/

class ChangeLogHelper extends kHelper
{

	/**
	 * Forgets changes.
	 *
	 * @param string $main_prefix Main prefix.
	 *
	 * @return void
	 */
	public function forgetChanges($main_prefix)
	{
		$ses_var_name = $this->getSessionVariableName($main_prefix, $main_prefix);
		$this->Application->RemoveVar($ses_var_name);
	}

	/**
	 * Updates the foreign keys in the changelog for a given table based on the provided identifiers.
	 *
	 * This method ensures that all references to the temporary ID in the changelog are updated to use
	 * the live ID, while considering dependencies and relationships between items.
	 *
	 * @param array   $table_info    Table info.
	 * @param integer $live_id       Live ID.
	 * @param integer $temp_id       Temp ID.
	 * @param string  $caller_prefix Caller prefix.
	 *
	 * @return void
	 */
	public function updateForeignKeys(array $table_info, $live_id, $temp_id, $caller_prefix)
	{
		if ( $live_id == $temp_id ) {
			return;
		}

		$prefix = $table_info['Prefix'];
		$main_prefix = $this->Application->GetTopmostPrefix($prefix);

		$ses_var_name = $this->getSessionVariableName($main_prefix, $caller_prefix);
		$changes = $this->Application->RecallVar($ses_var_name);
		$changes = $changes ? unserialize($changes) : array();

		if ( !$changes ) {
			return;
		}

		foreach ( $changes as $key => $rec ) {
			// The main item changelog record.
			if ( $rec['Prefix'] == $prefix && $rec['ItemId'] == $temp_id ) {
				$changes[$key]['ItemId'] = $live_id;
			}

			// The subitem changelog record.
			if ( $rec['MasterPrefix'] == $prefix && $rec['MasterId'] == $temp_id ) {
				$changes[$key]['MasterId'] = $live_id;
			}

			// The parent item changelog record.
			if ( in_array($prefix, $rec['ParentPrefix']) && $rec['ParentId'][$prefix] == $temp_id ) {
				$changes[$key]['ParentId'][$prefix] = $live_id;

				if ( array_key_exists('DependentFields', $rec) ) {
					/*
					 * These are fields from the $rec['Prefix'] table!
					 * Used, when one of the dependent fields uses IdField of its changed parent item.
					 */
					$parent_table_key = $this->Application->getUnitOption($rec['Prefix'], 'ParentTableKey');
					$parent_table_key = is_array($parent_table_key) ? $parent_table_key[$prefix] : $parent_table_key;

					if ( $parent_table_key == $table_info['IdField'] ) {
						$foreign_key = $this->Application->getUnitOption($rec['Prefix'], 'ForeignKey');
						$foreign_key = is_array($foreign_key) ? $foreign_key[$prefix] : $foreign_key;

						$changes[$key]['DependentFields'][$foreign_key] = $live_id;
					}
				}
			}
		}

		$this->Application->StoreVar($ses_var_name, serialize($changes));
	}

	/**
	 * Logs changes for a database item, tracking relevant details for create, update, or delete actions.
	 *
	 * @param kDBItem    $object        Object.
	 * @param integer    $mode          Mode (e.g., create, update, delete).
	 * @param array|null $update_fields Update fields.
	 *
	 * @return void
	 */
	public function logChanges(kDBItem $object, $mode, array $update_fields = null)
	{
		if ( !$mode ) {
			return;
		}

		$prefix = $object->Prefix;
		$main_prefix = $this->Application->GetTopmostPrefix($prefix);

		$ses_var_name = $this->getSessionVariableName($main_prefix, $prefix);
		$changes = $this->Application->RecallVar($ses_var_name);
		$changes = $changes ? unserialize($changes) : array();

		$fields_hash = array(
			'Prefix' => $prefix,
			'ItemId' => $object->GetID(),
			'OccuredOn' => adodb_mktime(),
			'MasterPrefix' => $main_prefix,
			'Action' => $mode,
		);

		if ( $prefix == $main_prefix ) {
			// Main item.
			$fields_hash['MasterId'] = $object->GetID();
			$fields_hash['ParentPrefix'] = array($main_prefix);
			$fields_hash['ParentId'] = array($main_prefix => $object->GetID());
		}
		else {
			/*
			 * Subitem.
			 * Collect foreign key values (for serial reset).
			 */
			$foreign_keys = $this->Application->getUnitOption($prefix, 'ForeignKey', array());
			$dependent_fields = $fields_hash['ParentId'] = $fields_hash['ParentPrefix'] = array();
			/** @var Array $foreign_keys */

			if ( is_array($foreign_keys) ) {
				foreach ( $foreign_keys as $foreign_key_prefix => $foreign_key_field_name ) {
					$dependent_fields[$foreign_key_field_name] = $object->GetDBField($foreign_key_field_name);
					$fields_hash['ParentPrefix'][] = $foreign_key_prefix;
					$fields_hash['ParentId'][$foreign_key_prefix] = $object->getParentId($foreign_key_prefix);
				}
			}
			else {
				$dependent_fields[$foreign_keys] = $object->GetDBField($foreign_keys);
				$fields_hash['ParentPrefix'] = array(
					$this->Application->getUnitOption($prefix, 'ParentPrefix'),
				);
				$fields_hash['ParentId'][$fields_hash['ParentPrefix'][0]] = $object->getParentId('auto');
			}

			$fields_hash['DependentFields'] = $dependent_fields;

			// Works only when the main item is present in url when a subitem is changed.
			$master_id = $this->Application->GetVar($main_prefix . '_id');

			if ( $master_id === false ) {
				// Works in case when we're not editing topmost item, when subitem is created/updated/deleted.
				$master_id = $object->getParentId('auto', true);
			}

			$fields_hash['MasterId'] = $master_id;
		}

		switch ( $mode ) {
			case ChangeLog::UPDATE:
				$changed_fields = $object->GetChangedFields();

				if ( $update_fields ) {
					$changed_fields = array_intersect_key(
						$changed_fields,
						array_combine($update_fields, $update_fields)
					);
				}

				$to_save = array_merge($object->GetTitleField(), $changed_fields);
				break;

			case ChangeLog::CREATE:
				$to_save = $object->GetTitleField();
				break;

			case ChangeLog::DELETE:
				$to_save = array_merge($object->GetTitleField(), $object->GetRealFields());
				break;

			default:
				$to_save = array();
				break;
		}

		$fields_hash['Changes'] = serialize($to_save);
		$changes[] = $fields_hash;

		$this->Application->StoreVar($ses_var_name, serialize($changes));
	}

	/**
	 * Saves changes made in the temporary table to log.
	 *
	 * @param string  $prefix Prefix.
	 * @param boolean $save   Save changes.
	 *
	 * @return void
	 */
	public function saveLoggedChanges($prefix, $save = true)
	{
		$main_prefix = $this->Application->GetTopmostPrefix($prefix);

		// 1. get changes that were made.
		$ses_var_name = $this->getSessionVariableName($main_prefix, $prefix);
		$changes = $this->Application->RecallVar($ses_var_name);
		$changes = $changes ? unserialize($changes) : array();
		$this->Application->RemoveVar($ses_var_name);

		if ( !$changes ) {
			// No changes, skip processing.
			return;
		}

		// TODO: 2. optimize change log records (replace multiple changes to same record with one change record).
		$to_increment = array();

		// 3. collect serials to reset based on foreign keys
		foreach ( $changes as $index => $rec ) {
			if ( array_key_exists('DependentFields', $rec) ) {
				foreach ( $rec['DependentFields'] as $field_name => $field_value ) {
					// Will be "ci|ItemResourceId:345".
					$to_increment[] = $rec['Prefix'] . '|' . $field_name . ':' . $field_value;

					// Also reset sub-item prefix general serial.
					$to_increment[] = $rec['Prefix'];
				}

				unset($changes[$index]['DependentFields']);
			}

			// Remove keys that don't have corresponding columns in the "ChangeLogs" database table.
			unset($changes[$index]['ParentId'], $changes[$index]['ParentPrefix']);
		}

		// 4. collect serials to reset based on changed ids
		foreach ( $changes as $change ) {
			$to_increment[] = $change['MasterPrefix'] . '|' . $change['MasterId'];

			if ( $change['MasterPrefix'] != $change['Prefix'] ) {
				// Also reset sub-item prefix general serial.
				$to_increment[] = $change['Prefix'];

				// Will be "ci|ItemResourceId".
				$to_increment[] = $change['Prefix'] . '|' . $change['ItemId'];
			}
		}

		// 5. reset serials collected before
		$to_increment = array_unique($to_increment);
		$this->Application->incrementCacheSerial($prefix);

		foreach ( $to_increment as $to_increment_mixed ) {
			if ( strpos($to_increment_mixed, '|') !== false ) {
				list ($to_increment_prefix, $to_increment_id) = explode('|', $to_increment_mixed, 2);
				$this->Application->incrementCacheSerial($to_increment_prefix, $to_increment_id);
			}
			else {
				$this->Application->incrementCacheSerial($to_increment_mixed);
			}
		}

		// Save changes to a database.
		$session_log_id = $this->Application->RecallVar('_SessionLogId_');

		if ( !$save || !$session_log_id ) {
			// Saving changes to database disabled OR related session log missing.
			return;
		}

		$add_fields = array(
			'PortalUserId' => $this->Application->RecallVar('user_id'),
			'SessionLogId' => $session_log_id,
		);

		$change_log_table = $this->Application->getUnitOption('change-log', 'TableName');

		foreach ( $changes as $rec ) {
			$this->Conn->doInsert(array_merge($rec, $add_fields), $change_log_table);
		}

		$this->Application->incrementCacheSerial('change-log');

		$sql = 'UPDATE ' . $this->Application->getUnitOption('session-log', 'TableName') . '
				SET AffectedItems = AffectedItems + ' . count($changes) . '
				WHERE SessionLogId = ' . $session_log_id;
		$this->Conn->Query($sql);

		$this->Application->incrementCacheSerial('session-log');
	}

	/**
	 * Returns change log session variable name.
	 *
	 * @param string $main_prefix Main prefix.
	 * @param string $prefix      Prefix.
	 *
	 * @return string
	 */
	protected function getSessionVariableName($main_prefix, $prefix)
	{
		return $main_prefix . '_changes_' . $this->Application->GetTopmostWid($prefix);
	}

}