<?php
/**
 * Bibliotheca
 *
 * Copyright 2018-2023 Johannes Keßler
 *
 * This program 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.
 *
 *  This program 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 this program.  If not, see http://www.gnu.org/licenses/gpl-3.0.
 */

/**
 * Class ManageCollectionFields to manage fields from a existing collection
 */
class ManageCollectionFields {

	/**
	 * The database object
	 *
	 * @var mysqli
	 */
	private mysqli $_DB;

	/**
	 * The user object to query with
	 *
	 * @var Doomguy
	 */
	private Doomguy $_User;

	/**
	 * The collection we are working with
	 *
	 * @var string
	 */
	private string $_collectionId;

	/**
	 * Which db cols should not be removed
	 *
	 * @var array
	 */
	private array $_protectedDBCols = array(
		'id','created','modified','modificationuser','owner','group','rights'
	);

	/**
	 * Store existing fields info for runtime
	 *
	 * @var array
	 */
	private array $_cacheExistingSysFields = array();

	/**
	 * Store available fields info for runtime
	 *
	 * @var array
	 */
	private array $_cacheAvailableFields = array();

	/**
	 * ManageCollections constructor
	 *
	 * @param mysqli $databaseConnectionObject
	 * @param Doomguy $userObj
	 */
	public function __construct(mysqli $databaseConnectionObject, Doomguy $userObj) {
		$this->_DB = $databaseConnectionObject;
		$this->_User = $userObj;
	}

	/**
	 * The id from the collection we are working with
	 *
	 * @param string $id
	 */
	public function setCollection(string $id): void {
		if(!empty($id)) {
			$this->_collectionId = $id;
		}
	}

	/**
	 * Get available fields based on user
	 *
	 * @param bool $refresh
	 * @return array
	 * @todo No rights implemented yet. Maybe not needed. Management done by hand directly on DB
	 */
	public function getAvailableFields(bool $refresh=false): array {

		if($refresh === false && !empty($this->_cacheAvailableFields)) {
			return $this->_cacheAvailableFields;
		}

		$queryStr = "SELECT `id`, `identifier`, `displayname`, `type`,
						`createstring`, `value`
					FROM `".DB_PREFIX."_sys_fields`
					ORDER BY `displayname`";
		if(QUERY_DEBUG) Summoner::sysLog("[QUERY] ".__METHOD__." query: ".Summoner::cleanForLog($queryStr));
		try {
			$query = $this->_DB->query($queryStr);
			if($query !== false && $query->num_rows > 0) {
				while(($result = $query->fetch_assoc()) != false) {
					$this->_cacheAvailableFields[$result['id']] = $result;
				}
			}
		}
		catch (Exception $e) {
            Summoner::sysLog("[ERROR] ".__METHOD__." mysql catch: ".$e->getMessage());
		}

		return $this->_cacheAvailableFields;
	}

	/**
	 * Simple comma separated number string
	 *
	 * @param string $string
	 * @return bool
	 */
	public function validateFieldSortString(string $string): bool {
		$ret = false;

		$_t = str_replace(",","",$string);
		if(Summoner::validate($_t, 'digit')) {
			$ret = true;
		}

		return $ret;
	}

	/**
	 * Deletes relations and data from the collection!
	 *
	 * $fieldsSortString have to be validated already
	 *
	 * @param string $fieldsSortString
	 * @return bool
	 */
	public function updateFields(string $fieldsSortString): bool {
		$ret = false;
		$ids = array();

		$fieldsSortString = trim($fieldsSortString, ", ");
		if(strstr($fieldsSortString, ",")) {
			$ids = explode(",", $fieldsSortString);
		}
		else {
			$ids[] = $fieldsSortString;
		}

		if(!empty($ids)) {

			$_newColumns = $this->_getSQLForCollectionColumns($ids);
			$_existingFields = $this->getExistingFields();

			// use the createsting info to determine if the field needs to be remove
			// from entry table or lookup table
			$_fieldsToCheckForDelete = $_existingFields;
			$queriesDeleteEntryTable = array();
			foreach($ids as $_id) {
				if(isset($_fieldsToCheckForDelete[$_id])) {
					unset($_fieldsToCheckForDelete[$_id]);
				}
			}
			if(!empty($_fieldsToCheckForDelete)) {
				foreach($_fieldsToCheckForDelete as $k=>$v)  {
					if(!empty($v['createstring'])) {
						$queriesDeleteEntryTable[] = "ALTER TABLE `".DB_PREFIX."_collection_entry_".$this->_collectionId."`
														DROP `".$v['identifier']."`";
					}
				}
			}

			$queryStrDeleteFields = "DELETE FROM `".DB_PREFIX."_collection_fields_".$this->_collectionId."`
						WHERE `fk_field_id` NOT IN (".implode(",",$ids).")";
			if(QUERY_DEBUG) Summoner::sysLog("[QUERY] ".__METHOD__." query: ".Summoner::cleanForLog($queryStrDeleteFields));

			$queryStrDeletee2l = "DELETE FROM `".DB_PREFIX."_collection_entry2lookup_".$this->_collectionId."`
						WHERE `fk_field` NOT IN (".implode(",",$ids).")";
			if(QUERY_DEBUG) Summoner::sysLog("[QUERY] ".__METHOD__." query: ".Summoner::cleanForLog($queryStrDeletee2l));

			$queryStrInsertFields = "INSERT INTO `".DB_PREFIX."_collection_fields_".$this->_collectionId."` (`fk_field_id`,`sort`) VALUES ";
			foreach ($ids as $k => $v) {
				$queryStrInsertFields .= "('".$this->_DB->real_escape_string($v)."','".$this->_DB->real_escape_string($k)."'),";
			}
			$queryStrInsertFields = trim($queryStrInsertFields, ",");
			$queryStrInsertFields .= " ON DUPLICATE KEY UPDATE `sort` = VALUES(`sort`)";
			if(QUERY_DEBUG) Summoner::sysLog("[QUERY] ".__METHOD__." query: ".Summoner::cleanForLog($queryStrInsertFields));

			if(!empty($_newColumns)) {
				$queryStrAlterEntry = array();
				foreach($_newColumns as $k=>$v) {
					$queryStrAlterEntry[] = "ALTER TABLE `".DB_PREFIX."_collection_entry_".$this->_collectionId."` ADD ".$v['createstring']."";
				}
			}

			// this is not good. mysql implicit commit is triggered with alter table.
			// needs a rewrite without alter table to fully use transactions..
			try {
				$this->_DB->begin_transaction(MYSQLI_TRANS_START_READ_WRITE);

				$this->_DB->query($queryStrDeleteFields);
				$this->_DB->query($queryStrDeletee2l);

				$this->_DB->commit();

				// mysql implicit commit
				if(!empty($queriesDeleteEntryTable)) {
					foreach($queriesDeleteEntryTable as $q) {
						if(QUERY_DEBUG) Summoner::sysLog("[QUERY] ".__METHOD__." query: ".Summoner::sysLog($q));
						$this->_DB->query($q);
					}
				}

				$this->_DB->begin_transaction(MYSQLI_TRANS_START_READ_WRITE);
				$this->_DB->query($queryStrInsertFields);
				$this->_DB->commit();

				// mysql implicit commit
				if(!empty($_newColumns)) {
					foreach ($queryStrAlterEntry as $q1) {
						if(QUERY_DEBUG) Summoner::sysLog("[QUERY] ".__METHOD__." query: ".Summoner::cleanForLog($q1));
						$this->_DB->query($q1);
					}
				}

				$ret = true;
			}
			catch (Exception $e) {
				$this->_DB->rollback();
                Summoner::sysLog("[ERROR] update fields ".__METHOD__." mysql catch: ".$e->getMessage());
			}
		}

		return $ret;
	}

	/**
	 * Get the fields for currently loaded collection.
	 *
	 * @param bool $refresh True to reload from DB
	 * @param bool $sortAZ
	 * @return array
	 */
	public function getExistingFields(bool $refresh=false, bool $sortAZ=false): array {
		if($refresh === false && !empty($this->_cacheExistingSysFields)) {
			return $this->_cacheExistingSysFields;
		}

		$this->_cacheExistingSysFields = array();

		$queryStr = "SELECT `cf`.`fk_field_id` AS id, 
                        `sf`.`type`, 
                        `sf`.`displayname`, 
                        `sf`.`identifier`,
						`sf`.`createstring`, 
						`sf`.`searchtype`
						FROM `".DB_PREFIX."_collection_fields_".$this->_collectionId."` AS cf
						LEFT JOIN `".DB_PREFIX."_sys_fields` AS sf ON `cf`.`fk_field_id` = `sf`.`id`";
		if($sortAZ === true) {
			$queryStr .= " ORDER BY `sf`.`displayname`";
		}
		else {
			$queryStr .= " ORDER BY `cf`.`sort`";
		}
		if(QUERY_DEBUG) Summoner::sysLog("[QUERY] ".__METHOD__." query: ".Summoner::cleanForLog($queryStr));
		try {
			$query = $this->_DB->query($queryStr);
			if($query !== false && $query->num_rows > 0) {
				while(($result = $query->fetch_assoc()) != false) {
					$this->_cacheExistingSysFields[$result['id']] = $result;
				}
			}
		}
		catch (Exception $e) {
            Summoner::sysLog("[ERROR] ".__METHOD__." mysql catch: ".$e->getMessage());
		}

		return $this->_cacheExistingSysFields;
	}

	/**
	 * return the simple search fields for loaded collection
	 * Every field witch has a column in the entry table is a simple search field.
	 * Name starts with entry
	 *
	 * @see Trite->getSimpleSearchFields()
	 *
	 * @return array
	 */
	public function getSimpleSearchFields(): array {
		$ret = array();

		$fields = $this->getExistingFields();
		if(!empty($fields)) {
			foreach($fields as $k=>$v) {
				if(isset($v['searchtype']) && strpos($v['searchtype'],'entry') !== false) {
					$ret[$k] = $v;
				}
			}
		}

        // add systemfields
		$def['created'] = array('identifier' => 'created', 'displayname' => 'sysfield.created', 'type' => 'systemfield');
		$def['modified'] = array('identifier' => 'modified', 'displayname' => 'sysfield.modified', 'type' => 'systemfield');

		return $def + $ret;
	}

	/**
	 * Get the column names from current collection entry table
	 *
	 * @return array
	 */
	private function _getExistingCollectionColumns(): array {
		$ret = array();

		$queryStr = "SHOW COLUMNS FROM `".DB_PREFIX."_collection_entry_".$this->_collectionId."`";
		if(QUERY_DEBUG) Summoner::sysLog("[QUERY] ".__METHOD__." query: ".Summoner::cleanForLog($queryStr));
		try {
			$query = $this->_DB->query($queryStr);
			if($query !== false && $query->num_rows > 0) {
				while(($result = $query->fetch_assoc()) != false) {
					if(!in_array($result['Field'], $this->_protectedDBCols, true)) {
						$ret[$result['Field']] = $result['Field'];
					}
				}
			}
		}
		catch (Exception $e) {
            Summoner::sysLog("[ERROR] ".__METHOD__." mysql catch: ".$e->getMessage());
		}

		return $ret;
	}

	/**
	 * Get the required SQL information from given field ids
	 * to create columns in entry table.
	 *
	 * @param array $columnIds sort=>fk_field_id
	 * @return array
	 */
	private function _getSQLForCollectionColumns(array $columnIds): array {
		$_fields = array();
		// enrich with information
		$_sysFields = $this->getAvailableFields();
		$_existingDBColumns = $this->_getExistingCollectionColumns();
		if(!empty($columnIds)) {
			foreach($columnIds as $sort=>$fieldId) {
				if(isset($_sysFields[$fieldId])) {
					$_fd = $_sysFields[$fieldId];
					if(isset($_existingDBColumns[$_fd['identifier']])) continue;
					if(empty($_fd['createstring'])) continue;
					$_fields[$fieldId] = $_fd;
				}
			}
		}
		return $_fields;
	}
}