<?php
/**
 * Copyright 2017 Wim van Ravesteijn
*
* This file is part of AEGEE-Europe Statutory Event Applications.
*
* AEGEE-Europe Statutory Event Applications 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.
*
* AEGEE-Europe Statutory Event Applications 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 AEGEE-Europe Statutory Event Applications.  If not, see
* <http://www.gnu.org/licenses/>.
*/

interface IDB {
	/**
	 * Fetch a row from a table
	 *
	 * @param string $table
	 * @param int $id
	 * @return array associative array
	 */
	public function fetchRow($table, $id);

	/**
	 * Select data
	 * 
	 * @param string $query
	 * @return int number of rows, -1 in case of error
	 */
	public function select($query);
	public function select2($query);
	
	/**
	 * Return associative array of last select
	 * 
	 * @return array associative array of last select
	 */
	public function fetchAssoc();
	public function fetchAssoc2();
	
	/**
	 * Adjusts the result pointer to an arbitrary row in the result
	 *
	 * @param int row
	 */
	public function dataSeek($row);
	public function dataSeek2($row);
	
	/**
	 * Free result
	 */
	public function freeResult();
	public function freeResult2();
	
	/**
	 * Return number of rows in result
	 */
	public function numRows();
	public function numRows2();
	
	/**
	 * Insert data into a table
	 * 
	 * @param string $table
	 * @param array $data
	 * @return int insertId, -1 in case of error
	 */
	public function insert($table, $data);

	/**
	 * Update a record
	 * 
	 * @param string $table
	 * @param int $id
	 * @param array $data
	 * @param string $idField
	 * @return boolean true on success, false otherwise
	 */
	public function update($table, $id, $data, $idField = "id");

	/**
	 * Delete data
	 * @param string $table
	 * @param int or array of int $ids
	 * @param string $idField
	 */
	public function delete($table, $ids, $idField = "id");
		
	/**
	 * Escape field for usage in select query. In case field contains a dot (.), it will be split and both sides will be escaped. May be an array
	 * 	of several fields
	 * 
	 * @param string $field
	 * @return string escaped field
	 */
	public function escapeField($field);

	/**
	 * Escape value for usage in select query
	 *
	 * @param string $value
	 * @return string escaped value
	 */
	public function escapeValue($value);
	
	/**
	 * Return the error generated by last query
	 * 
	 * @return string error
	 */
	public function getLastError();
}

interface DBMethod {
	public function toQuery(IDB $db);
}
	
class DBMethodConcat implements DBMethod {
	private $field;

	private $appendValue;

	public function __construct($field, $appendValue) {
		$this->field = $field;
		$this->appendValue = $appendValue;
	}

	public function toQuery(IDB $db) {
		return "CONCAT(" . $db->escapeField($this->field) . ", " . $db->escapeValue($this->appendValue) . ")";
	}
}

class DBMethodCount implements DBMethod {
	private $field;
	
	public function __construct($field) {
		$this->field = $field;
	}
	
	public function toQuery(IDB $db) {
		return "COUNT(" . $db->escapeField($this->field) . ")";
	}
}

class DBMethodLeft implements DBMethod {
	private $field;
	
	private $length;
	
	public function __construct($field, $length) {
		$this->field = $field;
		$this->length = $length;
	}
	
	public function toQuery(IDB $db) {
		return "LEFT(" . $db->escapeField($this->field) . ", " . $db->escapeValue($this->length) . ")";
	}
}

class DBMethodLength implements DBMethod {
	private $field;

	public function __construct($field) {
		$this->field = $field;
	}

	public function toQuery(IDB $db) {
		return "LENGTH(" . $db->escapeField($this->field) . ")";
	}
}

class DBMethodLower implements DBMethod {
	private $field;
	
	public function __construct($field) {
		$this->field = $field;
	}
	
	public function toQuery(IDB $db) {
		return "LOWER(" . $db->escapeField($this->field) . ")";
	}
}

class DBMethodMax implements DBMethod {
	private $field;
	
	public function __construct($field) {
		$this->field = $field;
	}
	
	public function toQuery(IDB $db) {
		return "MAX(" . $db->escapeField($this->field) . ")";
	}
}

class DBMethodMin implements DBMethod {
	private $field;

	public function __construct($field) {
		$this->field = $field;
	}

	public function toQuery(IDB $db) {
		return "MIN(" . $db->escapeField($this->field) . ")";
	}
}
?>