<?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 DBWhere {
	public function toQuery(IDB $db);
}

class DBWhereEquals implements DBWhere {
	private $field;
	
	private $value;
	
	public function __construct($field, $value) {
		$this->field = $field;
		$this->value = $value;
	}
	
	public function toQuery(IDB $db) {
		return $db->escapeField($this->field) . " = " . $db->escapeValue($this->value);
	}
}

class DBWhereNotEquals implements DBWhere {
	private $field;

	private $value;

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

	public function toQuery(IDB $db) {
		return $db->escapeField($this->field) . " != " . $db->escapeValue($this->value);
	}
}

class DBWhereGreaterEquals implements DBWhere {
	private $field;

	private $value;

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

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

class DBWhereSmallerEquals implements DBWhere {
	private $field;

	private $value;

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

	public function toQuery(IDB $db) {
		return $db->escapeField($this->field) . " <= " . $db->escapeValue($this->value);
	}
}

class DBWhereGreater implements DBWhere {
	private $field;

	private $value;

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

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

class DBWhereSmaller implements DBWhere {
	private $field;

	private $value;

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

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

class DBWhereIn implements DBWhere {
	private $field;
	
	private $values;
		
	public function __construct($field, array $values) {
		$this->field = $field;
		$this->values = $values;
	}
	
	public function toQuery(IDB $db) {
		$escapedValues = array();
		foreach($this->values as $value) {
			$escapedValues[] = $db->escapeValue($value);
		}
		return $db->escapeField($this->field) . " IN (" . implode(", ", $escapedValues) . ")";
	}
}

class DBWhereIsNull implements DBWhere {
	private $field;

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

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

class DBWhereIsNotNull implements DBWhere {
	private $field;

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

	public function toQuery(IDB $db) {
		return $db->escapeField($this->field) . " IS NOT NULL";
	}
}

class DBWhereOr implements DBWhere {
	private $whereParts;
	
	public function __construct(DBWhere ...$whereParts) {
		$this->whereParts = $whereParts;
	}
	
	public function toQuery(IDB $db) {
		$escapedParts = array();
		foreach($this->whereParts as $wherePart) {
			$escapedParts[] = $wherePart->toQuery($db);
		}
		return "(" . implode(" OR ", $escapedParts) . ")";
	}
}
?>