<?php
 
class SortDirection {
	const Ascending = 1;
	const Descending = -1;
}
 
interface Filter {
	public function filter($item);
}
 
interface Comparator {
	public function compare($a, $b);
}
 
class MultipleKeyValueFilter implements Filter {
	protected $kvPairs;
 
	public function __construct($kvPairs) {
		$this->kvPairs = $kvPairs;
	}
 
	public function filter($item) {
		$result = true;
 
		foreach ($this->kvPairs as $key => $value) {
			if ($item[$key] !== $value)
				$result &= false;
		}
 
		return $result;
	}
}
 
class KeyComparator implements Comparator {
	protected $direction;
	protected $transform;
	protected $key;
 
	public function __construct($key, $direction = SortDirection::Ascending, $transform = null) {
		$this->key = $key;
		$this->direction = $direction;
		$this->transform = $transform;
	}
 
	public function compare($a, $b) {
		$a = $a[$this->key];
		$b = $b[$this->key];
 
		if ($this->transform) {
			$a = $this->transform($a);
			$b = $this->transform($b);
		}
 
		return $a === $b ? 0 : (($a > $b ? 1 : -1) * $this->direction);
	}
}
 
class MultipleKeyComparator implements Comparator {
	protected $keys;
 
	public function __construct($keys) {
		$this->keys = $keys;
	}
 
	public function compare($a, $b) {
		$result = 0;
 
		foreach ($this->keys as $comparator) {
			if ($comparator instanceof KeyComparator) {
				$result = $comparator->compare($a, $b);
 
				if ($result !== 0) return $result;
			}
		}
 
		return $result;
	}
}
 
 
$array = array (
	'1' => array ('type' => 'blah2', 'category' => 'cat2', 'exp_range' => 'this_week' ),
    '2' => array ('type' => 'blah1', 'category' => 'cat1', 'exp_range' => 'this_week' ),
    '3' => array ('type' => 'blah1', 'category' => 'cat2', 'exp_range' => 'next_week' ),
    '4' => array ('type' => 'blah1', 'category' => 'cat1', 'exp_range' => 'next_week' )
);
 
$comparator = new MultipleKeyComparator(array(
	new KeyComparator('type'),
	new KeyComparator('exp_range')
));
 
usort($array, array($comparator, 'compare'));
 
echo "Sorted by multiple fields\n";
print_r($array);
 
$filter = new MultipleKeyValueFilter(array(
	'type' => 'blah1'
));
 
echo "Filtered by multiple fields\n";
print_r(array_filter($array, array($filter, 'filter')));

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