package LinkedListModule
import Wurstunit

public module LinkedListModule
	static thistype first = null
	static thistype last = null
	static int size = 0
	thistype prev
	thistype next

	construct()
		size++
		if size == 1
			first = this
			prev = null
		else
			prev = last
			last.next = this
			first.prev = this
		next = null
		last = this

	static function getFirst() returns thistype
		return first

	function getNext() returns thistype
		return next

	function getPrev() returns thistype
		return prev


	function remove()
		size--
		if this != first
			prev.next = next
		else
			first = next
		if this != last
			next.prev = prev
		else
			last = prev


	ondestroy
		remove()

	/** an iterator which iterates over all instances of this class */
	static function iterator() returns Iterator
		return new Iterator()

	static class Iterator
		LinkedListModule.thistype current = first
		function hasNext() returns boolean
			return current != null

		function next() returns LinkedListModule.thistype
			let res = current
			current = current.next
			return res

		function close()
			destroy this



class MyClass
	use LinkedListModule
	string str
	construct(string str)
		this.str = str

function allToString() returns string
	string res = ""
 	for x in MyClass
		res += x.str
	return res

@test
function test()
	let a = new MyClass("a")
	let b = new MyClass("b")
	let c = new MyClass("c")
	let d = new MyClass("d")

 	assertTrue(allToString() == "abcd")
 	destroy c
 	assertTrue(allToString() == "abd")
 	destroy d
 	assertTrue(allToString() == "ab")
 	destroy a
 	assertTrue(allToString() == "b")
 	destroy b
 	assertTrue(allToString() == "")

 @test
 function testDestroy()
 	new MyClass("a")
	let b = new MyClass("b")
	new MyClass("c")
	new MyClass("d")
 	string s = ""
 	for x in MyClass
		s += x.str
		if x == b
			destroy x
	assertTrue(s=="abcd")
	assertTrue(allToString() == "acd")
	for x in MyClass
		destroy x
	assertTrue(allToString() == "")