#include "d_range.h"
#include "d_zip.h"
#include <array>
#include <vector>

#define BOOST_TEST_DYN_LINK
#define BOOST_TEST_MODULE Rebirth zip
#include <boost/test/unit_test.hpp>

/* Test that a zipped range is empty when the component range is empty.
 */
BOOST_AUTO_TEST_CASE(zip_empty)
{
	bool empty = true;
	std::array<int, 0> a;
	for (auto &&v : zip(a))
	{
		(void)v;
		empty = false;
	}
	BOOST_TEST(empty);
}

/* Test that a zipped range is the length of the first sequence.
 *
 * Note that there is no test for when the first sequence is longer than
 * the later ones, since such a test would increment some iterators past
 * their end.
 */
BOOST_AUTO_TEST_CASE(zip_length)
{
	unsigned count = 0;
	std::array<int, 2> a;
	short b[4];
	for (auto &&v : zip(a, b))
	{
		(void)v;
		++ count;
	}
	BOOST_TEST(count == a.size());
}

/* Test that a zipped value references the underlying storage.
 */
BOOST_AUTO_TEST_CASE(zip_passthrough_modifications)
{
	std::array<int, 1> a{{1}};
	short b[1]{2};
	for (auto &&v : zip(a, b))
	{
		++ std::get<0>(v);
		++ std::get<1>(v);
	}
	BOOST_TEST(a[0] == 2);
	BOOST_TEST(b[0] == 3);
}

/* Test that a zipped range can zip an xrange, and produce the correct
 * underlying value.
 */
BOOST_AUTO_TEST_CASE(zip_xrange)
{
	for (auto &&v : zip(xrange(1u)))
	{
		BOOST_TEST(std::get<0>(v) == 0);
	}
}

/* Type system tests can be done at compile-time.  Applying them as
 * static_assert can produce a better error message than letting it fail
 * at runtime.
 */
template <typename Expected, typename zip_type, typename index_type = typename zip_type::index_type>
struct assert_index_type : std::true_type
{
	static_assert(std::is_same<Expected, index_type>::value);
};

static_assert(assert_index_type<void, decltype(zip(std::declval<std::array<int, 1>>(), std::declval<std::array<float, 1>>()))>::value);

template <typename T>
struct custom_index_type : std::array<int, 1>
{
	using index_type = T;
	void operator[](typename std::remove_reference<T>::type);
};
enum class e1 : unsigned char;
enum class e2 : unsigned char;

static_assert(assert_index_type<e1, decltype(zip(std::declval<custom_index_type<e1>&>(), std::declval<custom_index_type<e1>&>()))>::value);
static_assert(assert_index_type<void, decltype(zip(std::declval<custom_index_type<e1>&>(), std::declval<custom_index_type<e2>&>()))>::value);