#include <dropwhile.hpp>

#include "helpers.hpp"

#include <iterator>

#include <string>

#include <vector>

#include "catch.hpp"

using iter::dropwhile;

using Vec = const std::vector<int>;

TEST_CASE("dropwhile: skips initial elements", "[dropwhile]") {

Vec ns{1, 2, 3, 4, 5, 6, 7, 8};

std::vector<int> v;

SECTION("Normal call") {

auto d = dropwhile([](int i) { return i < 5; }, ns);

v.assign(std::begin(d), std::end(d));

}

SECTION("Pipe") {

auto d = ns | dropwhile([](int i) { return i < 5; });

v.assign(std::begin(d), std::end(d));

}

Vec vc = {5, 6, 7, 8};

REQUIRE(v == vc);

}

TEST_CASE(

"dropwhile: Works with different begin and end types", "[dropwhile]") {

CharRange cr{'f'};

auto d = dropwhile([](char c) { return c < 'c'; }, cr);

Vec v(d.begin(), d.end());

Vec vc{'c', 'd', 'e'};

REQUIRE(v == vc);

}

TEST_CASE("dropwhile: doesn't skip anything if it shouldn't", "[dropwhile]") {

Vec ns{3, 4, 5, 6};

auto d = dropwhile([](int i) { return i < 3; }, ns);

Vec v(std::begin(d), std::end(d));

Vec vc = {3, 4, 5, 6};

REQUIRE(v == vc);

}

TEST_CASE("dropwhile: skips all elements when all are true under predicate",

"[dropwhile]") {

Vec ns{3, 4, 5, 6};

auto d = dropwhile([](int i) { return i != 0; }, ns);

REQUIRE(std::begin(d) == std::end(d));

}

TEST_CASE("dropwhile: identity", "[dropwhile]") {

Vec ns{1, 2, 0, 3, 1, 0};

auto d = dropwhile(ns);

Vec v(std::begin(d), std::end(d));

Vec vc = {0, 3, 1, 0};

REQUIRE(v == vc);

}

TEST_CASE("dropwhile: empty case is empty", "[dropwhile]") {

Vec ns{};

auto d = dropwhile([](int i) { return i != 0; }, ns);

REQUIRE(std::begin(d) == std::end(d));

}

TEST_CASE("dropwhile: only drops from beginning", "[dropwhile]") {

Vec ns{1, 2, 3, 4, 5, 6, 5, 4, 3, 2, 1};

auto d = dropwhile([](int i) { return i < 5; }, ns);

Vec v(std::begin(d), std::end(d));

Vec vc = {5, 6, 5, 4, 3, 2, 1};

REQUIRE(v == vc);

}

TEST_CASE("dropwhile: operator->", "[dropwhile]") {

std::vector<std::string> vs = {"a", "ab", "abcdef", "abcdefghi"};

auto d = dropwhile([](const std::string& str) { return str.size() < 3; }, vs);

auto it = std::begin(d);

REQUIRE(it->size() == 6);

}

namespace {

int less_than_five(int i) {

return i < 5;

}

}

TEST_CASE("dropwhile: works with function pointer", "[dropwhile]") {

Vec ns{1, 2, 3, 4, 5, 6, 7, 8};

auto d = dropwhile(less_than_five, ns);

Vec v(std::begin(d), std::end(d));

Vec vc = {5, 6, 7, 8};

REQUIRE(v == vc);

}

TEST_CASE("dropwhile: binds to lvalues, moves rvalues", "[dropwhile]") {

itertest::BasicIterable<int> bi{1, 2, 3, 4};

SECTION("binds to lvalues") {

dropwhile(less_than_five, bi);

REQUIRE_FALSE(bi.was_moved_from());

}

SECTION("moves rvalues") {

dropwhile(less_than_five, std::move(bi));

REQUIRE(bi.was_moved_from());

}

}

TEST_CASE(

"dropwhile: doesn't move or copy elements of iterable", "[dropwhile]") {

constexpr itertest::SolidInt arr[] = {{6}, {7}, {8}};

for (auto&& i :

dropwhile([](const itertest::SolidInt&) { return false; }, arr)) {

(void)i;

}

}

TEST_CASE("dropwhile: iterator meets requirements", "[dropwhile]") {

std::string s{};

auto c = dropwhile([] { return true; }, s);

REQUIRE(itertest::IsIterator<decltype(std::begin(c))>::value);

}

template <typename T, typename U>

using ImpT = decltype(dropwhile(std::declval<T>(), std::declval<U>()));

TEST_CASE("dropwhile: has correct ctor and assign ops", "[dropwhile]") {

using T1 = ImpT<bool (*)(char c), std::string&>;

auto lam = [](char) { return false; };

using T2 = ImpT<decltype(lam), std::string>;

REQUIRE(itertest::IsMoveConstructibleOnly<T1>::value);

REQUIRE(itertest::IsMoveConstructibleOnly<T2>::value);

}