#include "iterator/join_iterator.h"

#include <vector>

#include "xcode_gtest_helper.h"

using iterator::EndAwareIterator;
using iterator::JoinIterator;

using testing::Not;

TEST(JoinIterator, FirstDereferencedElemIsTheFirstInTheChain) {
  std::vector<std::vector<int>> mv{{1, 2, 3}, {4, 5, 6}};
  EXPECT_THAT(*JoinIterator(mv), mv[0][0]);
}

TEST(JoinIterator, HoldsReferenceToContainedElements) {
  std::vector<std::vector<int>> mv{{1, 2, 3}, {4, 5, 6}};
  EXPECT_THAT(JoinIterator(mv).operator->(), &mv[0][0]);
}

TEST(JoinIterator, EmptyContainerBeginIsEnd) {
  std::vector<std::vector<int>> mv{{1, 2, 3}, {4, 5, 6}};
  JoinIterator it(mv);
  EXPECT_THAT(it, Not(iterator::sentinel));

  mv.clear();
  EXPECT_THAT(JoinIterator(mv), iterator::sentinel);
}

// TODO: This ought to be implemented as a compiles-test
TEST(JoinIterator, CanCastCompatibleIterators) {
  std::vector<std::vector<int>> mv{{1, 2, 3}, {4, 5, 6}};
  JoinIterator it(mv);
  iterator::JoinIterator<decltype(mv)::const_iterator>{it};
}

TEST(JoinIterator, CanAccessInternalIterator) {
  std::vector<std::vector<int>> mv{{1, 2, 3}, {4, 5, 6}};
  auto eai = EndAwareIterator(mv);
  JoinIterator it(eai);
  EXPECT_THAT(it.outer_iterator(), eai);
}

TEST(JoinIterator, CanAccessChildIterator) {
  std::vector<std::vector<int>> mv{{1, 2, 3}, {4, 5, 6}};
  JoinIterator it(mv);
  EXPECT_THAT(it.inner_iterator(), EndAwareIterator(mv[0]));
}

TEST(JoinIterator, PreIncrementAdvancesIterator) {
  std::vector<std::vector<int>> mv{{1, 2, 3}, {4, 5, 6}};
  JoinIterator it(mv);
  EXPECT_THAT(*it, 1);
  EXPECT_THAT(*++it, 2);
  EXPECT_THAT(*it, 2);
}

TEST(JoinIterator, PostIncrementReturnsCopyOfPrev) {
  std::vector<std::vector<int>> mv{{1, 2, 3}, {4, 5, 6}};
  JoinIterator it(mv);
  EXPECT_THAT(*it, 1);
  EXPECT_THAT(*it++, 1);
  EXPECT_THAT(*it, 2);
}

TEST(JoinIterator, MovesFromListToListWhenReachingEnd) {
  std::vector<std::vector<int>> mv{{1, 2, 3}, {4, 5, 6}};
  JoinIterator it(mv);
  std::advance(it, 2);
  EXPECT_THAT(*++it, mv[1][0]);
}

TEST(JoinIterator, SkipsOverEmptyElements) {
  std::vector<std::vector<int>> mv{{1, 2, 3}, {}, {4, 5, 6}};
  JoinIterator it(mv);
  std::advance(it, 2);
  EXPECT_THAT(*++it, mv[2][0]);
}