#include "iterator/end_aware_iterator.h"

#include <iostream>
#include <vector>

#include "xcode_gtest_helper.h"

using iterator::end_aware_iterator;

TEST(EndAwareIterator, IStreamIterator) {
  std::stringstream ss{"0 1 2 3"};
  end_aware_iterator eai{std::istream_iterator<int>(ss),
                         std::istream_iterator<int>()};

  EXPECT_TRUE(iterator::single_pass<decltype(eai)>);
}

// TODO: This ought to be implemented as a compiles-test
TEST(EndAwareIterator, CanCastCompatibleIterators) {
  std::vector<int> v{1, 2, 3, 4, 5};
  end_aware_iterator eai(v.begin(), v.end());

  end_aware_iterator<std::vector<int>::const_iterator>{eai};
}

TEST(EndAwareIterator, BeginWrapperIsEqualToBegin) {
  std::vector<int> v{1, 2, 3, 4, 5};

  EXPECT_EQ(*v.begin(), *end_aware_iterator(v.begin(), v.end()));
}

TEST(EndAwareIterator, MutableActionsArePassthrough) {
  std::vector<int> v{1, 2, 3, 4, 5};
  *end_aware_iterator(v.begin(), v.end()) = -1;

  EXPECT_EQ(v[0], -1);
}

TEST(EndAwareIterator, CanTellYouThatItsReachedEnd) {
  std::vector<int> v{1, 2, 3, 4, 5};
  end_aware_iterator it{v.end() - 1, v.end()};
  EXPECT_FALSE(it.at_end());
  ++it;
  EXPECT_EQ(it, end_aware_iterator(v.end(), v.end()));
  EXPECT_TRUE(it.at_end());
}

TEST(EndAwareIterator, EmptyIteratorIsEnd) {
  EXPECT_TRUE(end_aware_iterator<std::vector<int>::iterator>().at_end());
}

TEST(EndAwareIterator, PreIncrementAdvancesIterator) {
  std::vector<int> v{1, 2, 3, 4, 5};
  end_aware_iterator eai(v.begin(), v.end());

  EXPECT_EQ(*eai, 1);
  EXPECT_EQ(*++eai, 2);
  EXPECT_EQ(*eai, 2);
}

TEST(EndAwareIterator, PostIncrementReturnsCopyOfPrev) {
  std::vector<int> v{1, 2, 3, 4, 5};
  end_aware_iterator eai(v.begin(), v.end());

  EXPECT_EQ(*eai, 1);
  EXPECT_EQ(*eai++, 1);
  EXPECT_EQ(*eai, 2);
}

TEST(EndAwareIterator, CanIterateWithSentinel) {
  std::vector<int> v{1, 2, 3, 4, 5};
  size_t count{0};
  for (end_aware_iterator it(v); it != iterator::sentinel; ++it) {
    ++count;
  }

  EXPECT_EQ(count, 5);
}