// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.

// This unit test belongs in gutil, but it depends on test_main which is
// part of util.
#include "kudu/gutil/map-util.h"

#include <map>
#include <memory>
#include <set>
#include <string>
#include <unordered_map>
#include <utility>
#include <vector>

#include <gtest/gtest.h>

#include "kudu/gutil/strings/stringpiece.h"

template <class X> struct GoodFastHash;

using std::map;
using std::set;
using std::string;
using std::shared_ptr;
using std::unique_ptr;
using std::unordered_map;
using std::vector;

namespace kudu {

TEST(FloorTest, TestMapUtil) {
  map<int, int> my_map;

  ASSERT_EQ(nullptr, FindFloorOrNull(my_map, 5));

  my_map[5] = 5;
  ASSERT_EQ(5, *FindFloorOrNull(my_map, 6));
  ASSERT_EQ(5, *FindFloorOrNull(my_map, 5));
  ASSERT_EQ(nullptr, FindFloorOrNull(my_map, 4));

  my_map[1] = 1;
  ASSERT_EQ(5, *FindFloorOrNull(my_map, 6));
  ASSERT_EQ(5, *FindFloorOrNull(my_map, 5));
  ASSERT_EQ(1, *FindFloorOrNull(my_map, 4));
  ASSERT_EQ(1, *FindFloorOrNull(my_map, 1));
  ASSERT_EQ(nullptr, FindFloorOrNull(my_map, 0));
}

TEST(ComputeIfAbsentTest, TestComputeIfAbsent) {
  map<string, string> my_map;
  auto result = ComputeIfAbsent(&my_map, "key", []{ return "hello_world"; });
  ASSERT_EQ(*result, "hello_world");
  auto result2 = ComputeIfAbsent(&my_map, "key", [] { return "hello_world2"; });
  ASSERT_EQ(*result2, "hello_world");
}

TEST(ComputeIfAbsentTest, TestComputeIfAbsentAndReturnAbsense) {
  map<string, string> my_map;
  auto result = ComputeIfAbsentReturnAbsense(&my_map, "key", []{ return "hello_world"; });
  ASSERT_TRUE(result.second);
  ASSERT_EQ(*result.first, "hello_world");
  auto result2 = ComputeIfAbsentReturnAbsense(&my_map, "key", [] { return "hello_world2"; });
  ASSERT_FALSE(result2.second);
  ASSERT_EQ(*result2.first, "hello_world");
}

namespace {
// Simple struct to act as a container for a string. While not necessary per
// se, this is more representative of the expected usage of
// ComputePairIfAbsent* (i.e. pointing to internal state of more complex
// objects).
struct SimpleStruct {
  string str;
};
} // anonymous namespace

TEST(ComputePairIfAbsentTest, TestComputePairDestructState) {
  unordered_map<StringPiece, int, GoodFastHash<StringPiece>> string_to_idx;
  const string kBigKey = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa";
  string big_key = kBigKey;
  vector<SimpleStruct> big_structs;
  auto result = ComputePairIfAbsentReturnAbsense(&string_to_idx, big_key,
      [&] () -> std::pair<StringPiece, int> {
        int idx = big_structs.size();
        big_structs.emplace_back(SimpleStruct({ big_key }));
        return { big_structs.back().str, idx };
      });
  // Clear the original key state. This shouldn't have any effect on the map.
  big_key.clear();
  ASSERT_TRUE(result.second);
  ASSERT_EQ(*result.first, FindOrDie(string_to_idx, kBigKey));
  ASSERT_EQ(kBigKey, big_structs[*result.first].str);
}

TEST(FindPointeeOrNullTest, TestFindPointeeOrNull) {
  map<string, unique_ptr<string>> my_map;
  auto iter = my_map.emplace("key", unique_ptr<string>(new string("hello_world")));
  ASSERT_TRUE(iter.second);
  string* value = FindPointeeOrNull(my_map, "key");
  ASSERT_TRUE(value != nullptr);
  ASSERT_EQ(*value, "hello_world");
  my_map.erase(iter.first);
  value = FindPointeeOrNull(my_map, "key");
  ASSERT_TRUE(value == nullptr);
}

TEST(EraseKeyReturnValuePtrTest, TestRawAndSmartSmartPointers) {
  map<string, unique_ptr<string>> my_map;
  unique_ptr<string> value = EraseKeyReturnValuePtr(&my_map, "key");
  ASSERT_TRUE(value.get() == nullptr);
  my_map.emplace("key", unique_ptr<string>(new string("hello_world")));
  value = EraseKeyReturnValuePtr(&my_map, "key");
  ASSERT_EQ(*value, "hello_world");
  value.reset();
  value = EraseKeyReturnValuePtr(&my_map, "key");
  ASSERT_TRUE(value.get() == nullptr);
  map<string, shared_ptr<string>> my_map2;
  shared_ptr<string> value2 = EraseKeyReturnValuePtr(&my_map2, "key");
  ASSERT_TRUE(value2.get() == nullptr);
  my_map2.emplace("key", std::make_shared<string>("hello_world"));
  value2 = EraseKeyReturnValuePtr(&my_map2, "key");
  ASSERT_EQ(*value2, "hello_world");
  map<string, string*> my_map_raw;
  my_map_raw.emplace("key", new string("hello_world"));
  value.reset(EraseKeyReturnValuePtr(&my_map_raw, "key"));
  ASSERT_EQ(*value, "hello_world");
}

TEST(EmplaceTest, TestEmplace) {
  string key1("k");
  string key2("k2");
  // Map with move-only value type.
  map<string, unique_ptr<string>> my_map;
  unique_ptr<string> val(new string("foo"));
  ASSERT_TRUE(EmplaceIfNotPresent(&my_map, key1, std::move(val)));
  ASSERT_TRUE(ContainsKey(my_map, key1));
  ASSERT_FALSE(EmplaceIfNotPresent(&my_map, key1, nullptr))
      << "Should return false for already-present";

  val = unique_ptr<string>(new string("bar"));
  ASSERT_TRUE(EmplaceOrUpdate(&my_map, key2, std::move(val)));
  ASSERT_TRUE(ContainsKey(my_map, key2));
  ASSERT_EQ("bar", *FindOrDie(my_map, key2));
  val = unique_ptr<string>(new string("foobar"));
  ASSERT_FALSE(EmplaceOrUpdate(&my_map, key2, std::move(val)));
  ASSERT_EQ("foobar", *FindOrDie(my_map, key2));
}

TEST(LookupOrEmplaceTest, IntMap) {
  const string key = "mega";
  map<string, int> int_map;

  {
    const auto& val = LookupOrEmplace(&int_map, key, 0);
    ASSERT_EQ(0, val);
    auto* val_ptr = FindOrNull(int_map, key);
    ASSERT_NE(nullptr, val_ptr);
    ASSERT_EQ(0, *val_ptr);
  }

  {
    auto& val = LookupOrEmplace(&int_map, key, 10);
    ASSERT_EQ(0, val);
    ++val;
    auto* val_ptr = FindOrNull(int_map, key);
    ASSERT_NE(nullptr, val_ptr);
    ASSERT_EQ(1, *val_ptr);
  }

  {
    LookupOrEmplace(&int_map, key, 100) += 1000;
    auto* val_ptr = FindOrNull(int_map, key);
    ASSERT_NE(nullptr, val_ptr);
    ASSERT_EQ(1001, *val_ptr);
  }
}

TEST(LookupOrEmplaceTest, UniquePtrMap) {
  constexpr int key = 0;
  const string ref_str = "turbo";
  map<int, unique_ptr<string>> uptr_map;

  {
    unique_ptr<string> val(new string(ref_str));
    const auto& lookup_val = LookupOrEmplace(&uptr_map, key, std::move(val));
    ASSERT_EQ(nullptr, val.get());
    ASSERT_NE(nullptr, lookup_val.get());
    ASSERT_EQ(ref_str, *lookup_val);
  }

  {
    unique_ptr<string> val(new string("giga"));
    auto& lookup_val = LookupOrEmplace(&uptr_map, key, std::move(val));
    ASSERT_NE(nullptr, lookup_val.get());
    ASSERT_EQ(ref_str, *lookup_val);
    // Update the stored value.
    *lookup_val = "giga";
  }

  {
    unique_ptr<string> val(new string(ref_str));
    const auto& lookup_val = LookupOrEmplace(&uptr_map, key, std::move(val));
    ASSERT_NE(nullptr, lookup_val.get());
    ASSERT_EQ("giga", *lookup_val);
  }
}

TEST(EmplaceOrDieTest, MapLikeContainer) {
  constexpr int key = 0;
  const string ref_value_0 = "turbo";
  const string ref_value_1 = "giga";
  map<int, string> int_to_string;

  {
    auto& mapped = EmplaceOrDie(&int_to_string, key, "turbo");
    ASSERT_EQ(ref_value_0, mapped);
    mapped = "giga";
  }
  {
    const auto& mapped = FindOrDie(int_to_string, key);
    ASSERT_EQ(ref_value_1, mapped);
  }
}

TEST(EmplaceOrDieTest, SetLikeContainer) {
  const string ref_str = "turbo";
  set<string> strings;

  auto& value = EmplaceOrDie(&strings, "turbo");
  ASSERT_EQ(ref_str, value);
}

} // namespace kudu