#include <chrono>
#include <future>
#include <iostream>
#include <random>
#include <thread>

#include <glog/logging.h>

#include "data_structures/bitset/dynamic_bitset.hpp"
#include "data_structures/concurrent/concurrent_list.hpp"
#include "data_structures/concurrent/concurrent_map.hpp"
#include "data_structures/concurrent/concurrent_set.hpp"
#include "data_structures/concurrent/skiplist.hpp"

// NOTE: this file is highly coupled to data_structures
// TODO: REFACTOR

// Sets max number of threads that will be used in concurrent tests.
constexpr int max_no_threads = 8;

using std::cout;
using std::endl;
using map_t = ConcurrentMap<int, int>;
using set_t = ConcurrentSet<int>;

using namespace std::chrono_literals;

// Returns uniform random size_t generator from range [0,n>
auto rand_gen(size_t n) {
  std::default_random_engine generator;
  std::uniform_int_distribution<size_t> distribution(0, n - 1);
  return std::bind(distribution, generator);
}

// Returns random bool generator with distribution of 1 true for n false.
auto rand_gen_bool(size_t n = 1) {
  auto gen = rand_gen(n + 1);
  return [=]() mutable { return gen() == 0; };
}

// Checks for all owned keys if there data is data.
template <typename S>
void check_present_same(typename S::Accessor &acc, size_t data,
                        std::vector<size_t> &owned) {
  for (auto num : owned) {
    CHECK(acc.find(num)->second == data) << "My data is present and my";
  }
}

// Checks for all owned.second keys if there data is owned.first.
template <typename S>
void check_present_same(typename S::Accessor &acc,
                        std::pair<size_t, std::vector<size_t>> &owned) {
  check_present_same<S>(acc, owned.first, owned.second);
}

// Checks if reported size and traversed size are equal to given size.
template <typename S>
void check_size_list(S &acc, long long size) {
  // check size

  CHECK(acc.size() == size)
      << "Size should be " << size << ", but size is " << acc.size();

  // check count

  size_t iterator_counter = 0;

  for ([[gnu::unused]] auto elem : acc) {
    ++iterator_counter;
  }
  CHECK(static_cast<int64_t>(iterator_counter) == size)
      << "Iterator count should be " << size << ", but size is "
      << iterator_counter;
}
template <typename S>
void check_size(typename S::Accessor &acc, long long size) {
  // check size

  CHECK(acc.size() == size)
      << "Size should be " << size << ", but size is " << acc.size();

  // check count

  size_t iterator_counter = 0;

  for ([[gnu::unused]] auto elem : acc) {
    ++iterator_counter;
  }
  CHECK(static_cast<int64_t>(iterator_counter) == size)
      << "Iterator count should be " << size << ", but size is "
      << iterator_counter;
}

// Checks if order in list is maintened. It expects map
template <typename S>
void check_order(typename S::Accessor &acc) {
  if (acc.begin() != acc.end()) {
    auto last = acc.begin()->first;
    for (auto elem : acc) {
      if (!(last <= elem))
        std::cout << "Order isn't maintained. Before was: " << last
                  << " next is " << elem.first << "\n";
      last = elem.first;
    }
  }
}

void check_zero(size_t key_range, long array[], const char *str) {
  for (int i = 0; i < static_cast<int>(key_range); i++) {
    CHECK(array[i] == 0) << str << " doesn't hold it's guarantees. It has "
                         << array[i] << " extra elements.";
  }
}

void check_set(DynamicBitset<> &db, std::vector<bool> &set) {
  for (int i = 0; i < static_cast<int>(set.size()); i++) {
    CHECK(!(set[i] ^ db.at(i))) << "Set constraints aren't fullfilled.";
  }
}

// Runs given function in threads_no threads and returns vector of futures for
// there
// results.
template <class R, typename S>
std::vector<std::future<std::pair<size_t, R>>> run(
    size_t threads_no, S &skiplist,
    std::function<R(typename S::Accessor, size_t)> f) {
  std::vector<std::future<std::pair<size_t, R>>> futures;

  for (size_t thread_i = 0; thread_i < threads_no; ++thread_i) {
    std::packaged_task<std::pair<size_t, R>()> task([&skiplist, f, thread_i]() {
      return std::pair<size_t, R>(thread_i, f(skiplist.access(), thread_i));
    });                                    // wrap the function
    futures.push_back(task.get_future());  // get a future
    std::thread(std::move(task)).detach();
  }
  return futures;
}

// Runs given function in threads_no threads and returns vector of futures for
// there
// results.
template <class R>
std::vector<std::future<std::pair<size_t, R>>> run(size_t threads_no,
                                                   std::function<R(size_t)> f) {
  std::vector<std::future<std::pair<size_t, R>>> futures;

  for (size_t thread_i = 0; thread_i < threads_no; ++thread_i) {
    std::packaged_task<std::pair<size_t, R>()> task([f, thread_i]() {
      return std::pair<size_t, R>(thread_i, f(thread_i));
    });                                    // wrap the function
    futures.push_back(task.get_future());  // get a future
    std::thread(std::move(task)).detach();
  }
  return futures;
}

// Collects all data from futures.
template <class R>
auto collect(std::vector<std::future<R>> &collect) {
  std::vector<R> collection;
  for (auto &fut : collect) {
    collection.push_back(fut.get());
  }
  return collection;
}

std::vector<bool> collect_set(
    std::vector<std::future<std::pair<size_t, std::vector<bool>>>> &&futures) {
  std::vector<bool> set;
  for (auto &data : collect(futures)) {
    set.resize(data.second.size());
    for (int i = 0; i < static_cast<int>(data.second.size()); i++) {
      set[i] = set[i] | data.second[i];
    }
  }
  return set;
}

// Returns object which tracs in owned which (key,data) where added and
// downcounts.
template <class K, class D, class S>
auto insert_try(typename S::Accessor &acc, long long &downcount,
                std::vector<K> &owned) {
  return [&](K key, D data) mutable {
    if (acc.insert(key, data).second) {
      downcount--;
      owned.push_back(key);
    }
  };
}