#include <c10/util/irange.h>
#include "StoreTestCommon.hpp"

#include <cstdlib>
#include <future>
#include <iostream>
#include <system_error>
#include <thread>

#include <gtest/gtest.h>

#include <torch/csrc/distributed/c10d/PrefixStore.hpp>
#include <torch/csrc/distributed/c10d/TCPStore.hpp>

constexpr int64_t kShortStoreTimeoutMillis = 100;
constexpr int defaultTimeout = 20;

c10::intrusive_ptr<c10d::TCPStore> _createServer(
    bool useLibUV,
    int numWorkers = 1,
    int timeout = defaultTimeout) {
  return c10::make_intrusive<c10d::TCPStore>(
      "127.0.0.1",
      c10d::TCPStoreOptions{
          /* port */ 0,
          /* isServer */ true,
          numWorkers,
          /* waitWorkers */ false,
          /* timeout */ std::chrono::seconds(timeout),
          /* multiTenant */ false,
          /* masterListenFd */ c10::nullopt,
          /* useLibUV*/ useLibUV});
}

// Different ports for different tests.
void testHelper(bool useLibUV, const std::string& prefix = "") {
  constexpr auto numThreads = 16;
  constexpr auto numWorkers = numThreads + 1;

  auto serverTCPStore = _createServer(useLibUV, numWorkers);

  auto serverStore =
      c10::make_intrusive<c10d::PrefixStore>(prefix, serverTCPStore);
  // server store
  auto serverThread = std::thread([&serverStore, &serverTCPStore] {
    // Wait for all workers to join.
    serverTCPStore->waitForWorkers();

    // Basic set/get on the server store
    c10d::test::set(*serverStore, "key0", "value0");
    c10d::test::set(*serverStore, "key1", "value1");
    c10d::test::set(*serverStore, "key2", "value2");
    c10d::test::check(*serverStore, "key0", "value0");
    c10d::test::check(*serverStore, "key1", "value1");
    c10d::test::check(*serverStore, "key2", "value2");
    serverStore->add("counter", 1);
    auto numKeys = serverStore->getNumKeys();
    // We expect 5 keys since 3 are added above, 'counter' is added by the
    // helper thread, and the init key to coordinate workers.
    EXPECT_EQ(numKeys, 5);

    // Check compareSet, does not check return value
    c10d::test::compareSet(
        *serverStore, "key0", "wrongExpectedValue", "newValue");
    c10d::test::check(*serverStore, "key0", "value0");
    c10d::test::compareSet(*serverStore, "key0", "value0", "newValue");
    c10d::test::check(*serverStore, "key0", "newValue");

    auto delSuccess = serverStore->deleteKey("key0");
    // Ensure that the key was successfully deleted
    EXPECT_TRUE(delSuccess);
    auto delFailure = serverStore->deleteKey("badKeyName");
    // The key was not in the store so the delete operation should have failed
    // and returned false.
    EXPECT_FALSE(delFailure);
    numKeys = serverStore->getNumKeys();
    EXPECT_EQ(numKeys, 4);
    auto timeout = std::chrono::milliseconds(kShortStoreTimeoutMillis);
    serverStore->setTimeout(timeout);
    EXPECT_THROW(serverStore->get("key0"), c10::Error);
  });

  // Hammer on TCPStore
  std::vector<std::thread> threads;
  constexpr auto numIterations = 1000;
  c10d::test::Semaphore sem1, sem2;

  c10d::TCPStoreOptions opts{};
  opts.port = serverTCPStore->getPort();
  opts.numWorkers = numWorkers;

  // Each thread will have a client store to send/recv data
  std::vector<c10::intrusive_ptr<c10d::TCPStore>> clientTCPStores;
  std::vector<c10::intrusive_ptr<c10d::PrefixStore>> clientStores;
  for (const auto i : c10::irange(numThreads)) {
    clientTCPStores.push_back(
        c10::make_intrusive<c10d::TCPStore>("127.0.0.1", opts));
    clientStores.push_back(
        c10::make_intrusive<c10d::PrefixStore>(prefix, clientTCPStores[i]));
  }

  std::string expectedCounterRes =
      std::to_string(numThreads * numIterations + 1);

  for (const auto i : c10::irange(numThreads)) {
    threads.emplace_back(
        std::thread([=, &sem1, &sem2, &clientStores, &expectedCounterRes] {
          for (C10_UNUSED const auto j : c10::irange(numIterations)) {
            clientStores[i]->add("counter", 1);
          }
          // Let each thread set and get key on its client store
          std::string key = "thread_" + std::to_string(i);
          for (const auto j : c10::irange(numIterations)) {
            std::string val = "thread_val_" + std::to_string(j);
            c10d::test::set(*clientStores[i], key, val);
            c10d::test::check(*clientStores[i], key, val);
          }

          sem1.post();
          sem2.wait();
          // Check the counter results
          c10d::test::check(*clientStores[i], "counter", expectedCounterRes);
          // Now check other threads' written data
          for (const auto j : c10::irange(numThreads)) {
            if (j == i) {
              continue;
            }
            std::string key = "thread_" + std::to_string(i);
            std::string val = "thread_val_" + std::to_string(numIterations - 1);
            c10d::test::check(*clientStores[i], key, val);
          }
        }));
  }

  sem1.wait(numThreads);
  sem2.post(numThreads);

  for (auto& thread : threads) {
    thread.join();
  }

  serverThread.join();

  // Clear the store to test that client disconnect won't shutdown the store
  clientStores.clear();
  clientTCPStores.clear();

  // Check that the counter has the expected value
  c10d::test::check(*serverStore, "counter", expectedCounterRes);

  // Check that each threads' written data from the main thread
  for (const auto i : c10::irange(numThreads)) {
    std::string key = "thread_" + std::to_string(i);
    std::string val = "thread_val_" + std::to_string(numIterations - 1);
    c10d::test::check(*serverStore, key, val);
  }
}

TEST(TCPStoreTest, testHelper) {
  testHelper(false);
}

TEST(TCPStoreTest, testHelperUV) {
  testHelper(true);
}

TEST(TCPStoreTest, testHelperPrefix) {
  testHelper(false, "testPrefix");
}

TEST(TCPStoreTest, testHelperPrefixUV) {
  testHelper(true, "testPrefix");
}

TEST(TCPStoreTest, testCleanShutdown) {
  int numWorkers = 2;

  auto serverTCPStore = std::make_unique<c10d::TCPStore>(
      "127.0.0.1",
      0,
      numWorkers,
      true,
      std::chrono::seconds(defaultTimeout),
      /* wait */ false);
  c10d::test::set(*serverTCPStore, "key", "val");

  auto clientTCPStore = c10::make_intrusive<c10d::TCPStore>(
      "127.0.0.1",
      c10d::TCPStoreOptions{
          /* port */ serverTCPStore->getPort(),
          /* isServer */ false,
          numWorkers,
          /* waitWorkers */ false,
          /* timeout */ std::chrono::seconds(defaultTimeout)});
  clientTCPStore->get("key");

  auto clientThread = std::thread([&clientTCPStore] {
    EXPECT_THROW(clientTCPStore->get("invalid_key"), std::system_error);
  });

  // start server shutdown during a client request
  serverTCPStore = nullptr;

  clientThread.join();
}

void testMultiTenantStores(bool libUV) {
  c10d::TCPStoreOptions opts{};
  opts.isServer = true;
  opts.multiTenant = true;
  opts.useLibUV = libUV;

  // Construct two server stores on the same port.
  auto store1 = c10::make_intrusive<c10d::TCPStore>("localhost", opts);
  auto store2 = c10::make_intrusive<c10d::TCPStore>("localhost", opts);

  // Assert that the two stores share the same server.
  c10d::test::set(*store1, "key0", "value0");
  c10d::test::check(*store2, "key0", "value0");

  // Dispose the second instance and assert that the server is still alive.
  store2.reset();

  c10d::test::set(*store1, "key0", "value0");
  c10d::test::check(*store1, "key0", "value0");
}

TEST(TCPStoreTest, testMultiTenantStores) {
  testMultiTenantStores(false);
}

TEST(TCPStoreTest, testMultiTenantStoresUV) {
  testMultiTenantStores(true);
}