/** ==========================================================================
* 2013 by KjellKod.cc. This is PUBLIC DOMAIN to use at your own risk and comes
* with no warranties. This code is yours to share, use and modify with no
* strings attached and no restrictions or obligations.
 *
 * For more information see g3log/LICENSE or refer refer to http://unlicense.org
* ============================================================================*/

#include <gtest/gtest.h>
#include <iostream>
#include <atomic>
#include <vector>
#include <memory>
#include <thread>
#include <chrono>
#include <string>
#include <future>
#include <g3log/generated_definitions.hpp>
#include "testing_helpers.h"
#include "g3log/logmessage.hpp"
#include "g3log/logworker.hpp"


using namespace testing_helpers;
using namespace std;
TEST(Sink, OneSink) {
   using namespace g3;
   AtomicBoolPtr flag = make_shared < atomic<bool >> (false);
   AtomicIntPtr count = make_shared < atomic<int >> (0);
   {
      auto worker = g3::LogWorker::createLogWorker();
      auto handle = worker->addSink(std::make_unique<ScopedSetTrue>(flag, count), &ScopedSetTrue::ReceiveMsg);
      EXPECT_FALSE(flag->load());
      EXPECT_TRUE(0 == count->load());
      LogMessagePtr message{std::make_unique<LogMessage>("test", 0, "test", DEBUG)};
      message.get()->write().append("this message should trigger an atomic increment at the sink");
      worker->save(message);
   }
   EXPECT_TRUE(flag->load());
   EXPECT_TRUE(1 == count->load());
}



TEST(Sink, OneSinkRemove) {
   using namespace g3;
   AtomicBoolPtr flag = make_shared < atomic<bool >> (false);
   AtomicIntPtr count = make_shared < atomic<int >> (0);
   {
      auto worker = g3::LogWorker::createLogWorker();
      auto handle = worker->addSink(std::make_unique<ScopedSetTrue>(flag, count), &ScopedSetTrue::ReceiveMsg);
      EXPECT_FALSE(flag->load());
      EXPECT_TRUE(0 == count->load());
      LogMessagePtr message1{std::make_unique<LogMessage>("test", 0, "test", DEBUG)};
      message1.get()->write().append("this message should trigger an atomic increment at the sink");
      worker->save(message1);

      worker->removeSink(std::move(handle));
      EXPECT_TRUE(flag->load());
      EXPECT_TRUE(1 == count->load());

      LogMessagePtr message2{std::make_unique<LogMessage>("test", 0, "test", DEBUG)};
      message2.get()->write().append("this message is issued after all sinks are removed");
      worker->save(message2);
   }
   EXPECT_TRUE(1 == count->load());
}

// just compile test
TEST(Sink, DefaultSinkRemove){
   using namespace g3;
   AtomicBoolPtr flag = make_shared < atomic<bool >> (false);
   AtomicIntPtr count = make_shared < atomic<int >> (0);
   {
      auto worker = g3::LogWorker::createLogWorker();
      auto handle1 = worker->addDefaultLogger("test1",  "./");
      auto handle2 = worker->addDefaultLogger("test2",  "./");
      worker->removeSink(std::move(handle1));
      worker->removeAllSinks();
   }
}

TEST(Sink, NullSinkRemove) {
   using namespace g3;
   AtomicBoolPtr flag = make_shared < atomic<bool >> (false);
   AtomicIntPtr count = make_shared < atomic<int >> (0);
   {
      auto worker = g3::LogWorker::createLogWorker();
      std::unique_ptr<g3::SinkHandle<ScopedSetTrue>> nullsink;
      worker->removeSink(std::move(nullsink));
   }
}



namespace {
   using AtomicBoolPtr =  std::shared_ptr<std::atomic<bool>>;
   using AtomicIntPtr =  std::shared_ptr<std::atomic<int>>;
   using BoolList =  vector<AtomicBoolPtr>;
   using IntVector =  vector<AtomicIntPtr>;

   size_t countDestroyedFlags(BoolList& flags) {
      size_t destroyed_count = 0;
      for (auto& flag : flags) {
         if (flag->load()) {
            ++destroyed_count;
         }
      }
      return destroyed_count;
   }

   bool expectedMessagesPerSink(const size_t expected, IntVector& messages) {
      bool result = true;
      for (auto& count : messages) {
         result = result && (count->load() == expected);
      }
      return result;
   }

   size_t countTotalMessages(IntVector& messages) {
      size_t total_count = 0;
      for (auto& count : messages) {
         total_count += count->load();
      }
      return total_count;
   }


}

TEST(ConceptSink, OneHundredSinks) {
   using namespace g3;
   BoolList flags;
   IntVector counts;

   size_t kNumberOfItems = 100;
   for (size_t index = 0; index < kNumberOfItems; ++index) {
      flags.push_back(make_shared < atomic<bool >> (false));
      counts.push_back(make_shared < atomic<int >> (0));
   }

   {
      RestoreFileLogger logger{"./"};
      g3::LogWorker* worker = logger._scope->get(); //g3LogWorker::createLogWorker();
      size_t index = 0;
      for (auto& flag : flags) {
         auto& count = counts[index++];
         // ignore the handle
         worker->addSink(std::make_unique<ScopedSetTrue>(flag, count), &ScopedSetTrue::ReceiveMsg);
      }
      LogMessagePtr message1{std::make_unique<LogMessage>("test", 0, "test", DEBUG)};
      LogMessagePtr message2{std::make_unique<LogMessage>("test", 0, "test", DEBUG)};
      auto& write1 = message1.get()->write();
      write1.append("Hello to 100 receivers :)");
      worker->save(message1);

      auto& write2 = message2.get()->write();
      write2.append("Hello to 100 receivers :)");
      worker->save(message2);
      logger.reset();
   }
   // at the curly brace above the ScopedLogger will go out of scope and all the
   // 100 logging receivers will get their message to exit after all messages are
   // are processed
   auto destroyed = countDestroyedFlags(flags);
   auto messages = countTotalMessages(counts);
   ASSERT_TRUE(destroyed == kNumberOfItems);
   EXPECT_TRUE(expectedMessagesPerSink(2, counts));
   EXPECT_EQ(2 * kNumberOfItems, messages);
}

using SinkHandleT = std::unique_ptr<g3::SinkHandle<ScopedSetTrue>>;
void AddManySinks(size_t kNumberOfSinks, BoolList& flags, IntVector& counts,
                  std::vector<SinkHandleT>& sink_handles, g3::LogWorker* worker) {
   flags.clear();
   counts.clear();
   sink_handles.clear();
   sink_handles.reserve(kNumberOfSinks);
   for (size_t idx = 0; idx < kNumberOfSinks; ++idx) {
      flags.push_back(make_shared<atomic<bool>>(false));
      counts.push_back(make_shared<atomic<int>>(0));
      sink_handles.push_back(worker->addSink(std::make_unique<ScopedSetTrue>(flags[idx], counts[idx]), &ScopedSetTrue::ReceiveMsg));

   }
}

TEST(ConceptSink, OneHundredSinksRemoved) {
   using namespace g3;
   BoolList flags;
   IntVector counts;
   size_t kNumberOfItems = 100;
   std::vector<SinkHandleT> sink_handles;
   {
      RestoreFileLogger logger{"./"};
      g3::LogWorker* worker = logger._scope->get(); //think: g3LogWorker::createLogWorker();
      AddManySinks(kNumberOfItems, flags, counts, sink_handles, worker);
      LogMessagePtr message{std::make_unique<LogMessage>("test", 0, "test", DEBUG)};
      auto& write = message.get()->write();
      write.append("Hello to 100 receivers :)");
      worker->save(message);

      for (auto& x : sink_handles) {
         worker->removeSink(std::move(x));
      }
      EXPECT_EQ(kNumberOfItems, countDestroyedFlags(flags));
      EXPECT_EQ(kNumberOfItems, countTotalMessages(counts));
      // at the curly brace above the ScopedLogger will go out of scope. The logging sink removal
      // is synchronous and all the sinks are guaranteed to have received the message before the sink is removed.
   }
}

TEST(ConceptSink, OneHundredRemoveAllSinks) {
   using namespace g3;
   BoolList flags;
   IntVector counts;
   size_t kNumberOfItems = 100;
   std::vector<SinkHandleT> sink_handles;
   {
      RestoreFileLogger logger{"./"};
      g3::LogWorker* worker = logger._scope->get(); //think: g3LogWorker::createLogWorker();
      AddManySinks(kNumberOfItems, flags, counts, sink_handles, worker);

      LogMessagePtr message{std::make_unique<LogMessage>("test", 0, "test", DEBUG)};
      auto& write = message.get()->write();
      write.append("Hello to 100 receivers :)");
      worker->save(message);
      worker->removeAllSinks();
      EXPECT_EQ(kNumberOfItems, countDestroyedFlags(flags));
      EXPECT_EQ(kNumberOfItems, countTotalMessages(counts));
      // at the curly brace above the ScopedLogger will go out of scope. The logging sink removal
      // is synchronous and all the sinks are guaranteed to have received the message before the sink is removed.
   }
}


struct VoidReceiver {
   std::atomic<int>* _atomicCounter;
   explicit VoidReceiver(std::atomic<int>* counter) : _atomicCounter(counter) {}

   void receiveMsg(std::string msg) { /*ignored*/}
   void incrementAtomic() {
      (*_atomicCounter)++;
   }
};

TEST(ConceptSink, VoidCall__NoCall_ExpectingNoAdd) {
   std::atomic<int> counter{0};
   {
      std::unique_ptr<g3::LogWorker> worker{g3::LogWorker::createLogWorker()};
      auto handle = worker->addSink(std::make_unique<VoidReceiver>(&counter), &VoidReceiver::receiveMsg);
   }
   EXPECT_EQ(counter, 0);
}

TEST(ConceptSink, VoidCall__OneCall_ExpectingOneAdd) {
   std::atomic<int> counter{0};
   {
      std::unique_ptr<g3::LogWorker> worker{g3::LogWorker::createLogWorker()};
      auto handle = worker->addSink(std::make_unique<VoidReceiver>(&counter), &VoidReceiver::receiveMsg);
      std::future<void> ignored = handle->call(&VoidReceiver::incrementAtomic);
   }
   EXPECT_EQ(counter, 1);
}

TEST(ConceptSink, VoidCall__TwoCalls_ExpectingTwoAdd) {
   std::atomic<int> counter{0};
   {
      std::unique_ptr<g3::LogWorker> worker{g3::LogWorker::createLogWorker()};
      auto handle = worker->addSink(std::make_unique<VoidReceiver>(&counter), &VoidReceiver::receiveMsg);
      auto  voidFuture1 = handle->call(&VoidReceiver::incrementAtomic);
      auto  voidFuture2 = handle->call(&VoidReceiver::incrementAtomic);
      voidFuture1.wait();
      EXPECT_TRUE(counter >= 1);
   }
   EXPECT_EQ(counter, 2);
}


struct IntReceiver {
   std::atomic<int>* _atomicCounter;
   explicit IntReceiver(std::atomic<int>* counter) : _atomicCounter(counter) {}

   void receiveMsgDoNothing(std::string msg) { /*ignored*/}
   void receiveMsgIncrementAtomic(std::string msg) { incrementAtomic(); }
   int incrementAtomic() {
      (*_atomicCounter)++;
      int value = *_atomicCounter;
      return value;
   }
};

TEST(ConceptSink, IntCall__TwoCalls_ExpectingTwoAdd) {
   std::atomic<int> counter{0};
   {
      std::unique_ptr<g3::LogWorker> worker{g3::LogWorker::createLogWorker()};
      auto handle = worker->addSink(std::make_unique<IntReceiver>(&counter), &IntReceiver::receiveMsgDoNothing);
      std::future<int> intFuture1 = handle->call(&IntReceiver::incrementAtomic);
      EXPECT_EQ(intFuture1.get(), 1);
      EXPECT_EQ(counter, 1);

      auto intFuture2 = handle->call(&IntReceiver::incrementAtomic);
      EXPECT_EQ(intFuture2.get(), 2);

   }
   EXPECT_EQ(counter, 2);
}



void DoLogCalls(std::atomic<bool>*  doWhileTrue, size_t counter) {
   while (doWhileTrue->load()) {
      LOG(INFO) << "Calling from #" << counter;
      std::cout << "-";
      std::this_thread::yield();
   }
}

void DoSlowLogCalls(std::atomic<bool>*  doWhileTrue, size_t counter) {
   size_t messages = 0;
   while (doWhileTrue->load()) {
      LOG(INFO) << "Calling from #" << counter;
      ++messages;
      int random = rand() % 10 + 1; // Range 1-10
      std::this_thread::sleep_for(std::chrono::microseconds(random));
   }

   std::string out = "#" + std::to_string(counter) + " number of messages sent: " + std::to_string(messages) + "\n";
   std::cout << out;
}




TEST(ConceptSink, CannotCallSpawnTaskOnNullptrWorker) {
   auto FailedHelloWorld = [] { std::cout << "Hello World" << std::endl; };
   kjellkod::Active* active = nullptr;
   auto failed = g3::spawn_task(FailedHelloWorld, active);
   EXPECT_ANY_THROW(failed.get());
}

TEST(ConceptSink, AggressiveThreadCallsDuringAddAndRemoveSink) {
   std::atomic<bool> keepRunning{true};
   size_t numberOfCycles = 10;
   std::vector<std::thread> threads;
   const size_t numberOfThreads = std::thread::hardware_concurrency() / 2;
   threads.reserve(numberOfThreads);

   g3::internal::shutDownLogging();

   // Avoid annoying printouts at log shutdown
   stringstream cerr_buffer;
   testing_helpers::ScopedOut guard1(std::cerr, &cerr_buffer);
   std::unique_ptr<g3::LogWorker> worker{g3::LogWorker::createLogWorker()};
   g3::initializeLogging(worker.get());
   using SinkHandleT = std::unique_ptr<g3::SinkHandle<IntReceiver>>;
   std::vector<SinkHandleT> sink_handles;
   sink_handles.reserve(numberOfCycles);

   // these threads will continue to write to a logger
   // while the receiving logger is instantiated, and destroyed repeatedly
   for (size_t caller = 0; caller <= numberOfThreads; ++caller) {
      threads.push_back(std::thread(DoSlowLogCalls, &keepRunning, caller));
   }

   std::atomic<int> atomicCounter{0};

   std::cout << "Add sinks, remove sinks, " << numberOfCycles  << " times\n\tWhile " << numberOfThreads << " threads are continously doing LOG calls" << std::endl;
   for (size_t create = 0; create < numberOfCycles; ++create) {
      worker->removeAllSinks();
      sink_handles.clear();
      sink_handles.reserve(numberOfCycles);

      std::cout << ".";
      atomicCounter = 0;
      for (size_t sinkIdx = 0; sinkIdx < 2; ++sinkIdx) {
         sink_handles.push_back(worker->addSink(std::make_unique<IntReceiver>(&atomicCounter), &IntReceiver::receiveMsgIncrementAtomic));
      }
      // wait till some LOGS streaming in
      while (atomicCounter.load() < 10) {
         std::this_thread::yield();
      }

   } // g3log worker exists:  1) shutdownlogging 2) flush of queues and shutdown of sinks
   worker.reset();
   // exit the threads
   keepRunning = false;
   for (auto& t : threads) {
      t.join();
   }
   std::cout << "\nAll threads are joined " << std::endl;
}


// This test is commented out but kept here for documentation purposes.
// Actually shutting down and re-initializing the logger is not the intention of g3log.
// the are several initial setups that happen ONCE and the logger relies on the client
// to properly own the logworker that is the key object that receives and direct LOG calls.
// Making LOG calls thread safe through repeated initialization/shutdowns would come at a
// high expense of logworker existance synchronization checks.
//
// TEST(ConceptSink, DISABLED_AggressiveThreadCallsDuringShutdown) {
//    std::atomic<bool> keepRunning{true};

//    std::vector<std::thread> threads;
//    const size_t numberOfThreads = std::thread::hardware_concurrency();
//    threads.reserve(numberOfThreads);

//    g3::internal::shutDownLogging();

//    // Avoid annoying printouts at log shutdown
//    stringstream cerr_buffer;
//    testing_helpers::ScopedOut guard1(std::cerr, &cerr_buffer);

//    // these threads will continue to write to a logger
//    // while the receiving logger is instantiated, and destroyed repeatedly
//    for (size_t caller = 0; caller < numberOfThreads; ++ caller) {
//       threads.push_back(std::thread(DoLogCalls, &keepRunning, caller));
//    }

//    std::atomic<int> atomicCounter{0};
//    size_t numberOfCycles = 2500;
//    std::cout << "Create logger, delete active logger, " << numberOfCycles << " times\n\tWhile " << numberOfThreads << " threads are continously doing LOG calls" << std::endl;
//    std::cout << "Initialize logger / Shutdown logging #";
//    for (size_t create = 0; create < numberOfCycles; ++create) {
//       std::cout << ".";


//       std::unique_ptr<g3::LogWorker> worker{g3::LogWorker::createLogWorker()};
//       auto handle = worker->addSink(std::make_unique<IntReceiver>(&atomicCounter), &IntReceiver::receiveMsgIncrementAtomic);
//       g3::initializeLogging(worker.get());

//       // wait till some LOGS streaming in
//       atomicCounter = 0;
//       while (atomicCounter.load() < 10) {
//          std::this_thread::sleep_for(std::chrono::microseconds(1));
//       }
//    } // g3log worker exists:  1) shutdownlogging 2) flush of queues and shutdown of sinks

//    // exit the threads
//    keepRunning = false;
//    for (auto& t : threads) {
//       t.join();
//    }
//    std::cout << "\nAll threads are joined " << std::endl;
// }