/**
 * Orthanc - A Lightweight, RESTful DICOM Store
 * Copyright (C) 2012-2016 Sebastien Jodogne, Medical Physics
 * Department, University Hospital of Liege, Belgium
 * Copyright (C) 2017-2023 Osimis S.A., Belgium
 * Copyright (C) 2024-2024 Orthanc Team SRL, Belgium
 * Copyright (C) 2021-2024 Sebastien Jodogne, ICTEAM UCLouvain, Belgium
 *
 * This program is free software: you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation, either version 3 of
 * the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this program. If not, see
 * <http://www.gnu.org/licenses/>.
 **/


#if ORTHANC_UNIT_TESTS_LINK_FRAMEWORK == 1
// Must be the first to be sure to use the Orthanc framework shared library
#  include <OrthancFramework.h>
#endif

#include <gtest/gtest.h>

#include "../Sources/Cache/MemoryCache.h"
#include "../Sources/Cache/MemoryStringCache.h"
#include "../Sources/Cache/SharedArchive.h"
#include "../Sources/IDynamicObject.h"
#include "../Sources/Logging.h"
#include "../Sources/SystemToolbox.h"

#include <memory>
#include <algorithm>
#include <boost/thread.hpp>
#include <boost/lexical_cast.hpp>


TEST(LRU, Basic)
{
  Orthanc::LeastRecentlyUsedIndex<std::string> r;
  
  r.Add("d");
  r.Add("a");
  r.Add("c");
  r.Add("b");

  r.MakeMostRecent("a");
  r.MakeMostRecent("d");
  r.MakeMostRecent("b");
  r.MakeMostRecent("c");
  r.MakeMostRecent("d");
  r.MakeMostRecent("c");

  ASSERT_EQ("a", r.GetOldest());
  ASSERT_EQ("a", r.RemoveOldest());
  ASSERT_EQ("b", r.GetOldest());
  ASSERT_EQ("b", r.RemoveOldest());
  ASSERT_EQ("d", r.GetOldest());
  ASSERT_EQ("d", r.RemoveOldest());
  ASSERT_EQ("c", r.GetOldest());
  ASSERT_EQ("c", r.RemoveOldest());

  ASSERT_TRUE(r.IsEmpty());

  ASSERT_THROW(r.GetOldest(), Orthanc::OrthancException);
  ASSERT_THROW(r.RemoveOldest(), Orthanc::OrthancException);
}


TEST(LRU, Payload)
{
  Orthanc::LeastRecentlyUsedIndex<std::string, int> r;
  
  r.Add("a", 420);
  r.Add("b", 421);
  r.Add("c", 422);
  r.Add("d", 423);

  r.MakeMostRecent("a");
  r.MakeMostRecent("d");
  r.MakeMostRecent("b");
  r.MakeMostRecent("c");
  r.MakeMostRecent("d");
  r.MakeMostRecent("c");

  ASSERT_TRUE(r.Contains("b"));
  ASSERT_EQ(421, r.Invalidate("b"));
  ASSERT_FALSE(r.Contains("b"));

  int p;
  ASSERT_TRUE(r.Contains("a", p)); ASSERT_EQ(420, p);
  ASSERT_TRUE(r.Contains("c", p)); ASSERT_EQ(422, p);
  ASSERT_TRUE(r.Contains("d", p)); ASSERT_EQ(423, p);

  ASSERT_EQ("a", r.GetOldest());
  ASSERT_EQ(420, r.GetOldestPayload());
  ASSERT_EQ("a", r.RemoveOldest(p)); ASSERT_EQ(420, p);

  ASSERT_EQ("d", r.GetOldest());
  ASSERT_EQ(423, r.GetOldestPayload());
  ASSERT_EQ("d", r.RemoveOldest(p)); ASSERT_EQ(423, p);

  ASSERT_EQ("c", r.GetOldest());
  ASSERT_EQ(422, r.GetOldestPayload());
  ASSERT_EQ("c", r.RemoveOldest(p)); ASSERT_EQ(422, p);

  ASSERT_TRUE(r.IsEmpty());
}


TEST(LRU, PayloadUpdate)
{
  Orthanc::LeastRecentlyUsedIndex<std::string, int> r;
  
  r.Add("a", 420);
  r.Add("b", 421);
  r.Add("d", 423);

  r.MakeMostRecent("a", 424);
  r.MakeMostRecent("d", 421);

  ASSERT_EQ("b", r.GetOldest());
  ASSERT_EQ(421, r.GetOldestPayload());
  r.RemoveOldest();

  ASSERT_EQ("a", r.GetOldest());
  ASSERT_EQ(424, r.GetOldestPayload());
  r.RemoveOldest();

  ASSERT_EQ("d", r.GetOldest());
  ASSERT_EQ(421, r.GetOldestPayload());
  r.RemoveOldest();

  ASSERT_TRUE(r.IsEmpty());
}



TEST(LRU, PayloadUpdateBis)
{
  Orthanc::LeastRecentlyUsedIndex<std::string, int> r;
  
  r.AddOrMakeMostRecent("a", 420);
  r.AddOrMakeMostRecent("b", 421);
  r.AddOrMakeMostRecent("d", 423);
  r.AddOrMakeMostRecent("a", 424);
  r.AddOrMakeMostRecent("d", 421);

  ASSERT_EQ("b", r.GetOldest());
  ASSERT_EQ(421, r.GetOldestPayload());
  r.RemoveOldest();

  ASSERT_EQ("a", r.GetOldest());
  ASSERT_EQ(424, r.GetOldestPayload());
  r.RemoveOldest();

  ASSERT_EQ("d", r.GetOldest());
  ASSERT_EQ(421, r.GetOldestPayload());
  r.RemoveOldest();

  ASSERT_TRUE(r.IsEmpty());
}

TEST(LRU, GetAllKeys)
{
  Orthanc::LeastRecentlyUsedIndex<std::string, int> r;
  std::vector<std::string> keys;

  r.AddOrMakeMostRecent("a", 420);
  r.GetAllKeys(keys);

  ASSERT_EQ(1u, keys.size());
  ASSERT_EQ("a", keys[0]);

  r.AddOrMakeMostRecent("b", 421);
  r.GetAllKeys(keys);

  ASSERT_EQ(2u, keys.size());
  ASSERT_TRUE(std::find(keys.begin(), keys.end(),"a") != keys.end());
  ASSERT_TRUE(std::find(keys.begin(), keys.end(),"b") != keys.end());
}



namespace
{
  class Integer : public Orthanc::IDynamicObject
  {
  private:
    std::string& log_;
    int value_;

  public:
    Integer(std::string& log, int v) : log_(log), value_(v)
    {
    }

    virtual ~Integer() ORTHANC_OVERRIDE
    {
      LOG(INFO) << "Removing cache entry for " << value_;
      log_ += boost::lexical_cast<std::string>(value_) + " ";
    }
  };

  class IntegerProvider : public Orthanc::Deprecated::ICachePageProvider
  {
  public:
    std::string log_;

    virtual Orthanc::IDynamicObject* Provide(const std::string& s) ORTHANC_OVERRIDE
    {
      LOG(INFO) << "Providing " << s;
      return new Integer(log_, boost::lexical_cast<int>(s));
    }
  };
}


TEST(MemoryCache, Basic)
{
  IntegerProvider provider;

  {
    Orthanc::Deprecated::MemoryCache cache(provider, 3);
    cache.Access("42");  // 42 -> exit
    cache.Access("43");  // 43, 42 -> exit
    cache.Access("45");  // 45, 43, 42 -> exit
    cache.Access("42");  // 42, 45, 43 -> exit
    cache.Access("43");  // 43, 42, 45 -> exit
    cache.Access("47");  // 45 is removed; 47, 43, 42 -> exit 
    cache.Access("44");  // 42 is removed; 44, 47, 43 -> exit
    cache.Access("42");  // 43 is removed; 42, 44, 47 -> exit
    // Closing the cache: 47, 44, 42 are successively removed
  }

  ASSERT_EQ("45 42 43 47 44 42 ", provider.log_);
}





namespace
{
  class S : public Orthanc::IDynamicObject
  {
  private:
    std::string value_;

  public:
    explicit S(const std::string& value) : value_(value)
    {
    }

    const std::string& GetValue() const
    {
      return value_;
    }
  };
}


TEST(LRU, SharedArchive)
{
  std::string first, second;
  Orthanc::SharedArchive a(3);
  first = a.Add(new S("First item"));
  second = a.Add(new S("Second item"));

  for (int i = 1; i < 100; i++)
  {
    a.Add(new S("Item " + boost::lexical_cast<std::string>(i)));
    
    // Continuously protect the two first items
    {
      Orthanc::SharedArchive::Accessor accessor(a, first);
      ASSERT_TRUE(accessor.IsValid());
      ASSERT_EQ("First item", dynamic_cast<S&>(accessor.GetItem()).GetValue());
    }

    {
      Orthanc::SharedArchive::Accessor accessor(a, second);
      ASSERT_TRUE(accessor.IsValid());
      ASSERT_EQ("Second item", dynamic_cast<S&>(accessor.GetItem()).GetValue());
    }

    {
      Orthanc::SharedArchive::Accessor accessor(a, "nope");
      ASSERT_FALSE(accessor.IsValid());
      ASSERT_THROW(accessor.GetItem(), Orthanc::OrthancException);
    }
  }

  std::list<std::string> i;
  a.List(i);

  size_t count = 0;
  for (std::list<std::string>::const_iterator
         it = i.begin(); it != i.end(); ++it)
  {
    if (*it == first ||
        *it == second)
    {
      count++;
    }
  }

  ASSERT_EQ(2u, count);
}


TEST(MemoryStringCache, Basic)
{
  Orthanc::MemoryStringCache c;
  ASSERT_THROW(c.SetMaximumSize(0), Orthanc::OrthancException);
  
  c.SetMaximumSize(3);

  std::string v;
  {
    Orthanc::MemoryStringCache::Accessor a(c);
    ASSERT_FALSE(a.Fetch(v, "key1"));
  }

  {
    Orthanc::MemoryStringCache::Accessor a(c);
    ASSERT_FALSE(a.Fetch(v, "key1"));
    a.Add("key1", "a");
    ASSERT_TRUE(a.Fetch(v, "key1"));
    ASSERT_EQ("a", v);

    ASSERT_FALSE(a.Fetch(v, "key2"));
    ASSERT_FALSE(a.Fetch(v, "key3"));

    a.Add("key2", "b");
    ASSERT_TRUE(a.Fetch(v, "key1"));
    ASSERT_EQ("a", v);
    ASSERT_TRUE(a.Fetch(v, "key2"));
    ASSERT_EQ("b", v);

    a.Add("key3", "too-large-value");
    ASSERT_TRUE(a.Fetch(v, "key1"));
    ASSERT_EQ("a", v);
    ASSERT_TRUE(a.Fetch(v, "key2"));
    ASSERT_EQ("b", v);
    ASSERT_FALSE(a.Fetch(v, "key3"));

    a.Add("key3", "c");
    ASSERT_TRUE(a.Fetch(v, "key2"));
    ASSERT_EQ("b", v);
    ASSERT_TRUE(a.Fetch(v, "key1"));
    ASSERT_EQ("a", v);
    ASSERT_TRUE(a.Fetch(v, "key3"));
    ASSERT_EQ("c", v);

    // adding a fourth value should remove the oldest accessed value (key2)
    a.Add("key4", "d");
    ASSERT_FALSE(a.Fetch(v, "key2"));
    ASSERT_TRUE(a.Fetch(v, "key1"));
    ASSERT_EQ("a", v);
    ASSERT_TRUE(a.Fetch(v, "key3"));
    ASSERT_EQ("c", v);
    ASSERT_TRUE(a.Fetch(v, "key4"));
    ASSERT_EQ("d", v);

  }
}

TEST(MemoryStringCache, Invalidate)
{
  Orthanc::MemoryStringCache c;
  Orthanc::MemoryStringCache::Accessor a(c);

  a.Add("hello", "a");
  a.Add("hello2", "b");

  std::string v;
  ASSERT_TRUE(a.Fetch(v, "hello"));   
  ASSERT_EQ("a", v);
  ASSERT_TRUE(a.Fetch(v, "hello2"));  
  ASSERT_EQ("b", v);

  c.Invalidate("hello");
  ASSERT_FALSE(a.Fetch(v, "hello"));
  ASSERT_TRUE(a.Fetch(v, "hello2"));  
  ASSERT_EQ("b", v);
}


static int ThreadingScenarioHappyStep = 0;
static Orthanc::MemoryStringCache ThreadingScenarioHappyCache;

void ThreadingScenarioHappyThread1()
{
  // the first thread to call Fetch (will be in charge of adding)
  Orthanc::MemoryStringCache::Accessor a(ThreadingScenarioHappyCache);
  std::string v;

  LOG(INFO) << "Thread1 will fetch";
  if (!a.Fetch(v, "key1"))
  {
    LOG(INFO) << "Thread1 has fetch";
    ThreadingScenarioHappyStep = 1;
    
    // wait for the other thread to fetch too
    while (ThreadingScenarioHappyStep < 2)
    {
      Orthanc::SystemToolbox::USleep(10000);
    }
    LOG(INFO) << "Thread1 will add after a short sleep";
    Orthanc::SystemToolbox::USleep(100000);
    LOG(INFO) << "Thread1 will add";

    a.Add("key1", "value1");

    LOG(INFO) << "Thread1 has added";
  }
}

void ThreadingScenarioHappyThread2()
{
  Orthanc::MemoryStringCache::Accessor a(ThreadingScenarioHappyCache);
  std::string v;

  // nobody has added key2 -> go
  if (!a.Fetch(v, "key2"))
  {
    a.Add("key2", "value2");
  }

  // wait until thread 1 has completed its "Fetch" but not added yet
  while (ThreadingScenarioHappyStep < 1)
  {
    Orthanc::SystemToolbox::USleep(10000);
  }

  ThreadingScenarioHappyStep = 2;
  LOG(INFO) << "Thread2 will fetch";
  // this should wait until thread 1 has added
  if (!a.Fetch(v, "key1"))
  {
    ASSERT_FALSE(true); // this thread should not add since thread1 should have done it
  }
  LOG(INFO) << "Thread2 has fetched the value";
  ASSERT_EQ("value1", v);
}


TEST(MemoryStringCache, ThreadingScenarioHappy)
{
  boost::thread thread1 = boost::thread(ThreadingScenarioHappyThread1);
  boost::thread thread2 = boost::thread(ThreadingScenarioHappyThread2);

  thread1.join();
  thread2.join();
}


static int ThreadingScenarioFailureStep = 0;
static Orthanc::MemoryStringCache ThreadingScenarioFailureCache;

void ThreadingScenarioFailureThread1()
{
  // the first thread to call Fetch (will be in charge of adding)
  Orthanc::MemoryStringCache::Accessor a(ThreadingScenarioFailureCache);
  std::string v;

  LOG(INFO) << "Thread1 will fetch";
  if (!a.Fetch(v, "key1"))
  {
    LOG(INFO) << "Thread1 has fetch";
    ThreadingScenarioFailureStep = 1;
    
    // wait for the other thread to fetch too
    while (ThreadingScenarioFailureStep < 2)
    {
      Orthanc::SystemToolbox::USleep(10000);
    }
    LOG(INFO) << "Thread1 will add after a short sleep";
    Orthanc::SystemToolbox::USleep(100000);
    LOG(INFO) << "Thread1 fails to add because of an error";
  }
}

void ThreadingScenarioFailureThread2()
{
  Orthanc::MemoryStringCache::Accessor a(ThreadingScenarioFailureCache);
  std::string v;

  // wait until thread 1 has completed its "Fetch" but not added yet
  while (ThreadingScenarioFailureStep < 1)
  {
    Orthanc::SystemToolbox::USleep(10000);
  }

  ThreadingScenarioFailureStep = 2;
  LOG(INFO) << "Thread2 will fetch and wait for thread1 to add";
  // this should wait until thread 1 has added
  if (!a.Fetch(v, "key1"))
  {
    LOG(INFO) << "Thread2 has been awaken and will add since Thread1 has failed to add";
    a.Add("key1", "value1");
  }
  LOG(INFO) << "Thread2 has added the value";
}


TEST(MemoryStringCache, ThreadingScenarioFailure)
{
  boost::thread thread1 = boost::thread(ThreadingScenarioFailureThread1);
  boost::thread thread2 = boost::thread(ThreadingScenarioFailureThread2);

  thread1.join();
  thread2.join();
}


static int ThreadingScenarioInvalidateStep = 0;
static Orthanc::MemoryStringCache ThreadingScenarioInvalidateCache;

void ThreadingScenarioInvalidateThread1()
{
  // the first thread to call Fetch (will be in charge of adding)
  Orthanc::MemoryStringCache::Accessor a(ThreadingScenarioInvalidateCache);
  std::string v;

  LOG(INFO) << "Thread1 will fetch";
  if (!a.Fetch(v, "key1"))
  {
    LOG(INFO) << "Thread1 has fetch";
    ThreadingScenarioInvalidateStep = 1;
    
    // wait for the other thread to fetch too
    while (ThreadingScenarioInvalidateStep < 2)
    {
      Orthanc::SystemToolbox::USleep(10000);
    }
    LOG(INFO) << "Thread1 will invalidate after a short sleep";
    Orthanc::SystemToolbox::USleep(100000);
    LOG(INFO) << "Thread1 is invalidating";
    ThreadingScenarioInvalidateCache.Invalidate("key1");
  }
}

void ThreadingScenarioInvalidateThread2()
{
  Orthanc::MemoryStringCache::Accessor a(ThreadingScenarioInvalidateCache);
  std::string v;

  // wait until thread 1 has completed its "Fetch" but not added yet
  while (ThreadingScenarioInvalidateStep < 1)
  {
    Orthanc::SystemToolbox::USleep(10000);
  }

  ThreadingScenarioInvalidateStep = 2;
  LOG(INFO) << "Thread2 will fetch and wait for thread1 to add";
  // this should wait until thread 1 has added
  if (!a.Fetch(v, "key1"))
  {
    LOG(INFO) << "Thread2 has been awaken because thread1 has invalidated the key";
  }
}


TEST(MemoryStringCache, ThreadingScenarioInvalidate)
{
  boost::thread thread1 = boost::thread(ThreadingScenarioInvalidateThread1);
  boost::thread thread2 = boost::thread(ThreadingScenarioInvalidateThread2);

  thread1.join();
  thread2.join();
}