/**
 * Orthanc - A Lightweight, RESTful DICOM Store
 * Copyright (C) 2012-2015 Sebastien Jodogne, Medical Physics
 * Department, University Hospital of Liege, Belgium
 *
 * This program is free software: you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * In addition, as a special exception, the copyright holders of this
 * program give permission to link the code of its release with the
 * OpenSSL project's "OpenSSL" library (or with modified versions of it
 * that use the same license as the "OpenSSL" library), and distribute
 * the linked executables. You must obey the GNU General Public License
 * in all respects for all of the code used other than "OpenSSL". If you
 * modify file(s) with this exception, you may extend this exception to
 * your version of the file(s), but you are not obligated to do so. If
 * you do not wish to do so, delete this exception statement from your
 * version. If you delete this exception statement from all source files
 * in the program, then also delete it here.
 * 
 * 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
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 **/


#include "PrecompiledHeadersUnitTests.h"
#include "gtest/gtest.h"

#include <glog/logging.h>
#include <memory>
#include <boost/thread.hpp>
#include <boost/lexical_cast.hpp>
#include "../Core/IDynamicObject.h"
#include "../Core/Cache/MemoryCache.h"


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());
}




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

    int GetValue() const 
    {
      return value_;
    }
  };

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

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


TEST(MemoryCache, Basic)
{
  IntegerProvider provider;

  {
    Orthanc::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_);
}