// **********************************************************************
//
// Copyright (c) 2003-2006 ZeroC, Inc. All rights reserved.
//
// This copy of Ice is licensed to you under the terms described in the
// ICE_LICENSE file included in this distribution.
//
// **********************************************************************

#include <Ice/LoggerUtil.h>
#include <Ice/Locator.h>
#include <IceGrid/AdapterCache.h>
#include <IceGrid/NodeSessionI.h>
#include <IceGrid/ServerCache.h>
#include <IceGrid/NodeCache.h>

using namespace std;
using namespace IceGrid;

namespace IceGrid
{

struct ServerLoadCI : binary_function<ServerAdapterEntryPtr&, ServerAdapterEntryPtr&, bool>
{
    ServerLoadCI(LoadSample loadSample) : _loadSample(loadSample) { }

    bool operator()(const pair<string, ServerAdapterEntryPtr>& lhs, const pair<string, ServerAdapterEntryPtr>& rhs)
    {
	float lhsl = 1.0f;
	try
	{
	    lhsl = lhs.second->getLeastLoadedNodeLoad(_loadSample);
	}
	catch(const ServerNotExistException&)
	{
	}
	catch(const NodeUnreachableException&)
	{
	}

	float rhsl = 1.0f;
	try
	{
	    rhsl = rhs.second->getLeastLoadedNodeLoad(_loadSample);
	}
	catch(const ServerNotExistException&)
	{
	}
	catch(const NodeUnreachableException&)
	{
	}
	return lhsl < rhsl;
    }

    LoadSample _loadSample;
};

}

AdapterEntryPtr
AdapterCache::get(const string& id) const
{
    Lock sync(*this);
    AdapterCache& self = const_cast<AdapterCache&>(*this);
    AdapterEntryPtr entry = self.getImpl(id);
    if(!entry)
    {
	throw AdapterNotExistException(id);
    }
    return entry;
}

ReplicaGroupEntryPtr
AdapterCache::getReplicaGroup(const string& id, bool create) const
{
    Lock sync(*this);
    AdapterCache& self = const_cast<AdapterCache&>(*this);
    
    AdapterEntryPtr entry = self.getImpl(id);
    if(!entry && create)
    {
	return ReplicaGroupEntryPtr::dynamicCast(self.addImpl(id, new ReplicaGroupEntry(self, id)));
    }
    ReplicaGroupEntryPtr repEntry = ReplicaGroupEntryPtr::dynamicCast(entry);
    if(!repEntry)
    {
	throw AdapterNotExistException(id);
    }
    return repEntry;
}

ServerAdapterEntryPtr
AdapterCache::getServerAdapter(const string& id, bool create) const
{
    Lock sync(*this);
    AdapterCache& self = const_cast<AdapterCache&>(*this);
    
    AdapterEntryPtr entry = self.getImpl(id);
    if(!entry && create)
    {
	return ServerAdapterEntryPtr::dynamicCast(self.addImpl(id, new ServerAdapterEntry(self, id)));
    }
    ServerAdapterEntryPtr svrEntry = ServerAdapterEntryPtr::dynamicCast(entry);
    if(!svrEntry)
    {
	throw AdapterNotExistException(id);
    }
    return svrEntry;
}

AdapterEntryPtr
AdapterCache::addImpl(const string& id, const AdapterEntryPtr& entry)
{
    if(_traceLevels && _traceLevels->adapter > 0)
    {
	Ice::Trace out(_traceLevels->logger, _traceLevels->adapterCat);
	out << "added adapter `" << id << "'";	
    }    
    return Cache<string, AdapterEntry>::addImpl(id, entry);
}

AdapterEntryPtr
AdapterCache::removeImpl(const string& id)
{
    if(_traceLevels && _traceLevels->adapter > 0)
    {
	Ice::Trace out(_traceLevels->logger, _traceLevels->adapterCat);
	out << "removed adapter `" << id << "'";	
    }    
    return Cache<string, AdapterEntry>::removeImpl(id);
}

AdapterEntry::AdapterEntry(Cache<string, AdapterEntry>& cache, const std::string& id) : 
    _cache(*dynamic_cast<AdapterCache*>(&cache)),
    _id(id)
{
}

bool
AdapterEntry::canRemove()
{
    return true;
}

ServerAdapterEntry::ServerAdapterEntry(Cache<string, AdapterEntry>& cache, const std::string& id) : 
    AdapterEntry(cache, id)
{
}

vector<pair<string, AdapterPrx> >
ServerAdapterEntry::getProxies(bool, int& nReplicas)
{
    vector<pair<string, AdapterPrx> > adapters;
    try
    {
	nReplicas = 1;
	adapters.push_back(make_pair(_id, getProxy()));
    }
    catch(const NodeUnreachableException&)
    {
    }
    return adapters;
}

float
ServerAdapterEntry::getLeastLoadedNodeLoad(LoadSample loadSample) const
{
    return getServer()->getLoad(loadSample);
}

string
ServerAdapterEntry::getApplication() const
{
    return getServer()->getApplication();
}

void
ServerAdapterEntry::set(const ServerEntryPtr& server, const string& replicaGroupId)
{
    {
	Lock sync(*this);
	_server = server;
	_replicaGroupId = replicaGroupId;
    }
    if(!replicaGroupId.empty())
    {
	_cache.getReplicaGroup(replicaGroupId)->addReplica(_id, this);
    }
}

void
ServerAdapterEntry::destroy()
{
    string replicaGroupId;
    {
	Lock sync(*this);
	replicaGroupId = _replicaGroupId;
    }
    if(!replicaGroupId.empty())
    {
	_cache.getReplicaGroup(replicaGroupId)->removeReplica(_id);
    }
    _cache.remove(_id);
}

AdapterPrx
ServerAdapterEntry::getProxy(const string& replicaGroupId) const
{
    if(replicaGroupId.empty())
    {
	return getServer()->getAdapter(_id);
    }
    else
    {
	Lock sync(*this);
	if(_replicaGroupId != replicaGroupId)
	{
	    throw Ice::InvalidReplicaGroupIdException();
	}
	return _server->getAdapter(_id);
    }
}

ServerEntryPtr
ServerAdapterEntry::getServer() const
{
    Lock sync(*this);
    assert(_server);
    return _server;
}

ReplicaGroupEntry::ReplicaGroupEntry(Cache<string, AdapterEntry>& cache, const std::string& id) : 
    AdapterEntry(cache, id),
    _lastReplica(0)
{
}

void
ReplicaGroupEntry::set(const string& application, const LoadBalancingPolicyPtr& policy)
{
    Lock sync(*this);
    _application = application;
    if(policy)
    {
	_loadBalancing = policy;
	istringstream is(policy->nReplicas);
	is >> _loadBalancingNReplicas;
	if(_loadBalancingNReplicas < 1)
	{
	    _loadBalancingNReplicas = 1;
	}

	AdaptiveLoadBalancingPolicyPtr alb = AdaptiveLoadBalancingPolicyPtr::dynamicCast(_loadBalancing);
	if(alb)
	{
	    if(alb->loadSample == "1")
	    {
		_loadSample = LoadSample1;
	    }
	    else if(alb->loadSample == "5")
	    {
		_loadSample = LoadSample5;
	    }
	    else if(alb->loadSample == "15")
	    {
		_loadSample = LoadSample15;
	    }
	    else
	    {
		_loadSample = LoadSample1;
	    }
	}
    }
    else
    {
	_loadBalancing = 0;
	_loadBalancingNReplicas = 0;
    }
}

void
ReplicaGroupEntry::addReplica(const string& replicaId, const ServerAdapterEntryPtr& adapter)
{
    Lock sync(*this);
    _replicas.push_back(make_pair(replicaId, adapter));
}

void
ReplicaGroupEntry::removeReplica(const string& replicaId)
{
    Lock sync(*this);
    for(ReplicaSeq::iterator p = _replicas.begin(); p != _replicas.end(); ++p)
    {
	if(replicaId == p->first)
	{
	    _replicas.erase(p);		
	    // Make sure _lastReplica is still within the bounds.
	    _lastReplica = _replicas.empty() ? 0 : _lastReplica % static_cast<int>(_replicas.size());
	    break;
	}
    }
}

vector<pair<string, AdapterPrx> >
ReplicaGroupEntry::getProxies(bool allRegistered, int& nReplicas)
{
    ReplicaSeq replicas;
    bool adaptive = false;
    LoadSample loadSample = LoadSample1;
    {
	Lock sync(*this);
	if(_replicas.empty())
	{
	    return vector<pair<string, AdapterPrx> >();
	}

	nReplicas = _loadBalancingNReplicas > 0 ? _loadBalancingNReplicas : static_cast<int>(_replicas.size());
	replicas.reserve(_replicas.size());
	if(!_loadBalancing)
	{
	    replicas = _replicas;
	}
	if(RoundRobinLoadBalancingPolicyPtr::dynamicCast(_loadBalancing))
	{
	    for(unsigned int i = 0; i < _replicas.size(); ++i)
	    {
		replicas.push_back(_replicas[(_lastReplica + i) % _replicas.size()]);
	    }
	    _lastReplica = (_lastReplica + 1) % static_cast<int>(_replicas.size());
	}
	else if(AdaptiveLoadBalancingPolicyPtr::dynamicCast(_loadBalancing))
	{
	    replicas = _replicas;
	    adaptive = true;
	    loadSample = _loadSample;
	}
	else// if(RandomLoadBalancingPolicyPtr::dynamicCast(_loadBalancing))
	{
	    replicas = _replicas;
	    random_shuffle(replicas.begin(), replicas.end());
	}
    }

    if(adaptive)
    {
	//
	// This must be done outside the synchronization block since
	// the sort() will call and lock each server entry.
	//
	random_shuffle(replicas.begin(), replicas.end());
	sort(replicas.begin(), replicas.end(), ServerLoadCI(loadSample));
    }

    //
    // Retrieve the proxy of each adapter from the server. The adapter
    // might not exist anymore at this time or the node might not be
    // reachable.
    //
    vector<pair<string, AdapterPrx> > adapters;
    for(ReplicaSeq::const_iterator p = replicas.begin(); p != replicas.end(); ++p)
    {
	try
	{
	    adapters.push_back(make_pair(p->first, p->second->getProxy()));
	}
	catch(AdapterNotExistException&)
	{
	}
	catch(const NodeUnreachableException&)
	{
	    if(allRegistered)
	    {
		adapters.push_back(make_pair(p->first, AdapterPrx()));
	    }
	}
    }
    return adapters;
}

float
ReplicaGroupEntry::getLeastLoadedNodeLoad(LoadSample loadSample) const
{
    ReplicaSeq replicas;
    {
	Lock sync(*this);
	replicas = _replicas;
    }

    //
    // This must be done outside the synchronization block since
    // min_element() will call and lock each server entry.
    //
    random_shuffle(replicas.begin(), replicas.end());
    AdapterEntryPtr adpt = min_element(replicas.begin(), replicas.end(), ServerLoadCI(loadSample))->second;
    return adpt->getLeastLoadedNodeLoad(loadSample);
}

string
ReplicaGroupEntry::getApplication() const
{
    Lock sync(*this);
    return _application;
}