/*
 * (C) Copyright 1996-2017 ECMWF.
 * 
 * This software is licensed under the terms of the Apache Licence Version 2.0
 * which can be obtained at http://www.apache.org/licenses/LICENSE-2.0. 
 * In applying this licence, ECMWF does not waive the privileges and immunities 
 * granted to it by virtue of its status as an intergovernmental organisation nor
 * does it submit to any jurisdiction.
 */

/// @date   Jun 2011
/// @author Baudouin Raoult
/// @author Tiago Quintino


#include "eckit/config/Resource.h"
#include "eckit/container/MappedArray.h"
#include "eckit/container/SharedMemArray.h"
#include "eckit/filesystem/FileSpace.h"
#include "eckit/filesystem/LocalPathName.h"
#include "eckit/io/cluster/ClusterDisks.h"
#include "eckit/io/cluster/NodeInfo.h"
#include "eckit/parser/JSON.h"
#include "eckit/parser/Tokenizer.h"
#include "eckit/thread/AutoLock.h"


namespace eckit {

//----------------------------------------------------------------------------------------------------------------------

class ClusterDisk {
	bool active_;
	bool offLine_;
	time_t lastSeen_;
	char node_[256];
	char type_[256];
	char path_[2048];

public:
	ClusterDisk(const std::string& node, const std::string& type, const std::string& path) :
		active_(true), offLine_(false), lastSeen_(::time(0))
	{
		zero(node_);
		strncpy(node_, node.c_str(), sizeof(node_) - 1);
		zero(type_);
		strncpy(type_, type.c_str(), sizeof(type_) - 1);
		zero(path_);
		strncpy(path_, path.c_str(), sizeof(path_) - 1);
	}

	bool operator<(const ClusterDisk& other) const
	{
		if(strcmp(path_, other.path_) < 0)
			return true;
		return false;
	}

	void active(bool on)
	{
		active_ = on;
	}
	void offLine(bool on)
	{
		offLine_ = on;
	}

	bool active() const
	{
		return active_;
	}
	bool offLine() const
	{
		return offLine_;
	}
	time_t lastSeen() const
	{
		return lastSeen_;
	}
	void lastSeen(time_t n)
	{
		lastSeen_ = n;
	}

	const char* node() const
	{
		return node_;
	}
	const char* type() const
	{
		return type_;
	}
	const char* path() const
	{
		return path_;
	}

	friend std::ostream& operator<<(std::ostream&, const ClusterDisk&);

	void json(JSON& s) const
	{
		s.startObject();
		s << "lastSeen" << lastSeen_;
		s << "offLine" << offLine_;
		s << "node" << node_;
		s << "type" << type_;
		s << "path" << path_;
		s.endObject();
	}

};
std::ostream& operator<<(std::ostream& s, const ClusterDisk& d)
{
	s << "ClusterDisk[" << d.node_ << "," << d.type_ << "," << d.path_ << "," << (::time(0) - d.lastSeen_) << 
        "," << (d.offLine_ ? "off" : "on") << "-line" <<
        "]";
	return s;
}

inline unsigned long version(ClusterDisk*)
{
	return 1;
}

//----------------------------------------------------------------------------------------------------------------------

class DiskArray : private eckit::NonCopyable {

public:

    typedef ClusterDisk*       iterator;
    typedef const ClusterDisk* const_iterator;

    virtual ~DiskArray() {}

    virtual void sync() = 0;
    virtual void lock() = 0;
    virtual void unlock() = 0;

    virtual iterator begin() = 0;
    virtual iterator end() = 0;
    virtual const_iterator begin() const = 0;
    virtual const_iterator end()   const = 0;

    virtual unsigned long size() = 0;
    virtual ClusterDisk& operator[](unsigned long n) = 0;
};

class MemoryMappedDiskArray : public DiskArray {

    virtual void sync() { map_.sync(); }
    virtual void lock() { map_.lock(); }
    virtual void unlock()  { map_.unlock(); }

    virtual iterator begin()  { return map_.begin(); }
    virtual iterator end()    { return map_.end(); }

    virtual const_iterator begin() const   { return map_.begin(); }
    virtual const_iterator end()   const   { return map_.end(); }

    virtual unsigned long size()   { return map_.size(); }
    virtual ClusterDisk& operator[](unsigned long n) { return map_[n]; }

    MappedArray<ClusterDisk> map_;

public:

    MemoryMappedDiskArray(const PathName& path, unsigned long size) :
        DiskArray(),
        map_(path, size)
    {}
};

class SharedMemoryDiskArray : public DiskArray {

    virtual void sync() { map_.sync(); }
    virtual void lock() { map_.lock(); }
    virtual void unlock()  { map_.unlock(); }

    virtual iterator begin()  { return map_.begin(); }
    virtual iterator end()    { return map_.end(); }

    virtual const_iterator begin() const   { return map_.begin(); }
    virtual const_iterator end()   const   { return map_.end(); }

    virtual unsigned long size()   { return map_.size(); }
    virtual ClusterDisk& operator[](unsigned long n) { return map_[n]; }

    SharedMemArray<ClusterDisk> map_;

public:

    SharedMemoryDiskArray(const PathName& path, const std::string& name, unsigned long size) :
        DiskArray(),
        map_(path, name, size)
    {}
};

static DiskArray* clusterDisks = 0;
static pthread_once_t once = PTHREAD_ONCE_INIT;

static void diskarray_init()
{
    LocalPathName path("~/etc/cluster/disks"); // Avoid recursion...
    size_t disksArraySize  = Resource<size_t>("disksArraySize", 10240);

    std::string diskArrayType = Resource<std::string>("disksArrayType","MemoryMapped");

    if(diskArrayType == "MemoryMapped")
        clusterDisks = new MemoryMappedDiskArray(path, disksArraySize);
    else if(diskArrayType == "SharedMemory")
        clusterDisks = new SharedMemoryDiskArray(path, "/etc-cluster-disks", disksArraySize);
    else {
        std::ostringstream oss;
        oss << "Invalid diskArrayType : " << diskArrayType << ", valid types are 'MemoryMapped' and 'SharedMemory'" << std::endl;
        throw eckit::BadParameter(oss.str(), Here());
    }
}


void ClusterDisks::reset()
{
    pthread_once(&once, diskarray_init);
	AutoLock<DiskArray> lock(*clusterDisks);

	for(DiskArray::iterator k = clusterDisks->begin(); k != clusterDisks->end(); ++k)
		(*k).active(false);
}

void ClusterDisks::cleanup()
{
    /*
    pthread_once(&once, diskarray_init);
    AutoLock<DiskArray> lock(*clusterDisks);

	for(DiskArray::iterator k = clusterDisks->begin(); k != clusterDisks->end(); ++k)
        if((*k).active() && (*k).offline())
        {
            Log::info() << "Forget " << (*k) << std::endl;
            (*k).active(false);
        }
    */
    reset();
}

void ClusterDisks::forget(const NodeInfo& info)
{
	if(info.name() == "marsfs")
	{
		time_t now = ::time(0);
        pthread_once(&once, diskarray_init);
        AutoLock<DiskArray> lock(*clusterDisks);

		for(DiskArray::iterator k = clusterDisks->begin(); k != clusterDisks->end(); ++k)
		{
			if(info.node() == (*k).node())
			{
				(*k).active(false);
			}

			(*k).lastSeen(now);
		}
	}
}

void ClusterDisks::offLine(const NodeInfo& info)
{
	if(info.name() == "marsfs")
	{
		time_t now = ::time(0);
        pthread_once(&once, diskarray_init);
        AutoLock<DiskArray> lock(*clusterDisks);

		//cout << "=========== ClusterDisks::forget "  << info << std::endl;

		for(DiskArray::iterator k = clusterDisks->begin(); k != clusterDisks->end(); ++k)
		{
			if(info.node() == (*k).node())
			{
				(*k).offLine(true);
			}
			(*k).lastSeen(now);
		}
	}
}

void ClusterDisks::update(const std::string& node, const std::string& type, const std::vector<std::string>& disks)
{

    pthread_once(&once, diskarray_init);

	AutoLock<DiskArray> lock(*clusterDisks);

	for(DiskArray::iterator k = clusterDisks->begin(); k != clusterDisks->end(); ++k)
	{
		if(type == (*k).type() && node == (*k).node())
		{
			(*k).active(false);
		}
	}

	for(std::vector<std::string>::const_iterator j = disks.begin(); j != disks.end(); ++j)
	{
		ClusterDisk c(node, type, *j);
        DiskArray::iterator k = std::lower_bound(clusterDisks->begin(), clusterDisks->end(), c);
		if(k != clusterDisks->end() && !(c < *k))
		{
			// Log::info() << "=========== Update " << node << "-" << type << " " << *j << std::endl;
			// TODO check for change of node or type
			*k = c;

		}
		else
		{
			ASSERT(!(*clusterDisks)[0].active());
			//	Log::info() << "================ New " << node << "-" << type << " " << * j << std::endl;
			(*clusterDisks)[0] = c;
			std::sort(clusterDisks->begin(), clusterDisks->end());
		}
	}

}

void ClusterDisks::list(std::ostream& out)
{
    pthread_once(&once, diskarray_init);

	AutoLock<DiskArray> lock(*clusterDisks);
	for(DiskArray::const_iterator k = clusterDisks->begin(); k != clusterDisks->end(); ++k)
	{
		if((*k).active())
			out << *k << std::endl;
	}
}

void ClusterDisks::json(JSON& j)
{
    pthread_once(&once, diskarray_init);

	j.startList();

	AutoLock<DiskArray> lock(*clusterDisks);
	for(DiskArray::const_iterator k = clusterDisks->begin(); k != clusterDisks->end(); ++k)
	{
		if((*k).active())
		{
			(*k).json(j);
		}
	}

	j.endList();

}

time_t ClusterDisks::lastModified(const std::string& type)
{

    pthread_once(&once, diskarray_init);

	AutoLock<DiskArray> lock(*clusterDisks);

	time_t last = 0;

	for(DiskArray::const_iterator k = clusterDisks->begin(); k != clusterDisks->end(); ++k)
	{
		if((*k).active() && ((*k).type() == type))
            last = std::max(last, (*k).lastSeen());
	}

	return last;
}

void ClusterDisks::load(const std::string& type, std::vector<std::string>& disks)
{

    pthread_once(&once, diskarray_init);

	AutoLock<DiskArray> lock(*clusterDisks);
	for(DiskArray::const_iterator k = clusterDisks->begin(); k != clusterDisks->end(); ++k)
	{
		if((*k).active() && ((*k).type() == type))
		{
			disks.push_back(std::string("marsfs://") + (*k).node() + (*k).path());
		}
	}

}

std::string ClusterDisks::node(const std::string& path)
{

    pthread_once(&once, diskarray_init);

	DiskArray::const_iterator j = clusterDisks->end();

	AutoLock<DiskArray> lock(*clusterDisks);
	for(DiskArray::const_iterator k = clusterDisks->begin(); k != clusterDisks->end(); ++k)
	{
		if((*k).active() && (path.find((*k).path()) == 0))
		{
			if(j != clusterDisks->end())
			{
                std::ostringstream os;
				os << "Two nodes found for [" << path << "] "
                   << "marsfs://" << (*j).node() << "/" << (*j).path() << "and "
                   << "marsfs://" << (*k).node() << "/" << (*k).path();

                throw SeriousBug(os.str());
			}
			j = k;
		}
	}





	if(j == clusterDisks->end())
	{
        // Look for local names
       
        // This is ineficent, but is should be called very rarely

        if(LocalPathName(path).exists())
            return NodeInfo::thisNode().node();

        
        LocalPathName df("~/etc/disks/df");
        std::ifstream in(df.localPath());
        char line[1024];
        while(in.getline(line,sizeof(line)))
        {
            if(line[0] != 0  || line[0] != '#')
            {
                Tokenizer tokenize(", \t");
                std::vector<std::string> tokens;
                tokenize(line, tokens);
                if(tokens.size() == 2)
                {
                    const FileSpace &fs = FileSpace::lookUp(tokens[0]);
                    const std::vector<PathName>& v = fs.fileSystems();
                    for(size_t j = 0; j<v.size(); ++j)
                    {
                        if(path.find(v[j].asString()) == 0)
                        {
                            Log::info() << "ClusterDisks::node [" << path << "] is on " << v[j] << std::endl;
                            return "local";
                        }
                    }
                }
            }
        }

    
        std::ostringstream os;
        os << "No node found for [" << path << "]";
        throw SeriousBug(os.str());
	}

	return (*j).node();

}

//----------------------------------------------------------------------------------------------------------------------

} // namespace eckit

