/*
 * Copyright (c) 2015, PHILIPPE TILLET. All rights reserved.
 *
 * This file is part of ISAAC.
 *
 * ISAAC 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 2.1 of the License, or (at your option) any later version.
 *
 * This library 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 library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA 02110-1301  USA
 */
#include "isaac/driver/backend.h"
#include "isaac/driver/buffer.h"
#include "isaac/driver/context.h"
#include "isaac/driver/command_queue.h"
#include "isaac/driver/program_cache.h"

#include <assert.h>
#include <stdexcept>
#include <vector>

namespace isaac
{

namespace driver
{

/*-----------------------------------*/
//----------  Temporaries -----------*/
/*-----------------------------------*/

void backend::workspaces::release()
{
    for(auto & x: cache_)
        delete x.second;
    cache_.clear();
}

driver::Buffer & backend::workspaces::get(CommandQueue const & key)
{
    if(cache_.find(key)==cache_.end())
        return *cache_.insert(std::make_pair(key, new Buffer(key.context(), SIZE))).first->second;
    return *cache_.at(key);
}

std::map<CommandQueue, Buffer * > backend::workspaces::cache_;

/*-----------------------------------*/
//----------  Programs --------------*/
/*-----------------------------------*/

void backend::programs::release()
{
    for(auto & x: cache_)
        delete x.second;
    cache_.clear();
}

ProgramCache & backend::programs::get(CommandQueue const & queue, expression_type expression, numeric_type dtype)
{
    std::tuple<CommandQueue, expression_type, numeric_type> key(queue, expression, dtype);
    if(cache_.find(key)==cache_.end())
        return *cache_.insert(std::make_pair(key, new ProgramCache())).first->second;
    return *cache_.at(key);
}

std::map<std::tuple<CommandQueue, expression_type, numeric_type>, ProgramCache * >  backend::programs::cache_;

/*-----------------------------------*/
//------------  Queues --------------*/
/*-----------------------------------*/

void backend::queues::init(std::list<const Context *> const & contexts)
{
    for(Context const * ctx : contexts)
        if(cache_.find(*ctx)==cache_.end())
        cache_.insert(std::make_pair(*ctx, std::vector<CommandQueue*>{new CommandQueue(*ctx, ctx->device(), default_queue_properties)}));
}

void backend::queues::release()
{
    for(auto & x: cache_)
        for(auto & y: x.second)
            delete y;
    cache_.clear();
}


CommandQueue & backend::queues::get(Context const & context, unsigned int id)
{
  init(std::list<Context const *>(1,&context));
  for(auto & x : cache_)
    if(x.first==context)
        return *x.second[id];
  throw;
}

void backend::queues::get(Context const & context, std::vector<CommandQueue*> & queues)
{
    init(std::list<Context const *>(1,&context));
    queues = cache_.at(context);
}

std::map<Context, std::vector<CommandQueue*> > backend::queues::cache_;

/*-----------------------------------*/
//------------  Contexts ------------*/
/*-----------------------------------*/

void backend::contexts::init(std::vector<Platform> const & platforms)
{
    for(Platform const & platform: platforms)
    {
        std::vector<Device> devices;
        platform.devices(devices);
        for(Device const & device: devices)
            cache_.push_back(new Context(device));
    }
}

void backend::contexts::release()
{
    for(auto & x: cache_)
        delete x;
    cache_.clear();
}

Context const & backend::contexts::import(CUcontext context)
{
  for(driver::Context const * x: cache_)
      if(x->handle().cu()==context)
          return *x;
  cache_.emplace_back(new Context(context, false));
  return *cache_.back();
}

Context const & backend::contexts::import(cl_context context)
{
  for(driver::Context const * x: cache_)
      if(x->handle().cl()==context)
          return *x;
  cache_.emplace_back(new Context(context, false));
  return *cache_.back();
}


Context const & backend::contexts::get_default()
{
  backend::init();
  std::list<Context const *>::const_iterator it = cache_.begin();
  std::advance(it, default_device);
  return **it;
}

void backend::contexts::get(std::list<Context const *> & contexts)
{
  backend::init();
  contexts = cache_;
}

std::list<Context const *> backend::contexts::cache_;



/*-----------------------------------*/
//------------  General -------------*/
/*-----------------------------------*/

void backend::platforms(std::vector<Platform> & platforms)
{
    bool has_cuda = false;

    //if cuda is here
    if(dispatch::cuinit())
    {
        if(dispatch::nvrtcinit()){
            platforms.push_back(Platform(CUDA));
            has_cuda = true;
        }
        else
            throw std::runtime_error("ISAAC: Unable to find NVRTC. Make sure you are using CUDA >= 7.0");
    }

    //if OpenCL is here
    if(dispatch::clinit())
    {
        cl_uint nplatforms;
        ocl::check(dispatch::dispatch::clGetPlatformIDs(0, NULL, &nplatforms));
        std::vector<cl_platform_id> clplatforms(nplatforms);
        ocl::check(dispatch::dispatch::clGetPlatformIDs(nplatforms, clplatforms.data(), NULL));
        for(cl_platform_id p: clplatforms){
            Platform tmp(p);
            if(tmp.name().find("CUDA")!=std::string::npos && has_cuda)
                continue;
            platforms.push_back(tmp);
        }
    }

    if(platforms.empty())
        throw std::runtime_error("ISAAC: No backend available. Make sure OpenCL and/or CUDA are available in your library path");
}

void backend::synchronize(Context const & context)
{
    for(CommandQueue * queue: queues::cache_.at(context))
        queue->synchronize();
}


void backend::release()
{
    backend::programs::release();
    backend::workspaces::release();
    backend::queues::release();
    backend::contexts::release();
}


void backend::init()
{
  if(!contexts::cache_.empty())
      return;
  std::vector<Platform> platforms;
  backend::platforms(platforms);
  contexts::init(platforms);
  queues::init(contexts::cache_);
}

unsigned int backend::default_device = 0;

cl_command_queue_properties backend::default_queue_properties = 0;


}

}