/*
 * Copyright (c) 2018 Samsung Electronics Co., Ltd. All Rights Reserved
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef __NEURUN_COMPILER_BACKEND_RESOLVER_H__
#define __NEURUN_COMPILER_BACKEND_RESOLVER_H__

#include <unordered_map>
#include <typeindex>

#include "util/logging.h"
#include "backend/Backend.h"
#include "backend/BackendManager.h"
#include "backend/ITensorBuilder.h"
#include "model/OperationIndexMap.h"

namespace neurun
{
namespace compiler
{

class BackendResolver
{
public:
  BackendResolver(const model::Operands &operands,
                  const std::vector<const backend::Backend *> &backends,
                  const std::shared_ptr<backend::custom::KernelRegistry> &registry)
  {
    for (const auto backend : backends)
    {
      _context_manager.emplace(backend, backend->newContext(operands, registry));
    }
  }

  ~BackendResolver() = default;
  BackendResolver(const BackendResolver &obj);
  BackendResolver(BackendResolver &&obj) = default;
  BackendResolver &operator=(const BackendResolver &obj);
  BackendResolver &operator=(BackendResolver &&obj) = default;

public:
  const backend::BackendContext *getBackendContext(const model::OperationIndex &index) const
  {
    return _context_manager.at(_gen_map.at(index)).get();
  }

  const backend::BackendContext *getBackendContext(const backend::Backend *backend) const
  {
    return _context_manager.at(backend).get();
  }

  backend::TensorBuilderSet tensor_builders() const
  {
    backend::TensorBuilderSet ret;
    for (const auto &e : _context_manager)
    {
      ret.insert(e.second->tensor_builder);
    }
    return ret;
  }

  const backend::Backend *getBackend(const model::OperationIndex &index) const
  {
    return getBackendContext(index)->backend;
  }

  void setBackend(const model::OperationIndex &index, const backend::Backend *backend)
  {
    _gen_map[index] = backend;
  }

  void iterate(const std::function<void(const model::OperationIndex &,
                                        const backend::BackendContext &)> &fn) const
  {
    for (const auto &e : _gen_map)
    {
      fn(e.first, *_context_manager.at(e.second));
    }
  }

private:
  std::unordered_map<const backend::Backend *, std::unique_ptr<backend::BackendContext>>
      _context_manager;
  model::OperationIndexMap<const backend::Backend *> _gen_map;
};

} // namespace compiler
} // namespace neurun

#endif // __NEURUN_COMPILER_BACKEND_RESOLVER_H__