/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 */

/*!
 * \file file_utils.h
 * \brief Minimum file manipulation utils for runtime.
 */
#ifndef TVM_RUNTIME_FILE_UTILS_H_
#define TVM_RUNTIME_FILE_UTILS_H_

#include <tvm/ffi/container/map.h>
#include <tvm/ffi/string.h>

#include <string>
#include <unordered_map>

#include "meta_data.h"

namespace tvm {
namespace runtime {
/*!
 * \brief Get file format from given file name or format argument.
 * \param file_name The name of the file.
 * \param format The format of the file.
 */
std::string GetFileFormat(const std::string& file_name, const std::string& format);

/*!
 * \return the directory in which TVM stores cached files.
 *         May be set using TVM_CACHE_DIR; defaults to system locations.
 */
std::string GetCacheDir();

/*!
 * \brief Get meta file path given file name and format.
 * \param file_name The name of the file.
 */
std::string GetMetaFilePath(const std::string& file_name);

/*!
 * \brief Get file basename (i.e. without leading directories)
 * \param file_name The name of the file.
 * \return the base name
 */
std::string GetFileBasename(const std::string& file_name);

/*!
 * \brief Load binary file into a in-memory buffer.
 * \param file_name The name of the file.
 * \param data The data to be loaded.
 */
void LoadBinaryFromFile(const std::string& file_name, std::string* data);

/*!
 * \brief Load binary file into a in-memory buffer.
 * \param file_name The name of the file.
 * \param data The binary data to be saved.
 */
void SaveBinaryToFile(const std::string& file_name, const std::string& data);

/*!
 * \brief Save meta data to file.
 * \param file_name The name of the file.
 * \param fmap The function info map.
 */
void SaveMetaDataToFile(const std::string& file_name,
                        const std::unordered_map<std::string, FunctionInfo>& fmap);

/*!
 * \brief Load meta data to file.
 * \param file_name The name of the file.
 * \param fmap The function info map.
 */
void LoadMetaDataFromFile(const std::string& file_name,
                          std::unordered_map<std::string, FunctionInfo>* fmap);

/*!
 * \brief Copy the content of an existing file to another file.
 * \param src_file_name Path to the source file.
 * \param dest_file_name Path of the destination file.  If this file already exists,
 *    replace its content.
 */
void CopyFile(const std::string& src_file_name, const std::string& dest_file_name);

/*!
 * \brief Remove (unlink) a file.
 * \param file_name The file name.
 */
void RemoveFile(const std::string& file_name);

constexpr uint64_t kTVMTensorListMagic = 0xF7E58D4F05049CB7;
/*!
 * \brief Load parameters from a string.
 * \param param_blob Serialized string of parameters.
 * \return Map of parameter name to parameter value.
 */
ffi::Map<ffi::String, Tensor> LoadParams(const std::string& param_blob);
/*!
 * \brief Load parameters from a stream.
 * \param strm Stream to load parameters from.
 * \return Map of parameter name to parameter value.
 */
ffi::Map<ffi::String, Tensor> LoadParams(dmlc::Stream* strm);
/*!
 * \brief Serialize parameters to a byte array.
 * \param params Parameters to save.
 * \return ffi::String containing binary parameter data.
 */
std::string SaveParams(const ffi::Map<ffi::String, Tensor>& params);
/*!
 * \brief Serialize parameters to a stream.
 * \param strm Stream to write to.
 * \param params Parameters to save.
 */
void SaveParams(dmlc::Stream* strm, const ffi::Map<ffi::String, Tensor>& params);

/*!
 * \brief A dmlc stream which wraps standard file operations.
 */
struct SimpleBinaryFileStream : public dmlc::Stream {
 public:
  SimpleBinaryFileStream(const std::string& path, std::string mode) {
    const char* fname = path.c_str();

    CHECK(mode == "wb" || mode == "rb") << "Only allowed modes are 'wb' and 'rb'";
    read_ = mode == "rb";
    fp_ = std::fopen(fname, mode.c_str());
    CHECK(fp_ != nullptr) << "Unable to open file " << path;
  }
  virtual ~SimpleBinaryFileStream(void) { this->Close(); }
  virtual size_t Read(void* ptr, size_t size) {
    CHECK(read_) << "File opened in write-mode, cannot read.";
    CHECK(fp_ != nullptr) << "File is closed";
    return std::fread(ptr, 1, size, fp_);
  }
  virtual size_t Write(const void* ptr, size_t size) {
    CHECK(!read_) << "File opened in read-mode, cannot write.";
    CHECK(fp_ != nullptr) << "File is closed";
    size_t nwrite = std::fwrite(ptr, 1, size, fp_);
    int err = std::ferror(fp_);

    CHECK_EQ(err, 0) << "SimpleBinaryFileStream.Write incomplete: " << std::strerror(err);
    return nwrite;
  }
  inline void Close(void) {
    if (fp_ != nullptr) {
      std::fclose(fp_);
      fp_ = nullptr;
    }
  }

 private:
  std::FILE* fp_ = nullptr;
  bool read_;
};  // class SimpleBinaryFileStream

}  // namespace runtime
}  // namespace tvm
#endif  // TVM_RUNTIME_FILE_UTILS_H_