/* This file is part of the Pangolin Project.
 * http://github.com/stevenlovegrove/Pangolin
 *
 * Copyright (c) 2011 Steven Lovegrove
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use,
 * copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following
 * conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */

#pragma once

#include <iostream>
#include <streambuf>
#include <fstream>

#include <pangolin/platform.h>
#include <thread>
#include <mutex>
#include <condition_variable>

#ifdef _LINUX_
// On linux, using posix file i/o to allow sync writes.
#define USE_POSIX_FILE_IO
#endif

namespace pangolin
{

class PANGOLIN_EXPORT threadedfilebuf : public std::streambuf
{
public:
    ~threadedfilebuf();
    threadedfilebuf();
    threadedfilebuf(const std::string& filename, size_t buffer_size_bytes);
    
    void open(const std::string& filename, size_t buffer_size_bytes);
    void close();
    void force_close();
    
    void operator()();
    
protected:
    void soft_close();

    //! Override streambuf::xsputn for asynchronous write
    std::streamsize xsputn(const char * s, std::streamsize n) override;

    //! Override streambuf::overflow for asynchronous write
    int overflow(int c) override;

    std::streampos seekoff(
        std::streamoff off, std::ios_base::seekdir way,
        std::ios_base::openmode which = std::ios_base::in | std::ios_base::out
    ) override;
    
#ifdef USE_POSIX_FILE_IO
    int filenum = -1;
#else
    std::filebuf file;
#endif

    char* mem_buffer;
    std::streamsize mem_size;
    std::streamsize mem_max_size;
    std::streamsize mem_start;
    std::streamsize mem_end;

    std::streampos input_pos;
    
    std::mutex update_mutex;
    std::condition_variable cond_queued;
    std::condition_variable cond_dequeued;
    std::thread write_thread;

    bool should_run;
    bool is_pipe;
};

}