/* -*- c++ -*- */
/*
 * Copyright 2003,2008,2011,2012 Free Software Foundation, Inc.
 *
 * This file is part of GNU Radio
 *
 * GNU Radio is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3, or (at your option)
 * any later version.
 *
 * GNU Radio 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with GNU Radio; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street,
 * Boston, MA 02110-1301, USA.
 */

#include <gnuradio/fft/fft.h>
#include <gnuradio/gr_complex.h>
#include <gnuradio/sys_paths.h>
#include <fftw3.h>
#include <volk/volk.h>

#ifdef _WIN32 // http://www.fftw.org/install/windows.html#DLLwisdom
static void my_fftw_write_char(char c, void* f) { fputc(c, (FILE*)f); }
#define fftw_export_wisdom_to_file(f) fftw_export_wisdom(my_fftw_write_char, (void*)(f))
#define fftwf_export_wisdom_to_file(f) fftwf_export_wisdom(my_fftw_write_char, (void*)(f))
#define fftwl_export_wisdom_to_file(f) fftwl_export_wisdom(my_fftw_write_char, (void*)(f))

static int my_fftw_read_char(void* f) { return fgetc((FILE*)f); }
#define fftw_import_wisdom_from_file(f) fftw_import_wisdom(my_fftw_read_char, (void*)(f))
#define fftwf_import_wisdom_from_file(f) \
    fftwf_import_wisdom(my_fftw_read_char, (void*)(f))
#define fftwl_import_wisdom_from_file(f) \
    fftwl_import_wisdom(my_fftw_read_char, (void*)(f))
#include <fcntl.h>
#include <io.h>
#define O_NOCTTY 0
#define O_NONBLOCK 0
#endif //_WIN32

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <cassert>
#include <stdexcept>

#include <boost/filesystem/operations.hpp>
#include <boost/filesystem/path.hpp>
#include <boost/interprocess/sync/file_lock.hpp>
namespace fs = boost::filesystem;

namespace gr {
namespace fft {
static boost::mutex wisdom_thread_mutex;
boost::interprocess::file_lock wisdom_lock;
static bool wisdom_lock_init_done = false; // Modify while holding 'wisdom_thread_mutex'

gr_complex* malloc_complex(int size)
{
    return (gr_complex*)volk_malloc(sizeof(gr_complex) * size, volk_get_alignment());
}

float* malloc_float(int size)
{
    return (float*)volk_malloc(sizeof(float) * size, volk_get_alignment());
}

double* malloc_double(int size)
{
    return (double*)volk_malloc(sizeof(double) * size, volk_get_alignment());
}

void free(void* b) { volk_free(b); }

boost::mutex& planner::mutex()
{
    static boost::mutex s_planning_mutex;

    return s_planning_mutex;
}

static std::string wisdom_filename()
{
    static fs::path path;
    path = fs::path(gr::appdata_path()) / ".gr_fftw_wisdom";
    return path.string();
}

static void wisdom_lock_init()
{
    if (wisdom_lock_init_done)
        return;

    const std::string wisdom_lock_file = wisdom_filename() + ".lock";
    // std::cerr << "Creating FFTW wisdom lockfile: " << wisdom_lock_file << std::endl;
    int fd =
        open(wisdom_lock_file.c_str(), O_WRONLY | O_CREAT | O_NOCTTY | O_NONBLOCK, 0666);
    if (fd < 0) {
        throw std::runtime_error("Failed to create FFTW wisdom lockfile: " +
                                 wisdom_lock_file);
    }
    close(fd);
    wisdom_lock = boost::interprocess::file_lock(wisdom_lock_file.c_str());
    wisdom_lock_init_done = true;
}

static void lock_wisdom()
{
    wisdom_thread_mutex.lock();
    wisdom_lock_init();
    wisdom_lock.lock();
}

static void unlock_wisdom()
{
    // Assumes 'lock_wisdom' has already been called (i.e. this file_lock is valid)
    wisdom_lock.unlock();
    wisdom_thread_mutex.unlock();
}

static void import_wisdom()
{
    const std::string filename = wisdom_filename();
    FILE* fp = fopen(filename.c_str(), "r");
    if (fp != 0) {
        int r = fftwf_import_wisdom_from_file(fp);
        fclose(fp);
        if (!r) {
            fprintf(stderr, "gr::fft: can't import wisdom from %s\n", filename.c_str());
        }
    }
}

static void config_threading(int nthreads)
{
    static int fftw_threads_inited = 0;

#ifdef FFTW3F_THREADS
    if (fftw_threads_inited == 0) {
        fftw_threads_inited = 1;
        fftwf_init_threads();
    }

    fftwf_plan_with_nthreads(nthreads);
#endif
}

static void export_wisdom()
{
    const std::string filename = wisdom_filename();
    FILE* fp = fopen(filename.c_str(), "w");
    if (fp != 0) {
        fftwf_export_wisdom_to_file(fp);
        fclose(fp);
    } else {
        fprintf(stderr, "fft_impl_fftw: ");
        perror(filename.c_str());
    }
}

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

fft_complex::fft_complex(int fft_size, bool forward, int nthreads)
{
    // Hold global mutex during plan construction and destruction.
    planner::scoped_lock lock(planner::mutex());

    assert(sizeof(fftwf_complex) == sizeof(gr_complex));

    if (fft_size <= 0) {
        throw std::out_of_range("fft_impl_fftw: invalid fft_size");
    }

    d_fft_size = fft_size;
    d_inbuf = (gr_complex*)volk_malloc(sizeof(gr_complex) * inbuf_length(),
                                       volk_get_alignment());
    if (d_inbuf == 0) {
        throw std::runtime_error("volk_malloc");
    }
    d_outbuf = (gr_complex*)volk_malloc(sizeof(gr_complex) * outbuf_length(),
                                        volk_get_alignment());
    if (d_outbuf == 0) {
        volk_free(d_inbuf);
        throw std::runtime_error("volk_malloc");
    }

    d_nthreads = nthreads;
    config_threading(nthreads);
    lock_wisdom();
    import_wisdom(); // load prior wisdom from disk

    d_plan = fftwf_plan_dft_1d(fft_size,
                               reinterpret_cast<fftwf_complex*>(d_inbuf),
                               reinterpret_cast<fftwf_complex*>(d_outbuf),
                               forward ? FFTW_FORWARD : FFTW_BACKWARD,
                               FFTW_MEASURE);

    if (d_plan == NULL) {
        fprintf(stderr, "gr::fft: error creating plan\n");
        throw std::runtime_error("fftwf_plan_dft_1d failed");
    }
    export_wisdom(); // store new wisdom to disk
    unlock_wisdom();
}

fft_complex::~fft_complex()
{
    // Hold global mutex during plan construction and destruction.
    planner::scoped_lock lock(planner::mutex());

    fftwf_destroy_plan((fftwf_plan)d_plan);
    volk_free(d_inbuf);
    volk_free(d_outbuf);
}

void fft_complex::set_nthreads(int n)
{
    if (n <= 0) {
        throw std::out_of_range("gr::fft: invalid number of threads");
    }
    d_nthreads = n;

#ifdef FFTW3F_THREADS
    fftwf_plan_with_nthreads(d_nthreads);
#endif
}

void fft_complex::execute() { fftwf_execute((fftwf_plan)d_plan); }

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

fft_real_fwd::fft_real_fwd(int fft_size, int nthreads)
{
    // Hold global mutex during plan construction and destruction.
    planner::scoped_lock lock(planner::mutex());

    assert(sizeof(fftwf_complex) == sizeof(gr_complex));

    if (fft_size <= 0) {
        throw std::out_of_range("gr::fft: invalid fft_size");
    }

    d_fft_size = fft_size;
    d_inbuf = (float*)volk_malloc(sizeof(float) * inbuf_length(), volk_get_alignment());
    if (d_inbuf == 0) {
        throw std::runtime_error("volk_malloc");
    }

    d_outbuf = (gr_complex*)volk_malloc(sizeof(gr_complex) * outbuf_length(),
                                        volk_get_alignment());
    if (d_outbuf == 0) {
        volk_free(d_inbuf);
        throw std::runtime_error("volk_malloc");
    }

    d_nthreads = nthreads;
    config_threading(nthreads);
    lock_wisdom();
    import_wisdom(); // load prior wisdom from disk

    d_plan = fftwf_plan_dft_r2c_1d(
        fft_size, d_inbuf, reinterpret_cast<fftwf_complex*>(d_outbuf), FFTW_MEASURE);

    if (d_plan == NULL) {
        fprintf(stderr, "gr::fft::fft_real_fwd: error creating plan\n");
        throw std::runtime_error("fftwf_plan_dft_r2c_1d failed");
    }
    export_wisdom(); // store new wisdom to disk
    unlock_wisdom();
}

fft_real_fwd::~fft_real_fwd()
{
    // Hold global mutex during plan construction and destruction.
    planner::scoped_lock lock(planner::mutex());

    fftwf_destroy_plan((fftwf_plan)d_plan);
    volk_free(d_inbuf);
    volk_free(d_outbuf);
}

void fft_real_fwd::set_nthreads(int n)
{
    if (n <= 0) {
        throw std::out_of_range(
            "gr::fft::fft_real_fwd::set_nthreads: invalid number of threads");
    }
    d_nthreads = n;

#ifdef FFTW3F_THREADS
    fftwf_plan_with_nthreads(d_nthreads);
#endif
}

void fft_real_fwd::execute() { fftwf_execute((fftwf_plan)d_plan); }

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

fft_real_rev::fft_real_rev(int fft_size, int nthreads)
{
    // Hold global mutex during plan construction and destruction.
    planner::scoped_lock lock(planner::mutex());

    assert(sizeof(fftwf_complex) == sizeof(gr_complex));

    if (fft_size <= 0) {
        throw std::out_of_range("gr::fft::fft_real_rev: invalid fft_size");
    }

    d_fft_size = fft_size;
    d_inbuf = (gr_complex*)volk_malloc(sizeof(gr_complex) * inbuf_length(),
                                       volk_get_alignment());
    if (d_inbuf == 0) {
        throw std::runtime_error("volk_malloc");
    }

    d_outbuf = (float*)volk_malloc(sizeof(float) * outbuf_length(), volk_get_alignment());
    if (d_outbuf == 0) {
        volk_free(d_inbuf);
        throw std::runtime_error("volk_malloc");
    }

    d_nthreads = nthreads;
    config_threading(nthreads);
    lock_wisdom();
    import_wisdom(); // load prior wisdom from disk

    // FIXME If there's ever a chance that the planning functions
    // will be called in multiple threads, we've got to ensure single
    // threaded access.  They are not thread-safe.
    d_plan = fftwf_plan_dft_c2r_1d(
        fft_size, reinterpret_cast<fftwf_complex*>(d_inbuf), d_outbuf, FFTW_MEASURE);

    if (d_plan == NULL) {
        fprintf(stderr, "gr::fft::fft_real_rev: error creating plan\n");
        throw std::runtime_error("fftwf_plan_dft_c2r_1d failed");
    }
    export_wisdom(); // store new wisdom to disk
    unlock_wisdom();
}

fft_real_rev::~fft_real_rev()
{
    // Hold global mutex during plan construction and destruction.
    planner::scoped_lock lock(planner::mutex());

    fftwf_destroy_plan((fftwf_plan)d_plan);
    volk_free(d_inbuf);
    volk_free(d_outbuf);
}

void fft_real_rev::set_nthreads(int n)
{
    if (n <= 0) {
        throw std::out_of_range(
            "gr::fft::fft_real_rev::set_nthreads: invalid number of threads");
    }
    d_nthreads = n;

#ifdef FFTW3F_THREADS
    fftwf_plan_with_nthreads(d_nthreads);
#endif
}

void fft_real_rev::execute() { fftwf_execute((fftwf_plan)d_plan); }

} /* namespace fft */
} /* namespace gr */
