/*

 * Copyright (c) 2013 Nicolas George

 *

 * This file is part of FFmpeg.

 *

 * FFmpeg 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.

 *

 * FFmpeg 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 FFmpeg; if not, write to the Free Software Foundation, Inc.,

 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

#include <float.h>

#include "libavutil/avassert.h"

#include "libavutil/channel_layout.h"

#include "libavutil/eval.h"

#include "libavutil/opt.h"

#include "audio.h"

#include "avfilter.h"

#include "internal.h"

typedef struct SineContext {

    const AVClass *class;

    double frequency;

    double beep_factor;

    char *samples_per_frame;

    AVExpr *samples_per_frame_expr;

    int sample_rate;

    int64_t duration;

    int16_t *sin;

    int64_t pts;

    uint32_t phi;  ///< current phase of the sine (2pi = 1<<32)

    uint32_t dphi; ///< phase increment between two samples

    unsigned beep_period;

    unsigned beep_index;

    unsigned beep_length;

    uint32_t phi_beep;  ///< current phase of the beep

    uint32_t dphi_beep; ///< phase increment of the beep

} SineContext;

#define CONTEXT SineContext

#define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM

#define OPT_GENERIC(name, field, def, min, max, descr, type, deffield, ...) \

    { name, descr, offsetof(CONTEXT, field), AV_OPT_TYPE_ ## type,          \

      { .deffield = def }, min, max, FLAGS, __VA_ARGS__ }

#define OPT_INT(name, field, def, min, max, descr, ...) \

    OPT_GENERIC(name, field, def, min, max, descr, INT, i64, __VA_ARGS__)

#define OPT_DBL(name, field, def, min, max, descr, ...) \

    OPT_GENERIC(name, field, def, min, max, descr, DOUBLE, dbl, __VA_ARGS__)

#define OPT_DUR(name, field, def, min, max, descr, ...) \

    OPT_GENERIC(name, field, def, min, max, descr, DURATION, str, __VA_ARGS__)

#define OPT_STR(name, field, def, min, max, descr, ...) \

    OPT_GENERIC(name, field, def, min, max, descr, STRING, str, __VA_ARGS__)

static const AVOption sine_options[] = {

    OPT_DBL("frequency",         frequency,            440, 0, DBL_MAX,   "set the sine frequency",),

    OPT_DBL("f",                 frequency,            440, 0, DBL_MAX,   "set the sine frequency",),

    OPT_DBL("beep_factor",       beep_factor,            0, 0, DBL_MAX,   "set the beep frequency factor",),

    OPT_DBL("b",                 beep_factor,            0, 0, DBL_MAX,   "set the beep frequency factor",),

    OPT_INT("sample_rate",       sample_rate,        44100, 1, INT_MAX,   "set the sample rate",),

    OPT_INT("r",                 sample_rate,        44100, 1, INT_MAX,   "set the sample rate",),

    OPT_DUR("duration",          duration,               0, 0, INT64_MAX, "set the audio duration",),

    OPT_DUR("d",                 duration,               0, 0, INT64_MAX, "set the audio duration",),

    OPT_STR("samples_per_frame", samples_per_frame, "1024", 0, 0,         "set the number of samples per frame",),

    {NULL}

};

AVFILTER_DEFINE_CLASS(sine);

#define LOG_PERIOD 15

#define AMPLITUDE 4095

#define AMPLITUDE_SHIFT 3

{

    unsigned step, i, c, s, k, new_k, n2;

    /* Principle: if u = exp(i*a1) and v = exp(i*a2), then

       exp(i*(a1+a2)/2) = (u+v) / length(u+v) */

        /* k = (1 << 16) * amplitude / length(u+v)

           In exact values, k is constant at a given step */

            /* Newton's method to solve n² * k² = unit² */

            while (1) {

            }

        }

    }

    /* Unshift amplitude */

    /* Use symmetries to fill the other three quarters */

static const char *const var_names[] = {

    "n",

    "pts",

    "t",

    "TB",

    NULL

};

enum {

    VAR_N,

    VAR_PTS,

    VAR_T,

    VAR_TB,

    VAR_VARS_NB

};

{

    int ret;

    }

                        NULL, NULL, NULL, NULL, 0, sine);

}

{

{

    static const int64_t chlayouts[] = { AV_CH_LAYOUT_MONO, -1 };

    static const enum AVSampleFormat sample_fmts[] = { AV_SAMPLE_FMT_S16,

                                                       AV_SAMPLE_FMT_NONE };

    AVFilterFormats *formats;

    AVFilterChannelLayouts *layouts;

    int ret;

}

{

}

{

    AVFrame *frame;

    };

    int16_t *samples;

               "defaulting to 1024\n", nb_samples);

    }

        av_assert1(nb_samples >= 0);

    }

        }

    }

}

static const AVFilterPad sine_outputs[] = {

    {

        .name          = "default",

        .type          = AVMEDIA_TYPE_AUDIO,

        .request_frame = request_frame,

        .config_props  = config_props,

    },

    { NULL }

};

AVFilter ff_asrc_sine = {

    .name          = "sine",

    .description   = NULL_IF_CONFIG_SMALL("Generate sine wave audio signal."),

    .query_formats = query_formats,

    .init          = init,

    .uninit        = uninit,

    .priv_size     = sizeof(SineContext),

    .inputs        = NULL,

    .outputs       = sine_outputs,

    .priv_class    = &sine_class,

};