/*
  * Copyright (c) 2016 Paul B Mahol
  *
  * 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
  */
 
 /**
  * @file
  * SpectrumSynth filter
  * @todo support float pixel format
  */
 
 #include "libavcodec/avfft.h"
 #include "libavutil/avassert.h"
 #include "libavutil/channel_layout.h"

 #include "libavutil/ffmath.h"

 #include "libavutil/opt.h"
 #include "libavutil/parseutils.h"
 #include "avfilter.h"
 #include "formats.h"
 #include "audio.h"
 #include "video.h"
 #include "internal.h"
 #include "window_func.h"
 
 enum MagnitudeScale { LINEAR, LOG, NB_SCALES };
 enum SlideMode      { REPLACE, SCROLL, FULLFRAME, RSCROLL, NB_SLIDES };
 enum Orientation    { VERTICAL, HORIZONTAL, NB_ORIENTATIONS };
 
 typedef struct SpectrumSynthContext {
     const AVClass *class;
     int sample_rate;
     int channels;
     int scale;
     int sliding;
     int win_func;
     float overlap;
     int orientation;
 
     AVFrame *magnitude, *phase;
     FFTContext *fft;            ///< Fast Fourier Transform context
     int fft_bits;               ///< number of bits (FFT window size = 1<<fft_bits)
     FFTComplex **fft_data;      ///< bins holder for each (displayed) channels
     int win_size;
     int size;
     int nb_freq;
     int hop_size;
     int start, end;
     int xpos;
     int xend;
     int64_t pts;
     float factor;
     AVFrame *buffer;
     float *window_func_lut;     ///< Window function LUT
 } SpectrumSynthContext;
 
 #define OFFSET(x) offsetof(SpectrumSynthContext, x)
 #define A AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_AUDIO_PARAM
 #define V AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
 
 static const AVOption spectrumsynth_options[] = {
     { "sample_rate", "set sample rate",  OFFSET(sample_rate), AV_OPT_TYPE_INT, {.i64 = 44100}, 15,  INT_MAX, A },
     { "channels",    "set channels",     OFFSET(channels), AV_OPT_TYPE_INT, {.i64 = 1}, 1, 8, A },
     { "scale",       "set input amplitude scale", OFFSET(scale), AV_OPT_TYPE_INT, {.i64 = LOG}, 0, NB_SCALES-1, V, "scale" },
         { "lin",  "linear",      0, AV_OPT_TYPE_CONST, {.i64=LINEAR}, 0, 0, V, "scale" },
         { "log",  "logarithmic", 0, AV_OPT_TYPE_CONST, {.i64=LOG},    0, 0, V, "scale" },
     { "slide", "set input sliding mode", OFFSET(sliding), AV_OPT_TYPE_INT, {.i64 = FULLFRAME}, 0, NB_SLIDES-1, V, "slide" },
         { "replace",   "consume old columns with new",   0, AV_OPT_TYPE_CONST, {.i64=REPLACE},   0, 0, V, "slide" },
         { "scroll",    "consume only most right column", 0, AV_OPT_TYPE_CONST, {.i64=SCROLL},    0, 0, V, "slide" },
         { "fullframe", "consume full frames",            0, AV_OPT_TYPE_CONST, {.i64=FULLFRAME}, 0, 0, V, "slide" },
         { "rscroll",   "consume only most left column",  0, AV_OPT_TYPE_CONST, {.i64=RSCROLL},   0, 0, V, "slide" },
     { "win_func", "set window function", OFFSET(win_func), AV_OPT_TYPE_INT, {.i64 = 0}, 0, NB_WFUNC-1, A, "win_func" },
         { "rect",     "Rectangular",      0, AV_OPT_TYPE_CONST, {.i64=WFUNC_RECT},     0, 0, A, "win_func" },
         { "bartlett", "Bartlett",         0, AV_OPT_TYPE_CONST, {.i64=WFUNC_BARTLETT}, 0, 0, A, "win_func" },
         { "hann",     "Hann",             0, AV_OPT_TYPE_CONST, {.i64=WFUNC_HANNING},  0, 0, A, "win_func" },
         { "hanning",  "Hanning",          0, AV_OPT_TYPE_CONST, {.i64=WFUNC_HANNING},  0, 0, A, "win_func" },
         { "hamming",  "Hamming",          0, AV_OPT_TYPE_CONST, {.i64=WFUNC_HAMMING},  0, 0, A, "win_func" },
         { "sine",     "Sine",             0, AV_OPT_TYPE_CONST, {.i64=WFUNC_SINE},     0, 0, A, "win_func" },
     { "overlap", "set window overlap",  OFFSET(overlap), AV_OPT_TYPE_FLOAT, {.dbl=1}, 0,  1, A },
     { "orientation", "set orientation", OFFSET(orientation), AV_OPT_TYPE_INT, {.i64=VERTICAL}, 0, NB_ORIENTATIONS-1, V, "orientation" },
         { "vertical",   NULL, 0, AV_OPT_TYPE_CONST, {.i64=VERTICAL},   0, 0, V, "orientation" },
         { "horizontal", NULL, 0, AV_OPT_TYPE_CONST, {.i64=HORIZONTAL}, 0, 0, V, "orientation" },
     { NULL }
 };
 
 AVFILTER_DEFINE_CLASS(spectrumsynth);
 
 static int query_formats(AVFilterContext *ctx)
 {
     SpectrumSynthContext *s = ctx->priv;
     AVFilterFormats *formats = NULL;
     AVFilterChannelLayouts *layout = NULL;
     AVFilterLink *magnitude = ctx->inputs[0];
     AVFilterLink *phase = ctx->inputs[1];
     AVFilterLink *outlink = ctx->outputs[0];
     static const enum AVSampleFormat sample_fmts[] = { AV_SAMPLE_FMT_FLTP, AV_SAMPLE_FMT_NONE };
     static const enum AVPixelFormat pix_fmts[] = { AV_PIX_FMT_GRAY8, AV_PIX_FMT_GRAY16,
                                                    AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUVJ444P,
                                                    AV_PIX_FMT_YUV444P16, AV_PIX_FMT_NONE };
     int ret, sample_rates[] = { 48000, -1 };
 
     formats = ff_make_format_list(sample_fmts);
     if ((ret = ff_formats_ref         (formats, &outlink->in_formats        )) < 0 ||
         (ret = ff_add_channel_layout  (&layout, FF_COUNT2LAYOUT(s->channels))) < 0 ||
         (ret = ff_channel_layouts_ref (layout , &outlink->in_channel_layouts)) < 0)
         return ret;
 
     sample_rates[0] = s->sample_rate;
     formats = ff_make_format_list(sample_rates);
     if (!formats)
         return AVERROR(ENOMEM);
     if ((ret = ff_formats_ref(formats, &outlink->in_samplerates)) < 0)
         return ret;
 
     formats = ff_make_format_list(pix_fmts);
     if (!formats)
         return AVERROR(ENOMEM);
     if ((ret = ff_formats_ref(formats, &magnitude->out_formats)) < 0)
         return ret;
 
     formats = ff_make_format_list(pix_fmts);
     if (!formats)
         return AVERROR(ENOMEM);
     if ((ret = ff_formats_ref(formats, &phase->out_formats)) < 0)
         return ret;
 
     return 0;
 }
 
 static int config_output(AVFilterLink *outlink)
 {
     AVFilterContext *ctx = outlink->src;
     SpectrumSynthContext *s = ctx->priv;
     int width = ctx->inputs[0]->w;
     int height = ctx->inputs[0]->h;
     AVRational time_base  = ctx->inputs[0]->time_base;
     AVRational frame_rate = ctx->inputs[0]->frame_rate;
     int i, ch, fft_bits;
     float factor, overlap;
 
     outlink->sample_rate = s->sample_rate;
     outlink->time_base = (AVRational){1, s->sample_rate};
 
     if (width  != ctx->inputs[1]->w ||
         height != ctx->inputs[1]->h) {
         av_log(ctx, AV_LOG_ERROR,
                "Magnitude and Phase sizes differ (%dx%d vs %dx%d).\n",
                width, height,
                ctx->inputs[1]->w, ctx->inputs[1]->h);
         return AVERROR_INVALIDDATA;
     } else if (av_cmp_q(time_base, ctx->inputs[1]->time_base) != 0) {
         av_log(ctx, AV_LOG_ERROR,
                "Magnitude and Phase time bases differ (%d/%d vs %d/%d).\n",
                time_base.num, time_base.den,
                ctx->inputs[1]->time_base.num,
                ctx->inputs[1]->time_base.den);
         return AVERROR_INVALIDDATA;
     } else if (av_cmp_q(frame_rate, ctx->inputs[1]->frame_rate) != 0) {
         av_log(ctx, AV_LOG_ERROR,
                "Magnitude and Phase framerates differ (%d/%d vs %d/%d).\n",
                frame_rate.num, frame_rate.den,
                ctx->inputs[1]->frame_rate.num,
                ctx->inputs[1]->frame_rate.den);
         return AVERROR_INVALIDDATA;
     }
 
     s->size = s->orientation == VERTICAL ? height / s->channels : width / s->channels;
     s->xend = s->orientation == VERTICAL ? width : height;
 
     for (fft_bits = 1; 1 << fft_bits < 2 * s->size; fft_bits++);
 
     s->win_size = 1 << fft_bits;
     s->nb_freq = 1 << (fft_bits - 1);
 
     s->fft = av_fft_init(fft_bits, 1);
     if (!s->fft) {
         av_log(ctx, AV_LOG_ERROR, "Unable to create FFT context. "
                "The window size might be too high.\n");
         return AVERROR(EINVAL);
     }
     s->fft_data = av_calloc(s->channels, sizeof(*s->fft_data));
     if (!s->fft_data)
         return AVERROR(ENOMEM);
     for (ch = 0; ch < s->channels; ch++) {
         s->fft_data[ch] = av_calloc(s->win_size, sizeof(**s->fft_data));
         if (!s->fft_data[ch])
             return AVERROR(ENOMEM);
     }
 
     s->buffer = ff_get_audio_buffer(outlink, s->win_size * 2);
     if (!s->buffer)
         return AVERROR(ENOMEM);
 
     /* pre-calc windowing function */
     s->window_func_lut = av_realloc_f(s->window_func_lut, s->win_size,
                                       sizeof(*s->window_func_lut));
     if (!s->window_func_lut)
         return AVERROR(ENOMEM);

     generate_window_func(s->window_func_lut, s->win_size, s->win_func, &overlap);

     if (s->overlap == 1)
         s->overlap = overlap;
     s->hop_size = (1 - s->overlap) * s->win_size;
     for (factor = 0, i = 0; i < s->win_size; i++) {
         factor += s->window_func_lut[i] * s->window_func_lut[i];
     }
     s->factor = (factor / s->win_size) / FFMAX(1 / (1 - s->overlap) - 1, 1);
 
     return 0;
 }
 
 static int request_frame(AVFilterLink *outlink)
 {
     AVFilterContext *ctx = outlink->src;
     SpectrumSynthContext *s = ctx->priv;
     int ret;
 
     if (!s->magnitude) {
         ret = ff_request_frame(ctx->inputs[0]);
         if (ret < 0)
             return ret;
     }
     if (!s->phase) {
         ret = ff_request_frame(ctx->inputs[1]);
         if (ret < 0)
             return ret;
     }
     return 0;
 }
 
 static void read16_fft_bin(SpectrumSynthContext *s,
                            int x, int y, int f, int ch)
 {
     const int m_linesize = s->magnitude->linesize[0];
     const int p_linesize = s->phase->linesize[0];
     const uint16_t *m = (uint16_t *)(s->magnitude->data[0] + y * m_linesize);
     const uint16_t *p = (uint16_t *)(s->phase->data[0] + y * p_linesize);
     float magnitude, phase;
 
     switch (s->scale) {
     case LINEAR:
         magnitude = m[x] / (double)UINT16_MAX;
         break;
     case LOG:
         magnitude = ff_exp10(((m[x] / (double)UINT16_MAX) - 1.) * 6.);
         break;

     default:
         av_assert0(0);

     }
     phase = ((p[x] / (double)UINT16_MAX) * 2. - 1.) * M_PI;
 
     s->fft_data[ch][f].re = magnitude * cos(phase);
     s->fft_data[ch][f].im = magnitude * sin(phase);
 }
 
 static void read8_fft_bin(SpectrumSynthContext *s,
                           int x, int y, int f, int ch)
 {
     const int m_linesize = s->magnitude->linesize[0];
     const int p_linesize = s->phase->linesize[0];
     const uint8_t *m = (uint8_t *)(s->magnitude->data[0] + y * m_linesize);
     const uint8_t *p = (uint8_t *)(s->phase->data[0] + y * p_linesize);
     float magnitude, phase;
 
     switch (s->scale) {
     case LINEAR:
         magnitude = m[x] / (double)UINT8_MAX;
         break;
     case LOG:
         magnitude = ff_exp10(((m[x] / (double)UINT8_MAX) - 1.) * 6.);
         break;

     default:
         av_assert0(0);

     }
     phase = ((p[x] / (double)UINT8_MAX) * 2. - 1.) * M_PI;
 
     s->fft_data[ch][f].re = magnitude * cos(phase);
     s->fft_data[ch][f].im = magnitude * sin(phase);
 }
 
 static void read_fft_data(AVFilterContext *ctx, int x, int h, int ch)
 {
     SpectrumSynthContext *s = ctx->priv;
     AVFilterLink *inlink = ctx->inputs[0];
     int start = h * (s->channels - ch) - 1;
     int end = h * (s->channels - ch - 1);
     int y, f;
 
     switch (s->orientation) {
     case VERTICAL:
         switch (inlink->format) {
         case AV_PIX_FMT_YUV444P16:
         case AV_PIX_FMT_GRAY16:
             for (y = start, f = 0; y >= end; y--, f++) {
                 read16_fft_bin(s, x, y, f, ch);
             }
             break;
         case AV_PIX_FMT_YUVJ444P:
         case AV_PIX_FMT_YUV444P:
         case AV_PIX_FMT_GRAY8:
             for (y = start, f = 0; y >= end; y--, f++) {
                 read8_fft_bin(s, x, y, f, ch);
             }
             break;
         }
         break;
     case HORIZONTAL:
         switch (inlink->format) {
         case AV_PIX_FMT_YUV444P16:
         case AV_PIX_FMT_GRAY16:
             for (y = end, f = 0; y <= start; y++, f++) {
                 read16_fft_bin(s, y, x, f, ch);
             }
             break;
         case AV_PIX_FMT_YUVJ444P:
         case AV_PIX_FMT_YUV444P:
         case AV_PIX_FMT_GRAY8:
             for (y = end, f = 0; y <= start; y++, f++) {
                 read8_fft_bin(s, y, x, f, ch);
             }
             break;
         }
         break;
     }
 }
 
 static void synth_window(AVFilterContext *ctx, int x)
 {
     SpectrumSynthContext *s = ctx->priv;
     const int h = s->size;
     int nb = s->win_size;
     int y, f, ch;
 
     for (ch = 0; ch < s->channels; ch++) {
         read_fft_data(ctx, x, h, ch);
 
         for (y = h; y <= s->nb_freq; y++) {
             s->fft_data[ch][y].re = 0;
             s->fft_data[ch][y].im = 0;
         }
 
         for (y = s->nb_freq + 1, f = s->nb_freq - 1; y < nb; y++, f--) {
             s->fft_data[ch][y].re =  s->fft_data[ch][f].re;
             s->fft_data[ch][y].im = -s->fft_data[ch][f].im;
         }
 
         av_fft_permute(s->fft, s->fft_data[ch]);
         av_fft_calc(s->fft, s->fft_data[ch]);
     }
 }
 
 static int try_push_frame(AVFilterContext *ctx, int x)
 {
     SpectrumSynthContext *s = ctx->priv;
     AVFilterLink *outlink = ctx->outputs[0];
     const float factor = s->factor;
     int ch, n, i, ret;
     int start, end;
     AVFrame *out;
 
     synth_window(ctx, x);
 
     for (ch = 0; ch < s->channels; ch++) {
         float *buf = (float *)s->buffer->extended_data[ch];
         int j, k;
 
         start = s->start;
         end = s->end;
         k = end;
         for (i = 0, j = start; j < k && i < s->win_size; i++, j++) {
             buf[j] += s->fft_data[ch][i].re;
         }
 
         for (; i < s->win_size; i++, j++) {
             buf[j] = s->fft_data[ch][i].re;
         }
 
         start += s->hop_size;
         end = j;
 
         if (start >= s->win_size) {
             start -= s->win_size;
             end -= s->win_size;
 
             if (ch == s->channels - 1) {
                 float *dst;

                 int c;

 
                 out = ff_get_audio_buffer(outlink, s->win_size);
                 if (!out) {
                     av_frame_free(&s->magnitude);
                     av_frame_free(&s->phase);
                     return AVERROR(ENOMEM);
                 }
 
                 out->pts = s->pts;
                 s->pts += s->win_size;

                 for (c = 0; c < s->channels; c++) {

                     dst = (float *)out->extended_data[c];
                     buf = (float *)s->buffer->extended_data[c];
 
                     for (n = 0; n < s->win_size; n++) {
                         dst[n] = buf[n] * factor;
                     }
                     memmove(buf, buf + s->win_size, s->win_size * 4);
                 }
 
                 ret = ff_filter_frame(outlink, out);

                 if (ret < 0)
                     return ret;

             }
         }
     }
 
     s->start = start;
     s->end = end;
 
     return 0;
 }
 
 static int try_push_frames(AVFilterContext *ctx)
 {
     SpectrumSynthContext *s = ctx->priv;
     int ret, x;
 
     if (!(s->magnitude && s->phase))
         return 0;
 
     switch (s->sliding) {
     case REPLACE:
         ret = try_push_frame(ctx, s->xpos);
         s->xpos++;
         if (s->xpos >= s->xend)
             s->xpos = 0;
         break;
     case SCROLL:
         s->xpos = s->xend - 1;
         ret = try_push_frame(ctx, s->xpos);

         break;

     case RSCROLL:
         s->xpos = 0;
         ret = try_push_frame(ctx, s->xpos);
         break;
     case FULLFRAME:
         for (x = 0; x < s->xend; x++) {
             ret = try_push_frame(ctx, x);
             if (ret < 0)
                 break;
         }
         break;

     default:
         av_assert0(0);

     }
 
     av_frame_free(&s->magnitude);
     av_frame_free(&s->phase);
     return ret;
 }
 
 static int filter_frame_magnitude(AVFilterLink *inlink, AVFrame *magnitude)
 {
     AVFilterContext *ctx = inlink->dst;
     SpectrumSynthContext *s = ctx->priv;
 
     s->magnitude = magnitude;
     return try_push_frames(ctx);
 }
 
 static int filter_frame_phase(AVFilterLink *inlink, AVFrame *phase)
 {
     AVFilterContext *ctx = inlink->dst;
     SpectrumSynthContext *s = ctx->priv;
 
     s->phase = phase;
     return try_push_frames(ctx);
 }
 
 static av_cold void uninit(AVFilterContext *ctx)
 {
     SpectrumSynthContext *s = ctx->priv;
     int i;
 
     av_frame_free(&s->magnitude);
     av_frame_free(&s->phase);
     av_frame_free(&s->buffer);
     av_fft_end(s->fft);
     if (s->fft_data) {
         for (i = 0; i < s->channels; i++)
             av_freep(&s->fft_data[i]);
     }
     av_freep(&s->fft_data);
     av_freep(&s->window_func_lut);
 }
 
 static const AVFilterPad spectrumsynth_inputs[] = {
     {
         .name         = "magnitude",
         .type         = AVMEDIA_TYPE_VIDEO,
         .filter_frame = filter_frame_magnitude,
         .needs_fifo   = 1,
     },
     {
         .name         = "phase",
         .type         = AVMEDIA_TYPE_VIDEO,
         .filter_frame = filter_frame_phase,
         .needs_fifo   = 1,
     },
     { NULL }
 };
 
 static const AVFilterPad spectrumsynth_outputs[] = {
     {
         .name          = "default",
         .type          = AVMEDIA_TYPE_AUDIO,
         .config_props  = config_output,
         .request_frame = request_frame,
     },
     { NULL }
 };
 
 AVFilter ff_vaf_spectrumsynth = {
     .name          = "spectrumsynth",
     .description   = NULL_IF_CONFIG_SMALL("Convert input spectrum videos to audio output."),
     .uninit        = uninit,
     .query_formats = query_formats,
     .priv_size     = sizeof(SpectrumSynthContext),
     .inputs        = spectrumsynth_inputs,
     .outputs       = spectrumsynth_outputs,
     .priv_class    = &spectrumsynth_class,
 };