/*
  * 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 "libavutil/avassert.h"

 #include "libavutil/opt.h"

 #include "avfilter.h"

 #include "filters.h"

 #include "framesync.h"

 #include "internal.h"
 
 #define OFFSET(member) offsetof(FFFrameSync, member)

 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_FILTERING_PARAM
 

 static const char *framesync_name(void *ptr)
 {
     return "framesync";
 }
 

 static const AVOption framesync_options[] = {
     { "eof_action", "Action to take when encountering EOF from secondary input ",
         OFFSET(opt_eof_action), AV_OPT_TYPE_INT, { .i64 = EOF_ACTION_REPEAT },
         EOF_ACTION_REPEAT, EOF_ACTION_PASS, .flags = FLAGS, "eof_action" },
         { "repeat", "Repeat the previous frame.",   0, AV_OPT_TYPE_CONST, { .i64 = EOF_ACTION_REPEAT }, .flags = FLAGS, "eof_action" },
         { "endall", "End both streams.",            0, AV_OPT_TYPE_CONST, { .i64 = EOF_ACTION_ENDALL }, .flags = FLAGS, "eof_action" },
         { "pass",   "Pass through the main input.", 0, AV_OPT_TYPE_CONST, { .i64 = EOF_ACTION_PASS },   .flags = FLAGS, "eof_action" },
     { "shortest", "force termination when the shortest input terminates", OFFSET(opt_shortest), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, FLAGS },

     { "repeatlast", "extend last frame of secondary streams beyond EOF", OFFSET(opt_repeatlast), AV_OPT_TYPE_BOOL, { .i64 = 1 }, 0, 1, FLAGS },

     { NULL }
 };

 static const AVClass framesync_class = {
     .version                   = LIBAVUTIL_VERSION_INT,
     .class_name                = "framesync",
     .item_name                 = framesync_name,
     .category                  = AV_CLASS_CATEGORY_FILTER,

     .option                    = framesync_options,

     .parent_log_context_offset = OFFSET(parent),
 };
 
 enum {
     STATE_BOF,
     STATE_RUN,
     STATE_EOF,
 };
 

 static int consume_from_fifos(FFFrameSync *fs);
 

 const AVClass *framesync_get_class(void)

 {
     return &framesync_class;
 }
 

 void ff_framesync_preinit(FFFrameSync *fs)

 {
     if (fs->class)
         return;
     fs->class  = &framesync_class;
     av_opt_set_defaults(fs);
 }
 

 int ff_framesync_init(FFFrameSync *fs, AVFilterContext *parent, unsigned nb_in)

 {

     /* For filters with several outputs, we will not be able to assume which
        output is relevant for ff_outlink_frame_wanted() and
        ff_outlink_set_status(). To be designed when needed. */
     av_assert0(parent->nb_outputs == 1);
 

     ff_framesync_preinit(fs);

     fs->parent = parent;
     fs->nb_in  = nb_in;
 
     fs->in = av_calloc(nb_in, sizeof(*fs->in));
     if (!fs->in)
         return AVERROR(ENOMEM);
     return 0;
 }
 

 static void framesync_eof(FFFrameSync *fs)
 {
     fs->eof = 1;
     fs->frame_ready = 0;
     ff_outlink_set_status(fs->parent->outputs[0], AVERROR_EOF, AV_NOPTS_VALUE);
 }
 

 static void framesync_sync_level_update(FFFrameSync *fs)
 {
     unsigned i, level = 0;
 
     for (i = 0; i < fs->nb_in; i++)
         if (fs->in[i].state != STATE_EOF)
             level = FFMAX(level, fs->in[i].sync);
     av_assert0(level <= fs->sync_level);
     if (level < fs->sync_level)
         av_log(fs, AV_LOG_VERBOSE, "Sync level %u\n", level);
     if (level)
         fs->sync_level = level;
     else

         framesync_eof(fs);

 }
 

 int ff_framesync_configure(FFFrameSync *fs)

 {
     unsigned i;
     int64_t gcd, lcm;
 

     if (!fs->opt_repeatlast || fs->opt_eof_action == EOF_ACTION_PASS) {
         fs->opt_repeatlast = 0;
         fs->opt_eof_action = EOF_ACTION_PASS;
     }
     if (fs->opt_shortest || fs->opt_eof_action == EOF_ACTION_ENDALL) {
         fs->opt_shortest = 1;
         fs->opt_eof_action = EOF_ACTION_ENDALL;
     }
     if (fs->opt_shortest) {
         for (i = 0; i < fs->nb_in; i++)
             fs->in[i].after = EXT_STOP;
     }
     if (!fs->opt_repeatlast) {
         for (i = 1; i < fs->nb_in; i++) {
             fs->in[i].after = EXT_NULL;
             fs->in[i].sync  = 0;
         }
     }
 

     if (!fs->time_base.num) {
         for (i = 0; i < fs->nb_in; i++) {
             if (fs->in[i].sync) {
                 if (fs->time_base.num) {
                     gcd = av_gcd(fs->time_base.den, fs->in[i].time_base.den);
                     lcm = (fs->time_base.den / gcd) * fs->in[i].time_base.den;
                     if (lcm < AV_TIME_BASE / 2) {
                         fs->time_base.den = lcm;
                         fs->time_base.num = av_gcd(fs->time_base.num,
                                                    fs->in[i].time_base.num);
                     } else {
                         fs->time_base.num = 1;
                         fs->time_base.den = AV_TIME_BASE;
                         break;
                     }
                 } else {
                     fs->time_base = fs->in[i].time_base;
                 }
             }
         }
         if (!fs->time_base.num) {
             av_log(fs, AV_LOG_ERROR, "Impossible to set time base\n");
             return AVERROR(EINVAL);
         }
         av_log(fs, AV_LOG_VERBOSE, "Selected %d/%d time base\n",
                fs->time_base.num, fs->time_base.den);
     }
 
     for (i = 0; i < fs->nb_in; i++)
         fs->in[i].pts = fs->in[i].pts_next = AV_NOPTS_VALUE;
     fs->sync_level = UINT_MAX;
     framesync_sync_level_update(fs);
 
     return 0;
 }
 

 static int framesync_advance(FFFrameSync *fs)

 {
     unsigned i;
     int64_t pts;

     int ret;

     while (!(fs->frame_ready || fs->eof)) {
         ret = consume_from_fifos(fs);
         if (ret <= 0)
             return ret;

         pts = INT64_MAX;
         for (i = 0; i < fs->nb_in; i++)
             if (fs->in[i].have_next && fs->in[i].pts_next < pts)

                 pts = fs->in[i].pts_next;
         if (pts == INT64_MAX) {

             framesync_eof(fs);

             break;
         }
         for (i = 0; i < fs->nb_in; i++) {
             if (fs->in[i].pts_next == pts ||
                 (fs->in[i].before == EXT_INFINITY &&
                  fs->in[i].state == STATE_BOF)) {
                 av_frame_free(&fs->in[i].frame);
                 fs->in[i].frame      = fs->in[i].frame_next;
                 fs->in[i].pts        = fs->in[i].pts_next;
                 fs->in[i].frame_next = NULL;
                 fs->in[i].pts_next   = AV_NOPTS_VALUE;
                 fs->in[i].have_next  = 0;
                 fs->in[i].state      = fs->in[i].frame ? STATE_RUN : STATE_EOF;
                 if (fs->in[i].sync == fs->sync_level && fs->in[i].frame)
                     fs->frame_ready = 1;
                 if (fs->in[i].state == STATE_EOF &&
                     fs->in[i].after == EXT_STOP)

                     framesync_eof(fs);

             }
         }
         if (fs->frame_ready)
             for (i = 0; i < fs->nb_in; i++)
                 if ((fs->in[i].state == STATE_BOF &&
                      fs->in[i].before == EXT_STOP))
                     fs->frame_ready = 0;
         fs->pts = pts;
     }

     return 0;

 }
 
 static int64_t framesync_pts_extrapolate(FFFrameSync *fs, unsigned in,
                                          int64_t pts)
 {
     /* Possible enhancement: use the link's frame rate */
     return pts + 1;
 }
 
 static void framesync_inject_frame(FFFrameSync *fs, unsigned in, AVFrame *frame)
 {
     int64_t pts;
 
     av_assert0(!fs->in[in].have_next);

     av_assert0(frame);
     pts = av_rescale_q(frame->pts, fs->in[in].time_base, fs->time_base);
     frame->pts = pts;

     fs->in[in].frame_next = frame;
     fs->in[in].pts_next   = pts;
     fs->in[in].have_next  = 1;
 }
 

 static void framesync_inject_status(FFFrameSync *fs, unsigned in, int status, int64_t pts)

 {

     av_assert0(!fs->in[in].have_next);
     pts = fs->in[in].state != STATE_RUN || fs->in[in].after == EXT_INFINITY
         ? INT64_MAX : framesync_pts_extrapolate(fs, in, fs->in[in].pts);
     fs->in[in].sync = 0;
     framesync_sync_level_update(fs);
     fs->in[in].frame_next = NULL;
     fs->in[in].pts_next   = pts;
     fs->in[in].have_next  = 1;

 }
 

 int ff_framesync_get_frame(FFFrameSync *fs, unsigned in, AVFrame **rframe,

                             unsigned get)

 {
     AVFrame *frame;
     unsigned need_copy = 0, i;
     int64_t pts_next;
     int ret;
 
     if (!fs->in[in].frame) {
         *rframe = NULL;
         return 0;
     }
     frame = fs->in[in].frame;
     if (get) {
         /* Find out if we need to copy the frame: is there another sync
            stream, and do we know if its current frame will outlast this one? */
         pts_next = fs->in[in].have_next ? fs->in[in].pts_next : INT64_MAX;
         for (i = 0; i < fs->nb_in && !need_copy; i++)
             if (i != in && fs->in[i].sync &&
                 (!fs->in[i].have_next || fs->in[i].pts_next < pts_next))
                 need_copy = 1;
         if (need_copy) {
             if (!(frame = av_frame_clone(frame)))
                 return AVERROR(ENOMEM);
             if ((ret = av_frame_make_writable(frame)) < 0) {
                 av_frame_free(&frame);
                 return ret;
             }
         } else {
             fs->in[in].frame = NULL;
         }
         fs->frame_ready = 0;
     }
     *rframe = frame;
     return 0;
 }
 

 void ff_framesync_uninit(FFFrameSync *fs)

 {
     unsigned i;
 
     for (i = 0; i < fs->nb_in; i++) {
         av_frame_free(&fs->in[i].frame);
         av_frame_free(&fs->in[i].frame_next);
     }
 
     av_freep(&fs->in);
 }
 

 static int consume_from_fifos(FFFrameSync *fs)

 {

     AVFilterContext *ctx = fs->parent;
     AVFrame *frame = NULL;
     int64_t pts;
     unsigned i, nb_active, nb_miss;
     int ret, status;

     nb_active = nb_miss = 0;
     for (i = 0; i < fs->nb_in; i++) {
         if (fs->in[i].have_next || fs->in[i].state == STATE_EOF)
             continue;
         nb_active++;
         ret = ff_inlink_consume_frame(ctx->inputs[i], &frame);
         if (ret < 0)

             return ret;

         if (ret) {
             av_assert0(frame);
             framesync_inject_frame(fs, i, frame);
         } else {
             ret = ff_inlink_acknowledge_status(ctx->inputs[i], &status, &pts);
             if (ret > 0) {
                 framesync_inject_status(fs, i, status, pts);
             } else if (!ret) {
                 nb_miss++;
             }
         }
     }
     if (nb_miss) {
         if (nb_miss == nb_active && !ff_outlink_frame_wanted(ctx->outputs[0]))
             return FFERROR_NOT_READY;
         for (i = 0; i < fs->nb_in; i++)
             if (!fs->in[i].have_next && fs->in[i].state != STATE_EOF)
                 ff_inlink_request_frame(ctx->inputs[i]);
         return 0;

     }

     return 1;
 }

 int ff_framesync_activate(FFFrameSync *fs)

 {
     int ret;
 
     ret = framesync_advance(fs);
     if (ret < 0)
         return ret;

     if (fs->eof || !fs->frame_ready)
         return 0;
     ret = fs->on_event(fs);
     if (ret < 0)

         return ret;

     fs->frame_ready = 0;

     return 0;

 }

 int ff_framesync_init_dualinput(FFFrameSync *fs, AVFilterContext *parent)

 {
     int ret;
 

     ret = ff_framesync_init(fs, parent, 2);

     if (ret < 0)
         return ret;
     fs->in[0].time_base = parent->inputs[0]->time_base;
     fs->in[1].time_base = parent->inputs[1]->time_base;
     fs->in[0].sync   = 2;
     fs->in[0].before = EXT_STOP;
     fs->in[0].after  = EXT_INFINITY;
     fs->in[1].sync   = 1;
     fs->in[1].before = EXT_NULL;
     fs->in[1].after  = EXT_INFINITY;
     return 0;
 }
 

 int ff_framesync_dualinput_get(FFFrameSync *fs, AVFrame **f0, AVFrame **f1)

 {
     AVFilterContext *ctx = fs->parent;
     AVFrame *mainpic = NULL, *secondpic = NULL;

     int ret;

     if ((ret = ff_framesync_get_frame(fs, 0, &mainpic,   1)) < 0 ||
         (ret = ff_framesync_get_frame(fs, 1, &secondpic, 0)) < 0) {

         av_frame_free(&mainpic);
         return ret;
     }
     av_assert0(mainpic);
     mainpic->pts = av_rescale_q(fs->pts, fs->time_base, ctx->outputs[0]->time_base);
     if (ctx->is_disabled)
         secondpic = NULL;
     *f0 = mainpic;
     *f1 = secondpic;
     return 0;
 }
 

 int ff_framesync_dualinput_get_writable(FFFrameSync *fs, AVFrame **f0, AVFrame **f1)

 {
     int ret;
 

     ret = ff_framesync_dualinput_get(fs, f0, f1);

     if (ret < 0)
         return ret;
     ret = ff_inlink_make_frame_writable(fs->parent->inputs[0], f0);
     if (ret < 0) {
         av_frame_free(f0);
         av_frame_free(f1);
         return ret;
     }
     return 0;
 }