/*
 * Copyright (c) 2018 NVIDIA Corporation.  All rights reserved.
 *
 * NVIDIA Corporation and its licensors retain all intellectual property
 * and proprietary rights in and to this software, related documentation
 * and any modifications thereto.  Any use, reproduction, disclosure or
 * distribution of this software and related documentation without an express
 * license agreement from NVIDIA Corporation is strictly prohibited.
 *
 */

#include <gst/gst.h>
#include <glib.h>
#include <math.h>
#include <string.h>
#include <sys/time.h>

#include <vector>
#include <string>
#include <iostream>

#include "gstnvdsmeta.h"
#include "gst-nvmessage.h"

std::vector<std::string> videoPath;

/* The muxer output resolution must be set if the input streams will be of
 * different resolution. The muxer will scale all the input frames to this
 * resolution. */
#define MUXER_OUTPUT_WIDTH 1920
#define MUXER_OUTPUT_HEIGHT 1080

/* Muxer batch formation timeout, for e.g. 40 millisec. Should ideally be set
 * based on the fastest source's framerate. */
#define MUXER_BATCH_TIMEOUT_USEC 4000000

#define TILED_OUTPUT_WIDTH 1920
#define TILED_OUTPUT_HEIGHT 1080

/* NVIDIA Decoder source pad memory feature. This feature signifies that source
 * pads having this capability will push GstBuffers containing cuda buffers. */
#define GST_CAPS_FEATURES_NVMM "memory:NVMM"

#define FPS_PRINT_INTERVAL 300

static gboolean
bus_call (GstBus * bus, GstMessage * msg, gpointer data)
{
  GMainLoop *loop = (GMainLoop *) data;
  switch (GST_MESSAGE_TYPE (msg)) {
    case GST_MESSAGE_EOS:
      g_print ("End of stream\n");
      g_main_loop_quit (loop);
      break;
    case GST_MESSAGE_WARNING:
    {
      gchar *debug;
      GError *error;
      gst_message_parse_warning (msg, &error, &debug);
      g_printerr ("WARNING from element %s: %s\n",
          GST_OBJECT_NAME (msg->src), error->message);
      g_free (debug);
      g_printerr ("Warning: %s\n", error->message);
      g_error_free (error);
      break;
    }
    case GST_MESSAGE_ERROR:
    {
      gchar *debug;
      GError *error;
      gst_message_parse_error (msg, &error, &debug);

      std::cout << "ERROR: " << GST_MESSAGE_SRC_NAME(msg) << std::endl;
      std::cout << "seqnum: " << msg->seqnum << std::endl;

      g_printerr ("ERROR from element %s: %s\n",
          GST_OBJECT_NAME (msg->src), error->message);
      if (debug)
        g_printerr ("Error details: %s\n", debug);
      g_free (debug);
      g_error_free (error);
      g_main_loop_quit (loop);
      break;
    }
    case GST_MESSAGE_ELEMENT:
    {
      if (gst_nvmessage_is_stream_eos (msg)) {
        guint stream_id;
        if (gst_nvmessage_parse_stream_eos (msg, &stream_id)) {
          g_print ("Got EOS from stream %d\n", stream_id);
        }
      }
      break;
    }
    default:
      break;
  }
  return TRUE;
}

static void
cb_newpad (GstElement * decodebin, GstPad * decoder_src_pad, gpointer data)
{
  g_print ("In cb_newpad\n");
  GstCaps *caps = gst_pad_get_current_caps (decoder_src_pad);
  const GstStructure *str = gst_caps_get_structure (caps, 0);
  const gchar *name = gst_structure_get_name (str);
  GstElement *source_bin = (GstElement *) data;
  GstCapsFeatures *features = gst_caps_get_features (caps, 0);

  /* Need to check if the pad created by the decodebin is for video and not
   * audio. */
  if (!strncmp (name, "video", 5)) {
    /* Link the decodebin pad only if decodebin has picked nvidia
     * decoder plugin nvdec_*. We do this by checking if the pad caps contain
     * NVMM memory features. */
    if (gst_caps_features_contains (features, GST_CAPS_FEATURES_NVMM)) {
      /* Get the source bin ghost pad */
      GstPad *bin_ghost_pad = gst_element_get_static_pad (source_bin, "src");
      if (!gst_ghost_pad_set_target (GST_GHOST_PAD (bin_ghost_pad),
              decoder_src_pad)) {
        g_printerr ("Failed to link decoder src pad to source bin ghost pad\n");
      }
      gst_object_unref (bin_ghost_pad);
    } else {
      g_printerr ("Error: Decodebin did not pick nvidia decoder plugin.\n");
    }
  }
}

static void
decodebin_child_added (GstChildProxy * child_proxy, GObject * object,
    gchar * name, gpointer user_data)
{
  g_print ("Decodebin child added: %s\n", name);
  if (g_strrstr (name, "decodebin") == name) {
    g_signal_connect (G_OBJECT (object), "child-added",
        G_CALLBACK (decodebin_child_added), user_data);
  }
  if (g_strstr_len (name, -1, "nvv4l2decoder") == name) {
    g_print ("Seting bufapi_version\n");
    //g_object_set (object, "bufapi-version", TRUE, NULL);
    g_object_set(object, "drop-frame-interval", 2, NULL);
  }
}

static GstElement *
create_source_bin (guint index, gchar * uri)
{
  GstElement *bin = NULL, *uri_decode_bin = NULL;
  gchar bin_name[16] = { };

  g_snprintf (bin_name, 15, "source-bin-%02d", index);
  /* Create a source GstBin to abstract this bin's content from the rest of the
   * pipeline */
  bin = gst_bin_new (bin_name);

  /* Source element for reading from the uri.
   * We will use decodebin and let it figure out the container format of the
   * stream and the codec and plug the appropriate demux and decode plugins. */
  uri_decode_bin = gst_element_factory_make ("uridecodebin", "uri-decode-bin");

  if (!bin || !uri_decode_bin) {
    g_printerr ("One element in source bin could not be created.\n");
    return NULL;
  }

  /* We set the input uri to the source element */
  g_object_set (G_OBJECT (uri_decode_bin), "uri", uri, NULL);



  /* Connect to the "pad-added" signal of the decodebin which generates a
   * callback once a new pad for raw data has beed created by the decodebin */
  g_signal_connect (G_OBJECT (uri_decode_bin), "pad-added",
      G_CALLBACK (cb_newpad), bin);
  g_signal_connect (G_OBJECT (uri_decode_bin), "child-added",
      G_CALLBACK (decodebin_child_added), bin);

  gst_bin_add (GST_BIN (bin), uri_decode_bin);

  /* We need to create a ghost pad for the source bin which will act as a proxy
   * for the video decoder src pad. The ghost pad will not have a target right
   * now. Once the decode bin creates the video decoder and generates the
   * cb_newpad callback, we will set the ghost pad target to the video decoder
   * src pad. */
  if (!gst_element_add_pad (bin, gst_ghost_pad_new_no_target ("src",
              GST_PAD_SRC))) {
    g_printerr ("Failed to add ghost pad in source bin\n");
    return NULL;
  }

  return bin;
}

int
main (int argc, char *argv[])
{
  GMainLoop *loop = NULL;
  GstElement *pipeline = NULL, *streammux = NULL, *sink = NULL,
      *nvvidconv = NULL,  *tiler = NULL;
  GstBus *bus = NULL;
  guint bus_watch_id;
  guint i, num_sources;
  guint tiler_rows, tiler_columns;

  videoPath.emplace_back("rtsp://admin:ropeok123@172.17.178.236:554/main");

  num_sources = videoPath.size();

  /* Standard GStreamer initialization */
  gst_init (NULL,NULL);
  loop = g_main_loop_new (NULL, FALSE);

  /* Create gstreamer elements */
  /* Create Pipeline element that will form a connection of other elements */
  pipeline = gst_pipeline_new ("dstest3-pipeline");

  /* Create nvstreammux instance to form batches from one or more sources. */
  streammux = gst_element_factory_make ("nvstreammux", "stream-muxer");

  if (!pipeline || !streammux) {
    g_printerr ("One element could not be created. Exiting.\n");
    return -1;
  }
  gst_bin_add (GST_BIN (pipeline), streammux);

  for (i = 0; i < num_sources; i++) {
    GstPad *sinkpad, *srcpad;
    gchar pad_name[16] = { };
    GstElement *source_bin = create_source_bin (i, (gchar*)videoPath[i].c_str());

    if (!source_bin) {
      g_printerr ("Failed to create source bin. Exiting.\n");
      return -1;
    }

    gst_bin_add (GST_BIN (pipeline), source_bin);

    g_snprintf (pad_name, 15, "sink_%u", i);
    sinkpad = gst_element_get_request_pad (streammux, pad_name);
    if (!sinkpad) {
      g_printerr ("Streammux request sink pad failed. Exiting.\n");
      return -1;
    }

    srcpad = gst_element_get_static_pad (source_bin, "src");
    if (!srcpad) {
      g_printerr ("Failed to get src pad of source bin. Exiting.\n");
      return -1;
    }

    if (gst_pad_link (srcpad, sinkpad) != GST_PAD_LINK_OK) {
      g_printerr ("Failed to link source bin to stream muxer. Exiting.\n");
      return -1;
    }

    gst_object_unref (srcpad);
    gst_object_unref (sinkpad);
  }

  /* Use nvtiler to composite the batched frames into a 2D tiled array based
   * on the source of the frames. */
  tiler = gst_element_factory_make ("nvmultistreamtiler", "nvtiler");

  /* Use convertor to convert from NV12 to RGBA as required by nvosd */
  nvvidconv = gst_element_factory_make ("nvvideoconvert", "nvvideo-converter");

  /* Finally render the osd output */
  sink = gst_element_factory_make ("nveglglessink", "nvvideo-renderer");

  if (!tiler || !nvvidconv || !sink) {
    g_printerr ("One element could not be created. Exiting.\n");
    return -1;
  }

  g_object_set (G_OBJECT (streammux), "width", MUXER_OUTPUT_WIDTH, "height",
      MUXER_OUTPUT_HEIGHT, "batch-size", num_sources,
      "batched-push-timeout", MUXER_BATCH_TIMEOUT_USEC, NULL);

  tiler_rows = (guint) sqrt (num_sources);
  tiler_columns = (guint) ceil (1.0 * num_sources / tiler_rows);
  /* we set the tiler properties here */
  g_object_set (G_OBJECT (tiler), "rows", tiler_rows, "columns", tiler_columns,
      "width", TILED_OUTPUT_WIDTH, "height", TILED_OUTPUT_HEIGHT, NULL);

  g_object_set (G_OBJECT (sink), "sync", false, NULL);

  /* we add a message handler */
  bus = gst_pipeline_get_bus (GST_PIPELINE (pipeline));
  bus_watch_id = gst_bus_add_watch (bus, bus_call, loop);
  gst_object_unref (bus);

  /* Set up the pipeline */
  /* we add all elements into the pipeline */
  gst_bin_add_many (GST_BIN (pipeline), tiler, nvvidconv, sink,
      NULL);

  /* we link the elements together
   * nvstreammux -> nvinfer -> nvtiler -> nvvidconv -> nvosd -> video-renderer */
  if (!gst_element_link_many (streammux, tiler, nvvidconv, sink,
          NULL)) {
    g_printerr ("Elements could not be linked. Exiting.\n");
    return -1;
  }


  /* Set the pipeline to "playing" state */
  g_print ("Now playing:");
  for (i = 0; i < num_sources; i++) {
    g_print (" %s.\n", videoPath[i]);
  }
  g_print ("\n");

  gst_element_set_state (pipeline, GST_STATE_PLAYING);

  /* Wait till pipeline encounters an error or EOS */
  g_print ("Running...\n");
  g_main_loop_run (loop);

  /* Out of the main loop, clean up nicely */
  g_print ("Returned, stopping playback\n");
  gst_element_set_state (pipeline, GST_STATE_NULL);
  g_print ("Deleting pipeline\n");
  gst_object_unref (GST_OBJECT (pipeline));
  g_source_remove (bus_watch_id);
  g_main_loop_unref (loop);
  return 0;
}