/*
 * Copyright (c) 2018, Alliance for Open Media. All rights reserved
 *
 * This source code is subject to the terms of the BSD 2 Clause License and
 * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
 * was not distributed with this source code in the LICENSE file, you can
 * obtain it at www.aomedia.org/license/software. If the Alliance for Open
 * Media Patent License 1.0 was not distributed with this source code in the
 * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
 */

// Lightfield Bitstream Parsing
// ============================
//
// This is an lightfield bitstream parsing example. It takes an input file
// containing the whole compressed lightfield bitstream(ivf file), and parses it
// and constructs and outputs a new bitstream that can be decoded by an AV1
// decoder. The output bitstream contains tile list OBUs.  num_references is
// the number of references encoded at the beginning of the light field file.
// After running the lightfield encoder, run lightfield bitstream parsing:
// examples/lightfield_bitstream_parsing vase10x10.ivf vase_tile_list.ivf 64

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

#include "aom/aom_decoder.h"
#include "aom/aom_encoder.h"
#include "aom/aom_integer.h"
#include "aom/aomdx.h"
#include "aom_dsp/bitwriter_buffer.h"
#include "common/tools_common.h"
#include "common/video_reader.h"
#include "common/video_writer.h"

static const char *exec_name;

void usage_exit(void) {
  fprintf(stderr, "Usage: %s <infile> <outfile> <num_references> \n",
          exec_name);
  exit(EXIT_FAILURE);
}

#define ALIGN_POWER_OF_TWO(value, n) \
  (((value) + ((1 << (n)) - 1)) & ~((1 << (n)) - 1))

// SB size: 64x64
const uint8_t output_frame_width_in_tiles_minus_1 = 512 / 64 - 1;
const uint8_t output_frame_height_in_tiles_minus_1 = 512 / 64 - 1;

// Spec:
// typedef struct {
//   uint8_t anchor_frame_idx;
//   uint8_t tile_row;
//   uint8_t tile_col;
//   uint16_t coded_tile_data_size_minus_1;
//   uint8_t *coded_tile_data;
// } TILE_LIST_ENTRY;

// Tile list entry provided by the application
typedef struct {
  int image_idx;
  int reference_idx;
  int tile_col;
  int tile_row;
} TILE_LIST_INFO;

// M references: 0 - M-1; N images(including references): 0 - N-1;
// Note: order the image index incrementally, so that we only go through the
// bitstream once to construct the tile list.
const int num_tile_lists = 2;
const uint16_t tile_count_minus_1 = 9 - 1;
const TILE_LIST_INFO tile_list[2][9] = {
  { { 16, 0, 4, 5 },
    { 83, 3, 13, 2 },
    { 57, 2, 2, 6 },
    { 31, 1, 11, 5 },
    { 2, 0, 7, 4 },
    { 77, 3, 9, 9 },
    { 49, 1, 0, 1 },
    { 6, 0, 3, 10 },
    { 63, 2, 5, 8 } },
  { { 65, 2, 11, 1 },
    { 42, 1, 3, 7 },
    { 88, 3, 8, 4 },
    { 76, 3, 1, 15 },
    { 1, 0, 2, 2 },
    { 19, 0, 5, 6 },
    { 60, 2, 4, 0 },
    { 25, 1, 11, 15 },
    { 50, 2, 5, 4 } },
};

int main(int argc, char **argv) {
  aom_codec_ctx_t codec;
  AvxVideoReader *reader = NULL;
  AvxVideoWriter *writer = NULL;
  const AvxInterface *decoder = NULL;
  const AvxVideoInfo *info = NULL;
  int width, height;
  int num_references;
  int n, i;
  aom_codec_pts_t pts;

  exec_name = argv[0];
  if (argc != 4) die("Invalid number of arguments.");

  reader = aom_video_reader_open(argv[1]);
  if (!reader) die("Failed to open %s for reading.", argv[1]);

  num_references = (int)strtol(argv[3], NULL, 0);
  info = aom_video_reader_get_info(reader);
  width = info->frame_width;
  height = info->frame_height;

  // The writer to write out ivf file in tile list OBU, which can be decoded by
  // AV1 decoder.
  writer = aom_video_writer_open(argv[2], kContainerIVF, info);
  if (!writer) die("Failed to open %s for writing", argv[2]);

  decoder = get_aom_decoder_by_fourcc(info->codec_fourcc);
  if (!decoder) die("Unknown input codec.");
  printf("Using %s\n", aom_codec_iface_name(decoder->codec_interface()));

  if (aom_codec_dec_init(&codec, decoder->codec_interface(), NULL, 0))
    die_codec(&codec, "Failed to initialize decoder.");

  // Decode anchor frames.
  aom_codec_control_(&codec, AV1_SET_TILE_MODE, 0);

  for (i = 0; i < num_references; ++i) {
    aom_video_reader_read_frame(reader);

    size_t frame_size = 0;
    const unsigned char *frame =
        aom_video_reader_get_frame(reader, &frame_size);
    pts = (aom_codec_pts_t)aom_video_reader_get_frame_pts(reader);

    // Copy references bitstream directly.
    if (!aom_video_writer_write_frame(writer, frame, frame_size, pts))
      die_codec(&codec, "Failed to copy compressed anchor frame.");

    if (aom_codec_decode(&codec, frame, frame_size, NULL))
      die_codec(&codec, "Failed to decode frame.");
  }

  // Decode camera frames.
  aom_codec_control_(&codec, AV1_SET_TILE_MODE, 1);
  aom_codec_control_(&codec, AV1D_EXT_TILE_DEBUG, 1);

  FILE *infile = aom_video_reader_get_file(reader);
  // Record the offset of the first camera image.
  const FileOffset camera_frame_pos = ftello(infile);

  // Read out the first camera frame.
  aom_video_reader_read_frame(reader);

  // Copy first camera frame for getting camera frame header. This is done
  // only once.
  {
    size_t frame_size = 0;
    const unsigned char *frame =
        aom_video_reader_get_frame(reader, &frame_size);
    pts = (aom_codec_pts_t)aom_video_reader_get_frame_pts(reader);
    aom_tile_data frame_header_info = { 0, NULL, 0 };

    // Need to decode frame header to get camera frame header info. So, here
    // decoding 1 tile is enough.
    aom_codec_control_(&codec, AV1_SET_DECODE_TILE_ROW, 0);
    aom_codec_control_(&codec, AV1_SET_DECODE_TILE_COL, 0);

    aom_codec_err_t aom_status =
        aom_codec_decode(&codec, frame, frame_size, NULL);
    if (aom_status) die_codec(&codec, "Failed to decode tile.");

    aom_codec_control_(&codec, AV1D_GET_FRAME_HEADER_INFO, &frame_header_info);

    size_t obu_size_offset =
        (uint8_t *)frame_header_info.coded_tile_data - frame;
    size_t length_field_size = frame_header_info.coded_tile_data_size;
    // Remove ext-tile tile info.
    uint32_t frame_header_size = (uint32_t)frame_header_info.extra_size - 1;
    size_t bytes_to_copy =
        obu_size_offset + length_field_size + frame_header_size;

    unsigned char *frame_hdr_buf = (unsigned char *)malloc(bytes_to_copy);
    if (frame_hdr_buf == NULL)
      die_codec(&codec, "Failed to allocate frame header buffer.");

    memcpy(frame_hdr_buf, frame, bytes_to_copy);

    // Update frame header OBU size.
    size_t bytes_written = 0;
    if (aom_uleb_encode_fixed_size(
            frame_header_size, length_field_size, length_field_size,
            frame_hdr_buf + obu_size_offset, &bytes_written))
      die_codec(&codec, "Failed to encode the tile list obu size.");

    // Copy camera frame header bitstream.
    if (!aom_video_writer_write_frame(writer, frame_hdr_buf, bytes_to_copy,
                                      pts))
      die_codec(&codec, "Failed to copy compressed camera frame header.");
  }

  // Allocate a buffer to store tile list bitstream. Image format
  // AOM_IMG_FMT_I420.
  size_t data_sz =
      ALIGN_POWER_OF_TWO(width, 5) * ALIGN_POWER_OF_TWO(height, 5) * 12 / 8;
  unsigned char *tl_buf = (unsigned char *)malloc(data_sz);
  if (tl_buf == NULL) die_codec(&codec, "Failed to allocate tile list buffer.");

  aom_codec_pts_t tl_pts = pts;

  // Process 1 tile list.
  for (n = 0; n < num_tile_lists; n++) {
    unsigned char *tl = tl_buf;
    struct aom_write_bit_buffer wb = { tl, 0 };
    unsigned char *saved_obu_size_loc = NULL;
    uint32_t tile_list_obu_header_size = 0;
    uint32_t tile_list_obu_size = 0;

    // Write the tile list OBU header that is 1 byte long.
    aom_wb_write_literal(&wb, 0, 1);  // forbidden bit.
    aom_wb_write_literal(&wb, 8, 4);  // tile list OBU: "1000"
    aom_wb_write_literal(&wb, 0, 1);  // obu_extension = 0
    aom_wb_write_literal(&wb, 1, 1);  // obu_has_size_field
    aom_wb_write_literal(&wb, 0, 1);  // reserved
    tl++;
    tile_list_obu_header_size++;

    // Write the OBU size using a fixed length_field_size of 4 bytes.
    saved_obu_size_loc = tl;
    aom_wb_write_literal(&wb, 0, 32);
    tl += 4;
    tile_list_obu_header_size += 4;

    // write_tile_list_obu()
    aom_wb_write_literal(&wb, output_frame_width_in_tiles_minus_1, 8);
    aom_wb_write_literal(&wb, output_frame_height_in_tiles_minus_1, 8);
    aom_wb_write_literal(&wb, tile_count_minus_1, 16);
    tl += 4;
    tile_list_obu_size += 4;

    // Write each tile's data
    for (i = 0; i <= tile_count_minus_1; i++) {
      aom_tile_data tile_data = { 0, NULL, 0 };

      int image_idx = tile_list[n][i].image_idx;
      int ref_idx = tile_list[n][i].reference_idx;
      int tc = tile_list[n][i].tile_col;
      int tr = tile_list[n][i].tile_row;
      int frame_cnt = -1;

      // Reset bit writer to the right location.
      wb.bit_buffer = tl;
      wb.bit_offset = 0;

      // Seek to the first camera image.
      fseeko(infile, camera_frame_pos, SEEK_SET);

      // Read out the camera image
      while (frame_cnt != image_idx) {
        aom_video_reader_read_frame(reader);
        frame_cnt++;
      }

      size_t frame_size = 0;
      const unsigned char *frame =
          aom_video_reader_get_frame(reader, &frame_size);

      aom_codec_control_(&codec, AV1_SET_DECODE_TILE_ROW, tr);
      aom_codec_control_(&codec, AV1_SET_DECODE_TILE_COL, tc);

      aom_codec_err_t aom_status =
          aom_codec_decode(&codec, frame, frame_size, NULL);
      if (aom_status) die_codec(&codec, "Failed to decode tile.");

      aom_codec_control_(&codec, AV1D_GET_TILE_DATA, &tile_data);

      // Copy over tile info.
      //  uint8_t anchor_frame_idx;
      //  uint8_t tile_row;
      //  uint8_t tile_col;
      //  uint16_t coded_tile_data_size_minus_1;
      //  uint8_t *coded_tile_data;
      uint32_t tile_info_bytes = 5;
      aom_wb_write_literal(&wb, ref_idx, 8);
      aom_wb_write_literal(&wb, tr, 8);
      aom_wb_write_literal(&wb, tc, 8);
      aom_wb_write_literal(&wb, (int)tile_data.coded_tile_data_size - 1, 16);
      tl += tile_info_bytes;

      memcpy(tl, (uint8_t *)tile_data.coded_tile_data,
             tile_data.coded_tile_data_size);
      tl += tile_data.coded_tile_data_size;

      tile_list_obu_size +=
          tile_info_bytes + (uint32_t)tile_data.coded_tile_data_size;
    }

    // Write tile list OBU size.
    size_t bytes_written = 0;
    if (aom_uleb_encode_fixed_size(tile_list_obu_size, 4, 4, saved_obu_size_loc,
                                   &bytes_written))
      die_codec(&codec, "Failed to encode the tile list obu size.");

    // Copy the tile list.
    if (!aom_video_writer_write_frame(
            writer, tl_buf, tile_list_obu_header_size + tile_list_obu_size,
            tl_pts))
      die_codec(&codec, "Failed to copy compressed tile list.");

    tl_pts++;
  }

  free(tl_buf);
  if (aom_codec_destroy(&codec)) die_codec(&codec, "Failed to destroy codec");
  aom_video_writer_close(writer);
  aom_video_reader_close(reader);

  return EXIT_SUCCESS;
}