/*
 * 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 "cbs/cbs.h"
#include "cbs/cbs_vp9.h"
#include "cbs_internal.h"


static int cbs_vp9_read_s(CodedBitstreamContext *ctx, GetBitContext *gbc,
  int width, const char *name,
  const int *subscripts, int32_t *write_to) {
  uint32_t magnitude;
  int position, sign;
  int32_t value;

  if(ctx->trace_enable)
    position = get_bits_count(gbc);

  if(get_bits_left(gbc) < width + 1) {
    av_log(ctx->log_ctx, AV_LOG_ERROR, "Invalid signed value at "
                                       "%s: bitstream ended.\n",
      name);
    return AVERROR_INVALIDDATA;
  }

  magnitude = get_bits(gbc, width);
  sign      = get_bits1(gbc);
  value     = sign ? -(int32_t)magnitude : magnitude;

  if(ctx->trace_enable) {
    char bits[33];
    int i;
    for(i = 0; i < width; i++)
      bits[i] = magnitude >> (width - i - 1) & 1 ? '1' : '0';
    bits[i]     = sign ? '1' : '0';
    bits[i + 1] = 0;

    ff_cbs_trace_syntax_element(ctx, position, name, subscripts,
      bits, value);
  }

  *write_to = value;
  return 0;
}

static int cbs_vp9_write_s(CodedBitstreamContext *ctx, PutBitContext *pbc,
  int width, const char *name,
  const int *subscripts, int32_t value) {
  uint32_t magnitude;
  int sign;

  if(put_bits_left(pbc) < width + 1)
    return AVERROR(ENOSPC);

  sign      = value < 0;
  magnitude = sign ? -value : value;

  if(ctx->trace_enable) {
    char bits[33];
    int i;
    for(i = 0; i < width; i++)
      bits[i] = magnitude >> (width - i - 1) & 1 ? '1' : '0';
    bits[i]     = sign ? '1' : '0';
    bits[i + 1] = 0;

    ff_cbs_trace_syntax_element(ctx, put_bits_count(pbc),
      name, subscripts, bits, value);
  }

  put_bits(pbc, width, magnitude);
  put_bits(pbc, 1, sign);

  return 0;
}

static int cbs_vp9_read_increment(CodedBitstreamContext *ctx, GetBitContext *gbc,
  uint32_t range_min, uint32_t range_max,
  const char *name, uint32_t *write_to) {
  uint32_t value;
  int position, i;
  char bits[8];

  av_assert0(range_min <= range_max && range_max - range_min < sizeof(bits) - 1);
  if(ctx->trace_enable)
    position = get_bits_count(gbc);

  for(i = 0, value = range_min; value < range_max;) {
    if(get_bits_left(gbc) < 1) {
      av_log(ctx->log_ctx, AV_LOG_ERROR, "Invalid increment value at "
                                         "%s: bitstream ended.\n",
        name);
      return AVERROR_INVALIDDATA;
    }
    if(get_bits1(gbc)) {
      bits[i++] = '1';
      ++value;
    }
    else {
      bits[i++] = '0';
      break;
    }
  }

  if(ctx->trace_enable) {
    bits[i] = 0;
    ff_cbs_trace_syntax_element(ctx, position, name, NULL, bits, value);
  }

  *write_to = value;
  return 0;
}

static int cbs_vp9_write_increment(CodedBitstreamContext *ctx, PutBitContext *pbc,
  uint32_t range_min, uint32_t range_max,
  const char *name, uint32_t value) {
  int len;

  av_assert0(range_min <= range_max && range_max - range_min < 8);
  if(value < range_min || value > range_max) {
    av_log(ctx->log_ctx, AV_LOG_ERROR, "%s out of range: "
                                       "%" PRIu32 ", but must be in [%" PRIu32 ",%" PRIu32 "].\n",
      name, value, range_min, range_max);
    return AVERROR_INVALIDDATA;
  }

  if(value == range_max)
    len = range_max - range_min;
  else
    len = value - range_min + 1;
  if(put_bits_left(pbc) < len)
    return AVERROR(ENOSPC);

  if(ctx->trace_enable) {
    char bits[8];
    int i;
    for(i = 0; i < len; i++) {
      if(range_min + i == value)
        bits[i] = '0';
      else
        bits[i] = '1';
    }
    bits[i] = 0;
    ff_cbs_trace_syntax_element(ctx, put_bits_count(pbc),
      name, NULL, bits, value);
  }

  if(len > 0)
    put_bits(pbc, len, (1 << len) - 1 - (value != range_max));

  return 0;
}

static int cbs_vp9_read_le(CodedBitstreamContext *ctx, GetBitContext *gbc,
  int width, const char *name,
  const int *subscripts, uint32_t *write_to) {
  uint32_t value;
  int position, b;

  av_assert0(width % 8 == 0);

  if(ctx->trace_enable)
    position = get_bits_count(gbc);

  if(get_bits_left(gbc) < width) {
    av_log(ctx->log_ctx, AV_LOG_ERROR, "Invalid le value at "
                                       "%s: bitstream ended.\n",
      name);
    return AVERROR_INVALIDDATA;
  }

  value = 0;
  for(b = 0; b < width; b += 8)
    value |= get_bits(gbc, 8) << b;

  if(ctx->trace_enable) {
    char bits[33];
    int i;
    for(b = 0; b < width; b += 8)
      for(i = 0; i < 8; i++)
        bits[b + i] = value >> (b + i) & 1 ? '1' : '0';
    bits[b] = 0;

    ff_cbs_trace_syntax_element(ctx, position, name, subscripts,
      bits, value);
  }

  *write_to = value;
  return 0;
}

static int cbs_vp9_write_le(CodedBitstreamContext *ctx, PutBitContext *pbc,
  int width, const char *name,
  const int *subscripts, uint32_t value) {
  int b;

  av_assert0(width % 8 == 0);

  if(put_bits_left(pbc) < width)
    return AVERROR(ENOSPC);

  if(ctx->trace_enable) {
    char bits[33];
    int i;
    for(b = 0; b < width; b += 8)
      for(i = 0; i < 8; i++)
        bits[b + i] = value >> (b + i) & 1 ? '1' : '0';
    bits[b] = 0;

    ff_cbs_trace_syntax_element(ctx, put_bits_count(pbc),
      name, subscripts, bits, value);
  }

  for(b = 0; b < width; b += 8)
    put_bits(pbc, 8, value >> b & 0xff);

  return 0;
}

#define HEADER(name)                \
  do {                              \
    ff_cbs_trace_header(ctx, name); \
  } while(0)

#define CHECK(call) \
  do {              \
    err = (call);   \
    if(err < 0)     \
      return err;   \
  } while(0)

#define FUNC_NAME(rw, codec, name) cbs_##codec##_##rw##_##name
#define FUNC_VP9(rw, name) FUNC_NAME(rw, vp9, name)
#define FUNC(name) FUNC_VP9(READWRITE, name)

#define SUBSCRIPTS(subs, ...) (subs > 0 ? ((int[subs + 1]) { subs, __VA_ARGS__ }) : NULL)

#define f(width, name) \
  xf(width, name, current->name, 0, )
#define s(width, name) \
  xs(width, name, current->name, 0, )
#define fs(width, name, subs, ...) \
  xf(width, name, current->name, subs, __VA_ARGS__)
#define ss(width, name, subs, ...) \
  xs(width, name, current->name, subs, __VA_ARGS__)

#define READ
#define READWRITE read
#define RWContext GetBitContext

#define xf(width, name, var, subs, ...)               \
  do {                                                \
    uint32_t value;                                   \
    CHECK(ff_cbs_read_unsigned(ctx, rw, width, #name, \
      SUBSCRIPTS(subs, __VA_ARGS__),                  \
      &value, 0, (1 << width) - 1));                  \
    var = value;                                      \
  } while(0)
#define xs(width, name, var, subs, ...)         \
  do {                                          \
    int32_t value;                              \
    CHECK(cbs_vp9_read_s(ctx, rw, width, #name, \
      SUBSCRIPTS(subs, __VA_ARGS__), &value));  \
    var = value;                                \
  } while(0)


#define increment(name, min, max)                                    \
  do {                                                               \
    uint32_t value;                                                  \
    CHECK(cbs_vp9_read_increment(ctx, rw, min, max, #name, &value)); \
    current->name = value;                                           \
  } while(0)

#define fle(width, name, subs, ...)                    \
  do {                                                 \
    CHECK(cbs_vp9_read_le(ctx, rw, width, #name,       \
      SUBSCRIPTS(subs, __VA_ARGS__), &current->name)); \
  } while(0)

#define delta_q(name)                          \
  do {                                         \
    uint8_t delta_coded;                       \
    int8_t delta_q;                            \
    xf(1, name.delta_coded, delta_coded, 0, ); \
    if(delta_coded)                            \
      xs(4, name.delta_q, delta_q, 0, );       \
    else                                       \
      delta_q = 0;                             \
    current->name = delta_q;                   \
  } while(0)

#define prob(name, subs, ...)                              \
  do {                                                     \
    uint8_t prob_coded;                                    \
    uint8_t prob;                                          \
    xf(1, name.prob_coded, prob_coded, subs, __VA_ARGS__); \
    if(prob_coded)                                         \
      xf(8, name.prob, prob, subs, __VA_ARGS__);           \
    else                                                   \
      prob = 255;                                          \
    current->name = prob;                                  \
  } while(0)

#define fixed(width, name, value)                     \
  do {                                                \
    av_unused uint32_t fixed_value;                   \
    CHECK(ff_cbs_read_unsigned(ctx, rw, width, #name, \
      0, &fixed_value, value, value));                \
  } while(0)

#define infer(name, value) \
  do {                     \
    current->name = value; \
  } while(0)

#define byte_alignment(rw) (get_bits_count(rw) % 8)

#include "cbs_vp9_syntax_template.c"

#undef READ
#undef READWRITE
#undef RWContext
#undef xf
#undef xs
#undef increment
#undef fle
#undef delta_q
#undef prob
#undef fixed
#undef infer
#undef byte_alignment


#define WRITE
#define READWRITE write
#define RWContext PutBitContext

#define xf(width, name, var, subs, ...)                \
  do {                                                 \
    CHECK(ff_cbs_write_unsigned(ctx, rw, width, #name, \
      SUBSCRIPTS(subs, __VA_ARGS__),                   \
      var, 0, (1 << width) - 1));                      \
  } while(0)
#define xs(width, name, var, subs, ...)          \
  do {                                           \
    CHECK(cbs_vp9_write_s(ctx, rw, width, #name, \
      SUBSCRIPTS(subs, __VA_ARGS__), var));      \
  } while(0)

#define increment(name, min, max)                                            \
  do {                                                                       \
    CHECK(cbs_vp9_write_increment(ctx, rw, min, max, #name, current->name)); \
  } while(0)

#define fle(width, name, subs, ...)                   \
  do {                                                \
    CHECK(cbs_vp9_write_le(ctx, rw, width, #name,     \
      SUBSCRIPTS(subs, __VA_ARGS__), current->name)); \
  } while(0)

#define delta_q(name)                              \
  do {                                             \
    xf(1, name.delta_coded, !!current->name, 0, ); \
    if(current->name)                              \
      xs(4, name.delta_q, current->name, 0, );     \
  } while(0)

#define prob(name, subs, ...)                                        \
  do {                                                               \
    xf(1, name.prob_coded, current->name != 255, subs, __VA_ARGS__); \
    if(current->name != 255)                                         \
      xf(8, name.prob, current->name, subs, __VA_ARGS__);            \
  } while(0)

#define fixed(width, name, value)                      \
  do {                                                 \
    CHECK(ff_cbs_write_unsigned(ctx, rw, width, #name, \
      0, value, value, value));                        \
  } while(0)

#define infer(name, value)                                                              \
  do {                                                                                  \
    if(current->name != (value)) {                                                      \
      av_log(ctx->log_ctx, AV_LOG_WARNING, "Warning: "                                  \
                                           "%s does not match inferred value: "         \
                                           "%" PRId64 ", but should be %" PRId64 ".\n", \
        #name, (int64_t)current->name, (int64_t)(value));                               \
    }                                                                                   \
  } while(0)

#define byte_alignment(rw) (put_bits_count(rw) % 8)

#include "cbs_vp9_syntax_template.c"

#undef WRITE
#undef READWRITE
#undef RWContext
#undef xf
#undef xs
#undef increment
#undef fle
#undef delta_q
#undef prob
#undef fixed
#undef infer
#undef byte_alignment


static int cbs_vp9_split_fragment(CodedBitstreamContext *ctx,
  CodedBitstreamFragment *frag,
  int header) {
  uint8_t superframe_header;
  int err;

  if(frag->data_size == 0)
    return AVERROR_INVALIDDATA;

  // Last byte in the packet.
  superframe_header = frag->data[frag->data_size - 1];

  if((superframe_header & 0xe0) == 0xc0) {
    VP9RawSuperframeIndex sfi;
    GetBitContext gbc;
    size_t index_size, pos;
    int i;

    index_size = 2 + (((superframe_header & 0x18) >> 3) + 1) *
                       ((superframe_header & 0x07) + 1);

    if(index_size > frag->data_size)
      return AVERROR_INVALIDDATA;

    err = init_get_bits(&gbc, frag->data + frag->data_size - index_size,
      8 * index_size);
    if(err < 0)
      return err;

    err = cbs_vp9_read_superframe_index(ctx, &gbc, &sfi);
    if(err < 0)
      return err;

    pos = 0;
    for(i = 0; i <= sfi.frames_in_superframe_minus_1; i++) {
      if(pos + sfi.frame_sizes[i] + index_size > frag->data_size) {
        av_log(ctx->log_ctx, AV_LOG_ERROR, "Frame %d too large "
                                           "in superframe: %" PRIu32 " bytes.\n",
          i, sfi.frame_sizes[i]);
        return AVERROR_INVALIDDATA;
      }

      err = ff_cbs_insert_unit_data(frag, -1, 0,
        frag->data + pos,
        sfi.frame_sizes[i],
        frag->data_ref);
      if(err < 0)
        return err;

      pos += sfi.frame_sizes[i];
    }
    if(pos + index_size != frag->data_size) {
      av_log(ctx->log_ctx, AV_LOG_WARNING, "Extra padding at "
                                           "end of superframe: %zu bytes.\n",
        frag->data_size - (pos + index_size));
    }

    return 0;
  }
  else {
    err = ff_cbs_insert_unit_data(frag, -1, 0,
      frag->data, frag->data_size,
      frag->data_ref);
    if(err < 0)
      return err;
  }

  return 0;
}

static int cbs_vp9_read_unit(CodedBitstreamContext *ctx,
  CodedBitstreamUnit *unit) {
  VP9RawFrame *frame;
  GetBitContext gbc;
  int err, pos;

  err = init_get_bits(&gbc, unit->data, 8 * unit->data_size);
  if(err < 0)
    return err;

  err = ff_cbs_alloc_unit_content2(ctx, unit);
  if(err < 0)
    return err;
  frame = unit->content;

  err = cbs_vp9_read_frame(ctx, &gbc, frame);
  if(err < 0)
    return err;

  pos = get_bits_count(&gbc);
  av_assert0(pos % 8 == 0);
  pos /= 8;
  av_assert0(pos <= unit->data_size);

  if(pos == unit->data_size) {
    // No data (e.g. a show-existing-frame frame).
  }
  else {
    frame->data_ref = av_buffer_ref(unit->data_ref);
    if(!frame->data_ref)
      return AVERROR(ENOMEM);

    frame->data      = unit->data + pos;
    frame->data_size = unit->data_size - pos;
  }

  return 0;
}

static int cbs_vp9_write_unit(CodedBitstreamContext *ctx,
  CodedBitstreamUnit *unit,
  PutBitContext *pbc) {
  VP9RawFrame *frame = unit->content;
  int err;

  err = cbs_vp9_write_frame(ctx, pbc, frame);
  if(err < 0)
    return err;

  // Frame must be byte-aligned.
  av_assert0(put_bits_count(pbc) % 8 == 0);

  if(frame->data) {
    if(frame->data_size > put_bits_left(pbc) / 8)
      return AVERROR(ENOSPC);

    flush_put_bits(pbc);
    memcpy(put_bits_ptr(pbc), frame->data, frame->data_size);
    skip_put_bytes(pbc, frame->data_size);
  }

  return 0;
}

static int cbs_vp9_assemble_fragment(CodedBitstreamContext *ctx,
  CodedBitstreamFragment *frag) {
  int err;

  if(frag->nb_units == 1) {
    // Output is just the content of the single frame.

    CodedBitstreamUnit *frame = &frag->units[0];

    frag->data_ref = av_buffer_ref(frame->data_ref);
    if(!frag->data_ref)
      return AVERROR(ENOMEM);

    frag->data      = frame->data;
    frag->data_size = frame->data_size;
  }
  else {
    // Build superframe out of frames.

    VP9RawSuperframeIndex sfi;
    PutBitContext pbc;
    AVBufferRef *ref;
    uint8_t *data;
    size_t size, max, pos;
    int i, size_len;

    if(frag->nb_units > 8) {
      av_log(ctx->log_ctx, AV_LOG_ERROR, "Too many frames to "
                                         "make superframe: %d.\n",
        frag->nb_units);
      return AVERROR(EINVAL);
    }

    max = 0;
    for(i = 0; i < frag->nb_units; i++)
      if(max < frag->units[i].data_size)
        max = frag->units[i].data_size;

    if(max < 2)
      size_len = 1;
    else
      size_len = av_log2(max) / 8 + 1;
    av_assert0(size_len <= 4);

    sfi.superframe_marker            = VP9_SUPERFRAME_MARKER;
    sfi.bytes_per_framesize_minus_1  = size_len - 1;
    sfi.frames_in_superframe_minus_1 = frag->nb_units - 1;

    size = 2;
    for(i = 0; i < frag->nb_units; i++) {
      size += size_len + frag->units[i].data_size;
      sfi.frame_sizes[i] = frag->units[i].data_size;
    }

    ref = av_buffer_alloc(size + AV_INPUT_BUFFER_PADDING_SIZE);
    if(!ref)
      return AVERROR(ENOMEM);
    data = ref->data;
    memset(data + size, 0, AV_INPUT_BUFFER_PADDING_SIZE);

    pos = 0;
    for(i = 0; i < frag->nb_units; i++) {
      av_assert0(size - pos > frag->units[i].data_size);
      memcpy(data + pos, frag->units[i].data,
        frag->units[i].data_size);
      pos += frag->units[i].data_size;
    }
    av_assert0(size - pos == 2 + frag->nb_units * size_len);

    init_put_bits(&pbc, data + pos, size - pos);

    err = cbs_vp9_write_superframe_index(ctx, &pbc, &sfi);
    if(err < 0) {
      av_log(ctx->log_ctx, AV_LOG_ERROR, "Failed to write "
                                         "superframe index.\n");
      av_buffer_unref(&ref);
      return err;
    }

    av_assert0(put_bits_left(&pbc) == 0);
    flush_put_bits(&pbc);

    frag->data_ref  = ref;
    frag->data      = data;
    frag->data_size = size;
  }

  return 0;
}

static void cbs_vp9_flush(CodedBitstreamContext *ctx) {
  CodedBitstreamVP9Context *vp9 = ctx->priv_data;

  memset(vp9->ref, 0, sizeof(vp9->ref));
}

static const CodedBitstreamUnitTypeDescriptor cbs_vp9_unit_types[] = {
  CBS_UNIT_TYPE_INTERNAL_REF(0, VP9RawFrame, data),
  CBS_UNIT_TYPE_END_OF_LIST
};

const CodedBitstreamType ff_cbs_type_vp9 = {
  .codec_id = AV_CODEC_ID_VP9,

  .priv_data_size = sizeof(CodedBitstreamVP9Context),

  .unit_types = cbs_vp9_unit_types,

  .split_fragment = &cbs_vp9_split_fragment,
  .read_unit      = &cbs_vp9_read_unit,
  .write_unit     = &cbs_vp9_write_unit,

  .flush = &cbs_vp9_flush,

  .assemble_fragment = &cbs_vp9_assemble_fragment,
};