/*

 * Copyright (c) 2016, 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.

 */

#include <assert.h>

#include <stdlib.h>

#include "config/aom_config.h"

#include "aom_scale/yv12config.h"

#include "av1/common/common.h"

#include "av1/encoder/encoder.h"

#include "av1/encoder/extend.h"

#include "av1/encoder/lookahead.h"

/* Return the buffer at the given absolute index and increment the index */

static struct lookahead_entry *pop(struct lookahead_ctx *ctx, int *idx) {

  int index = *idx;

  struct lookahead_entry *buf = ctx->buf + index;

  assert(index < ctx->max_sz);

  if (++index >= ctx->max_sz) index -= ctx->max_sz;

  *idx = index;

  return buf;

}

void av1_lookahead_destroy(struct lookahead_ctx *ctx) {

  if (ctx) {

    if (ctx->buf) {

      int i;

      for (i = 0; i < ctx->max_sz; i++) aom_free_frame_buffer(&ctx->buf[i].img);

      free(ctx->buf);

    }

    free(ctx);

  }

}

struct lookahead_ctx *av1_lookahead_init(

    unsigned int width, unsigned int height, unsigned int subsampling_x,

    unsigned int subsampling_y, int use_highbitdepth, unsigned int depth,

    const int border_in_pixels, int byte_alignment, int num_lap_buffers,

    bool is_all_intra, int enable_global_motion) {

  int lag_in_frames = AOMMAX(1, depth);

  // For all-intra frame encoding, previous source frames are not required.

  // Hence max_pre_frames is set to 0 in this case. As previous source frames

  // are accessed using a negative index to av1_lookahead_peek(), setting

  // max_pre_frames to 0 will cause av1_lookahead_peek() to return NULL for a

  // negative index.

  const uint8_t max_pre_frames = is_all_intra ? 0 : MAX_PRE_FRAMES;

  // Add the lags to depth and clamp

  depth += num_lap_buffers;

  depth = clamp(depth, 1, MAX_TOTAL_BUFFERS);

  // Allocate memory to keep previous source frames available.

  depth += max_pre_frames;

  // Allocate the lookahead structures

  struct lookahead_ctx *ctx = calloc(1, sizeof(*ctx));

  if (ctx) {

    unsigned int i;

    ctx->max_sz = depth;

    ctx->push_frame_count = 0;

    ctx->max_pre_frames = max_pre_frames;

    ctx->read_ctxs[ENCODE_STAGE].pop_sz = ctx->max_sz - ctx->max_pre_frames;

    ctx->read_ctxs[ENCODE_STAGE].valid = 1;

    if (num_lap_buffers) {

      ctx->read_ctxs[LAP_STAGE].pop_sz = lag_in_frames;

      ctx->read_ctxs[LAP_STAGE].valid = 1;

    }

    ctx->buf = calloc(depth, sizeof(*ctx->buf));

    if (!ctx->buf) goto fail;

    for (i = 0; i < depth; i++) {

      if (aom_realloc_frame_buffer(

              &ctx->buf[i].img, width, height, subsampling_x, subsampling_y,

              use_highbitdepth, border_in_pixels, byte_alignment, NULL, NULL,

              NULL, enable_global_motion))

        goto fail;

    }

  }

  return ctx;

fail:

  av1_lookahead_destroy(ctx);

  return NULL;

}

int av1_lookahead_push(struct lookahead_ctx *ctx, const YV12_BUFFER_CONFIG *src,

                       int64_t ts_start, int64_t ts_end, int use_highbitdepth,

                       aom_enc_frame_flags_t flags) {

  int width = src->y_crop_width;

  int height = src->y_crop_height;

  int uv_width = src->uv_crop_width;

  int uv_height = src->uv_crop_height;

  int subsampling_x = src->subsampling_x;

  int subsampling_y = src->subsampling_y;

  int larger_dimensions, new_dimensions;

  assert(ctx->read_ctxs[ENCODE_STAGE].valid == 1);

  if (ctx->read_ctxs[ENCODE_STAGE].sz + 1 + ctx->max_pre_frames > ctx->max_sz)

    return 1;

  ctx->read_ctxs[ENCODE_STAGE].sz++;

  if (ctx->read_ctxs[LAP_STAGE].valid) {

    ctx->read_ctxs[LAP_STAGE].sz++;

  }

  struct lookahead_entry *buf = pop(ctx, &ctx->write_idx);

  new_dimensions = width != buf->img.y_crop_width ||

                   height != buf->img.y_crop_height ||

                   uv_width != buf->img.uv_crop_width ||

                   uv_height != buf->img.uv_crop_height;

  larger_dimensions = width > buf->img.y_width || height > buf->img.y_height ||

                      uv_width > buf->img.uv_width ||

                      uv_height > buf->img.uv_height;

  assert(!larger_dimensions || new_dimensions);

  if (larger_dimensions) {

    YV12_BUFFER_CONFIG new_img;

    memset(&new_img, 0, sizeof(new_img));

    if (aom_alloc_frame_buffer(&new_img, width, height, subsampling_x,

                               subsampling_y, use_highbitdepth,

                               AOM_BORDER_IN_PIXELS, 0))

      return 1;

    aom_free_frame_buffer(&buf->img);

    buf->img = new_img;

  } else if (new_dimensions) {

    buf->img.y_crop_width = src->y_crop_width;

    buf->img.y_crop_height = src->y_crop_height;

    buf->img.uv_crop_width = src->uv_crop_width;

    buf->img.uv_crop_height = src->uv_crop_height;

    buf->img.subsampling_x = src->subsampling_x;

    buf->img.subsampling_y = src->subsampling_y;

  }

  // Partial copy not implemented yet

  av1_copy_and_extend_frame(src, &buf->img);

  buf->ts_start = ts_start;

  buf->ts_end = ts_end;

  buf->display_idx = ctx->push_frame_count;

  buf->flags = flags;

  ++ctx->push_frame_count;

  aom_remove_metadata_from_frame_buffer(&buf->img);

  aom_copy_metadata_to_frame_buffer(&buf->img, src->metadata);

  return 0;

}

struct lookahead_entry *av1_lookahead_pop(struct lookahead_ctx *ctx, int drain,

                                          COMPRESSOR_STAGE stage) {

  struct lookahead_entry *buf = NULL;

  if (ctx) {

    struct read_ctx *read_ctx = &ctx->read_ctxs[stage];

    assert(read_ctx->valid == 1);

    if (read_ctx->sz && (drain || read_ctx->sz == read_ctx->pop_sz)) {

      buf = pop(ctx, &read_ctx->read_idx);

      read_ctx->sz--;

    }

  }

  return buf;

}

struct lookahead_entry *av1_lookahead_peek(struct lookahead_ctx *ctx, int index,

                                           COMPRESSOR_STAGE stage) {

  struct lookahead_entry *buf = NULL;

  if (ctx == NULL) {

    return buf;

  }

  struct read_ctx *read_ctx = &ctx->read_ctxs[stage];

  assert(read_ctx->valid == 1);

  if (index >= 0) {

    // Forward peek

    if (index < read_ctx->sz) {

      index += read_ctx->read_idx;

      if (index >= ctx->max_sz) index -= ctx->max_sz;

      buf = ctx->buf + index;

    }

  } else if (index < 0) {

    // Backward peek

    if (-index <= ctx->max_pre_frames) {

      index += (int)(read_ctx->read_idx);

      if (index < 0) index += (int)(ctx->max_sz);

      buf = ctx->buf + index;

    }

  }

  return buf;

}

unsigned int av1_lookahead_depth(struct lookahead_ctx *ctx,

                                 COMPRESSOR_STAGE stage) {

  assert(ctx != NULL);

  struct read_ctx *read_ctx = &ctx->read_ctxs[stage];

  assert(read_ctx->valid == 1);

  return read_ctx->sz;

}

int av1_lookahead_pop_sz(struct lookahead_ctx *ctx, COMPRESSOR_STAGE stage) {

  assert(ctx != NULL);

  struct read_ctx *read_ctx = &ctx->read_ctxs[stage];

  assert(read_ctx->valid == 1);

  return read_ctx->pop_sz;

}