/*
 * 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 "./aom_config.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,
#if CONFIG_HIGHBITDEPTH
                                         int use_highbitdepth,
#endif
                                         unsigned int depth) {
  struct lookahead_ctx *ctx = NULL;

  // Clamp the lookahead queue depth
  depth = clamp(depth, 1, MAX_LAG_BUFFERS);

  // Allocate memory to keep previous source frames available.
  depth += MAX_PRE_FRAMES;

  // Allocate the lookahead structures
  ctx = calloc(1, sizeof(*ctx));
  if (ctx) {
    const int legacy_byte_alignment = 0;
    unsigned int i;
    ctx->max_sz = depth;
    ctx->buf = calloc(depth, sizeof(*ctx->buf));
    if (!ctx->buf) goto bail;
    for (i = 0; i < depth; i++)
      if (aom_alloc_frame_buffer(&ctx->buf[i].img, width, height, subsampling_x,
                                 subsampling_y,
#if CONFIG_HIGHBITDEPTH
                                 use_highbitdepth,
#endif
                                 AOM_BORDER_IN_PIXELS, legacy_byte_alignment))
        goto bail;
  }
  return ctx;
bail:
  av1_lookahead_destroy(ctx);
  return NULL;
}

#define USE_PARTIAL_COPY 0

int av1_lookahead_push(struct lookahead_ctx *ctx, YV12_BUFFER_CONFIG *src,
                       int64_t ts_start, int64_t ts_end,
#if CONFIG_HIGHBITDEPTH
                       int use_highbitdepth,
#endif
                       aom_enc_frame_flags_t flags) {
  struct lookahead_entry *buf;
#if USE_PARTIAL_COPY
  int row, col, active_end;
  int mb_rows = (src->y_height + 15) >> 4;
  int mb_cols = (src->y_width + 15) >> 4;
#endif
  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;

  if (ctx->sz + 1 + MAX_PRE_FRAMES > ctx->max_sz) return 1;
  ctx->sz++;
  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 USE_PARTIAL_COPY
  // TODO(jkoleszar): This is disabled for now, as
  // av1_copy_and_extend_frame_with_rect is not subsampling/alpha aware.

  // Only do this partial copy if the following conditions are all met:
  // 1. Lookahead queue has has size of 1.
  // 2. Active map is provided.
  // 3. This is not a key frame, golden nor altref frame.
  if (!new_dimensions && ctx->max_sz == 1 && active_map && !flags) {
    for (row = 0; row < mb_rows; ++row) {
      col = 0;

      while (1) {
        // Find the first active macroblock in this row.
        for (; col < mb_cols; ++col) {
          if (active_map[col]) break;
        }

        // No more active macroblock in this row.
        if (col == mb_cols) break;

        // Find the end of active region in this row.
        active_end = col;

        for (; active_end < mb_cols; ++active_end) {
          if (!active_map[active_end]) break;
        }

        // Only copy this active region.
        av1_copy_and_extend_frame_with_rect(src, &buf->img, row << 4, col << 4,
                                            16, (active_end - col) << 4);

        // Start again from the end of this active region.
        col = active_end;
      }

      active_map += mb_cols;
    }
  } else {
#endif
    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,
#if CONFIG_HIGHBITDEPTH
                                 use_highbitdepth,
#endif
                                 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);
#if USE_PARTIAL_COPY
  }
#endif

  buf->ts_start = ts_start;
  buf->ts_end = ts_end;
  buf->flags = flags;
  return 0;
}

struct lookahead_entry *av1_lookahead_pop(struct lookahead_ctx *ctx,
                                          int drain) {
  struct lookahead_entry *buf = NULL;

  if (ctx && ctx->sz && (drain || ctx->sz == ctx->max_sz - MAX_PRE_FRAMES)) {
    buf = pop(ctx, &ctx->read_idx);
    ctx->sz--;
  }
  return buf;
}

struct lookahead_entry *av1_lookahead_peek(struct lookahead_ctx *ctx,
                                           int index) {
  struct lookahead_entry *buf = NULL;

  if (index >= 0) {
    // Forward peek
    if (index < ctx->sz) {
      index += ctx->read_idx;
      if (index >= ctx->max_sz) index -= ctx->max_sz;
      buf = ctx->buf + index;
    }
  } else if (index < 0) {
    // Backward peek
    if (-index <= MAX_PRE_FRAMES) {
      index += (int)(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) { return ctx->sz; }