/*
 * Copyright (c) 2020, 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.
 */

/*!\file
 * \brief Declares high level functions to search through intra modes.
 */
#ifndef AOM_AV1_ENCODER_INTRA_MODE_SEARCH_H_
#define AOM_AV1_ENCODER_INTRA_MODE_SEARCH_H_

#include "av1/encoder/encoder.h"

#ifdef __cplusplus
extern "C" {
#endif

/*! \brief Variables related to intra-mode search during inter frame coding.
 *
 * \ingroup intra_mode_search
 * This is a set of variables used during intra-mode search for inter frames.
 * This includes an histogram of gradient speed features and a cache of uv
 * prediction to avoid repeated search of chroma prediction.
 */
typedef struct IntraModeSearchState {
  /*!
   * \brief The best luma intra-mode found so far
   */
  PREDICTION_MODE best_intra_mode;

  /** \name Speed feature variables
   * Variables to help with pruning some luma intra-modes during inter frame
   * coding process.
   */
  /**@{*/
  /*!
   * \brief Whether to terminate all intra mode search.
   */
  int skip_intra_modes;
  /*!
   * \brief Whether a directional mode is pruned.
   */
  uint8_t directional_mode_skip_mask[INTRA_MODES];
  /*!
   * \brief Whether \ref directional_mode_skip_mask is valid for pruning.
   */
  int dir_mode_skip_mask_ready;
  /**@}*/

  /** \name Chroma mode search cache
   * A cache of the best chroma prediction mode to avoid having to search for
   * chroma predictions repeatedly in \ref av1_handle_intra_mode()
   */
  /**@{*/
  int rate_uv_intra;          /*!< \brief Total rate to transmit uv_mode */
  int rate_uv_tokenonly;      /*!< \brief Rate transmit txfm tokens */
  int64_t dist_uvs;           /*!< \brief Distortion of the uv_mode's recon */
  int skip_uvs;               /*!< \brief Whether the uv txfm is skippable */
  UV_PREDICTION_MODE mode_uv; /*!< \brief The best uv mode */
  PALETTE_MODE_INFO pmi_uv;   /*!< \brief Color map if mode_uv is palette */
  int8_t uv_angle_delta;      /*!< \brief Angle delta if mode_uv directional */
  /**@}*/

  /*!
   * \brief Keep track of best intra rd for use in compound mode.
   */
  int64_t best_pred_rd[REFERENCE_MODES];
} IntraModeSearchState;

/*!\brief Evaluate a given intra-mode for inter frames.
 *
 * \ingroup intra_mode_search
 * \callgraph
 * \callergraph
 * This function handles an intra-mode prediction when the current frame is an
 * inter frame. This is the intra-mode counterpart of handle_inter_mode. This
 * function first performs an intra prediction using the mode specified by
 * x->e_mbd.mi[0]->mode, then it searches over *all* available chroma intra
 * predictions by calling av1_rd_pick_intra_sbuv_mode. To avoid repeated
 * computation for chroma mode search, a cache of the best chroma mode and its
 * rd statistics is kept in intra_search_state that is retrieved when
 * av1_handle_intra_mode is called more than once. This function does *not*
 * support palette mode prediction in the luma channel, but it does search for
 * palette mode in the chroma channel.
 *
 * \param[in]    intra_search_state Structure to hold the best luma intra mode
 *                                  and cache chroma prediction for speed up.
 * \param[in]    cpi                Top-level encoder structure.
 * \param[in]    x                  Pointer to structure holding all the data
 *                                  for the current macroblock.
 * \param[in]    bsize              Current partition block size.
 * \param[in]    ref_frame_cost     The entropy cost for signaling that the
 *                                  current ref frame is an intra frame.
 * \param[in]    ctx                Structure to hold the number of 4x4 blks to
 *                                  copy the tx_type and txfm_skip arrays.
 * \param[in]    rd_stats           Struct to keep track of the current
 *                                  intra-mode's rd_stats.
 * \param[in]    rd_stats_y         Struct to keep track of the current
 *                                  intra-mode's rd_stats (luma only).
 * \param[in]    rd_stats_uv        Struct to keep track of the current
 *                                  intra-mode's rd_stats (chroma only).
 * \param[in]    best_rd            Best RD seen for this block so far.
 * \param[in]    best_intra_rd      Best intra RD seen for this block so far.
 *
 * \return Returns the rdcost of the current intra-mode if it's available,
 * otherwise returns INT64_MAX. The corresponding values in x->e_mbd.mi[0],
 * rd_stats, rd_stats_y/uv, and best_intra_rd are also updated. Moreover, in the
 * first evocation of the function, the chroma intra mode result is cached in
 * intra_search_state to be used in subsequent calls. In the first evaluation
 * with directional mode, a prune_mask computed with histogram of gradient is
 * also stored in intra_search_state.
 */
int64_t av1_handle_intra_mode(IntraModeSearchState *intra_search_state,
                              const AV1_COMP *cpi, MACROBLOCK *x,
                              BLOCK_SIZE bsize, unsigned int ref_frame_cost,
                              const PICK_MODE_CONTEXT *ctx, RD_STATS *rd_stats,
                              RD_STATS *rd_stats_y, RD_STATS *rd_stats_uv,
                              int64_t best_rd, int64_t *best_intra_rd);

/*!\brief Evaluate luma palette mode for inter frames.
 *
 * \ingroup intra_mode_search
 * \callergraph
 * \callgraph
 * This function handles luma palette mode when the current frame is an
 * inter frame. This is similar to \ref av1_handle_intra_mode(), but is
 * specialized for palette mode. See \ref av1_handle_intra_mode() for the
 * details.
 *
 * \param[in]    intra_search_state Structure to hold the best luma intra mode
 *                                  and cache chroma prediction for speed up.
 * \param[in]    cpi                Top-level encoder structure.
 * \param[in]    x                  Pointer to structure holding all the data
 *                                  for the current macroblock.
 * \param[in]    bsize              Current partition block size.
 * \param[in]    ref_frame_cost     The entropy cost for signaling that the
 *                                  current ref frame is an intra frame.
 * \param[in]    ctx                Structure to hold the number of 4x4 blks to
 *                                  copy the tx_type and txfm_skip arrays.
 * \param[in]    this_rd_cost       Struct to keep track of palette mode's
 *                                  rd_stats.
 * \param[in]    best_rd            Best RD seen for this block so far.
 *
 * \return Returns whether luma palette mode can skip the txfm. The
 * corresponding mbmi, this_rd_costs, intra_search_state, and tx_type arrays in
 * ctx are also updated.
 */
int av1_search_palette_mode(IntraModeSearchState *intra_search_state,
                            const AV1_COMP *cpi, MACROBLOCK *x,
                            BLOCK_SIZE bsize, unsigned int ref_frame_cost,
                            PICK_MODE_CONTEXT *ctx, RD_STATS *this_rd_cost,
                            int64_t best_rd);

/*!\brief Perform intra-mode search on luma channels for intra frames.
 *
 * \ingroup intra_mode_search
 * \callgraph
 * \callergraph
 * This function performs intra-mode search on the luma channel when the
 * current frame is intra-only. This function does not search intrabc mode,
 * but it does search palette and filter_intra.
 *
 * \param[in]    cpi                Top-level encoder structure.
 * \param[in]    x                  Pointer to structure holding all the data
 *                                  for the current macroblock.
 * \param[in]    rate               The total rate needed to predict the current
 *                                  chroma block.
 * \param[in]    rate_tokenonly     The rate without the cost of sending the
 *                                  prediction modes.
 *                                  chroma block.
 *                                  after the reconstruction.
 * \param[in]    distortion         The chroma distortion of the best prediction
 *                                  after the reconstruction.
 * \param[in]    skippable          Whether we can skip txfm process.
 * \param[in]    bsize              Current partition block size.
 * \param[in]    best_rd            Best RD seen for this block so far.
 * \param[in]    ctx                Structure to hold the number of 4x4 blks to
 *                                  copy the tx_type and txfm_skip arrays.
 *
 * \return Returns the rd_cost if this function finds a mode better than
 * best_rd, otherwise returns INT64_MAX. This also updates the mbmi, the rate
 * and distortion, and the tx_type arrays in ctx.
 */
int64_t av1_rd_pick_intra_sby_mode(const AV1_COMP *const cpi, MACROBLOCK *x,
                                   int *rate, int *rate_tokenonly,
                                   int64_t *distortion, int *skippable,
                                   BLOCK_SIZE bsize, int64_t best_rd,
                                   PICK_MODE_CONTEXT *ctx);

/*!\brief Perform intra-mode search on chroma channels.
 *
 * \ingroup intra_mode_search
 * \callergraph
 * \callgraph
 * This function performs intra-mode search on the chroma channels. Just like
 * \ref av1_rd_pick_intra_sby_mode(), this function searches over palette mode
 * (filter_intra is not available on chroma planes). Unlike \ref
 * av1_rd_pick_intra_sby_mode() this function is used by both inter and intra
 * frames.
 *
 * \param[in]    cpi                Top-level encoder structure.
 * \param[in]    x                  Pointer to structure holding all the data
 *                                  for the current macroblock.
 * \param[in]    rate               The total rate needed to predict the current
 *                                  chroma block.
 * \param[in]    rate_tokenonly     The rate without the cost of sending the
 *                                  prediction modes.
 *                                  chroma block.
 *                                  after the reconstruction.
 * \param[in]    distortion         The chroma distortion of the best prediction
 *                                  after the reconstruction.
 * \param[in]    skippable          Whether we can skip txfm process.
 * \param[in]    bsize              Current partition block size.
 * \param[in]    max_tx_size        The maximum tx_size available
 *
 * \return Returns the rd_cost of the best uv mode found. This also updates the
 * mbmi, the rate and distortion, distortion.
 */
int64_t av1_rd_pick_intra_sbuv_mode(const AV1_COMP *const cpi, MACROBLOCK *x,
                                    int *rate, int *rate_tokenonly,
                                    int64_t *distortion, int *skippable,
                                    BLOCK_SIZE bsize, TX_SIZE max_tx_size);

/*! \brief Return the number of colors in src. Used by palette mode.
 */
int av1_count_colors(const uint8_t *src, int stride, int rows, int cols,
                     int *val_count);

/*! \brief See \ref av1_count_colors(), but for highbd.
 */
int av1_count_colors_highbd(const uint8_t *src8, int stride, int rows, int cols,
                            int bit_depth, int *val_count);

#ifdef __cplusplus
}  // extern "C"
#endif

#endif  // AOM_AV1_ENCODER_INTRA_MODE_SEARCH_H_