/* eval.c - static position evaluation.
 *
 * Copyright (C) 2021 Bruno Raoult ("br")
 * Licensed under the GNU General Public License v3.0 or later.
 * Some rights reserved. See COPYING.
 *
 * You should have received a copy of the GNU General Public License along with this
 * program. If not, see <https://www.gnu.org/licenses/gpl-3.0-standalone.html>.
 *
 * SPDX-License-Identifier: GPL-3.0-or-later <https://spdx.org/licenses/GPL-3.0-or-later.html>
 *
 */

#include <stdio.h>

#include <list.h>
#include <debug.h>

#include "eval.h"

inline eval_t eval_material(pos_t *pos, bool color)
{
    eval_t res = 0;

    /* I need to do something about the king, if it can be potentially taken
     * if pseudo-moves include a pinned piece on King.
     */
    for (uint piece = PAWN; piece < KING; piece <<= 1) {
        uint bb = PIECETOBB(piece);
#       ifdef DEBUG_EVAL
        log_f(2, "color=%u piece=%u bb=%u=%c count=%ul val=%ld\n",
              color, piece, bb, P_LETTER(piece), popcount64(pos->bb[color][bb]),
              P_VALUE(piece));
#       endif
        /* attention here */
        res += popcount64(pos->bb[color][bb]) * P_VALUE(piece);
    }
    return res;
}

inline eval_t eval_mobility(pos_t *pos, bool color)
{
    return popcount64(pos->controlled[color]);
}

inline eval_t eval_square_control(pos_t *pos, bool color)
{
    return pos->mobility[color];
}

eval_t eval(pos_t *pos)
{
    eval_t material[2] = {0}, control[2] = {0};

    /* 1) pieces value */
    material[WHITE] = eval_material(pos, WHITE);
    material[BLACK] = eval_material(pos, BLACK);

#   ifdef DEBUG_EVAL
    log_f(2, "material: W:%d B:%d diff=%d\n",
          material[WHITE], material[BLACK], material[WHITE] - material[BLACK]);
#   endif

    /* 2) square control: 10 square controls diff = 1 pawn */
    control[WHITE] = eval_square_control(pos, WHITE);
    control[BLACK] = eval_square_control(pos, BLACK);

#   ifdef DEBUG_EVAL
    log_f(2, "square control: W:%d B:%d diff=%d\n",
          control[WHITE], control[BLACK],
          (control[WHITE] - control[BLACK]) * 10);
#   endif

    /* 3) mobility: 10 mobility diff = 1 pawn
     */
#   ifdef DEBUG_EVAL
    log_f(2, "mobility: W:%u B:%u diff=%d\n",
          pos->mobility[WHITE], pos->mobility[BLACK],
          (pos->mobility[WHITE] - pos->mobility[BLACK]) * 10);
#   endif

    eval_t res = material[WHITE] - material[BLACK] +
        (control[WHITE] - control[BLACK]) * 10 +
        (pos->mobility[WHITE] - pos->mobility[BLACK]) * 10;
#   ifdef DEBUG_EVAL
    log_f(2, "eval: %d\n", res);
#   endif

    return res;
}

#ifdef BIN_eval
#include "fen.h"
#include "move.h"

int main(int ac, char**av)
{
    pos_t *pos;
    eval_t res;

    debug_init(5);
    piece_pool_init();
    moves_pool_init();
    pos_pool_init();
    pos = pos_get();

    if (ac == 1) {
        pos_startpos(pos);
    } else {
        fen2pos(pos, av[1]);
    }

    pos_print(pos);
    pos_pieces_print(pos);

    moves_gen(pos, OPPONENT(pos->turn), false);
    //moves_print(pos, M_PR_SEPARATE);
    //pos_print(pos);
    //pos_pieces_print(pos);
    moves_gen(pos, pos->turn, true);
    moves_print(pos, M_PR_SEPARATE);
    res = eval(pos);
    printf("eval=%d centipawns)\n", res);
}
#endif