#include "alphabeta_search.h"

int value1(int side[])
{
    int v = side[houses];
    if (v > 24) /* win */
        return 100;
    if (v == 24) /* draw or better */
        return 50;
    return v;
}

int value(int thisside[], int otherside[])
{
    return value1(thisside) - value1(otherside);
}

int alpha_beta_bestmove(int depth, int thisside[], int otherside[], int *vp)
{
    int ts1[BOARD_SIZE], os1[BOARD_SIZE];
    int best_move = -1;
    int alpha = MIN_INFINITY;
    int current_value;
    for (int move = 0; move < houses; move++)
    {
        memcpy(ts1, thisside, BOARD_ARRAY_SIZE);
        memcpy(os1, otherside, BOARD_ARRAY_SIZE);
        if (plyfull(move, ts1, os1))
        {
            current_value = value(ts1, os1);
            if (depth > 0 && current_value <= 50 && current_value >= -50)
            {
                current_value = -helper_alpha_beta_search(depth - 1, -MAX_INFINITY, -alpha, os1, ts1);
            }

            if (current_value > alpha)
            {
                best_move = move;
                alpha = current_value;
            }
        }
    }

    *vp = alpha;
    return best_move;
}

int helper_alpha_beta_search(int depth, int alpha, int beta, int thisside[], int otherside[])
{
    int ts1[BOARD_SIZE], os1[BOARD_SIZE];
    for (int move = 0; move < houses; move++)
    {
        memcpy(ts1, thisside, BOARD_ARRAY_SIZE);
        memcpy(os1, otherside, BOARD_ARRAY_SIZE);

        if (plyfull(move, ts1, os1))
        {
            int current_value = value(ts1, os1);
            if (depth > 0 && current_value <= 50 && current_value >= -50)
            {
                current_value = -helper_alpha_beta_search(depth - 1, -beta, -alpha, os1, ts1);
            }

            if (current_value > alpha)
            {
                if (current_value >= beta)
                {
                    return current_value;
                }
                alpha = current_value;
            }
        }
    }
    return alpha;
}