/* This file is a part of othello-ai-guile-c
 *
 * Copyright (C) 2021  Robby Zambito
 *
 * othello-ai-guile-c is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * othello-ai-guile-c is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

#define _GNU_SOURCE

#include <libguile.h>
#include <stdlib.h>

#include "othello.h"
#include "othello_board.h"
#include "othello_move.h"

static enum player_color **board;

enum player_color **get_board() { return board; }

SCM scm_get_board() { return scm_board_from_c_board(board); }

void initialize_board() {
  board = calloc(8, sizeof(enum player_color *));
  for (int i = 0; i < 8; i++) {
    board[i] = calloc(8, sizeof(enum player_color));
  }

  // Set all the positions to empty
  for (int i = 0; i < 8; i++) {
    for (int j = 0; j < 8; j++) {
      board[i][j] = EMPTY;
    }
  }

  // Fill the starting positions
  board[3][3] = WHITE;
  board[3][4] = BLACK;
  board[4][3] = BLACK;
  board[4][4] = WHITE;
}

enum player_color get_winner(enum player_color **board,
                             enum player_color current_player, int *white_score,
                             int *black_score) {

  int ws = 0, bs = 0;
  for (int row = 0; row < 8; row++) {
    for (int col = 0; col < 8; col++) {
      // This takes advantage of the fact that the 1 is the same thing as a
      // true, and 0 is the same thing as a false. This will count the number of
      // white and black spaces.
      ws += (int)(board[row][col] == WHITE);
      bs += (int)(board[row][col] == BLACK);
    }
  }

  if (white_score != NULL) {
    *white_score = ws;
  }
  if (black_score != NULL) {
    *black_score = bs;
  }

  return ws > bs ? WHITE : bs > ws ? BLACK : EMPTY;
}

SCM scm_get_winner(SCM scm_board, SCM scm_current_player) {
  enum player_color **board = scm_board_to_c_board(scm_board);
  enum player_color current_player = scm_player_to_c_player(scm_current_player);

  enum player_color res = get_winner(board, current_player, NULL, NULL);
  free_board(board);
  return scm_player_from_c_player(res);
}

// Should be freed be the caller
enum player_color **copy_board(enum player_color **other) {
  enum player_color **board = calloc(8, sizeof(enum player_color *));

  for (int i = 0; i < 8; i++) {
    board[i] = calloc(8, sizeof(enum player_color));
    for (int j = 0; j < 8; j++) {
      board[i][j] = other[i][j];
    }
  }

  return board;
}

void free_board(enum player_color **board) {
  for (int i = 0; i < 8; i++) {
    free(board[i]);
  }
  free(board);
}

SCM scm_board_from_c_board(enum player_color **board) {
  // 2D list of empty rows
  SCM scm_board = scm_make_list(scm_from_int(8), SCM_EOL);

  for (int i = 0; i < 8; i++) {
    // cons up each row.
    for (int j = 7; j >= 0; j--) {
      if (board[i][j] == WHITE) {
        scm_list_set_x(scm_board, scm_from_int(i),
                       scm_cons(scm_from_utf8_symbol("white"),
                                scm_list_ref(scm_board, scm_from_int(i))));
      } else if (board[i][j] == BLACK) {
        scm_list_set_x(scm_board, scm_from_int(i),
                       scm_cons(scm_from_utf8_symbol("black"),
                                scm_list_ref(scm_board, scm_from_int(i))));
      } else {
        scm_list_set_x(scm_board, scm_from_int(i),
                       scm_cons(scm_from_utf8_symbol("empty"),
                                scm_list_ref(scm_board, scm_from_int(i))));
      }
    }
  }

  return scm_board;
}

enum player_color **scm_board_to_c_board(SCM scm_board) {
  enum player_color **board = calloc(8, sizeof(enum player_color *));
  for (int i = 0; i < 8; i++) {
    board[i] = calloc(8, sizeof(enum player_color));
    for (int j = 0; j < 8; j++) {
      if (scm_is_true(
              scm_eq_p(scm_list_ref(scm_list_ref(scm_board, scm_from_int(i)),
                                    scm_from_int(j)),
                       scm_from_utf8_symbol("white")))) {
        board[i][j] = WHITE;
      } else if (scm_is_true(scm_eq_p(
                     scm_list_ref(scm_list_ref(scm_board, scm_from_int(i)),
                                  scm_from_int(j)),
                     scm_from_utf8_symbol("black")))) {
        board[i][j] = BLACK;
      } else {
        board[i][j] = EMPTY;
      }
    }
  }

  return board;
}

void print_board(enum player_color **board) {
  puts("  0 1 2 3 4 5 6 7");

  for (int row = 0; row < 8; row++) {
    printf("%d ", row);

    for (int col = 0; col < 8; col++) {
      printf("%c ", board[row][col]);
    }
    printf("\n");
  }
}

void scm_print_board(SCM scm_board) {
  enum player_color **board =
      SCM_UNBNDP(scm_board) ? get_board() : scm_board_to_c_board(scm_board);

  print_board(board);
}