/* 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 <stdio.h>

#include <errno.h>
#include <libguile.h>
#include <readline/history.h>
#include <readline/readline.h>
#include <stdlib.h>
#include <string.h>

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

#define STREQ(a, b) (strcmp(a, b) == 0)

static enum player_color current_player;
#define other_player (current_player == WHITE ? BLACK : WHITE)

enum player_color get_current_player(void) { return current_player; }

SCM scm_get_current_player() {
  return scm_player_from_c_player(current_player);
}

SCM scm_get_other_player() { return scm_player_from_c_player(other_player); }

SCM scm_player_from_c_player(enum player_color player) {
  switch (player) {
  case WHITE:
    return scm_from_utf8_symbol("white");
  case BLACK:
    return scm_from_utf8_symbol("black");
  default:
    return scm_from_utf8_symbol("empty");
  }
}

enum player_color scm_player_to_c_player(SCM player) {
  if (scm_is_true(scm_eq_p(player, scm_from_utf8_symbol("white")))) {
    return WHITE;
  } else if (scm_is_true(scm_eq_p(player, scm_from_utf8_symbol("black")))) {
    return BLACK;
  } else {
    return EMPTY;
  }
}

static struct move current_player_move(enum player_color current_player,
                                       char *player_one_strategy_path,
                                       char *player_two_strategy_path,
                                       struct move *flipped_by_last_turn,
                                       size_t flipped_by_last_turn_length) {
  struct move move = {-1, -1};

  if ((current_player == WHITE && player_one_strategy_path == NULL) ||
      (current_player == BLACK && player_two_strategy_path == NULL)) {
    move = prompt_get_move(current_player, flipped_by_last_turn,
                           flipped_by_last_turn_length);
  } else if (current_player == WHITE) {
    move = get_scm_move(player_one_strategy_path);
  } else if (current_player == BLACK) {
    move = get_scm_move(player_two_strategy_path);
  }

  return move;
}

enum player_color game_loop(char *player_one_strategy_path,
                            char *player_two_strategy_path, int *white_score,
                            int *black_score) {
  initialize_board();

  if (player_one_strategy_path == NULL || player_two_strategy_path == NULL) {
    using_history();
  }

  current_player = WHITE;

  struct move *flipped_by_last_turn = malloc(sizeof(struct move));
  size_t flipped_by_last_turn_length = 0;
  size_t flipped_by_last_turn_capacity = 1;

  while (has_valid_moves(get_board(), current_player)) {
    struct move move = current_player_move(
        current_player, player_one_strategy_path, player_two_strategy_path,
        flipped_by_last_turn, flipped_by_last_turn_length);

    if ((flipped_by_last_turn_length = apply_move(
             get_board(), current_player, move, &flipped_by_last_turn,
             &flipped_by_last_turn_capacity))) {
      current_player = other_player;
    }
  }

  if (player_one_strategy_path == NULL || player_two_strategy_path == NULL) {
    rl_clear_history();
  }

  free(flipped_by_last_turn);

  return get_winner(get_board(), current_player, white_score, black_score);
}

#undef other_player