/* 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 <libguile.h>
#include <readline/history.h>
#include <readline/readline.h>

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

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

static void print_help() {
  puts("To enter a move, enter the two row and column seperated by spaces.\n"
       "For example `0 0` will select the top left corner.\n\n"
       "p - Print the board again\n"
       "g - Drop into a guile repl\n"
       "\n"
       "In the guile repl you can define an AI to use for the current"
       "player.\n"
       "After you define an AI for that player, it will be used for the rest "
       "of the game instead of prompting for input for that user.\n");
}

static char *prompt_player(enum player_color current_player) {
  switch (current_player) {
  case WHITE:
    return "Player 1 [h for help] > ";
  case BLACK:
    return "Player 2 [h for help] > ";
  default:
    perror("There is no current player");
    exit(EXIT_FAILURE);
  }
}

/*static void inner_main(void *closure, int argc, char **argv) {*/
  /*(void)closure;*/
  /*scm_shell(argc, argv);*/
/*}*/

struct move prompt_get_move(enum player_color current_player) {
  // Initialize move to an invalid move.
  struct move move = {-1, -1};

  char *prompt = prompt_player(current_player);
  do {
    char *input = readline(prompt);

    if (input != NULL) {
      add_history(input);
      if (STREQ(input, "h")) {
        print_help();
      } else if (STREQ(input, "p")) {
        print_board();
      /*} else if (STREQ(input, "g")) {*/
        /*int argc = 1;*/
        /*char **argv = calloc(1, sizeof(char *));*/
        /*argv[0] = "othello";*/
        /*[>scm_with_guile(void *(*func)(void *), void *data)<]*/
        /*scm_boot_guile(argc, argv, inner_main, NULL);*/
        /*free(argv);*/
      } else {
        sscanf(input, "%d %d", &move.row, &move.col);
      }
    } else {
      // If input was NULL, we have reached an EOF and would like to exit.
      free(input);
      exit(0);
    }

    free(input);
  } while (!is_valid_move(current_player, move));

  return move;
}

/* Returns true if the move was valid */
bool apply_move(enum player_color **board, enum player_color current_player, struct move move) {

  // The move must be a positive position.
  if (move.row < 0 || move.col < 0) {
    return false;
  }

  // The move must be below the upper bounds of teh board.
  if (move.row > 8 || move.col > 8) {
    return false;
  }

  // The move must be an empty spot.
  if (board[move.row][move.col] != EMPTY) {
    return false;
  }

  // Flip in up direction
  bool flipped_up = false;
  for (int i = move.row - 1;
       i > 0 && board[i][move.col] != EMPTY && !flipped_up; i--) {
    if (board[i][move.col] == current_player) {
      if (i < move.row - 1) {
        for (int j = move.row; j > i; j--) {
          board[j][move.col] = current_player;
        }
        flipped_up = true;
      } else {
        break;
      }
    }
  }

  // Flip in down direction
  bool flipped_down = false;
  for (int i = move.row + 1;
       i < 8 && board[i][move.col] != EMPTY && !flipped_down; i++) {
    if (board[i][move.col] == current_player) {
      if (i > move.row + 1) {
        for (int j = move.row; j < i; j++) {
          board[j][move.col] = current_player;
        }
        flipped_down = true;
      } else {
        break;
      }
    }
  }

  // Flip in left direction
  bool flipped_left = false;
  for (int i = move.col - 1;
       i > 0 && board[move.row][i] != EMPTY && !flipped_left; i--) {
    if (board[move.row][i] == current_player) {
      if (i < move.col - 1) {
        for (int j = move.col; j > i; j--) {
          board[move.row][j] = current_player;
        }
        flipped_left = true;
      } else {
        break;
      }
    }
  }

  // Flip in right direction
  bool flipped_right = false;
  for (int i = move.col + 1;
       i < 8 && board[move.row][i] != EMPTY && !flipped_right; i++) {
    if (board[move.row][i] == current_player) {
      if (i > move.col + 1) {
        for (int j = move.col; j < i; j++) {
          board[move.row][j] = current_player;
        }
        flipped_right = true;
      } else {
        break;
      }
    }
  }

  return flipped_up || flipped_down || flipped_left || flipped_right;
}

struct move get_scm_move(FILE *strategy) {
  // Initialize move to an invalid move.
  struct move move = {-1, -1};
  return move;
  (void)strategy;
}