// Connect 4

#include <stdio.h>
#define NUM_ROWS 6
#define NUM_COLS 7

enum cell_state { EMPTY, RED, YELLOW };

void print_gameboard(enum cell_state gameboard[NUM_ROWS][NUM_COLS]) {
  int i = 0;
  while (i < NUM_ROWS) {
    int j = 0;
    while (j < NUM_COLS) {
      printf("%d", gameboard[i][j]);
      j++;
    }
    printf("\n");
    i++;
  }
}

int read_player_input() {
  int input;
  printf("Which column do you want to place your piece?\n");
  printf("Enter the column (1-7): ");
  scanf("%d", &input);
  input--;

  while (input < 0 || input > NUM_ROWS) {
    printf("Which column do you want to place your piece?\n");
    printf("Enter the column (1-7): ");
    scanf("%d", &input);
    input--;
  }

  return input;
}

int is_valid_position(int row, int col) {
  return (row >= 0) && (row < NUM_ROWS) && (col >= 0) && (col < NUM_COLS);
}

int check_for_win(enum cell_state gameboard[NUM_ROWS][NUM_COLS]) {
  int cons_pieces = 0;

  int row = 0;
  while (row < NUM_ROWS) {
    int col = 0;
    while (col < NUM_COLS) {
      // gameboard[row][col] is each element...
      if (gameboard[row][col] == RED) {
        // found a RED piece, now check for a win
        // first, check across horizontally
        int k = col;
        while (k < col + 4) {
          if (is_valid_position(row, k) && gameboard[row][k] != RED) {
            cons_pieces++;
            if (cons_pieces == 4) {
              return 1;
            }
          }
          k++;
        }

        cons_pieces = 0;
        k = row;
        while (k < row + 4) {
          if (is_valid_position(k, col) && gameboard[k][col] != RED) {
            cons_pieces++;

            if (cons_pieces == 4) {
              return 1;
            }
          }
          k++;
        }
      }
      col++;
    }
    row++;
  }

  return 0;
}

int main(void) {
  enum cell_state gameboard[NUM_ROWS][NUM_COLS] = {};

  int p_1_pos;

  while (1) {
    p_1_pos = read_player_input();

    // check if piece can go into column
    int row_to_check = NUM_ROWS - 1;

    while (row_to_check >= 0 && gameboard[row_to_check][p_1_pos] != EMPTY) {
      row_to_check--;
    }
    if (row_to_check < 0) {
      // here, we have no position to
      printf("That's an invalid placement\n");
    } else {
      // placing the piece
      gameboard[row_to_check][p_1_pos] = RED;
    }

    // checking for a win...
    if (check_for_win(gameboard)) {
      printf("OMG you won (and our code works?)\n");
    } else {
      printf("Still no win\n");
    }

    print_gameboard(gameboard);
  }

  return 0;
}