#include <iostream>

#include <stdio.h>
#include <cstdlib>
#include <conio.h>

using namespace std;

char **board;

int width = 32, height = 16;

typedef struct SnakePiece {
    int x;
    int y;
    SnakePiece *next;
} SnakePiece;

SnakePiece *head = NULL;

int headx, heady,
    tailx, taily,
    len;

int x_increment, y_increment;

void initialize_board () {
    //printf ("Height: ");
    //scanf ("%d", &height);

    //printf ("Width: ");
    //scanf("%d", &width);

    board = (char **) malloc (sizeof(char *) * height);

    for (int i = 0; i < height; i++) {
        board[i] = (char *) malloc (sizeof(char) * width);
    }

    for (int i = 0; i < height; i++) {
        for (int j = 0; j < width; j++) {
            board[i][j] = ' ';
        }
    }

    for (int i = 0; i < width; i++) {
        board[height-1][i] = '#';
        board[0][i] = '#';
    }

    for (int i = 0; i < height; i++) {
        board[i][width-1] = '#';
        board[i][0] = '#';
    }
}

void show_board () {
    for (int i = 0; i < height; i++) {
        for (int j = 0; j < width; j++) {
            printf ("%c", board[i][j]);
        }

        printf ("\n");
    }
}

void add_piece (int x_data, int y_data) {
    SnakePiece *new_piece = (SnakePiece *) malloc (sizeof(SnakePiece));

    new_piece->x = x_data;
    new_piece->y = y_data;

    tailx = x_data;
    taily = y_data;

    new_piece->next = head;
    head = new_piece;

    len++;
}

void initialize_snake () {
    headx = tailx = height/2-1;
    heady = taily = width/2-1;

    add_piece (headx, heady);

    for (int i = 0; i < 3; i++) {
        add_piece (tailx+1, taily);
    }
}

void move_snake () {

    SnakePiece *ptr;

    ptr = head;

    for (int i = 0; i < len; i++) {
        board[ptr->x][ptr->y] = ' ';

        ptr = ptr->next;
    }

    ptr = head;

    int old_x, old_y;

    for (int i = 0; i < len; i++) {
        if (i == len-1) {
            old_x = ptr->x;
            old_y = ptr->y;

            if (x_increment == -1 && (headx + x_increment) == 0) {
                ptr->x = height-2;

                headx = ptr->x;
            } else if (x_increment == 1 && (headx + x_increment) == height-1) {
                ptr->x = 1;

                headx = ptr->x;
            } else if (y_increment == -1 && (heady + y_increment) == 0) {
                ptr->y = width-2;

                heady = ptr->y;
            } else if (y_increment == 1 && (heady + y_increment) == width-1) {
                ptr->y = 1;

                heady = ptr->y;
            } else {
                ptr->x += x_increment;
                ptr->y += y_increment;

                headx = ptr->x;
                heady = ptr->y;

                break;
            }
        }

        ptr = ptr->next;
    }

    ptr = head;

    int old_x2, old_y2;

    for (int i = 0; i < len-1; i++) {
        for (int j = 0; j < (len-1)-i; j++) {
            if (j == (len-2)-i) {
                old_x2 = ptr->x;
                old_y2 = ptr->y;

                ptr->x = old_x;
                ptr->y = old_y;

                old_x = old_x2;
                old_y = old_y2;
            }

            ptr = ptr->next;
        }

        ptr = head;
    }

    tailx = ptr->x;
    taily = ptr->y;
}

void convert_move (char c) {
    if (c == 'w') {
        x_increment = -1;
        y_increment = 0;
    } else if (c == 's') {
        x_increment = 1;
        y_increment = 0;
    } else if (c == 'a') {
        x_increment = 0;
        y_increment = -1;
    } else if (c == 'd') {
        x_increment = 0;
        y_increment = 1;
    }
}

void show_coords() {
    SnakePiece *ptr;

    ptr = head;

    while (ptr) {
        printf ("%d %d\n", ptr->x, ptr->y);

        ptr = ptr->next;
    }

    /*for (int i = 0; i < len; i++) {
        for (int j = 0; j < len-i; j++) {
            if (j == (len-1)-i) {
                printf ("%d %d\n", ptr->x, ptr->y);
            }

            ptr = ptr->next;
        }

        ptr = head;
    }*/

    printf ("\n");
}

void draw_snake () {
    SnakePiece *ptr;

    ptr = head;

    int x, y;

    for (int i = 0; i < len; i++) {
        x = ptr->x;
        y = ptr->y;

        board[x][y] = 'o';

        ptr = ptr->next;
    }

    board[headx][heady] = '@';
}

int main()
{
    initialize_board();

    initialize_snake();

    char c = 'w';

    convert_move(c);

    while (true) {
        if (_kbhit()) {
            c = _getch();

            convert_move(c);
        }

        move_snake();

        draw_snake();

        show_board();

        system("cls");
    }

    return 0;
}