snake.c

#include <stdio.h>
#include <stdlib.h>
#include <termios.h>
#include <unistd.h>
#include <fcntl.h>
#include <time.h>
#include "queue.h"

#define WIDTH   50
#define HEIGHT  20
#define UP     'w'
#define DOWN   's'
#define LEFT   'a'
#define RIGHT  'd'
#define EXIT   'q'
#define PAUSE  ' '

int score, fruitX, fruitY, gameOver;
Queue *psnake;

void ttyMode(int enable) 
{
    struct termios ttystate;
    tcgetattr(STDIN_FILENO, &ttystate);

    int flags = fcntl(STDIN_FILENO, F_GETFL, 0);

    if (enable) {
        ttystate.c_lflag &= ~(ICANON | ECHO);
        fcntl(STDIN_FILENO, F_SETFL, flags | O_NONBLOCK);
    }
    else {
        ttystate.c_lflag |= ICANON | ECHO;
        fcntl(STDIN_FILENO, F_SETFL, flags & ~O_NONBLOCK);
    }

    tcsetattr(STDIN_FILENO,TCSANOW, &ttystate);
}

void setUp () 
{
    enum direction dir = STOP;
    int x = WIDTH / 2;
    int y = HEIGHT / 2;
    initQueue(psnake);
    enQueue(psnake, x, y, dir);
    fruitX = rand() % (WIDTH - 2) + 1;
    fruitY = rand() % (HEIGHT - 2) + 1;
}

void fieldDraw()
{
    system("clear");

    for (int i = 0; i < WIDTH; i++) 
        printf("#");
    printf ("\n");
    for (int i = 0; i < HEIGHT - 1; i++) {
        printf("#");
        for (int j = 0; j < WIDTH - 2; j++) {
            int tailPrinted = 0;
            Node *pnode = psnake->front;
            while (pnode != NULL) {
                if (pnode->tailX == j && pnode->tailY == i) {
                    if (pnode == psnake->front)
                        printf("O");
                    else
                        printf("o");
                    tailPrinted = 1;
                    break;
                }
                pnode = pnode->next;
            }
            if (!tailPrinted) {
                if (fruitX == j && fruitY == i)
                    printf("F");
                else 
                    printf(" ");
            }
        }
        printf("#\n");
    }
    for (int i = 0; i < WIDTH; i++) 
        printf("#");
    printf("\nGlobal score: %d\n", score);
}

void inputLogic() 
{
    char ch;
    if (read(STDIN_FILENO, &ch, 1) > 0) {
        switch (ch) {
            case LEFT:
                if (psnake->front->tailDir != RIGHT_DIR)
                    psnake->front->tailDir = LEFT_DIR;
                break;
            case RIGHT:
                if (psnake->front->tailDir != LEFT_DIR)
                    psnake->front->tailDir = RIGHT_DIR;
                break;
            case UP:
                if (psnake->front->tailDir != DOWN_DIR)
                    psnake->front->tailDir = UP_DIR;
                break;
            case DOWN:
                if (psnake->front->tailDir != UP_DIR)
                    psnake->front->tailDir = DOWN_DIR;
                break;
            case PAUSE:
                psnake->front->tailDir = STOP;
                break;
            case EXIT:
                gameOver = 1;
                psnake->front->tailDir = STOP;
                break;
            default:
                break;
        }
    }
}

void snakeLogic() 
{
    int oldX = psnake->front->tailX;
    int oldY = psnake->front->tailY;
    enum direction oldDir = psnake->front->tailDir;

    switch(psnake->front->tailDir) {
        case LEFT_DIR:
            psnake->front->tailX--;
            break;
        case RIGHT_DIR:
            psnake->front->tailX++;
            break;
        case UP_DIR:
            psnake->front->tailY--;
            break;
        case DOWN_DIR:
            psnake->front->tailY++;
            break;
        default:
            break;
    }

    if (psnake->front->tailDir == LEFT_DIR && psnake->front->tailX <= 0)
        psnake->front->tailX = WIDTH - 2;
    if (psnake->front->tailDir == RIGHT_DIR && psnake->front->tailX >= WIDTH - 1)
        psnake->front->tailX = 1;
    if (psnake->front->tailDir == UP_DIR && psnake->front->tailY <= 0)
        psnake->front->tailY = HEIGHT - 2;
    if (psnake->front->tailDir == DOWN_DIR && psnake->front->tailY >= HEIGHT - 1)
        psnake->front->tailY = 1;

    if (psnake->front->tailX == fruitX && psnake->front->tailY == fruitY) {
        score += 10;
        fruitX = rand() % (WIDTH - 2) + 1;
        fruitY = rand() % (HEIGHT - 2) + 1;
        enQueue(psnake, oldX, oldY, oldDir);
    }
    else if (psnake->sizeTail > 0) {
        Node *current = psnake->rear;
            while (current != psnake->front) {
                current->tailX = current->prev->tailX;
                current->tailY = current->prev->tailY;
                current->tailDir = current->prev->tailDir;
                current = current->prev;
        }
    }
}

int main(void) {
    srand(time(NULL));
    psnake = (Queue *)malloc(sizeof(Queue));
    setUp();
    ttyMode(1);
    while (!gameOver) {
        fieldDraw();
        inputLogic();
        snakeLogic();
        usleep(100000 * 2.5);
    }

    ttyMode(0);
    emptyQueue(psnake);
    free(psnake);
    printf("Game Over! Final score: %d\n", score);
    return 0;
}