#include "snake.h"
#include <stdlib.h>

struct snake* add_snake(struct snake* snake,int x,int y){
    struct snake* newHead = (struct snake*) malloc(sizeof(struct snake));
    newHead->x = x;
    newHead->y = y;
    newHead->next = snake;

    /*struct snake* temp = snake;
    int myX, myY;

    while(temp->next != NULL){
        myX = temp->x; //
        myY = temp->y;
        temp->x = temp->next->x; //указатель на позицию следующего элемента по Х
        temp->y = temp->next->y;//указатель на позицию следующего элемента по У
        temp = temp->next;
    }

    //temp->next = (struct snake*) calloc(1, sizeof(struct snake));
    temp->next->x = temp->x - (myX - temp->x);
    temp->next->y = temp->y - (myX - temp->y);
    temp->next->next = NULL;*/

    return newHead;
}

struct snake* remove_snake(struct snake* snake){
    struct snake* temp = snake;

    if(snake == NULL){
        return snake;
    }
    else if(snake->next == NULL){
        free(snake);
        return snake;
    }

    while(temp->next->next != NULL){
        temp = temp->next; // проход до последнего кусочка
    }

    temp->next = NULL;
    temp = temp->next;
    free(temp);

    return snake;
}

void free_snake(struct snake* sn){
    struct snake* temp = sn;

    while(sn != NULL){
        temp = sn;
        sn = sn->next;
        temp->next = NULL;
    }

    free(sn);
}

int is_snake(struct snake* snake,int x,int y){
    struct snake* temp = snake;

    while(temp->next != NULL){
        if(x == temp->x && y == temp->y){
            return 1;
        }
        temp = temp->next;
    }

    return 0;
}

int step_state(struct state* st){
    int nx = (st->snake->x + st->sx);
    int ny = (st->snake->y + st->sy);

    for(int i = 0; i < FOOD_COUNT; i++){
        if(nx == st->foodx[i] &&  ny == st->foody[i]){
            st->snake = add_snake(st->snake, st->foodx[i], st->foody[i]);
            st->foodx[i] = -1;
            st->foody[i] = -1;
            for(int j = 0; j < FOOD_COUNT; j++){
                if(st->foodx[i] != -1 || st->foody[i] != -1){
                    break;
                }
                else if(st->foodx[i] == -1 && st->foody[i] == -1 && j == FOOD_COUNT - 1){
                    return END_FOOD;
                }
            }
            return END_CONTINUE;
        }
    }

    for(struct snake* temp = st->snake; temp != NULL; temp = temp->next){
        if((nx == temp->x && ny == temp->y) || (nx < 0 || nx >= st->width || ny < 0 || ny >= st->height)){
            return END_SNAKE;
        }
    }

    st->snake = add_snake(st->snake, nx, ny);
    remove_snake(st->snake);

    return END_CONTINUE;
}