From ce4506119d0f009e09b1a340301ff672fdc99838 Mon Sep 17 00:00:00 2001
From: Roman Khaliavka <roman.khaliavka@student.tuke.sk>
Date: Wed, 23 Apr 2025 14:15:14 +0000
Subject: [PATCH] a3

---
 a3/snake.c | 76 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 76 insertions(+)
 create mode 100644 a3/snake.c

diff --git a/a3/snake.c b/a3/snake.c
new file mode 100644
index 0000000..c90ec0e
--- /dev/null
+++ b/a3/snake.c
@@ -0,0 +1,76 @@
+#include "snake.h"
+#include <stdlib.h>
+
+// Pridá nový diel hada na začiatok (hlavu)
+struct snake* add_snake(struct snake* snake, int x, int y){
+    struct snake* new_head = malloc(sizeof(struct snake));
+    if(!new_head){
+      return NULL;
+    }
+    new_head->x = x;
+    new_head->y = y;
+    new_head->next = snake;
+    return new_head;
+}
+
+// Odstráni posledný diel hada (chvost)
+struct snake* remove_snake(struct snake* snake){
+    if(!snake || !snake->next){
+        free(snake);
+        return NULL;
+    }
+
+    struct snake* current = snake;
+    while (current->next && current->next->next){
+        current = current->next;
+    }
+    free(current->next);
+    current->next = NULL;
+    return snake;
+}
+
+// Zistí, či sa na daných súradniciach nachádza časť hada
+int is_snake(struct snake* snake, int x, int y){
+    while(snake){
+        if(snake->x == x && snake->y == y){
+            return 1;
+        }
+        snake = snake->next;
+    }
+    return 0;
+}
+
+// Uvoľní pamäť všetkých častí hada
+void free_snake(struct snake* sn){
+    while(sn){
+        struct snake* next = sn->next;
+        free(sn);
+        sn = next;
+    }
+}
+
+	// Spraví jeden krok hry – aktualizuje stav podľa pohybu
+int step_state(struct state* state){
+    int newx = state->snake->x + state->sx;
+    int newy = state->snake->y + state->sy;
+
+    if(newx < 0 || newx >= state->width || newy < 0 || newy >= state->height)
+        return END_WALL;
+
+    if(is_snake(state->snake, newx, newy))
+        return END_SNAKE;
+
+    for(int i = 0; i < FOOD_COUNT; i++){
+        if(state->foodx[i] == newx && state->foody[i] == newy){
+            state->foodx[i] = -1;
+            state->foody[i] = -1;
+            state->snake = add_snake(state->snake, newx, newy);
+            place_food(state);
+            return END_CONTINUE;
+        }
+    }
+
+    state->snake = add_snake(state->snake, newx, newy);
+    state->snake = remove_snake(state->snake);
+    return END_CONTINUE;
+}