#include "a_train.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>


struct car* add_car(struct car* first, const char* target) {
    struct car* newcar = (struct car*)calloc(1, sizeof(struct car)); 
    if (newcar == NULL) {
        printf("Chyba: nepodarilo sa alokovať pamäť.\n");
        exit(1);
    }

    strcpy(newcar->value, target); 
    newcar->next = NULL; 

    if (first == NULL) {
        return newcar;
    }

    struct car* current = first;
    while (current->next != NULL) {
        current = current->next;
    }

    current->next = newcar;
    return first;
}


void print_train(struct car* first) {
    struct car* current = first;

    if (current == NULL) {
        printf("Vlak je prázdny.\n");
        return;
    }

    while (current != NULL) {
        printf("%s\n", current->value); 
        current = current->next;
    }
}


void cancel_train(struct car* first) {
    if (first == NULL) {
        return;
    }

    cancel_train(first->next);
    free(first);
}


struct car* clear_train(struct car* first, const char* target) {
    struct car* prev = NULL;
    struct car* current = first;

    while (current != NULL) {
        if (strcmp(current->value, target) == 0) {
            if (prev == NULL) {
                struct car* temp = current->next;
                free(current);
                current = temp;
                first = current;
            } else {
                prev->next = current->next;
                free(current);
                current = prev->next;
            }
        } else {
            prev = current;
            current = current->next;
        }
    }
    
    return first;
}