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

struct car* add_car(struct car* first, const char* target) {
    struct car* newcar = calloc(1, sizeof(struct car));
    if (newcar == NULL) {
        return first;
    }

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

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

    struct car* this = first;
    while (this->next != NULL) {
        this = this->next;
    }
    this->next = newcar;
    return first;
}
void print_train(struct car* first) {
    struct car* this = first;
    while (this != NULL) {
        printf("%s\n", this->value);
        this = this->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* current = first;
    struct car* prev = NULL;

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

    return first;
}