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

// Добавление вагона в конец списка
struct car* add_car(struct car* first, const char* target) {
    struct car* new_car = (struct car*)malloc(sizeof(struct car));
    if (!new_car) {
        return first;
    }
    
    strncpy(new_car->value, target, SIZE);
    new_car->value[SIZE - 1] = '\0';
    new_car->next = NULL;
    
    if (first == NULL) {
        return new_car;
    }
    
    struct car* current = first;
    while (current->next != NULL) {
        current = current->next;
    }
    
    current->next = new_car;
    return first;
}

// Вывод содержимого поезда
void print_train(struct car* first) {
    struct car* current = first;
    
    if (current == NULL) {
        printf("The train is empty.\n");
        return;
    }

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

// Удаление всех вагонов, освобождение памяти
void cancel_train(struct car* first) {
    struct car* current = first;
    
    while (current != NULL) {
        struct car* next = current->next;
        free(current);
        current = next;
    }
}

// Удаление вагонов с заданным направлением
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;
}