#include "list_ops.h"
#include <stdlib.h>
#include <string.h>

list_t *new_list(size_t length, list_element_t elements[]){
    list_t *novy = malloc(sizeof(list_t) + length * sizeof(list_element_t));
    if (novy == NULL){
        return NULL;
    }

    novy->length = length;

    if (elements != NULL) {
        for (size_t i = 0; i < length; i++){
            novy->elements[i] = elements[i];
        }
    }

    return novy;
}

list_t *append_list(list_t *list1, list_t *list2){
    if (list1 == NULL || list2 == NULL){
        return NULL;
    }

    size_t celkova_dlzka = list1->length + list2->length;

    list_t *spojeny = malloc(sizeof(list_t) + celkova_dlzka * sizeof(list_element_t));
    if (spojeny == NULL) {
        return NULL;
    }

    spojeny->length = celkova_dlzka;

    for (size_t i = 0; i < list1->length; i++){
        spojeny->elements[i] = list1->elements[i];
    }

    for (size_t i = 0; i < list2->length; i++){
        spojeny->elements[list1->length + i] = list2->elements[i];
    }

    return spojeny;
}

list_t *filter_list(list_t *list, bool (*filter)(list_element_t)){
    if (list == NULL || filter == NULL){
        return NULL;
    }

    size_t pocet = 0;
    for (size_t i = 0; i < list->length; i++){
        if (filter(list->elements[i])){
            pocet++;
        }
    }

    list_t *filtrovany = malloc(sizeof(list_t) + pocet * sizeof(list_element_t));
    if (filtrovany == NULL){
        return NULL;
    }

    filtrovany->length = pocet;

    size_t index = 0;
    for (size_t i = 0; i < list->length; i++){
        if (filter(list->elements[i])){
            filtrovany->elements[index] = list->elements[i];
            index++;
        }
    }

    return filtrovany;
}

size_t length_list(list_t *list){
    if (list == NULL){
        return 0;
    }
    return list->length;
}

list_t *map_list(list_t *list, list_element_t (*map)(list_element_t)){
    if (list == NULL || map == NULL){
        return NULL;
    }

    list_t *mapovany = malloc(sizeof(list_t) + list->length * sizeof(list_element_t));
    if (mapovany == NULL){
        return NULL;
    }

    mapovany->length = list->length;

    for (size_t i = 0; i < list->length; i++){
        mapovany->elements[i] = map(list->elements[i]);
    }

    return mapovany;
}

list_element_t foldl_list(list_t *list, list_element_t initial,list_element_t (*foldl)(list_element_t, list_element_t)){
    if (list == NULL || foldl == NULL){
        return initial;
    }

    list_element_t vysledok = initial;

    for (size_t i = 0; i < list->length; i++){
        vysledok = foldl(vysledok, list->elements[i]);
    }

    return vysledok;
}

list_element_t foldr_list(list_t *list, list_element_t initial,list_element_t (*foldr)(list_element_t, list_element_t)){
    if (list == NULL || foldr == NULL){
        return initial;
    }

    list_element_t vysledok = initial;

    for (size_t i = list->length; i > 0; i--){
        vysledok = foldr(list->elements[i-1], vysledok);
    }

    return vysledok;
}

list_t *reverse_list(list_t *list){
    if (list == NULL){
        return NULL;
    }

    list_t *obrateny = malloc(sizeof(list_t) + list->length * sizeof(list_element_t));
    if (obrateny == NULL){
        return NULL;
    }

    obrateny->length = list->length;

    for (size_t i = 0; i < list->length; i++){
        obrateny->elements[i] = list->elements[list->length - 1 - i];
    }

    return obrateny;
}

void delete_list(list_t *list){
    free(list);
}