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

list_t *new_list(size_t length, list_element_t elements[]) {
    list_t *list = malloc(sizeof(list_t) + sizeof(list_element_t) * length);
    if (!list) return NULL;
    list->length = length;
    if (length && elements)
        memcpy(list->elements, elements, sizeof(list_element_t) * length);
    return list;
}

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

list_t *append_list(list_t *list1, list_t *list2) {
    size_t new_length = list1->length + list2->length;
    list_t *new_list_ptr = malloc(sizeof(list_t) + sizeof(list_element_t) * new_length);
    if (!new_list_ptr) return NULL;

    new_list_ptr->length = new_length;

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

    return new_list_ptr;
}

list_t *filter_list(list_t *list, bool (*filter)(list_element_t)) {
    size_t count = 0;

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

    list_t *new_list_ptr = malloc(sizeof(list_t) + sizeof(list_element_t) * count);
    if (!new_list_ptr) return NULL;

    new_list_ptr->length = count;

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

    return new_list_ptr;
}

size_t length_list(list_t *list) {
    return list->length;
}

list_t *map_list(list_t *list, list_element_t (*map)(list_element_t)) {
    list_t *new_list_ptr = malloc(sizeof(list_t) + sizeof(list_element_t) * list->length);
    if (!new_list_ptr) return NULL;

    new_list_ptr->length = list->length;

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

    return new_list_ptr;
}

list_element_t foldl_list(list_t *list, list_element_t initial,
                          list_element_t (*foldl)(list_element_t, list_element_t)) {
    list_element_t result = initial;
    for (size_t i = 0; i < list->length; i++) {
        result = foldl(result, list->elements[i]);
    }
    return result;
}

list_element_t foldr_list(list_t *list, list_element_t initial,
                          list_element_t (*foldr)(list_element_t, list_element_t)) {
    list_element_t result = initial;
    for (int i = (int)list->length - 1; i >= 0; i--) {
        result = foldr(list->elements[i], result);
    }
    return result;
}

list_t *reverse_list(list_t *list) {
    list_t *new_list_ptr = malloc(sizeof(list_t) + sizeof(list_element_t) * list->length);
    if (!new_list_ptr) return NULL;

    new_list_ptr->length = list->length;

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

    return new_list_ptr;
}