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

list_t* new_list(size_t length, list_element_t elements[]) {
    list_t* list = NULL;
    list_t* current = NULL;

    for (size_t i = 0; i < length; i++) {
        list_t* new_node = (list_t*)malloc(sizeof(list_t));
        new_node->data = elements[i];
        new_node->next = NULL;

        if (list == NULL) {
            list = new_node;
            current = list;
        } else {
            current->next = new_node;
            current = current->next;
        }
    }

    return list;
}

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

    list_t* current = list1;
    while (current->next != NULL) {
        current = current->next;
    }

    current->next = list2;
    return list1;
}

list_t* filter_list(list_t* list, bool (*filter)(list_element_t)) {
    list_t* filtered = NULL;
    list_t* current = list;
    list_t* filtered_current = NULL;

    while (current != NULL) {
        if (filter(current->data)) {
            list_t* new_node = (list_t*)malloc(sizeof(list_t));
            new_node->data = current->data;
            new_node->next = NULL;

            if (filtered == NULL) {
                filtered = new_node;
                filtered_current = filtered;
            } else {
                filtered_current->next = new_node;
                filtered_current = filtered_current->next;
            }
        }
        current = current->next;
    }

    return filtered;
}

size_t length_list(list_t* list) {
    size_t count = 0;
    list_t* current = list;
    while (current != NULL) {
        count++;
        current = current->next;
    }
    return count;
}

list_t* map_list(list_t* list, list_element_t (*map)(list_element_t)) {
    list_t* mapped = NULL;
    list_t* current = list;
    list_t* mapped_current = NULL;

    while (current != NULL) {
        list_element_t mapped_value = map(current->data);
        list_t* new_node = (list_t*)malloc(sizeof(list_t));
        new_node->data = mapped_value;
        new_node->next = NULL;

        if (mapped == NULL) {
            mapped = new_node;
            mapped_current = mapped;
        } else {
            mapped_current->next = new_node;
            mapped_current = mapped_current->next;
        }

        current = current->next;
    }

    return mapped;
}

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;
    list_t* current = list;

    while (current != NULL) {
        result = foldl(result, current->data);
        current = current->next;
    }

    return result;
}

list_t* reverse_list(list_t* list) {
    list_t* prev = NULL;
    list_t* current = list;
    list_t* next;

    while (current != NULL) {
        next = current->next;
        current->next = prev;
        prev = current;
        current = next;
    }

    return prev;
}

void delete_list(list_t* list) {
    while (list != NULL) {
        list_t* temp = list;
        list = list->next;
        free(temp);
    }
}