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

ArrayList new_arlst(int num_elems) {
    ArrayList new_list;
    new_list.free = NULL;
    new_list.size = 0;
    new_list.capacity = num_elems;
    new_list.items = calloc(num_elems, sizeof(void *));

    return new_list;
}

ArrayList new_arlst_wfree(int num_elems, void (*nfree)(void *ptr)) {
    ArrayList new_list = new_arlst(num_elems);
    new_list.free = nfree;
    return new_list;
}

ArrayList new_arlst_using_array(void **array, int length) {
    ArrayList l = new_arlst(length);
    free(l.items);
    l.items = array;
    return l;
}

ArrayList new_arlst_using_array_wfree(void **array, int length, 
        void (*f)(void *)) {
    ArrayList l = new_arlst_using_array(array, length);
    l.free = f;
    return l;
}

ArrayList new_arlst_from_array(void *array, size_t elem_size, int length) {
    ArrayList l = new_arlst(length);
    l.free = free;

    for (int i = 0; i < length; i++) {
        void *item = calloc(1, elem_size);
        void *start = array + i * elem_size;
        memmove(item, start, elem_size);
        arlst_add(&l, item);
    }
    return l;
}

void *arlst_get(ArrayList *l, int id) {
    // out of bounds
    if (id < 0 || id >= l->size) {
        return 0;
    }

    return l->items[id];
}

void * arlst_del(ArrayList *l, int id) {
    void *item = arlst_get(l, id);

    if (!item) {
        return NULL;
    }

    l->size--;
    // move elements backward
    for (int i = id; i < l->size; i++) {
        l->items[i] = l->items[i+1];
    }


    // shrink capacity if neccessary
    if (D_SHRINK_THRESHOLD != 0 
            || l->size < (100 / D_SHRINK_THRESHOLD) * l->capacity) {

        size_t new_size = l-> size + (l->capacity * (100 / D_SHRINK_THRESHOLD) * 
                100 / D_GROW_AMOUNT);

//        l->items = reallocarray(l->items, new_size, sizeof(void *));
        l->items = realloc(l->items,  new_size * sizeof(void *));
    }

    return item;
}

int arlst_add(ArrayList *l, void *item) {
    int item_index = l->size;

    // grow if neccessary
    if (l->size == l->capacity) {
        size_t new_size = l->capacity + (100 / D_GROW_AMOUNT) * l->capacity;
        l->capacity = new_size;
        //l->items = (void **)reallocarray(l->items, new_size, sizeof(void *));
        l->items = (void **)realloc(l->items, new_size * sizeof(void *));
    }

    l->items[item_index] = item;
    l->size++;

    return 0;
}

void * arlst_pop(ArrayList *l) {
    l->size--;
    return l->items[l->size];
}

int arlst_push(ArrayList *l, void *item) {
    return arlst_add(l, item);
}

int arlst_destroy(ArrayList *l) {
    if (l->free != NULL) {
        for (int i = 0; i < l->size; i++) {
            l->free(l->items[i]);
        }
    }
    free(l->items);
    return 0;
}


ListFiFo new_fifo(int start_size) {
    ListFiFo l;
    memset(&l, 0, sizeof(ListFiFo));
    l.inner = new_arlst(start_size);
    l.size = &l.inner.size;
    return l;
}

void *fifo_get(ListFiFo *l) {
    if (l->fifo_head >= l->inner.size) {
        return NULL;
    }

    void *value = arlst_get(&l->inner, l->fifo_head);

    if (value != NULL) {
        l->fifo_head++;
    }

    if (l->fifo_head == l->inner.capacity
            || (l->fifo_head == l->inner.size 
            && l->inner.size >= D_MAX_QUEUE_LEN)) {
        // start rewriting from the beginning
        l->inner.size = 0;
        l->fifo_head = 0;
        // memset(l->inner.items, 0, sizeof(void *) * l->inner.capacity);
    }
    return value;
}

/* It is up to the caller to free any data stored */
int fifo_add(ListFiFo *l, void *i) {
    if (l->inner.size >= D_MAX_QUEUE_LEN) {
        return -1;
    }
    return arlst_add(&l->inner, i);
}