#include <fx/core/iterator.h>
#include <fx/core/queue.h>
#include <fx/ds/list.h>
#include <stdlib.h>
#include <string.h>

/*** PRIVATE DATA *************************************************************/

struct fx_list_entry {
	struct fx_queue_entry e_entry;
	void *e_data;
};

struct fx_list_p {
	struct fx_queue l_queue;
	size_t l_len;
};

struct fx_list_iterator_p {
	fx_list *_q;
	struct fx_list_p *_q_p;
	struct fx_queue_entry *_q_entry;

	size_t i;
	void *item;
	fx_list_entry *entry;
};

/*** PRIVATE FUNCTIONS ********************************************************/

static bool list_empty(struct fx_list_p *q)
{
	return q->l_len == 0;
}

static void *list_first_item(const struct fx_list_p *q)
{
	struct fx_queue_entry *entry = fx_queue_first(&q->l_queue);

	if (!entry) {
		return NULL;
	}

	struct fx_list_entry *list_entry
		= fx_unbox(struct fx_list_entry, entry, e_entry);

	return list_entry->e_data;
}

static void *list_last_item(const struct fx_list_p *q)
{
	struct fx_queue_entry *entry = fx_queue_last(&q->l_queue);

	if (!entry) {
		return NULL;
	}

	struct fx_list_entry *list_entry
		= fx_unbox(struct fx_list_entry, entry, e_entry);

	return list_entry->e_data;
}

static struct fx_list_entry *list_first_entry(const struct fx_list_p *q)
{
	struct fx_queue_entry *entry = fx_queue_first(&q->l_queue);

	if (!entry) {
		return NULL;
	}

	struct fx_list_entry *list_entry
		= fx_unbox(struct fx_list_entry, entry, e_entry);

	return list_entry;
}

static struct fx_list_entry *list_last_entry(const struct fx_list_p *q)
{
	struct fx_queue_entry *entry = fx_queue_last(&q->l_queue);

	if (!entry) {
		return NULL;
	}

	struct fx_list_entry *list_entry
		= fx_unbox(struct fx_list_entry, entry, e_entry);

	return list_entry;
}

static size_t list_length(const struct fx_list_p *q)
{
	return q->l_len;
}

static struct fx_list_entry *make_entry(void *item)
{
	struct fx_list_entry *entry = malloc(sizeof *entry);
	if (!entry) {
		return NULL;
	}

	memset(entry, 0x0, sizeof *entry);

	entry->e_data = item;

	return entry;
}

static struct fx_list_entry *list_insert_before(
	struct fx_list_p *q, void *ptr, struct fx_list_entry *before)
{
	struct fx_list_entry *entry = make_entry(ptr);
	if (!entry) {
		return NULL;
	}

	fx_queue_insert_before(&q->l_queue, &entry->e_entry, &before->e_entry);
	q->l_len++;
	return entry;
}

static struct fx_list_entry *list_insert_after(
	struct fx_list_p *q, void *ptr, struct fx_list_entry *after)
{
	struct fx_list_entry *entry = make_entry(ptr);
	if (!entry) {
		return NULL;
	}

	fx_queue_insert_after(&q->l_queue, &entry->e_entry, &after->e_entry);
	q->l_len++;
	return entry;
}

static struct fx_list_entry *list_push_front(struct fx_list_p *q, void *ptr)
{
	struct fx_list_entry *entry = make_entry(ptr);
	if (!entry) {
		return NULL;
	}

	fx_queue_push_front(&q->l_queue, &entry->e_entry);
	q->l_len++;
	return entry;
}

static struct fx_list_entry *list_push_back(struct fx_list_p *q, void *ptr)
{
	struct fx_list_entry *entry = make_entry(ptr);
	if (!entry) {
		return NULL;
	}

	fx_queue_push_back(&q->l_queue, &entry->e_entry);
	q->l_len++;
	return entry;
}

static void *list_pop_front(struct fx_list_p *q)
{
	struct fx_queue_entry *entry = fx_queue_pop_front(&q->l_queue);
	if (!entry) {
		return NULL;
	}

	struct fx_list_entry *list_entry
		= fx_unbox(struct fx_list_entry, entry, e_entry);

	void *item = list_entry->e_data;
	free(list_entry);

	q->l_len--;

	return item;
}

static void *list_pop_back(struct fx_list_p *q)
{
	struct fx_queue_entry *entry = fx_queue_pop_back(&q->l_queue);
	if (!entry) {
		return NULL;
	}

	struct fx_list_entry *list_entry
		= fx_unbox(struct fx_list_entry, entry, e_entry);

	void *item = list_entry->e_data;
	free(list_entry);

	q->l_len--;

	return item;
}

static struct fx_list_entry *find_item(struct fx_list_p *list, void *item)
{
	struct fx_queue_entry *entry = fx_queue_first(&list->l_queue);
	while (entry) {
		struct fx_list_entry *list_entry
			= fx_unbox(struct fx_list_entry, entry, e_entry);

		if (list_entry->e_data == item) {
			return list_entry;
		}

		entry = fx_queue_next(entry);
	}

	return NULL;
}

static fx_status list_delete_item(struct fx_list_p *q, void *ptr)
{
	struct fx_list_entry *entry = find_item(q, ptr);
	if (!entry) {
		return FX_ERR_NO_ENTRY;
	}

	fx_queue_delete(&q->l_queue, &entry->e_entry);
	q->l_len--;

	free(entry);

	return FX_SUCCESS;
}

static fx_status list_delete_entry(struct fx_list_p *q, struct fx_list_entry *entry)
{
	fx_queue_delete(&q->l_queue, &entry->e_entry);
	q->l_len--;

	free(entry);

	return FX_SUCCESS;
}

static void list_delete_all(struct fx_list_p *q)
{
	struct fx_queue_entry *entry = fx_queue_first(&q->l_queue);
	while (entry) {
		struct fx_list_entry *list_entry
			= fx_unbox(struct fx_list_entry, entry, e_entry);
		struct fx_queue_entry *next = fx_queue_next(entry);

		free(list_entry);
		entry = next;
	}

	q->l_len = 0;
}

/*** PUBLIC FUNCTIONS *********************************************************/

bool fx_list_empty(fx_list *q)
{
	FX_CLASS_DISPATCH_STATIC_0(FX_TYPE_LIST, list_empty, q);
}

void *fx_list_first_item(const fx_list *q)
{
	FX_CLASS_DISPATCH_STATIC_0(FX_TYPE_LIST, list_first_item, q);
}

void *fx_list_last_item(const fx_list *q)
{
	FX_CLASS_DISPATCH_STATIC_0(FX_TYPE_LIST, list_last_item, q);
}

struct fx_list_entry *fx_list_first_entry(const fx_list *q)
{
	FX_CLASS_DISPATCH_STATIC_0(FX_TYPE_LIST, list_first_entry, q);
}

struct fx_list_entry *fx_list_last_entry(const fx_list *q)
{
	FX_CLASS_DISPATCH_STATIC_0(FX_TYPE_LIST, fx_list_last_entry, q);
}

struct fx_list_entry *fx_list_next(const struct fx_list_entry *entry)
{
	if (!entry) {
		return NULL;
	}

	struct fx_queue_entry *next = fx_queue_next(&entry->e_entry);

	if (!next) {
		return NULL;
	}

	return fx_unbox(struct fx_list_entry, next, e_entry);
}

struct fx_list_entry *fx_list_prev(const struct fx_list_entry *entry)
{
	if (!entry) {
		return NULL;
	}

	struct fx_queue_entry *next = fx_queue_prev(&entry->e_entry);

	if (!next) {
		return NULL;
	}

	return fx_unbox(struct fx_list_entry, next, e_entry);
}

size_t fx_list_length(const fx_list *q)
{
	FX_CLASS_DISPATCH_STATIC_0(FX_TYPE_LIST, list_length, q);
}

struct fx_list_entry *fx_list_insert_before(
	fx_list *q, void *ptr, struct fx_list_entry *before)
{
	FX_CLASS_DISPATCH_STATIC(FX_TYPE_LIST, list_insert_before, q, ptr, before);
}

struct fx_list_entry *fx_list_insert_after(
	fx_list *q, void *ptr, struct fx_list_entry *after)
{
	FX_CLASS_DISPATCH_STATIC(FX_TYPE_LIST, list_insert_after, q, ptr, after);
}

struct fx_list_entry *fx_list_push_front(fx_list *q, void *ptr)
{
	FX_CLASS_DISPATCH_STATIC(FX_TYPE_LIST, list_push_front, q, ptr);
}

struct fx_list_entry *fx_list_push_back(fx_list *q, void *ptr)
{
	FX_CLASS_DISPATCH_STATIC(FX_TYPE_LIST, list_push_back, q, ptr);
}

void *fx_list_pop_front(fx_list *q)
{
	FX_CLASS_DISPATCH_STATIC_0(FX_TYPE_LIST, list_pop_front, q);
}

void *fx_list_pop_back(fx_list *q)
{
	FX_CLASS_DISPATCH_STATIC_0(FX_TYPE_LIST, list_pop_back, q);
}

fx_status fx_list_delete_item(fx_list *q, void *ptr)
{
	FX_CLASS_DISPATCH_STATIC(FX_TYPE_LIST, list_delete_item, q, ptr);
}

fx_status fx_list_delete_entry(fx_list *q, struct fx_list_entry *entry)
{
	FX_CLASS_DISPATCH_STATIC(FX_TYPE_LIST, list_delete_entry, q, entry);
}

void fx_list_delete_all(fx_list *q)
{
	FX_CLASS_DISPATCH_STATIC_0(FX_TYPE_LIST, list_delete_all, q);
}

void *fx_list_entry_value(const struct fx_list_entry *entry)
{
	return entry ? entry->e_data : NULL;
}

fx_iterator *fx_list_begin(fx_list *q)
{
	fx_list_iterator *it_obj = fx_object_create(FX_TYPE_LIST_ITERATOR);
	struct fx_list_iterator_p *it
		= fx_object_get_private(it_obj, FX_TYPE_LIST_ITERATOR);

	it->_q = q;
	it->_q_p = fx_object_get_private(q, FX_TYPE_LIST);
	it->_q_entry = fx_queue_first(&it->_q_p->l_queue);

	it->i = 0;
	it->entry = fx_unbox(struct fx_list_entry, it->_q_entry, e_entry);
	if (it->entry) {
		it->item = it->entry->e_data;
	}

	return 0;
}

const fx_iterator *fx_list_cbegin(const fx_list *q)
{
	fx_list_iterator *it_obj = fx_object_create(FX_TYPE_LIST_ITERATOR);
	struct fx_list_iterator_p *it
		= fx_object_get_private(it_obj, FX_TYPE_LIST_ITERATOR);

	it->_q = (fx_list *)q;
	it->_q_p = fx_object_get_private(q, FX_TYPE_LIST);
	it->_q_entry = fx_queue_first(&it->_q_p->l_queue);

	it->i = 0;
	it->entry = fx_unbox(struct fx_list_entry, it->_q_entry, e_entry);
	if (it->entry) {
		it->item = it->entry->e_data;
	}

	return 0;
}

/*** VIRTUAL FUNCTIONS ********************************************************/

static void list_init(fx_object *obj, void *priv)
{
	struct fx_list_p *list = priv;
}

static void list_fini(fx_object *obj, void *priv)
{
	struct fx_list_p *list = priv;
	list_delete_all(list);
}

/*** ITERATOR FUNCTIONS *******************************************************/

static enum fx_status iterator_move_next(const fx_iterator *obj)
{
	struct fx_list_iterator_p *it
		= fx_object_get_private(obj, FX_TYPE_LIST_ITERATOR);

	if (!it->_q_entry) {
		it->entry = NULL;
		it->item = NULL;
		return FX_ERR_NO_DATA;
	}

	it->_q_entry = fx_queue_next(it->_q_entry);
	if (!it->_q_entry) {
		it->entry = NULL;
		it->item = NULL;
		return FX_ERR_NO_DATA;
	}

	it->i++;
	it->entry = fx_unbox(struct fx_list_entry, it->_q_entry, e_entry);
	if (it->entry) {
		it->item = it->entry->e_data;
	}

	return it->entry != NULL;
}

static enum fx_status iterator_erase(fx_iterator *obj)
{
	struct fx_list_iterator_p *it
		= fx_object_get_private(obj, FX_TYPE_LIST_ITERATOR);

	if (!it->entry || !it->_q_entry) {
		return FX_ERR_OUT_OF_BOUNDS;
	}

	struct fx_queue_entry *next = fx_queue_next(it->_q_entry);

	fx_queue_delete(&it->_q_p->l_queue, it->_q_entry);
	free(it->entry);

	it->_q_entry = next;
	it->entry = fx_unbox(struct fx_list_entry, it->_q_entry, e_entry);
	if (it->entry) {
		it->item = it->entry->e_data;
	}

	return FX_SUCCESS;
}

static fx_iterator_value iterator_get_value(fx_iterator *obj)
{
	struct fx_list_iterator_p *it
		= fx_object_get_private(obj, FX_TYPE_LIST_ITERATOR);

	return FX_ITERATOR_VALUE_PTR(it->item);
}

static const fx_iterator_value iterator_get_cvalue(const fx_iterator *obj)
{
	struct fx_list_iterator_p *it
		= fx_object_get_private(obj, FX_TYPE_LIST_ITERATOR);

	return FX_ITERATOR_VALUE_CPTR(it->item);
}

/*** CLASS DEFINITION *********************************************************/

// ---- fx_list DEFINITION
FX_TYPE_CLASS_DEFINITION_BEGIN(fx_list)
	FX_TYPE_CLASS_INTERFACE_BEGIN(fx_object, FX_TYPE_OBJECT)
		FX_INTERFACE_ENTRY(to_string) = NULL;
	FX_TYPE_CLASS_INTERFACE_END(fx_object, FX_TYPE_OBJECT)

	FX_TYPE_CLASS_INTERFACE_BEGIN(fx_iterable, FX_TYPE_ITERABLE)
		FX_INTERFACE_ENTRY(it_begin) = fx_list_begin;
		FX_INTERFACE_ENTRY(it_cbegin) = fx_list_cbegin;
	FX_TYPE_CLASS_INTERFACE_END(fx_iterable, FX_TYPE_ITERABLE)
FX_TYPE_CLASS_DEFINITION_END(fx_list)

FX_TYPE_DEFINITION_BEGIN(fx_list)
	FX_TYPE_ID(0x8730e66f, 0x0fd9, 0x4773, 0x9bbd, 0x6428f6e495eb);
	FX_TYPE_CLASS(fx_list_class);
	FX_TYPE_IMPLEMENTS(FX_TYPE_ITERABLE);
	FX_TYPE_INSTANCE_PRIVATE(struct fx_list_p);
	FX_TYPE_INSTANCE_INIT(list_init);
	FX_TYPE_INSTANCE_FINI(list_fini);
FX_TYPE_DEFINITION_END(fx_list)

// ---- fx_list_iterator DEFINITION
FX_TYPE_CLASS_DEFINITION_BEGIN(fx_list_iterator)
	FX_TYPE_CLASS_INTERFACE_BEGIN(fx_object, FX_TYPE_OBJECT)
		FX_INTERFACE_ENTRY(to_string) = NULL;
	FX_TYPE_CLASS_INTERFACE_END(fx_object, FX_TYPE_OBJECT)

	FX_TYPE_CLASS_INTERFACE_BEGIN(fx_iterator, FX_TYPE_ITERATOR)
		FX_INTERFACE_ENTRY(it_move_next) = iterator_move_next;
		FX_INTERFACE_ENTRY(it_erase) = iterator_erase;
		FX_INTERFACE_ENTRY(it_get_value) = iterator_get_value;
		FX_INTERFACE_ENTRY(it_get_cvalue) = iterator_get_cvalue;
	FX_TYPE_CLASS_INTERFACE_END(fx_iterator, FX_TYPE_ITERATOR)
FX_TYPE_CLASS_DEFINITION_END(fx_list_iterator)

FX_TYPE_DEFINITION_BEGIN(fx_list_iterator)
	FX_TYPE_ID(0xd9658456, 0xdd80, 0x419a, 0xb23a, 0xb513013e6431);
	FX_TYPE_EXTENDS(FX_TYPE_ITERATOR);
	FX_TYPE_CLASS(fx_list_iterator_class);
	FX_TYPE_INSTANCE_PRIVATE(struct fx_list_iterator_p);
FX_TYPE_DEFINITION_END(fx_list_iterator)