#ifndef BLUELIB_CORE_QUEUE_H_
#define BLUELIB_CORE_QUEUE_H_

#include <blue/core/iterator.h>
#include <blue/core/status.h>
#include <stdbool.h>
#include <string.h>

#ifdef __cplusplus
extern "C" {
#endif

#define B_QUEUE_INIT       ((b_queue) {.q_first = NULL, .q_last = NULL})
#define B_QUEUE_ENTRY_INIT ((b_queue_entry) {.qe_next = NULL, .qe_prev = NULL})

#define b_queue_foreach(it, q)                                                 \
	for (int z__b_unique_name() = b_queue_iterator_begin(q, it);           \
	     (it)->entry != NULL; b_queue_iterator_next(it))

typedef struct b_queue_entry {
	struct b_queue_entry *qe_next;
	struct b_queue_entry *qe_prev;
} b_queue_entry;

typedef struct b_queue {
	b_queue_entry *q_first;
	b_queue_entry *q_last;
} b_queue;

typedef struct b_queue_iterator {
	b_iterator _base;
	size_t i;
	b_queue_entry *entry;
	b_queue *_q;
} b_queue_iterator;

static inline void b_queue_init(b_queue *q)
{
	memset(q, 0x00, sizeof *q);
}
static inline bool b_queue_empty(const b_queue *q)
{
	return q->q_first == NULL;
}

static inline b_queue_entry *b_queue_first(const b_queue *q)
{
	return q->q_first;
}
static inline b_queue_entry *b_queue_last(const b_queue *q)
{
	return q->q_last;
}
static inline b_queue_entry *b_queue_next(const b_queue_entry *entry)
{
	return entry->qe_next;
}
static inline b_queue_entry *b_queue_prev(const b_queue_entry *entry)
{
	return entry->qe_prev;
}

BLUE_API size_t b_queue_length(const b_queue *q);

BLUE_API void b_queue_insert_before(
	b_queue *q, b_queue_entry *entry, b_queue_entry *before);
BLUE_API void b_queue_insert_after(
	b_queue *q, b_queue_entry *entry, b_queue_entry *after);

BLUE_API void b_queue_push_front(b_queue *q, b_queue_entry *entry);
BLUE_API void b_queue_push_back(b_queue *q, b_queue_entry *entry);

BLUE_API b_queue_entry *b_queue_pop_front(b_queue *q);
BLUE_API b_queue_entry *b_queue_pop_back(b_queue *q);

BLUE_API void b_queue_delete(b_queue *q, b_queue_entry *entry);
BLUE_API void b_queue_delete_all(b_queue *q);

BLUE_API int b_queue_iterator_begin(const b_queue *q, b_queue_iterator *it);
BLUE_API bool b_queue_iterator_next(b_queue_iterator *it);
BLUE_API b_status b_queue_iterator_erase(b_queue_iterator *it);
BLUE_API bool b_queue_iterator_is_valid(const b_queue_iterator *it);

#ifdef __cplusplus
}
#endif

#endif