#ifndef SOCKS_QUEUE_H_
#define SOCKS_QUEUE_H_

#include <socks/libc/string.h>
#include <stdbool.h>

#ifdef __cplusplus
extern "C" {
#endif

#define QUEUE_CONTAINER(t, m, v) ((void *)((v) ? (uintptr_t)(v) - (offsetof(t, m)) : 0))

#define QUEUE_INIT ((struct queue){ .q_first = NULL, .q_last = NULL })
#define QUEUE_ENTRY_INIT ((struct queue_entry){ .qe_next = NULL, .qe_prev = NULL })

#define queue_foreach(iter_type, iter_name, queue_name, node_member) \
	for (iter_type *iter_name = (iter_type *)QUEUE_CONTAINER(iter_type, node_member, queue_first(queue_name)); \
	     iter_name; \
	     iter_name = (iter_type *)QUEUE_CONTAINER(iter_type, node_member, queue_next(&((iter_name)->node_member))))

#define queue_foreach_r(iter_type, iter_name, queue_name, node_member) \
	for (iter_type *iter_name = (iter_type *)QUEUE_CONTAINER(iter_type, node_member, queue_last(queue_name)); \
	     iter_name; \
	     iter_name = (iter_type *)QUEUE_CONTAINER(iter_type, node_member, queue_prev(&((iter_name)->node_member))))

struct queue_entry {
	struct queue_entry *qe_next;
	struct queue_entry *qe_prev;
};

struct queue {
	struct queue_entry *q_first;
	struct queue_entry *q_last;
};

static inline void queue_init(struct queue *q) { memset(q, 0x00, sizeof *q); }
static inline bool queue_empty(struct queue *q) { return q->q_first == NULL; }

static inline struct queue_entry *queue_first(struct queue *q) { return q->q_first; }
static inline struct queue_entry *queue_last(struct queue *q) { return q->q_last; }
static inline struct queue_entry *queue_next(struct queue_entry *entry) { return entry->qe_next; }
static inline struct queue_entry *queue_prev(struct queue_entry *entry) { return entry->qe_prev; }

extern size_t queue_length(struct queue *q);

extern void queue_insert_before(struct queue *q, struct queue_entry *entry, struct queue_entry *before);
extern void queue_insert_after(struct queue *q, struct queue_entry *entry, struct queue_entry *after);

extern void queue_push_front(struct queue *q, struct queue_entry *entry);
extern void queue_push_back(struct queue *q, struct queue_entry *entry);

extern struct queue_entry *queue_pop_front(struct queue *q);
extern struct queue_entry *queue_pop_back(struct queue *q);

extern void queue_delete(struct queue *q, struct queue_entry *entry);
extern void queue_delete_all(struct queue *q);

#ifdef __cplusplus
}
#endif

#endif