#ifndef _SEATD_POLLER_H
#define _SEATD_POLLER_H

#include <stdbool.h>
#include <stdint.h>

struct poller;
struct event_source_fd;
struct event_source_signal;

/*
 * These are the event types available from the poller.
 */
#define EVENT_READABLE 0x1
#define EVENT_WRITABLE 0x4
#define EVENT_ERROR    0x8
#define EVENT_HANGUP   0x10

/**
 * The callback type used by event_source_fd, passed to poller_add_fd.
 */
typedef int (*event_source_fd_func_t)(int fd, uint32_t mask, void *data);

/**
 * The interface that an event_source_fd must implement.
 */
struct event_source_fd_impl {
	int (*update)(struct event_source_fd *event_source, uint32_t mask);
	int (*destroy)(struct event_source_fd *event_source);
};

/**
 * The fd poller base class. This must be created by poller_add_fd.
 */
struct event_source_fd {
	const struct event_source_fd_impl *impl;
	event_source_fd_func_t func;

	int fd;
	uint32_t mask;
	void *data;
};

/**
 * Removes the event_source_fd from the poller and frees the structure.
 */
int event_source_fd_destroy(struct event_source_fd *event_source);

/**
 * Updates the poll mask applied to this fd, effective on the next poll.
 */
int event_source_fd_update(struct event_source_fd *event_source, uint32_t mask);

/**
 * The callback type used by event_source_signal, passed to poller_add_signal.
 */
typedef int (*event_source_signal_func_t)(int signal, void *data);

/**
 * The interface that an event_source_signal must implement.
 */
struct event_source_signal_impl {
	int (*destroy)(struct event_source_signal *event_source);
};

/*
 * The signal poller base class. This must be created by poller_add_signal.
 */
struct event_source_signal {
	const struct event_source_signal_impl *impl;
	event_source_signal_func_t func;

	int signal;
	void *data;
};

/**
 * Removes the event_source_siganl from the poller and frees the structure.
 */
int event_source_signal_destroy(struct event_source_signal *event_source);

/**
 * The interface that a poll backend must implement.
 */
struct poll_impl {
	struct poller *(*create)(void);
	int (*destroy)(struct poller *);

	struct event_source_fd *(*add_fd)(struct poller *, int fd, uint32_t mask,
					  event_source_fd_func_t func, void *data);
	struct event_source_signal *(*add_signal)(struct poller *, int signal,
						  event_source_signal_func_t func, void *data);

	int (*poll)(struct poller *);
};

/**
 * The poller base class. This must be created by poller_create.
 */
struct poller {
	const struct poll_impl *impl;
};

/**
 * Creates a poller with the best available polling backend. This poller must
 * be torn down with poller_destroy when it is no longer needed.
 */
struct poller *poller_create(void);

/**
 * Destroys the poller. This destroys all remaining event sources, tears down
 * the poller and frees the structure.
 */
int poller_destroy(struct poller *poller);

/**
 * Create an fd event source with the provided initial parameters. This event
 * source must be torn down with event_source_fd_destroy when it is no longer
 * needed.
 */
struct event_source_fd *poller_add_fd(struct poller *poller, int fd, uint32_t mask,
				      event_source_fd_func_t func, void *data);

/**
 * Create  signal event source with the provided initial parameters. This event
 * source must be torn down with event_source_signal_destroy when it is no
 * longer needed.
 */
struct event_source_signal *poller_add_signal(struct poller *poller, int signal,
					      event_source_signal_func_t func, void *data);

/**
 * Poll the poller. I don't know what you were expecting.
 */
int poller_poll(struct poller *poller);

#endif