#pragma once

#include <stdint.h>
#include "error.h"

#define DISCOVERY_MULTICAST_GROUP   "224.0.0.251"
#define DISCOVERY_PORT              5353
#define DISCOVERY_PROTOCOL_VERSION  1
#define DISCOVERY_MAX_NAME_LEN      255
#define DISCOVERY_MAX_PEERS         64

/* function_flags bits — matches protocol doc */
#define DISCOVERY_FLAG_SOURCE      (1u << 0)
#define DISCOVERY_FLAG_RELAY       (1u << 1)
#define DISCOVERY_FLAG_SINK        (1u << 2)
#define DISCOVERY_FLAG_CONTROLLER  (1u << 3)

struct Discovery_Peer {
	uint32_t  addr;            /* source IPv4, network byte order */
	uint16_t  site_id;
	uint16_t  tcp_port;
	uint16_t  function_flags;
	char      name[DISCOVERY_MAX_NAME_LEN + 1];
};

typedef void (*Discovery_Peer_Found_Cb)(const struct Discovery_Peer *peer, void *userdata);
typedef void (*Discovery_Peer_Lost_Cb)(const struct Discovery_Peer *peer, void *userdata);

struct Discovery_Config {
	/* our own identity */
	uint16_t    site_id;
	uint16_t    tcp_port;
	uint16_t    function_flags;
	const char *name;

	/* timing */
	uint32_t    interval_ms;       /* announcement interval; 0 = use default (5000) */
	uint32_t    timeout_intervals; /* missed intervals before peer_lost; 0 = use default (3) */

	/* callbacks */
	Discovery_Peer_Found_Cb  on_peer_found;  /* required */
	Discovery_Peer_Lost_Cb   on_peer_lost;   /* optional */
	void                    *userdata;
};

struct Discovery;

struct App_Error  discovery_create(struct Discovery **out, struct Discovery_Config *config);
struct App_Error  discovery_start(struct Discovery *d);
void              discovery_destroy(struct Discovery *d);