#ifndef CST_DISCOVER_H
#define CST_DISCOVER_H

#include <stddef.h>

#ifdef __cplusplus
extern "C" {
#endif

/* Same-Realm peer discovery: UDP multicast beacon + local instance file.
 * mDNS (_cst-parliament._tcp) can replace the beacon later without changing
 * this surface. */

#define CST_DISCOVER_PORT 45454
#define CST_DISCOVER_GROUP "239.255.77.77"

typedef struct {
  char instance_id[64];
  char realm_fp[33];
  char name[64];
  char host[64];
  int port;
} cst_peer_info_t;

typedef struct cst_discover cst_discover_t;

/* Advertise this instance and collect peers that share realm_fp.
 * peer_port is the TCP parliament port peers should dial. */
cst_discover_t *cst_discover_start(const char *realm_fp, const char *instance_id,
                                   const char *name, int peer_port);
void cst_discover_stop(cst_discover_t *d);

/* Copy up to max known peers (excluding self). Returns count. */
int cst_discover_peers(cst_discover_t *d, cst_peer_info_t *out, int max);

/* Same-machine registry under <config>/realm/local-instances.json. */
int cst_discover_local_put(const char *realm_fp, const char *instance_id,
                           const char *name, int peer_port);
int cst_discover_local_del(const char *instance_id);
int cst_discover_local_list(const char *realm_fp, cst_peer_info_t *out, int max);

#ifdef __cplusplus
}
#endif

#endif