/*
 * control_server.h - Control Socket Server for ETCP Monitoring
 * 
 * Provides TCP control interface for ETCP connection monitoring
 */

#ifndef CONTROL_SERVER_H
#define CONTROL_SERVER_H

#include "../tools/etcpmon/etcpmon_protocol.h"
#include "../lib/socket_compat.h"
#include <stdint.h>
#include <stdio.h>

#ifdef __cplusplus
extern "C" {
#endif

/* Forward declarations */
struct UTUN_INSTANCE;
struct UASYNC;

/* Forward declaration */
struct control_server;

/* Client connection state */
struct control_client {
    struct control_client* next;        /* Linked list */
    struct control_server* server;      /* Back pointer to server */
    socket_t fd;                        /* Client socket */
    void* socket_id;                    /* uasync socket ID */
    
    /* Receive buffer */
    uint8_t recv_buffer[ETCPMON_MAX_MSG_SIZE];
    uint16_t recv_len;                  /* Bytes received so far */
    
    /* Selected connection */
    uint64_t selected_peer_id;          /* 0 = none selected */
    
    /* Client state */
//    uint8_t connected;
};

/* Control server state */
struct control_server {
    struct UTUN_INSTANCE* instance;     /* Parent instance */
    struct UASYNC* ua;                  /* Async context */
    
    /* Listening socket */
    socket_t listen_fd;
    void* listen_socket_id;             /* uasync socket ID */
    struct sockaddr_storage bind_addr;  /* Bound address */
    
    /* Client connections */
    struct control_client* clients;     /* Linked list of clients */
    uint32_t client_count;              /* Number of connected clients */
    uint32_t max_clients;               /* Maximum allowed clients */
    
    /* Log file */
    FILE* log_file;
};

/* ============================================================================
 * Public API
 * ============================================================================ */

/* Initialize control server
 * 
 * Creates listening socket and registers with uasync
 * 
 * Parameters:
 *   server  - Server state structure to initialize
 *   ua      - uasync context for event handling
 *   instance - Parent utun instance
 *   bind_addr - Address to bind (from config control_sock)
 *   max_clients - Maximum concurrent client connections
 * 
 * Returns:
 *   0 on success, -1 on error
 */
int control_server_init(struct control_server* server,
                        struct UASYNC* ua,
                        struct UTUN_INSTANCE* instance,
                        struct sockaddr_storage* bind_addr,
                        uint32_t max_clients);

/* Shutdown control server
 * 
 * Closes all client connections and listening socket
 * 
 * Parameters:
 *   server - Server state to shutdown
 */
void control_server_shutdown(struct control_server* server);

/* Process periodic updates
 * 
 * Should be called periodically (e.g., from main loop) to send
 * metrics updates to clients that have selected connections
 * 
 * Parameters:
 *   server - Server state
 */
void control_server_process_updates(struct control_server* server);

/* Get number of connected clients
 * 
 * Parameters:
 *   server - Server state
 * 
 * Returns:
 *   Number of connected clients
 */
uint32_t control_server_get_client_count(const struct control_server* server);

#ifdef __cplusplus
}
#endif

#endif /* CONTROL_SERVER_H */