mpdws/mpd_ws.c

#include "mpd_ws.h"
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/select.h>
#include <syslog.h>
#include <time.h>
#include <unistd.h>

/* Global server instance for signal handling */
static struct mpd_ws_server *g_server = NULL;

/* Signal handler */
static void signal_handler(int sig) {
  (void)sig; /* Suppress unused param warning */
  if (g_server) {
    g_server->running = 0;
  }
}

/* WebSocket callback */
static int ws_callback(struct lws *wsi, enum lws_callback_reasons reason,
                       void *user, void *in, size_t len) {
  (void)user; /* Suppress unused param warnings */
  (void)in;
  (void)len;

  struct mpd_ws_server *server =
      (struct mpd_ws_server *)lws_context_user(lws_get_context(wsi));

  switch (reason) {
  case LWS_CALLBACK_ESTABLISHED:
    client_add(server, wsi);
    /* Send current song to new client */
    if (strlen(server->current_song) > 0) {
      lws_callback_on_writable(wsi);
    }
    break;

  case LWS_CALLBACK_CLOSED:
    client_remove(server, wsi);
    break;

  case LWS_CALLBACK_SERVER_WRITEABLE:
    if (strlen(server->current_song) > 0) {
      unsigned char buf[LWS_PRE + MAX_MESSAGE_SIZE];
      size_t msg_len = strlen(server->current_song);
      memcpy(&buf[LWS_PRE], server->current_song, msg_len);
      lws_write(wsi, &buf[LWS_PRE], msg_len, LWS_WRITE_TEXT);
    }
    break;

  case LWS_CALLBACK_RECEIVE:
    /* Ignore client input */
    break;

  default:
    break;
  }

  return 0;
}

/* WebSocket protocols */
static struct lws_protocols protocols[] = {
    {"mpd-protocol", ws_callback, 0, MAX_MESSAGE_SIZE, 0, NULL, 0},
    {NULL, NULL, 0, 0, 0, NULL, 0}};

/* Initialize the server */
int mpd_ws_init(struct mpd_ws_server *server) {
  memset(server, 0, sizeof(*server));

  /* Setup signal handlers */
  g_server = server;
  signal(SIGINT, signal_handler);
  signal(SIGTERM, signal_handler);

  /* Initialize syslog */
  openlog("mpd_ws", LOG_PID | LOG_NDELAY, LOG_DAEMON);

  /* Create WebSocket context */
  struct lws_context_creation_info info = {0};
  info.port = WEBSOCKET_PORT;
  info.protocols = protocols;
  info.gid = -1;
  info.uid = -1;
  info.user = server;

  server->ws_context = lws_create_context(&info);
  if (!server->ws_context) {
    syslog(LOG_ERR, "Failed to create WebSocket context");
    return -1;
  }

  syslog(LOG_INFO, "WebSocket server listening on port %d", WEBSOCKET_PORT);

  /* Connect to MPD */
  mpd_ws_connect(server);

  server->running = 1;
  return 0;
}

/* Main server loop */
void mpd_ws_run(struct mpd_ws_server *server) {
  time_t last_reconnect = 0;

  while (server->running) {
    /* Service WebSocket events */
    lws_service(server->ws_context, 10);

    /* Handle MPD reconnection */
    if (!mpd_ws_is_connected(server)) {
      time_t now = time(NULL);
      if (now - last_reconnect >= RECONNECT_INTERVAL_SEC) {
        if (mpd_ws_connect(server) == 0) {
          mpd_ws_update_song(server);
          mpd_ws_start_idle(server);
        }
        last_reconnect = now;
      }
      sleep(SELECT_TIMEOUT_SEC);
      continue;
    }

    /* Start idle mode if not active */
    if (!server->mpd_idle_active) {
      if (mpd_ws_start_idle(server) < 0) {
        mpd_ws_disconnect(server);
        continue;
      }
    }

    /* Check for MPD events */
    fd_set readfds;
    int mpd_fd = mpd_connection_get_fd(server->mpd_conn);
    struct timeval timeout = {0, SELECT_TIMEOUT_SEC};

    FD_ZERO(&readfds);
    FD_SET(mpd_fd, &readfds);

    int result = select(mpd_fd + 1, &readfds, NULL, NULL, &timeout);
    if (result > 0 && FD_ISSET(mpd_fd, &readfds)) {
      mpd_ws_process_idle(server);
      if (!mpd_ws_is_connected(server)) {
        mpd_ws_disconnect(server);
      }
    }
  }
}

/* Cleanup and shutdown */
void mpd_ws_cleanup(struct mpd_ws_server *server) {
  syslog(LOG_INFO, "Shutting down");

  mpd_ws_disconnect(server);

  if (server->ws_context) {
    lws_context_destroy(server->ws_context);
  }

  /* Free client list */
  while (server->clients) {
    struct client_session *next = server->clients->next;
    free(server->clients);
    server->clients = next;
  }

  closelog();
}

/* Stop the server */
void mpd_ws_stop(struct mpd_ws_server *server) { server->running = 0; }

/* Connect to MPD */
int mpd_ws_connect(struct mpd_ws_server *server) {
  if (server->mpd_conn) {
    mpd_connection_free(server->mpd_conn);
  }

  server->mpd_conn = mpd_connection_new(MPD_HOST, MPD_PORT, 0);
  if (mpd_connection_get_error(server->mpd_conn) != MPD_ERROR_SUCCESS) {
    syslog(LOG_ERR, "Failed to connect to MPD: %s",
           mpd_connection_get_error_message(server->mpd_conn));
    mpd_connection_free(server->mpd_conn);
    server->mpd_conn = NULL;
    return -1;
  }

  server->mpd_idle_active = 0;
  syslog(LOG_INFO, "Connected to MPD at %s:%d", MPD_HOST, MPD_PORT);
  return 0;
}

/* Disconnect from MPD */
void mpd_ws_disconnect(struct mpd_ws_server *server) {
  if (server->mpd_conn) {
    if (server->mpd_idle_active) {
      mpd_send_noidle(server->mpd_conn);
      mpd_response_finish(server->mpd_conn);
    }
    mpd_connection_free(server->mpd_conn);
    server->mpd_conn = NULL;
  }
  server->mpd_idle_active = 0;
}

/* Check if MPD is connected */
int mpd_ws_is_connected(struct mpd_ws_server *server) {
  return server->mpd_conn &&
         mpd_connection_get_error(server->mpd_conn) == MPD_ERROR_SUCCESS;
}

/* Update current song and broadcast */
void mpd_ws_update_song(struct mpd_ws_server *server) {
  if (!mpd_ws_is_connected(server)) {
    return;
  }

  mpd_command_list_begin(server->mpd_conn, false);
  mpd_send_current_song(server->mpd_conn);
  mpd_command_list_end(server->mpd_conn);

  struct mpd_song *song = mpd_recv_song(server->mpd_conn);
  if (mpd_connection_get_error(server->mpd_conn) != MPD_ERROR_SUCCESS) {
    syslog(LOG_ERR, "Failed to get current song: %s",
           mpd_connection_get_error_message(server->mpd_conn));
    return;
  }

  /* Create song message */
  if (song == NULL) {
    snprintf(server->current_song, MAX_MESSAGE_SIZE, "Now Playing: No song");
  } else {
    const char *artist = mpd_song_get_tag(song, MPD_TAG_ARTIST, 0);
    const char *title = mpd_song_get_tag(song, MPD_TAG_TITLE, 0);

    if (artist && title) {
      snprintf(server->current_song, MAX_MESSAGE_SIZE, "Now Playing: %s - %s",
               artist, title);
    } else if (title) {
      snprintf(server->current_song, MAX_MESSAGE_SIZE, "Now Playing: %s",
               title);
    } else {
      const char *uri = mpd_song_get_uri(song);
      snprintf(server->current_song, MAX_MESSAGE_SIZE, "Now Playing: %s",
               uri ? uri : "Unknown");
    }
  }

  syslog(LOG_DEBUG, "Broadcasting: %s", server->current_song);

  /* Only broadcast if song actually changed */
  if (strcmp(server->current_song, server->previous_song) != 0) {
    client_broadcast(server, server->current_song);
    strlcpy(server->previous_song, server->current_song,
            sizeof(server->previous_song));
  }

  if (song) {
    mpd_song_free(song);
  }
  mpd_response_finish(server->mpd_conn);
}

/* Start MPD idle mode */
int mpd_ws_start_idle(struct mpd_ws_server *server) {
  if (!mpd_ws_is_connected(server)) {
    return -1;
  }

  if (!mpd_send_idle_mask(server->mpd_conn, MPD_IDLE_PLAYER)) {
    syslog(LOG_ERR, "Failed to send idle command: %s",
           mpd_connection_get_error_message(server->mpd_conn));
    return -1;
  }

  server->mpd_idle_active = 1;
  return 0;
}

/* Process MPD idle response */
void mpd_ws_process_idle(struct mpd_ws_server *server) {
  if (!mpd_ws_is_connected(server) || !server->mpd_idle_active) {
    return;
  }

  enum mpd_idle events = mpd_recv_idle(server->mpd_conn, false);
  server->mpd_idle_active = 0;

  if (mpd_connection_get_error(server->mpd_conn) != MPD_ERROR_SUCCESS) {
    syslog(LOG_WARNING, "MPD idle error: %s",
           mpd_connection_get_error_message(server->mpd_conn));
    return;
  }

  if (events & MPD_IDLE_PLAYER) {
    mpd_ws_update_song(server);
  }

  /* Restart idle mode */
  mpd_ws_start_idle(server);
}

/* Add client */
void client_add(struct mpd_ws_server *server, struct lws *wsi) {
  struct client_session *client = malloc(sizeof(struct client_session));
  if (!client) {
    syslog(LOG_ERR, "Failed to allocate client session");
    return;
  }

  client->wsi = wsi;
  client->next = server->clients;
  server->clients = client;

  syslog(LOG_INFO, "Client connected");
}

/* Remove client */
void client_remove(struct mpd_ws_server *server, struct lws *wsi) {
  struct client_session **current = &server->clients;

  while (*current) {
    if ((*current)->wsi == wsi) {
      struct client_session *to_remove = *current;
      *current = (*current)->next;
      free(to_remove);
      syslog(LOG_INFO, "Client disconnected");
      return;
    }
    current = &(*current)->next;
  }
}

/* Broadcast message to all clients */
void client_broadcast(struct mpd_ws_server *server, const char *message) {
  struct client_session *client = server->clients;
  size_t len = strlen(message);

  while (client) {
    unsigned char buf[LWS_PRE + MAX_MESSAGE_SIZE];
    memcpy(&buf[LWS_PRE], message, len);

    if (lws_write(client->wsi, &buf[LWS_PRE], len, LWS_WRITE_TEXT) < 0) {
      syslog(LOG_WARNING, "Failed to write to websocket");
    }
    client = client->next;
  }
}