(* mclu: Mini Cloud
 * Copyright (C) 2014-2015 Red Hat Inc.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *)

(* Implement 'mclu on' and 'mclu off'. *)

open Printf

open Utils

let get_arg_speclist () = Arg.align [
]

let wake ~verbose nodes =
  let wol =
    match Config.path_wol with
    | Some wol -> wol
    | None ->
      eprintf "mclu: Wake-on-LAN is not available
Recompile mclu with the 'wol' program installed\n";
      exit 1 in

  (* Only wake nodes which are switched off. *)
  let nodes = List.filter (fun { Mclu_status.node_on = on } -> not on) nodes in
  let nodes = List.map (fun { Mclu_status.node = node } -> node) nodes in

  List.iter (
    function
    | { Mclu_conf.mac_addr = Some mac_addr } ->
      let cmd = sprintf "%s %s" (quote wol) (quote mac_addr) in
      if verbose then printf "%s\n%!" cmd;
      if Sys.command cmd <> 0 then (
        eprintf "mclu: wol: command failed\n";
        exit 1
      )
    | { Mclu_conf.hostname = hostname; mac_addr = None } ->
      eprintf "mclu: Wake-on-LAN is not configured for node %s
Edit mclu.conf and add 'mac=<MAC address>' to this host line.\n" hostname;
      exit 1
  ) nodes

let shutdown ~verbose nodes =
  (* Only shutdown nodes which are switched on. *)
  let nodes = List.filter (fun { Mclu_status.node_on = on } -> on) nodes in
  let nodes = List.map (fun { Mclu_status.node = node } -> node) nodes in

  (* Get the active guests on these nodes. *)
  let active_guests = Mclu_list.active_guests ~verbose ~nodes () in

  let errors = ref 0 in

  List.iter (
    fun ({ Mclu_conf.hostname = hostname } as node) ->
      let guests = try List.assoc node active_guests with Not_found -> [] in
      if guests <> [] then (
        eprintf "mclu: node %s has %d guest(s) running: %s
Shut down these guests before turning off the node.\n"
          hostname (List.length guests)
          (String.concat ", "
             (List.map (fun guest -> guest.Mclu_list.dom_name) guests));
        incr errors
      )
      else (
        (* We have to be cunning about this else ssh will return an error. *)
        let cmd =
          sprintf "ssh -o ForwardX11=no root@%s '(sleep 5; poweroff) </dev/null >/dev/null 2>&1 &'"
            (quote hostname) in
        if verbose then printf "%s\n%!" cmd;
        if Sys.command cmd <> 0 then (
          eprintf "mclu: %s: poweroff: command failed\n" hostname;
          incr errors
        )
      )
  ) nodes;

  if !errors > 0 then
    exit 1

let expand_wildcards exprs =
  let regexps = List.map regexp_of_glob exprs in
  let regexps = List.map Pcre.regexp regexps in

  let nodes = Mclu_status.node_statuses () in

  let nodes =
    List.filter (
      fun { Mclu_status.node = { Mclu_conf.hostname = hostname } } ->
        List.exists (fun rex -> Pcre.pmatch ~rex hostname) regexps
    ) nodes in

  if List.length nodes < List.length exprs then (
    eprintf "mclu: [on|off]: some wildcards don't match hostnames\n";
    exit 1
  );

  nodes

let run ~verbose ~on = function
  | (_::_) as xs ->
    let nodes = expand_wildcards xs in
    (if on then wake else shutdown) ~verbose nodes
  | [] ->
    eprintf "Usage: mclu [on|off] node|wildcard ...\n";
    exit 1