#compdef systemctl

# Copyright (c) 2011 Foudil Brétel <foudil.newbie+zshsystemctl@gmail.com>
#
# This file is released under the GPLv3.
#
# inspired from _yum and systemctl-bash-completion.sh (shipped with systemctl)
#
# TODO: enable options after commands. Ex: systemctl list-units --all --full

# Main dispatcher
_systemctl()
{
  local curcontext="$curcontext" state lstate line

  # -s for aggregated options like -aP
  _arguments -s \
    {-h,--help}'[Show help]' \
    '--version[Show package version]' \
    {-t,--type=}'[List only units of a particular type]:unit type:(automount device mount path service snapshot socket swap target timer)' \
    \*{-p,--property=}'[Show only properties by specific name]:unit property:' \
    {-a,--all}'[Show all units/properties, including dead/empty ones]' \
    '--failed[Show only failed units]' \
    "--full[Don't ellipsize unit names on output]" \
    '--fail[When queueing a new job, fail if conflicting jobs are pending]' \
    '--ignore-dependencies[When queueing a new job, ignore all its dependencies]' \
    '--kill-mode=[How to send signal]:killmode:(control-group process)' \
    '--kill-who=[Who to send signal to]:killwho:(main control all)' \
    {-s,--signal=}'[Which signal to send]:signal:_signals' \
    {-H,--host=}'[Show information for remote host]:userathost:_hosts_or_user_at_host' \
    {-P,--privileged}'[Acquire privileges before execution]' \
    {-q,--quiet}'[Suppress output]' \
    '--no-block[Do not wait until operation finished]' \
    "--no-wall[Don't send wall message before halt/power-off/reboot]" \
    "--no-reload[When enabling/disabling unit files, don't reload daemon configuration]" \
    '--no-legend[Do not print a legend, i.e. the column headers and the footer with hints]' \
    '--no-pager[Do not pipe output into a pager]' \
    '--no-ask-password[Do not ask for system passwords]' \
    '--order[When generating graph for dot, show only order]' \
    '--require[When generating graph for dot, show only requirement]' \
    '--system[Connect to system manager]' \
    '--user[Connect to user service manager]' \
    '--global[Enable/disable unit files globally]' \
    {-f,--force}'[When enabling unit files, override existing symlinks. When shutting down, execute action immediately]' \
    '--defaults[When disabling unit files, remove default symlinks only]' \
    '*::systemctl command:_systemctl_command'
}

_hosts_or_user_at_host()
{
  _alternative \
    'users-hosts:: _user_at_host' \
    'hosts:: _hosts'
}

(( $+functions[_systemctl_command] )) || _systemctl_command()
{
  local -a _systemctl_cmds
  _systemctl_cmds=(
    "list-units:List units"
    "start:Start (activate) one or more units"
    "stop:Stop (deactivate) one or more units"
    "reload:Reload one or more units"
    "restart:Start or restart one or more units"
    "condrestart:Restart one or more units if active"
    "try-restart:Restart one or more units if active"
    "reload-or-restart:Reload one or more units is possible, otherwise start or restart"
    "force-reload:Reload one or more units is possible, otherwise restart if active"
    "reload-or-try-restart:Reload one or more units is possible, otherwise restart if active"
    "isolate:Start one unit and stop all others"
    "kill:Send signal to processes of a unit"
    "is-active:Check whether units are active"
    "status:Show runtime status of one or more units"
    "show:Show properties of one or more units/jobs or the manager"
    "reset-failed:Reset failed state for all, one, or more units"
    "enable:Enable one or more unit files"
    "disable:Disable one or more unit files"
    "is-enabled:Check whether unit files are enabled"
    "load:Load one or more units"
    "list-jobs:List jobs"
    "cancel:Cancel all, one, or more jobs"
    "monitor:Monitor unit/job changes"
    "dump:Dump server status"
    "dot:Dump dependency graph for dot(1)"
    "snapshot:Create a snapshot"
    "delete:Remove one or more snapshots"
    "daemon-reload:Reload systemd manager configuration"
    "daemon-reexec:Reexecute systemd manager"
    "show-environment:Dump environment"
    "set-environment:Set one or more environment variables"
    "unset-environment:Unset one or more environment variables"
    "default:Enter system default mode"
    "rescue:Enter system rescue mode"
    "emergency:Enter system emergency mode"
    "halt:Shut down and halt the system"
    "poweroff:Shut down and power-off the system"
    "reboot:Shut down and reboot the system"
    "kexec:Shut down and reboot the system with kexec"
    "exit:Ask for user instance termination"
  )

  if (( CURRENT == 1 )); then
    _describe -t commands 'systemctl command' _systemctl_cmds || compadd "$@"
  else
    local curcontext="$curcontext"

    cmd="${${_systemctl_cmds[(r)$words[1]:*]%%:*}}"
    # Deal with any aliases
    case $cmd in
      condrestart) cmd="try-restart";;
      force-reload) cmd="reload-or-try-restart";;
    esac

    if (( $#cmd )); then
      curcontext="${curcontext%:*:*}:systemctl-${cmd}:"

      local update_policy
      zstyle -s ":completion:${curcontext}:" cache-policy update_policy
      if [[ -z "$update_policy" ]]; then
        zstyle ":completion:${curcontext}:" cache-policy _systemctl_caching_policy
      fi

      _call_function ret _systemctl_$cmd || _message 'no more arguments'
    else
      _message "unknown systemctl command: $words[1]"
    fi
    return ret
  fi
}

__check_option_nolegend()
{
  systemctl --no-legend --version 2>&1 | grep -q 'unrecognized option'
  print -Pn '%(?..--no-legend)'
}
nolegend=$(__check_option_nolegend)


# Fills the unit lists
_systemctl_all_units()
{
  if ( [[ ${+_sys_all_units} -eq 0 ]] || _cache_invalid SYS_ALL_UNITS ) &&
    ! _retrieve_cache SYS_ALL_UNITS;
  then
    _sys_all_units=( $(systemctl ${nolegend} list-units --full --all \
      | cut -d' ' -f1 2>/dev/null) )
    _store_cache SYS_ALL_UNITS _sys_all_units
  fi
}

_systemctl_inactive_units()
{
  _sys_inactive_units=( $(systemctl ${nolegend} list-units --full --all \
    | awk '$3 != "active" {print $1}' 2>/dev/null) )
}

_systemctl_active_units()
{
  _sys_active_units=( $(systemctl ${nolegend} list-units --full \
    | cut -d' ' -f1 2>/dev/null) )
}

_systemctl_failed_units()
{
  _sys_failed_units=( $(systemctl ${nolegend} list-units --full --failed \
    | cut -d' ' -f1 2>/dev/null) )
}

_filter_units_by_property () {
  local property=$1 value=$2 ; shift ; shift
  local -a units ; units=($*)
  local -a props ; props=( $(systemctl show --property "$property" -- \
    ${units[*]} | grep -v '^$') )
  for ((i=1; $i <= ${#units[*]}; i++)); do
    if [[ "${props[i]}" = "$property=$value" ]]; then
      echo "${units[i]}"
    fi
  done
}

# Completion functions for ALL_UNITS
for fun in enable disable is-active is-enabled status show ; do
  (( $+functions[_systemctl_$fun] )) || _systemctl_$fun()
  {
    _systemctl_all_units
    compadd "$@" -a - _sys_all_units
  }
done

# Completion functions for STARTABLE_UNITS
(( $+functions[_systemctl_start] )) || _systemctl_start()
{
  _systemctl_inactive_units
  compadd "$@" - $( _filter_units_by_property CanStart yes \
    ${_sys_inactive_units[*]} | grep -Ev '\.(device|snapshot)$' )
}

# Completion functions for RESTARTABLE_UNITS
for fun in restart reload-or-restart ; do
  (( $+functions[_systemctl_$fun] )) || _systemctl_$fun()
  {
    _systemctl_all_units
    compadd "$@" - $( _filter_units_by_property CanStart yes \
      ${_sys_all_units[*]} | grep -Ev '\.(device|snapshot|socket|timer)$' )
  }
done

# Completion functions for STOPPABLE_UNITS
for fun in stop kill try-restart condrestart ; do
  (( $+functions[_systemctl_$fun] )) || _systemctl_$fun()
  {
    _systemctl_active_units
    compadd "$@" - $( _filter_units_by_property CanStop yes \
      ${_sys_active_units[*]} )
  }
done

# Completion functions for RELOADABLE_UNITS
for fun in reload reload-or-try-restart force-reload ; do
  (( $+functions[_systemctl_$fun] )) || _systemctl_$fun()
  {
    _systemctl_active_units
    compadd "$@" - $( _filter_units_by_property CanReload yes \
      ${_sys_active_units[*]} )
  }
done

# Completion functions for ISOLATABLE_UNITS
(( $+functions[_systemctl_isolate] )) || _systemctl_isolate()
{
  _systemctl_all_units
  compadd "$@" - $( _filter_units_by_property AllowIsolate yes \
    ${_sys_all_units[*]} )
}

# Completion functions for FAILED_UNITS
(( $+functions[_systemctl_reset-failed] )) || _systemctl_reset-failed()
{
  _systemctl_failed_units
  compadd "$@" -a - _sys_failed_units || _message "no failed-unit found"
}

# Completion functions for JOBS
(( $+functions[_systemctl_cancel] )) || _systemctl_cancel()
{
  compadd "$@" - $(systemctl ${nolegend} list-jobs \
    | cut -d' ' -f1  2>/dev/null ) || _message "no job found"
}

# Completion functions for SNAPSHOTS
(( $+functions[_systemctl_delete] )) || _systemctl_delete()
{
  compadd "$@" - $(systemctl ${nolegend} list-units --type snapshot --full \
    --all | cut -d' ' -f1  2>/dev/null ) || _message "no snampshot found"
}

# Completion functions for ENVS
for fun in set-environment unset-environment ; do
  (( $+functions[_systemctl_$fun] )) || _systemctl_$fun()
  {
    local fun=$0 ; fun=${fun##_systemctl_}
    local suf
    if [[ "${fun}" = "set-environment" ]]; then
      suf='-S='
    fi

    compadd "$@" ${suf} - $(systemctl show-environment \
      | sed 's_\([^=]\+\)=.*_\1_' )
  }
done

# no completion for:
#   [STANDALONE]='daemon-reexec daemon-reload default dot dump emergency exit
#                 halt kexec list-jobs list-units monitor poweroff reboot
#                 rescue show-environment'
#         [NAME]='snapshot load'

_systemctl_caching_policy()
{
  local _sysunits
  local -a oldcache

  # rebuild if cache is more than a day old
  oldcache=( "$1"(mh+1) )
  (( $#oldcache )) && return 0

  _sysunits=($(systemctl ${nolegend} --full --all | cut -d' ' -f1))

  if (( $#_sysunits )); then
    for unit in $_sysunits; do
      [[ "$unit" -nt "$1" ]] && return 0
    done
  fi

  return 1
}

_systemctl "$@"

# Local Variables:
# mode: sh
# sh-indentation: 2
# indent-tabs-mode: nil
# sh-basic-offset: 2
# End: