#autoload

(( $+functions[_path_commands_caching_policy] )) ||
_path_commands_caching_policy() {

local file
local -a oldp dbfiles

# rebuild if cache is more than a week old
oldp=( "$1"(Nmw+1) )
(( $#oldp )) && return 0

dbfiles=(/usr/share/man/index.(bt|db|dir|pag)(N) \
  /usr/man/index.(bt|db|dir|pag)(N) \
  /var/cache/man/index.(bt|db|dir|pag)(N) \
  /var/catman/index.(bt|db|dir|pag)(N) \
  /usr/share/man/*/whatis(N))

for file in $dbfiles; do
  [[ $file -nt $1 ]] && return 0
done

return 1
}

_call_whatis() { 
  case "$(whatis --version)" in
  (whatis from *)
    local -A args
    zparseopts -D -A args s: r:
    apropos "${args[-r]:-"$@"}" | fgrep "($args[-s]"
    ;;
  (*) whatis "$@";;
  esac
}

_path_commands() {
local need_desc expl ret=1

if zstyle -t ":completion:${curcontext}:" extra-verbose; then
  local update_policy first
  if [[ $+_command_descriptions -eq 0 ]]; then
    first=yes
    typeset -A -g _command_descriptions
  fi
  zstyle -s ":completion:${curcontext}:" cache-policy update_policy
  [[ -z "$update_policy" ]] && zstyle ":completion:${curcontext}:" \
    cache-policy _path_commands_caching_policy
  if ( [[ -n $first ]] || _cache_invalid command-descriptions ) && \
    ! _retrieve_cache command-descriptions; then
    local line
    for line in "${(f)$(_call_program command-descriptions _call_whatis -s 1 -r .\\\*\; _call_whatis -s 6 -r .\\\* 2>/dev/null)}"; do
      [[ -n ${line:#(#b)([^ ]#) #\([^ ]#\)( #\[[^ ]#\]|)[ -]#(*)} ]] && continue;
      [[ -z $match[1] || -z $match[3] || -z ${${match[1]}:#*:*} ]] && continue;
      _command_descriptions[$match[1]]=$match[3]
    done
    _store_cache command-descriptions _command_descriptions
  fi

  (( $#_command_descriptions )) && need_desc=yes
fi

if [[ -n $need_desc ]]; then
  typeset -a dcmds descs cmds matches
  local desc cmd sep
  compadd "$@" -O matches -k commands
  for cmd in $matches; do
    desc=$_command_descriptions[$cmd]
    if [[ -z $desc ]]; then
      cmds+=$cmd
    else
      dcmds+=$cmd
      descs+="$cmd:$desc"
    fi
  done
  zstyle -s ":completion:${curcontext}:" list-separator sep || sep=--
  zformat -a descs " $sep " $descs
  descs=("${(@r:COLUMNS-1:)descs}")
  _wanted commands expl 'external command' \
    compadd "$@" -ld descs -a dcmds && ret=0
  _wanted commands expl 'external command' compadd "$@" -a cmds && ret=0
else
  _wanted commands expl 'external command' compadd "$@" -k commands && ret=0
fi
if [[ -o path_dirs ]]; then
  local -a path_dirs
  path_dirs=(${^path}/*(/N:t))
  (( ${#path_dirs} )) &&
  _wanted path-dirs expl 'directory in path' compadd "$@" -a path_dirs && ret=0

  if [[ $PREFIX$SUFFIX = */* ]]; then
    # Find command from path, not hashed
    _wanted commands expl 'external command' _path_files -W path -g '*(*)' &&
    ret=0
  fi
fi

return $ret
}

_path_commands "$@"