#autoload

# Complete the arguments of the current command according to the
# descriptions given as arguments to this function.

setopt localoptions extendedglob

local long args rest ws cur nth def nm expl descr action opt arg tmp
local single uns ret=1 soptseq soptseq1 sopts prefix line
local beg optbeg argbeg

# Associative arrays used to collect information about the options.

typeset -A opts dopts odopts
typeset -A oneshot

# See if we are using single-letter options.

if [[ "$1" = -s ]]; then
  shift
  single=yes
fi

# See if we support long options, too.

nth=$argv[(I)--]
if (( nth )); then
  long=( "${(@)argv[nth+1,-1]}" )
  argv=("${(@)argv[1,nth-1]}")
else
  long=()
fi

# Now parse the arguments...

args=()
nth=1
while (( $# )); do

  # This describes a one-shot option.

  if [[ "$1" = [-+]* ]]; then
    if [[ "$1" = *:* ]]; then

      # If the option name ends in a `-', the first argument comes
      # directly after the option, if it ends in a `+', the first
      # argument *may* come directly after the option, otherwise it
      # is in the next word.

      if [[ "$1" = [^:]##-:* ]]; then
	tmp="${${1%%:*}[1,-2]}"
        dopts[$tmp]="${1#*:}"
      elif [[ "$1" = [^:]##+:* ]]; then
	tmp="${${1%%:*}[1,-2]}"
        odopts[$tmp]="${1#*:}"
      else
        tmp="${1%%:*}"
        opts[$tmp]="${1#*:}"
      fi
    else
      tmp="$1"
      opts[$tmp]=''
    fi
    oneshot[$tmp]=yes
  elif [[ "$1" = \*[-+]* ]]; then

    # The same for options that may appear more than once.

    if [[ "$1" = *:* ]]; then
      if [[ "$1" = [^:]##-:* ]]; then
        tmp="${${1[2,-1]%%:*}[1,-2]}"
        dopts[$tmp]="${1#*:}"
      elif [[ "$1" = [^:]##+:* ]]; then
        tmp="${${1[2,-1]%%:*}[1,-2]}"
        odopts[$tmp]="${1#*:}"
      else
        tmp="${1[2,-1]%%:*}"
        opts[$tmp]="${1#*:}"
      fi
    else
      tmp="${1[2,-1]}"
      opts[$tmp]=''
    fi
    unset "oneshot[$tmp]"
  elif [[ "$1" = \*:* ]]; then

    # This is `*:...', describing `all other arguments'.

    rest="${1[3,-1]}"
  elif [[ "$1" = :* ]]; then

    # This is `:...', describing `the next argument'.

    args[nth++]="${1#*:}"
  else

    # And this is `n:...', describing the `n'th argument.

    args[${1%%:*}]="${1#*:}"
    nth=$(( ${1%%:*} + 1 ))
  fi
  shift
done

if [[ -n "$single" ]]; then
  soptseq="${(@j::)${(@M)${(@k)opts[(R)]}:#[-+]?}#[-+]}"
  if [[ -n "$soptseq" ]]; then
    soptseq="[$soptseq]#"
    soptseq1="$soptseq#"
  else
    soptseq=''
    soptseq1=''
  fi
  sopts="${(@j::)${(@M)${(@k)opts}:#[-+]?}#[-+]}${(@j::)${(@M)${(@k)dopts}:#[-+]?}#[-+]}${(@j::)${(@M)${(@k)odopts}:#[-+]?}#[-+]}"
else
  soptseq=''
  soptseq1=''
  sopts=''
fi

# Parse the command line...

ws=( "${(@)words[2,-1]}" )
cur=$(( CURRENT-2 ))
nth=1
line=( "$words[1]" )
beg=2
argbeg=2
optbeg=2

# ...until the current word is reached.

while [[ cur -gt 0 ]]; do

  # `def' holds the description for the option we are currently after.
  # Check if the next argument for the option is optional.

  if [[ "$def" = :* ]]; then
    opt=yes
  else
    opt=''
  fi
  arg=''

  # See if we are after an option getting n arguments ended by something
  # that matches the current word.

  if [[ "$def" = \**[^\\]:* && "$ws[1]" = ${~${(M)def#*[^\\]:}[2,-2]} ]]; then
    def=''
    shift 1 ws
    (( cur-- ))
    (( beg++ ))
    continue
  fi

  # Remove one description/action pair from `def' if that isn't empty.

  if [[ -n "$def" && "$def" != \** ]]; then
    if [[ "$def" = ?*[^\\]:*[^\\]:* ]]; then
      def="${def#?*[^\\]:*[^\\]:}"
      argbeg="$beg"
    else
      def=''
    fi
  elif [[ -z "$def" ]]; then

    # If it is empty, and the word starts with `--' and we should
    # complete long options, just ignore this word, otherwise make sure
    # we test for options below and handle normal arguments.

    if [[ $#long -eq 0 || "$ws[1]" != --* ]]; then
      opt=yes
      arg=yes
    else
      def=''
    fi
  fi

  if [[ -n "$opt" ]]; then

    # `opt' was set above if we have to test if the word is an option.
    # We first test for the simple options -- those without arguments or
    # those whose arguments have to be given as separate words.

    if (( $+opts[$ws[1]] )); then

      # Options that may only be given once are removed from the
      # associative array so that we don't offer them again.

      def="$opts[$ws[1]]"
      [[ -n "$oneshot[$ws[1]]" ]] && unset "opts[$ws[1]]"
    else
      uns=''
      if [[ -n "$sopts" && "$ws[1]" = [-+]${~soptseq}[$sopts] ]]; then
	tmp="${ws[1][1]}${ws[1][-1]}"
	if (( $+opts[$tmp] )); then
	  def="$opts[$tmp]"
	  optbeg="$beg"
	  argbeg="$beg"
	  uns="${ws[1][2,-1]}"
	  opt=''
	fi
      fi

      # If the word is none of the simple options, test for those
      # whose first argument has to or may come directly after the
      # option. This is done in two loops looking very much alike.

      if [[ -n "$opt" && $#dopts -ne 0 ]]; then

	# First we get the option names.

	tmp=( "${(@k)dopts}" )

	# Then we loop over them and see if the current word begins
	# with one of the option names.

	while (( $#tmp )); do
          if [[ -n "$sopts" && $tmp[1] = [-+]? ]]; then
	    if [[ "$ws[1]" = ${tmp[1][1]}${~soptseq}${tmp[1][2]}* ]]; then
	      uns="${ws[1][2,-1]%%${tmp[1][2]}*}${tmp[1][2]}"
	      break;
	    fi
	  elif [[ "$ws[1]" = ${tmp[1]}* ]]; then
            break
	  fi
	  shift 1 tmp
	done

	if (( $#tmp )); then

	  # It does. So use the description for it, but only from
	  # the second argument on, because we are searching the
	  # description for the next command line argument.

	  opt=''
	  def="$dopts[$tmp[1]]"
	  optbeg="$beg"
	  argbeg="$beg"
	  [[ -n "$oneshot[$tmp[1]]" ]] && unset "dopts[$tmp[1]]"
	  if [[ "$def" = [^*]*[^\\]:*[^\\]:* ]]; then
            def="${def#?*[^\\]:*[^\\]:}"
          else
            def=''
	  fi
        fi
      fi
      if [[ -n "$opt" && $#odopts -ne 0 ]]; then
	tmp=( "${(@k)odopts}" )
	while (( $#tmp )); do
          if [[ -n "$sopts" && $tmp[1] = [-+]? ]]; then
	    if [[ "$ws[1]" = ${tmp[1][1]}${~soptseq}${tmp[1][2]}* ]]; then
	      uns="${ws[1][2,-1]%%${tmp[1][2]}*}${tmp[1][2]}"
	      break;
	    fi
	  elif [[ "$ws[1]" = ${tmp[1]}* ]]; then
	    break
	  fi
	  shift 1 tmp
	done

	if (( $#tmp )); then
	  opt=''
	  def="$odopts[$tmp[1]]"
	  optbeg="$beg"
	  argbeg="$beg"
	  [[ -n "$oneshot[$tmp[1]]" ]] && unset "odopts[$tmp[1]]"

	  # For options whose first argument *may* come after the
	  # option, we skip over the first description only if there
	  # is something after the option name on the line.

	  if [[ ( -z "$sopts" && "$ws[1]" != "$tmp[1]" ) ||
                ( -n "$sopts" && ( ( $tmp[1] = [-+]? && "$ws[1]" != "${tmp[1][1]}"${~soptseq}"${tmp[1][2]}" ) ||
		  		   ( $tmp[1] != [-+]? && "$ws[1]" != "$tmp[1]" ) ) ) ]]; then
	    if [[ "$def" = [^*]*[^\\]:*[^\\]:* ]]; then
              def="${def#?*[^\\]:*[^\\]:}"
	      optbeg="$beg"
	      argbeg="$beg"
            else
              def=''
            fi
	  fi
        fi
      fi

      [[ -n "$sopts" && -n "$opt" && "$ws[1]" = [-+]${~soptseq} ]] && \
          uns="${ws[1][2,-1]}"

      if [[ -n "$uns" ]]; then
	uns="${(j::)${(@k)oneshot[(I)${ws[1][1]}[$uns]]#[-+]}}"
	unset "opts[${(@)^opts[(I)${ws[1][1]}[$uns]]}]" \
	      "dopts[${(@)^dopts[(I)${ws[1][1]}[$uns]]}]" \
	      "odopts[${(@)^odopts[(I)${ws[1][1]}[$uns]]}]"
      fi

      # If we didn't find a matching option description and we were
      # told to use normal argument descriptions, just increase
      # our counter `nth'.

      if [[ -n "$opt" && -n "$arg" ]]; then
        def=''
	line=( "$line[@]" "$ws[1]" )
	(( nth++ ))
      fi
    fi
  fi

  shift 1 ws
  (( cur-- ))
  (( beg++ ))
done

# Now generate the matches.

if [[ $#long -ne 0 && "$PREFIX" = --* ]]; then

  # If the current words starts with `--' and we should use long
  # options, just call...

  _long_options "$long[@]"

else

  nm="$compstate[nmatches]"

  if [[ -z "$def" || "$def" = :* ]]; then
      local pre="$PREFIX"

      uns=''

    # We either don't have a description for an argument of an option
    # or we have a description for a optional argument.

    if [[ -z "$def" ]]; then

      # If we have none at all, use the one for this argument position.

      def="$args[nth]"
      [[ -z "$def" ]] && def="$rest"

      if [[ "$def" = \** ]]; then
        def="${def#*[^\\]:}"
	[[ "$def" = :* ]] && def="$def[2,-1]"
	[[ "$def" = :* ]] && def="$def[2,-1]"
      fi
    fi

    # In any case, we have to complete option names here, but we may
    # be in a string that starts with an option name and continues with
    # the first argument, test that (again, two loops).

    opt=yes
    if (( $#dopts )); then

      # Get the option names.

      tmp=( "${(@k)dopts}" )
      prefix="$PREFIX"
      while (( $#tmp )); do
        if [[ -n "$sopts" && $tmp[1] = [-+]? ]] && compset -P "${tmp[1][1]}${~soptseq}${tmp[1][2]}"; then
          def="$dopts[$tmp[1]]"
	  opt=''
	  uns="${prefix[2,-1]%%${tmp[1][2]}*}${tmp[1][2]}"
	  break
        elif compset -P "$tmp[1]"; then

	  # The current string starts with the option name, so ignore
	  # that and complete the rest of the string.

	  def="$dopts[$tmp[1]]"
	  opt=''
	  break
        fi
	shift 1 tmp
      done
    fi
    if [[ -n "$opt" && $#odopts -ne 0 ]]; then
      tmp=( "${(@k)odopts}" )
      prefix="$PREFIX"
      while (( $#tmp )); do
        if [[ -n "$sopts" && $tmp[1] = [-+]? ]] && compset -P "${tmp[1][1]}${~soptseq}${tmp[1][2]}"; then
          def="$odopts[$tmp[1]]"
	  opt=''
	  uns="${prefix[2,-1]%%${tmp[1][2]}*}${tmp[1][2]}"
	  break
        elif compset -P "$tmp[1]"; then
	  def="$odopts[$tmp[1]]"
	  opt=''
	  break
        fi
	shift 1 tmp
      done
    fi

    [[ -n "$sopts" && -n "$opt" && "$PREFIX" = [-+]${~soptseq}[$sopts] ]] && \
        uns="${PREFIX[2,-1]}"

    if [[ -n "$uns" ]]; then
      uns="${(j::)${(@k)oneshot[(I)${ws[1][1]}[$uns]]#[-+]}}"
      unset "opts[${(@)^opts[(I)${pre[1]}[$uns]]}]" \
	    "dopts[${(@)^dopts[(I)${pre[1]}[$uns]]}]" \
	    "odopts[${(@)^odopts[(I)${pre[1]}[$uns]]}]"
    fi

    if [[ -n "$opt" ]]; then

      # We aren't in an argument directly after a option name, so
      # all option names are possible matches.

      if [[ "$compconfig[option_prefix]" != *(short|all)* ||
            "$PREFIX" = [-+]* ]]; then
        _description expl option
	if [[ -n "$sopts" && -n "$PREFIX" && "$PREFIX" = [-+]${~soptseq}[$sopts] ]]; then
	  if [[ "$PREFIX" = [-+]${~soptseq1} ]]; then
	    compadd "$expl[@]" -Q \
                    -y "( ${(k)opts} ${(k)dopts} ${(k)odopts} )" - \
                    "${PREFIX}${(@k)^opts[(I)${PREFIX[1]}?]#?}" \
		    "${PREFIX}${(@k)^dopts[(I)${PREFIX[1]}?]#?}" \
		    "${PREFIX}${(@k)^odopts[(I)${PREFIX[1]}?]#?}" && ret=0
	  else
	    # The last option takes an argument in next word.
	    compadd "$expl[@]" -Q - "${PREFIX}" && ret=0
	  fi
	else
          compadd "$expl[@]" -Q - "${(@k)opts}" "${(@k)odopts}" && ret=0
	  compadd "$expl[@]" -QS '' - "${(@k)dopts}" && ret=0
        fi
      fi
      [[ $#long -ne 0 &&
         ( "$compconfig[option_prefix]" != *(long|all)* ||
           "$PREFIX" = --* ) ]] && \
	  _long_options "$long[@]" && ret=0
    fi
  fi

  # Now add the matches from the description, if any.

  if [[ -n "$def" ]]; then

    # Ignore the leading colon or `*...' describing optional arguments.

    if [[ "$def" = :* ]]; then
      def="$def[2,-1]"
    elif [[ "$def" = \** ]]; then
      tmp="${${(M)def#*[^\\]:}[2,-2]}"
      def="${def#*[^\\]:}"

      if [[ "$def" = :* ]]; then
        if [[ "$def" = ::* ]]; then
          def="$def[3,-1]"
	  beg=$argbeg
	else
	  def="$def[2,-1]"
	  beg=$optbeg
	fi

	shift beg words
	(( CURRENT -= beg ))

	if [[ -n "$tmp" ]]; then
          tmp="$words[(ib:CURRENT:)${~tmp}]"
	  [[ tmp -le $#words ]] && words=( "${(@)words[1,tmp-1]}" )
	fi
      fi
    fi

    # Get the description and the action.

    descr="${${${(M)def#*[^\\]:}[1,-2]}//\\\\:/:}"
    if [[ "$def" = *[^\\]:*[^\\]:* ]]; then
      action="${${${(M)${def#*[^\\]:}#*[^\\]:}[1,-2]}//\\\\:/:}"
    else
      action="${${def#*[^\\]:}//\\\\:/:}"
    fi

    _description expl "$descr"

    if [[ -z "$action" ]]; then

      # An empty action means that we should just display a message.
      _message "$descr"
      return ret
    elif [[ "$action" = \(*\) ]]; then

      # Anything inside `(...)' is added directly.

      compadd "$expl[@]" - ${=action[2,-2]}
    elif [[ "$action" = \{*\} ]]; then

      # A string in braces is evaluated.

      eval "$action[2,-2]"

    elif [[ "$action" = \ * ]]; then

      # If the action starts with a space, we just call it.

      ${(e)=~action}
    else

      # Otherwise we call it with the description-arguments built above.

      action=( $=action )
      ${(e)action[1]} "$expl[@]" ${(e)~action[2,-1]}
    fi
  fi

  # Set the return value.

  [[ nm -ne "$compstate[nmatches]" ]]
fi