shopt -s extglob

_hg_commands()

{

    local all commands result

    all=($(hg --debug help | sed -e '1,/^list of commands:/d' \

				 -e '/^global options:/,$d' \

				 -e '/^ [^ ]/!d; s/^ //; s/[,:]//g;'))

    commands="${all[*]##debug*}"

    result=$(compgen -W "$commands" -- "$cur")

    # hide debug commands from users, but complete them if

    # there is no other possible command

    if [ "$result" = "" ]; then

	local debug

	debug=(${all[*]##!(debug*)})

	debug="${debug[*]/g/debug}"

	result=$(compgen -W "$debug" -- "$cur")

    fi

    COMPREPLY=(${COMPREPLY[@]:-} $result)

}

_hg_paths()

{

    local paths="$(hg paths | sed -e 's/ = .*$//')"

    COMPREPLY=(${COMPREPLY[@]:-} $( compgen -W "$paths" -- "$cur" ))

}

_hg_repos()

{

    local i

    for i in $( compgen -d -- "$cur" ); do

        test ! -d "$i"/.hg || COMPREPLY=(${COMPREPLY[@]:-} "$i")

    done

}

_hg_status()

{

    COMPREPLY=(${COMPREPLY[@]:-} $( compgen -W "$files" -- "$cur" ))

}

_hg_tags()

{

    local tags="$(hg tags | sed -e 's/[0-9]*:[a-f0-9]\{40\}$//; s/ *$//')"

    COMPREPLY=( ${COMPREPLY[@]:-} $(compgen -W "$tags" -- "$cur") )

}

# this is "kind of" ugly...

_hg_count_non_option()

{

    local i count=0

    local filters="$1"

    for (( i=1; $i<=$COMP_CWORD; i++ )); do

	if [[ "${COMP_WORDS[i]}" != -* ]]; then

	    if [[ ${COMP_WORDS[i-1]} == @($filters|$global_args) ]]; then

		continue

	    fi

	    count=$(($count + 1))

	fi

    done

    echo $(($count - 1))

}

_hg()

{

    local cur prev cmd opts i

    # global options that receive an argument

    local global_args='--cwd|-R|--repository'

    COMPREPLY=()

    cur="$2"

    prev="$3"

    # searching for the command

    # (first non-option argument that doesn't follow a global option that

    #  receives an argument)

    for (( i=1; $i<=$COMP_CWORD; i++ )); do

	if [[ ${COMP_WORDS[i]} != -* ]]; then

	    if [[ ${COMP_WORDS[i-1]} != @($global_args) ]]; then

		cmd="${COMP_WORDS[i]}"

		break

	    fi

	fi

    done

    if [[ "$cur" == -* ]]; then

	# this assumes that there are no commands with spaces in the name

	opts=$(hg -v help $cmd | sed -e '/^ *-/!d; s/ [^- ].*//')

	COMPREPLY=( ${COMPREPLY[@]:-} $(compgen -W "$opts" -- "$cur") )

	return

    fi

    # global options

    case "$prev" in

	-R|--repository)

	    _hg_repos

	    return

	;;

	--cwd)

	    # Stick with default bash completion

	    return

	;;

    esac

    if [ -z "$cmd" ] || [ $COMP_CWORD -eq $i ]; then

	_hg_commands

	return

    fi

    # canonicalize command name

    cmd=$(hg -q help "$cmd" | sed -e 's/^hg //; s/ .*//; 1q')

    if [ "$cmd" != status ] && [ "$prev" = -r ] || [ "$prev" = --rev ]; then

	_hg_tags

	return

    fi

    case "$cmd" in

	help)

	    _hg_commands

	;;

	export|manifest|update)

	    _hg_tags

	;;

	pull|push|outgoing|incoming)

	    _hg_paths

	    _hg_repos

	;;

	paths)

	    _hg_paths

	;;

	add)

	    _hg_status "u"

	;;

	commit)

	;;

	remove)

	;;

	forget)

	    _hg_status "a"

	;;

	diff)

	;;

	revert)

	;;

	clone)

	    local count=$(_hg_count_non_option)

	    if [ $count = 1 ]; then

		_hg_paths

	    fi

            _hg_repos

	;;

	debugindex|debugindexdot)

	    COMPREPLY=(${COMPREPLY[@]:-} $( compgen -f -X "!*.i" -- "$cur" ))

	;;

	debugdata)

	    COMPREPLY=(${COMPREPLY[@]:-} $( compgen -f -X "!*.d" -- "$cur" ))

	;;

    esac

}

complete -o bashdefault -o default -F _hg hg 2> /dev/null \

    || complete -o default -F _hg hg