_hg_commands()

{

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

                                       -e '/^global options:/Q' \

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

    # hide debug commands from users, but complete them if 

    # specifically asked for

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

	commands="$commands debugcheckstate debugstate debugindex"

	commands="$commands debugindexdot debugwalk"

    fi

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

}

_hg_paths()

{

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

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

	    for f in $filters; do

		if [[ ${COMP_WORDS[i-1]} == $f ]]; then

		    continue 2

		fi

	    done

	    count=$(($count + 1))

	fi

    done

    echo $(($count - 1))

}

_hg()

{

    local cur prev cmd opts i

    COMPREPLY=()

    cur="$2"

    prev="$3"

    # searching for the command 

    # (first non-option argument that doesn't follow -R/--repository)

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

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

	   && [ "${COMP_WORDS[i-1]}" != -R ] \

	   && [ "${COMP_WORDS[i-1]}" != --repository ]; then

	    cmd="${COMP_WORDS[i]}"

	    break

	fi

    done

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

	opts="$(hg -v help | sed -e '1,/^global options/d; /^ -/!d')"

	if [ -n "$cmd" ]; then

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

	fi

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

	return

    fi

    if [ "$prev" = -R ] || [ "$prev" = --repository ]; then

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

	return

    fi

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

	_hg_commands

	return

    fi

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

	_hg_tags

	return

    fi

    case "$cmd" in

	help)

	    _hg_commands

	;;

	export|manifest|update|checkout|up|co)

	    _hg_tags

	;;

	pull|push)

	    _hg_paths

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

	;;

	paths)

	    _hg_paths

	;;

	clone)

	    local count=$(_hg_count_non_option)

	    if [ $count = 1 ]; then

		_hg_paths

	    fi

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

	;;

	cat)

	    local count=$(_hg_count_non_option -o --output)

	    if [ $count = 2 ]; then

		_hg_tags

	    else

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

	    fi

	;;

	*) 

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

	;;

    esac

}

complete -o filenames -F _hg hg