#!/bin/sh

usage="\
pex is a PostgreSQL package manager.

Usage:
  pex audit [PACKAGE]...
  pex cat PACKAGE...
  pex create -n NAME URL
  pex debuild PACKAGE
  pex edit [PACKAGE]...
  pex fetch PACKAGE...
  pex home [PACKAGE]...
  pex info PACKAGE...
  pex init [REPO]
  pex install PACKAGE
  pex ls|list
  pex outdated
  pex repotest
  pex rpmbuild PACKAGE
  pex search [SUBSTRING]
  pex update [--rebase]
  pex upgrade [PACKAGE]...
"

PEX_HOMEPAGE='https://github.com/petere/pex'
PEX_DEFAULT_REMOTE='https://github.com/petere/pex-packages.git'

set -eu

: ${HOME=~}
: ${XDG_DATA_HOME=$HOME/.local/share}
: ${XDG_CONFIG_HOME=$HOME/.config}
: ${XDG_CACHE_HOME=$HOME/.cache}

LC_COLLATE=C
export LC_COLLATE

exec 6>&1

error() {
	echo "pex: $@" 1>&2
	exit 1
}

output() {
	echo "==> $@" 1>&6
}

assert() {
	if test "$@"; then
		:
	else
		set +u
		if test -n "$BASH"; then
			error "assertion failed: $@ (${FUNCNAME[1]})"
		else
			error "assertion failed: $@"
		fi
	fi
}


data_dir=$XDG_DATA_HOME/pex
packages_dir=$data_dir/packages
work_dir=$XDG_CACHE_HOME/pex


if which gmake >/dev/null 2>&1; then
	gnumake=gmake
else
	gnumake=make
fi

if which shasum >/dev/null 2>&1; then
	sha1sum=shasum
else
	sha1sum=sha1sum
fi


cmd_audit() {
	local pkg all_packages

	if [ $# -gt 0 ]; then
		for pkg; do
			_audit_one "$pkg"
		done
	else
		all_packages=$(_all_packages)
		for pkg in $all_packages; do
			_audit_one "$pkg"
		done
	fi
	output "Looks good"
}


cmd_cat() {
	local pkg package_file

	if [ $# -eq 0 ]; then
		error '"cat" takes at least one argument'
	fi

	for pkg; do
		package_file=$(_package_file "$pkg")
		cat "$package_file"
	done
}


cmd_edit() {
	local file files

	files=''

	if [ $# -eq 0 ]; then
		set $(cmd_search)
	fi
	for pkg; do
		file=$(_package_file "$pkg")
		files="$files $file"
	done

	_editor $files
}


cmd_create() {
	local downloaded_sha1 package_file pkg target url

	pkg=''

	while getopts 'n:' opt; do
		case $opt in
			n)
				pkg=$OPTARG;;
			*)
				exit 1;;
		esac
	done
	shift $(($OPTIND - 1))

	if [ $# -ne 1 ]; then
		error '"create" takes exactly one nonoption argument'
	fi

	# TODO: optionally autodetect name
	if [ -z "$pkg" ]; then
		error "name must be specified (-n)"
	fi

	if [ -e "$packages_dir/$pkg.yaml" ]; then
		error "package \"$pkg\" already exists (use \"pex edit\" to change it)"
	fi

	url=$1
	target=$(_download_target "$pkg" "$url")
	download "$url" "$target"
	downloaded_sha1=$(_sha1 "$target")
	package_file=$(_package_file "$pkg" true)
	cat <<EOF >"$package_file"
homepage: FIXME
url: $url
sha1: $downloaded_sha1
EOF
	cmd_edit "$pkg"
	echo "Use \"pex audit $pkg\" to check the package description."
}


cmd_debuild() {
	local homepage pgmajorversion pgversion pkg

	pkg=$1
	shift

	pgversion=$("$pg_config" --version)
	pgmajorversion=$(expr "$pgversion" : '^.* \([0-9][0-9]*\.[0-9][0-9]*\)')

	package_file=$(_package_file "$pkg")
	homepage=$(parse_yaml_field "$package_file" homepage)
	package_version=$(_package_version "$pkg")

	target=$(_fetch_one "$pkg")

	rm -rf "$work_dir/$pkg/debuild"
	mkdir -p "$work_dir/$pkg/debuild"

	(
		cd "$work_dir/$pkg/debuild"
		output "Unpacking $pkg"
		unpack "$target"
		ln -s $target ${pkg}_${package_version}.orig.tar.gz  # FIXME
		cd "$pkg"*  # FIXME
		rm -rf debian/
		mkdir debian
		echo 9 >debian/compat
		mkdir debian/source
		case $target in
			*.zip) echo '3.0 (native)' >debian/source/format;;
			*) echo '3.0 (quilt)' >debian/source/format;;
		esac
		: ${DEBFULLNAME=${NAME=$(getent passwd $(whoami) | cut -d : -f 5)}}
		: ${DEBEMAIL=${EMAIL=$(whoami)@$(hostname --fqdn)}}
		cat <<EOF >debian/control
Source: $pkg
Section: database
Priority: extra
Maintainer: $DEBFULLNAME <$DEBEMAIL>
Build-Depends: debhelper (>= 9), postgresql-server-dev-$pgmajorversion
Standards-Version: 3.9.3
Homepage: $homepage

Package: postgresql-$pgmajorversion-$pkg
Architecture: any
Depends: postgresql-$pgmajorversion, \${misc:Depends}, \${shlibs:Depends}
Description: $pkg
 This package of $pkg was automatically generated by pex.
EOF
		dch --create --package="$pkg" --newversion="${package_version}-1pex" 'Automatic changelog entry'
		dch -r -D pex --force-distribution ''
		cat <<EOF >debian/rules
#!/usr/bin/make -f

export PG_CONFIG = $pg_config
export USE_PGXS = 1

%:
	dh \$@

override_dh_auto_test: ;
EOF
		chmod a+x debian/rules
		output "Building Debian package $pkg"
		debuild --no-lintian "$@"
	) || exit
	output "Build results are in $work_dir/$pkg/debuild/"
}


cmd_fetch() {
	local pkg

	for pkg; do
		_fetch_one "$pkg" >/dev/null
	done
}


cmd_home() {
	local homepage homepages package_file pkg

	homepages=''

	if [ $# -gt 0 ]; then
		for pkg; do
			package_file=$(_package_file "$pkg")
			homepage=$(parse_yaml_field "$package_file" homepage)
			homepages="$homepages $homepage"
		done
	else
		homepages=$PEX_HOMEPAGE
	fi

	_browser $homepages
}


cmd_info() {
	local pkg

	if [ $# -eq 0 ]; then
		error '"info" takes at least one argument'
	fi

	for pkg; do
		_info_one "$pkg"
	done
}


cmd_init() {
	local remote

	if [ $# -eq 0 ]; then
		remote=$PEX_DEFAULT_REMOTE
	elif [ $# -eq 1 ]; then
		remote=$1
	else
		error '"init" takes zero or one arguments'
	fi
	mkdir -p "$data_dir"
	(
		cd "$data_dir"
		git clone -q $remote packages
	)
}


cmd_install() {
	local pkg if_not_exists

	if [ $# -gt 0 ] && [ x"$1" = x'--if-not-exists' ]; then
		if_not_exists=true
		shift
	else
		if_not_exists=false
	fi

	if [ $# -eq 0 ]; then
		error '"install" takes at least one argument'
	fi

	for pkg in "$@"; do
		_install_one "$pkg" false $if_not_exists
	done
}


cmd_list() {
	local installed_dir

	if [ $# -gt 0 ]; then
		error '"list" takes no arguments'
	fi

	installed_dir=$(_installed_dir)
	if [ ! -d "$installed_dir" ]; then
		return
	fi

	(
		cd "$installed_dir"
		ls -1 *.yaml 2>/dev/null | sed 's/\.yaml$//' | sort
	)

}


cmd_outdated() {
	local installed_dir installed_file pkg

	if [ $# -gt 0 ]; then
		error '"outdated" takes no arguments'
	fi

	installed_dir=$(_installed_dir)
	if [ ! -d "$installed_dir" ]; then
		return
	fi

	for installed_file in $(find "$installed_dir" -name "*.yaml" -print); do
		pkg=$(basename "$installed_file" .yaml)
		if _is_outdated "$pkg"; then
			echo "$pkg"
		fi
	done
}


cmd_repotest() {
	local i out pkg ret

	set $(cmd_search)
	echo "1..$#"
	ret=0
	i=0
	for pkg; do
		i=$(($i + 1))
		status=0
		out=$(_fetch_one "$pkg" 2>&1 6>&1) || status=$?
		if [ $status -eq 0 ]; then
			echo "ok $i $pkg"
		else
			echo "not ok $i $pkg"
			echo "$out" | grep -E -v '#+ 100\.0%' | sed 's/^/    # /'
			ret=1
		fi
	done
	exit $ret
}


cmd_rpmbuild() {
	local homepage package_file package_version pkg

	pkg=$1
	shift

	pgrpmname=$(rpm -q -f "$pg_config" --queryformat '%{NAME}') || error "$pgrpmname"
	test -n "$pgrpmname"

	package_file=$(_package_file "$pkg")
	homepage=$(parse_yaml_field "$package_file" homepage)
	package_version=$(_package_version "$pkg")

	target=$(_fetch_one "$pkg")
	target_basename=$(basename $target)

	rm -rf "$work_dir/$pkg/rpmbuild"
	mkdir -p "$work_dir/$pkg/rpmbuild"

	cat <<EOF >$work_dir/$pkg/rpmbuild/$pkg.spec
Name:           $pgrpmname-$pkg
Version:        $package_version
Release:        1%{?dist}
Summary:        $pkg
Group:          Databases
License:        unknown
URL:            $homepage
Source:         $target_basename

BuildRequires:  $pgrpmname

BuildRoot:      %{_tmppath}/%{name}-%{version}-%{release}-root-%(%{__id_u} -n)

%description
This package of $pkg was automatically generated by pex.

%prep
%setup -q -n $pkg-%{version}

%build
make %{?_smp_mflags} USE_PGXS=1 PG_CONFIG=$pg_config

%install
make %{?_smp_mflags} USE_PGXS=1 PG_CONFIG=$pg_config install DESTDIR=\$RPM_BUILD_ROOT

%clean
rm -rf \$RPM_BUILD_ROOT

%files
%defattr(-,root,root,-)
/
EOF

	rpm_sourcedir=$(rpmbuild -E '%_sourcedir' "$work_dir/$pkg/rpmbuild/$pkg.spec" 2>/dev/null || :)
	mkdir -p "$rpm_sourcedir"
	ln -sf "$target" "$rpm_sourcedir"

	output "Building RPM package $pkg"
	rpmbuild "$work_dir/$pkg/rpmbuild/$pkg.spec" "$@"
}


cmd_search() {
	if [ $# -gt 1 ]; then
		error '"search" takes zero or one arguments'
	fi
	(
		cd "$packages_dir"
		if [ $# -gt 0 ]; then
			(
				local a search

				search=$1

				ls -1 *"$search"*.yaml 2>/dev/null | sed 's/\.yaml$//'
				for a in $(sed -n 's/^aliases: *//p' *.yaml | tr -s ' ' '\n'); do
					case $a in *"$search"*) echo $a;; esac
				done
			) | sort -u
		else
			ls -1 *.yaml 2>/dev/null | sed 's/\.yaml$//' | sort -u
		fi
	)
}


cmd_update() {
	local changes
	(
		cd "$packages_dir"
		git pull -n "$@"
		changes=$(git diff ORIG_HEAD..HEAD --name-status *.yaml | sed 's/\.yaml$//')
		if echo "$changes" | grep -q '^A'; then
			output "New packages"
			echo "$changes" | sed -n 's/^A[[:space:]]*//p' | sort
		fi
		if echo "$changes" | grep -q '^M'; then
			output "Updated packages"
			echo "$changes" | sed -n 's/^M[[:space:]]*//p' | sort
		fi
	)
}


cmd_upgrade() {
	local pkg

	if [ $# -gt 0 ]; then
		for pkg; do
			_upgrade_one "$pkg"
		done
	else
		for pkg in $(cmd_list); do
			_upgrade_one "$pkg"
		done
	fi
}


_all_packages() {
	assert $# -eq 0
	(
		cd "$packages_dir"
		ls -1 *.yaml 2>/dev/null | sed 's/\.yaml$//' | sort
	)
}


_browser() {
	assert $# -ge 1

	set +u
	if [ -n "$BROWSER" ]; then
		$BROWSER "$@"
	elif [ $(uname -s) = 'Darwin' ]; then
		open "$@"
	elif which xdg-open >/dev/null 2>&1; then
		xdg-open "$@"
	elif which sensible-browser >/dev/null 2>&1; then
		sensible-browser "$@"
	else
		error "cannot find a suitable browser"
	fi
	set -u
}


_editor() {
	assert $# -gt 0

	set +u
	if [ -n "$EDITOR" ]; then
		$EDITOR "$@"
	elif which sensible-editor >/dev/null 2>&1; then
		sensible-editor "$@"
	else
		vi "$@"
	fi
	set -u
}


_installed_dir() {
	local pgsharedir

	pgsharedir=$("$pg_config" --sharedir)
	echo "$pgsharedir/pex/installed"
}


_package_file() {
	local filename pkg ignore_missing

	assert $# -eq 1 -o $# -eq 2
	pkg=$1
	ignore_missing=false
	if [ $# -ge 2 ]; then
		ignore_missing=$2
	fi

	if [ ! -d "$packages_dir" ]; then
		error "packages directory \"$packages_dir\" does not exist (Did you run \"pex init\"?)"
	fi
	filename="$packages_dir/$pkg.yaml"

	# resolve aliases
	if [ ! -f "$filename" ]; then
		res=$(grep -l '^aliases:.*\b'"$pkg"'\b' "$packages_dir"/*.yaml || [ $? -eq 1 ])
		if [ $(echo "$res" | wc -l) -gt 1 ]; then
			error "too many aliases: $res"
		fi
		if [ -n "$res" ]; then
			filename=$res
		fi
	fi

	if [ ! -f "$filename" ] && ! $ignore_missing; then
		error "package \"$pkg\" does not exist"
	fi
	echo "$filename"
}


_package_version() {
	local pkg package_file

	pkg=$1
	package_file=$(_package_file "$pkg")
	url=$(parse_yaml_field "$package_file" url)
	base=$(basename "$url")
	without_ext=$(echo "$base" | sed 's/\.[^.]*$//;s/\.tar//')

	case $without_ext in
		*-*)
			version=$(echo "$without_ext" | sed 's/^.*-//');;
		*_*)
			version=$(echo "$without_ext" | sed 's/^.*_//');;
		[0-9]*)
			version=$without_ext;;
		*)
			error "cannot detect version from \"$without_ext\"";;
	esac

	echo "$version" | sed 's/^v//'
}


_audit_one() {
	local homepage package_file package_name pkg

	assert $# -eq 1
	pkg=$1

	package_file=$(_package_file "$pkg")
	package_name=$(basename "$package_file" .yaml)

	output "Auditing $package_name"

	perl -MYAML -e 'use YAML;YAML::LoadFile("'"$package_file"'")'
	homepage=$(parse_yaml_field "$package_file" homepage)
	parse_yaml_field "$package_file" url >/dev/null
	parse_yaml_field "$package_file" sha1 >/dev/null

	if [ "$homepage" = FIXME ] || [ -z "$homepage" ]; then
		error "homepage field not filled in correctly"
	fi
}


_fetch_one() {
	local downloaded_sha1 package_file pkg sha1 target url

	assert $# -eq 1
	pkg=$1

	package_file=$(_package_file "$pkg")
	url=$(parse_yaml_field "$package_file" url)
	sha1=$(parse_yaml_field "$package_file" sha1)

	target=$(_download_target "$pkg" "$url")

	if [ -f "$target" ] && [ $(_sha1 "$target") = "$sha1" ]; then
		output "Already downloaded $pkg"
	else
		download "$url" "$target"
		downloaded_sha1=$(_sha1 "$target")
		if [ "$downloaded_sha1" != "$sha1" ]; then
			error "SHA1 mismatch\nExpected: $sha1\nActual: $downloaded_sha1"
		fi
	fi
	echo "$target"
}


_download_target() {
	local ext pkg url

	assert $# -eq 2
	pkg=$1
	url=$2

	mkdir -p "$work_dir/$pkg/download"
	write_cachedir_tag "$work_dir"

	ext=$(canonical_archive_extension "$url")
	echo "$work_dir/$pkg/download/$pkg.$ext"
}


_info_one() {
	local homepage package_file package_name pkg status url package_installed_file

	assert $# -eq 1
	pkg=$1

	package_file=$(_package_file "$pkg")
	package_name=$(basename "$package_file" .yaml)
	homepage=$(parse_yaml_field "$package_file" homepage)
	url=$(parse_yaml_field "$package_file" url)
	package_installed_file="$(_installed_dir)/$package_name.yaml"

	if [ ! -e "$package_installed_file" ]; then
		status='not installed'
	elif _is_outdated "$package_name"; then
		status='outdated'
	else
		status='installed'
	fi

	echo "$package_name"
	echo "homepage: $homepage"
	echo "url: $url"
	echo "status: $status"
}


_install_one() {
	local allow_upgrade package_file pkg target if_not_exists installed_dir

	assert $# -eq 3
	pkg=$1
	allow_upgrade=$2
	if_not_exists=$3

	package_file=$(_package_file "$pkg")

	installed_dir=$(_installed_dir)
	if [ -e "$installed_dir/$(basename "$package_file")" ] && ! $allow_upgrade; then
		if $if_not_exists; then
			exit 0
		fi
		error "package \"$pkg\" is already installed"
	fi

	target=$(_fetch_one "$pkg")

	rm -rf "$work_dir/$pkg/build"
	mkdir -p "$work_dir/$pkg/build"
	write_cachedir_tag "$work_dir"

	(
		cd "$work_dir/$pkg/build"
		output "Unpacking $pkg"
		unpack "$target"
		dir=$(find . -maxdepth 1 -mindepth 1 -type d)
		if [ $(echo "$dir" | wc -l) -gt 1 ]; then
			error "too many directories: $dir"
		fi
		cd "$dir"
		output "Building $pkg"
		if [ -x configure ]; then
			./configure \
				--bindir=$("$pg_config" --bindir) \
				--includedir=$("$pg_config" --includedir) \
				--libdir=$("$pg_config" --libdir) \
				--with-pgconfig=$("$pg_config" --bindir)/pg_config \
				PG_CONFIG="$pg_config" || exit
		fi
		"$gnumake" all USE_PGXS=1 PG_CONFIG="$pg_config" || exit
		output "Installing $pkg"
		$sudo "$gnumake" install USE_PGXS=1 PG_CONFIG="$pg_config" || exit
	) || exit

	$sudo mkdir -p "$installed_dir"
	$sudo cp "$package_file" "$installed_dir/"

	output "Package $pkg installed successfully"
}


_is_outdated() {
	local available_file available_sha1 installed_file installed_sha1 pkg

	assert $# -eq 1
	pkg=$1
	installed_file=$(_installed_dir)/$pkg.yaml

	installed_sha1=$(parse_yaml_field "$installed_file" sha1)
	available_file=$(_package_file "$pkg")
	if [ -e "$available_file" ]; then
		available_sha1=$(parse_yaml_field "$available_file" sha1)
		if [ "$installed_sha1" != "$available_sha1" ]; then
			return 0
		fi
	else
		return 0
	fi
	return 1
}


_sha1() {
	assert $# -eq 1
	"$sha1sum" "$1" | cut -d ' ' -f 1
}


_upgrade_one() {
	local installed_sha1 new_sha1 package_file package_name pkg installed_dir

	assert $# -eq 1
	pkg="$1"

	package_file=$(_package_file "$pkg")
	package_name=$(basename "$package_file" .yaml)

	installed_dir=$(_installed_dir)
	if [ ! -e "$installed_dir/$package_name.yaml" ]; then
		error "package \"$pkg\" is not installed"
	fi

	installed_sha1=$(parse_yaml_field "$installed_dir/$package_name.yaml" sha1)
	new_sha1=$(parse_yaml_field "$package_file" sha1)

	if [ "$installed_sha1" = "$new_sha1" ]; then
		output "Package $package_name already up to date"
		return
	fi

	_install_one "$pkg" true false
}


parse_yaml_field() {
	local field file val

	assert $# -eq 2
	file=$1
	field=$2

	val=$(cat "$file" | sed -n "s/^${field}: *//p")

	if [ -z "$val" ]; then
		error "field \"$field\" missing in file \"$file\""
	fi

	echo "$val"
}


canonical_archive_extension() {
	local file

	assert $# -eq 1
	file=$1

	case $file in
		*.zip)
			echo "zip";;
		*.tgz)
			echo "tar.gz";;
		*.tbz2)
			echo "tar.bz2";;
		*.tar.*)
			echo "$file" | sed 's,^.*\.\(tar\..*\)$,\1,';;
	esac
}


download() {
	local ext target url

	assert $# -eq 2
	url=$1
	target=$2
	ext=$(canonical_archive_extension "$target")

	output "Downloading $pkg from $url"
	curl --progress-bar --location -o "$target" "$url"
}


unpack() {
	local ext file

	assert $# -eq 1
	file=$1
	ext=$(canonical_archive_extension "$file")

	# FIXME: check directory structure
	case $ext in
		zip)
			unzip "$file";;
		tar.*)
			tar xvf "$file";;
		*)
			error "unsupported archive format: $file";;
	esac
}


write_cachedir_tag() {
	local dir

	assert $# -eq 1
	dir=$1

	if [ -e "$dir/CACHEDIR.TAG" ]; then
		return
	fi

	cat >$dir/CACHEDIR.TAG <<EOF
Signature: 8a477f597d28d172789f06886806bc55
# This file is a cache directory tag created by pex.
# For information about cache directory tags, see:
#	http://www.brynosaurus.com/cachedir/
EOF
}


_pg_config_from_datadir() {
	local out

	assert $# -eq 1
	# XXX doesn't handle spaces in installation directory name
	out=$(sed -n 's,^\([^ ]*/\)postgres.*$,\1/pg_config,p' "$1/postmaster.opts")
	if [ -z "$out" ]; then
		error "unrecognized file contents in \"$1/postmaster.opts\""
	fi
	echo "$out"
}


psql() {
	command psql -X "$@"
}


if [ $# -eq 0 ]; then
	error "usage: pex COMMAND [PACKAGE] (try \" --help\")"
fi

case $1 in
	--help|-\?)
		echo "$usage"; exit 0;;
	--cache)
		echo "$work_dir"; exit 0;;
	--repo|--repository)
		echo "$packages_dir"; exit 0;;
esac


pg_config=
sudo=

while getopts 'd:Dg:Gp:PS' opt; do
	case $opt in
		g)
			if [ -d "$OPTARG" ] && [ -e "$OPTARG/bin/pg_config" ]; then
				pg_config=$OPTARG/bin/pg_config
			elif [ -d "$OPTARG" ] && [ -e "$OPTARG/pg_config" ]; then
				pg_config=$OPTARG/pg_config
			else
				pg_config=$OPTARG
			fi
			;;
		G)
			pg_config=
			;;
		d)
			pg_config=$(_pg_config_from_datadir "$OPTARG")
			;;
		D)
			pg_config=$(_pg_config_from_datadir "$PGDATA")
			;;
		p)
			pgdata=$(psql -At -d postgres -p "$OPTARG" -c 'show data_directory')
			pg_config=$(_pg_config_from_datadir "$pgdata")
			;;
		P)
			pgdata=$(psql -At -d postgres -c 'show data_directory')
			pg_config=$(_pg_config_from_datadir "$pgdata")
			;;
		S)
			sudo=sudo
			;;
		*)
			exit 1
			;;
	esac
done

shift $(($OPTIND - 1))

if [ -z "$pg_config" ]; then
	pg_config=pg_config
else
	# convert to absolute path
	_pg_config_dir=$(dirname "$pg_config")
	_pg_config_base=$(basename "$pg_config")
	_pg_config_dir=$(cd "$_pg_config_dir" && pwd)
	pg_config=$_pg_config_dir/$_pg_config_base
fi


command=$1
shift

case $command in
	audit)
		cmd_audit "$@";;
	cat)
		cmd_cat "$@";;
	create)
		cmd_create "$@";;
	debuild)
		cmd_debuild "$@";;
	edit)
		cmd_edit "$@";;
	fetch)
		cmd_fetch "$@";;
	home)
		cmd_home "$@";;
	info)
		cmd_info "$@";;
	init)
		cmd_init "$@";;
	install)
		cmd_install "$@";;
	ls|list)
		cmd_list "$@";;
	outdated)
		cmd_outdated "$@";;
	repotest)
		cmd_repotest "$@";;
	rpmbuild)
		cmd_rpmbuild "$@";;
	search)
		cmd_search "$@";;
	update)
		cmd_update "$@";;
	upgrade)
		cmd_upgrade "$@";;
	help)
		echo "$usage";;
	*)
		error "invalid command: $command";;
esac