#!/bin/sh

########################################################################
PGRM=$(basename $0)

SHAREDIR=${SHAREDIR:-"/usr/share/monkeysphere"}
export SHAREDIR
. "${SHAREDIR}/common"

# date in UTF format if needed
DATE=$(date -u '+%FT%T')

# unset some environment variables that could screw things up
GREP_OPTIONS=

########################################################################
# FUNCTIONS
########################################################################

usage() {
cat <<EOF
usage: $PGRM <subcommand> [args]
Monkeysphere server admin tool.

subcommands:
  update-users (s) [USER]...                update authorized_keys file
  gen-key (g)                               generate gpg key for the host
  publish-key (p)                           publish host gpg to keyserver
  trust-key (t) KEYID [KEYID]...            mark keyid as trusted
  update-user-userid (u) USER UID [UID]...  add/update userid for user
  help (h,?)                                this help

EOF
}

# generate server gpg key
gen_key() {
    KEY_TYPE=${KEY_TYPE:-RSA}
    KEY_LENGTH=${KEY_LENGTH:-2048}
    KEY_USAGE=${KEY_USAGE:-encrypt,auth}
    SERVICE=${SERVICE:-ssh}
    HOSTNAME_FQDN=${HOSTNAME_FQDN:-$(hostname -f)}

    USERID=${USERID:-"$SERVICE"://"$HOSTNAME_FQDN"}

    echo "key parameters:"
    cat <<EOF
Key-Type: $KEY_TYPE
Key-Length: $KEY_LENGTH
Key-Usage: $KEY_USAGE
Name-Real: $USERID
EOF

    read -p "generate key? [Y|n]: " OK; OK=${OK:=Y}
    if [ ${OK/y/Y} != 'Y' ] ; then
	failure "aborting."
    fi

    if gpg --list-key ="$USERID" > /dev/null 2>&1 ; then
	failure "key for '$USERID' already exists"
    fi

    echo "generating server key..."
    gpg --batch --gen-key <<EOF
Key-Type: $KEY_TYPE
Key-Length: $KEY_LENGTH
Key-Usage: $KEY_USAGE
Name-Real: $USERID
%commit
EOF
}

# publish server key to keyserver
publish_key() {
    read -p "publish key to $KEYSERVER? [Y|n]: " OK; OK=${OK:=Y}
    if [ ${OK/y/Y} != 'Y' ] ; then
	failure "aborting."
    fi

    keyID=$(gpg --list-key --with-colons ="$USERID" 2> /dev/null | grep '^pub:' | cut -d: -f5)

    # dummy command so as not to publish fakes keys during testing
    # eventually:
    #gpg --send-keys --keyserver "$KEYSERVER" "$keyID"
    echo "gpg --send-keys --keyserver $KEYSERVER $keyID"
}

# trust key
trust_key() {
    for keyID ; do
	# get the key from the key server
	gpg --keyserver "$KEYSERVER" --recv-key "$keyID" || failure "could not retrieve key '$keyID'"

	# edit the key to change trust
	# FIXME: need to figure out how to automate this,
	# in a batch mode or something.
	gpg --edit-key "$keyID"
    done
}

########################################################################
# MAIN
########################################################################

COMMAND="$1"
[ "$COMMAND" ] || failure "Type '$PGRM help' for usage."
shift

# set ms home directory
MS_HOME=${MS_HOME:-"$ETC"}

# load configuration file
MS_CONF=${MS_CONF:-"$MS_HOME"/monkeysphere-server.conf}
[ -e "$MS_CONF" ] && . "$MS_CONF"

# set empty config variable with defaults
GNUPGHOME=${GNUPGHOME:-"$MS_HOME"/gnupg}
KEYSERVER=${KEYSERVER:-subkeys.pgp.net}
REQUIRED_KEY_CAPABILITY=${REQUIRED_KEY_CAPABILITY:-"e a"}
USER_CONTROLLED_AUTHORIZED_KEYS=${USER_CONTROLLED_AUTHORIZED_KEYS:-%h/.ssh/authorized_keys}
STAGING_AREA=${STAGING_AREA:-"$LIB"/stage}

export GNUPGHOME

# make sure gpg home exists with proper permissions
mkdir -p -m 0700 "$GNUPGHOME"

case $COMMAND in
    'update-users'|'s')
	if [ "$1" ] ; then
	    unames="$@"
	else
	    unames=$(ls -1 "$MS_HOME"/authorized_user_ids)
	fi

	for uname in $unames ; do
	    MODE="authorized_keys"
	    authorizedUserIDs="$MS_HOME"/authorized_user_ids/"$uname"
	    cacheDir="$STAGING_AREA"/"$uname"/user_keys
	    msAuthorizedKeys="$STAGING_AREA"/"$uname"/authorized_keys

            # make sure authorized_user_ids file exists
	    if [ ! -s "$authorizedUserIDs" ] ; then
		log "authorized_user_ids file for '$uname' is empty or does not exist."
		continue
	    fi

	    log "processing authorized_keys for user '$uname'..."

	    process_authorized_ids "$authorizedUserIDs" "$cacheDir"

            # write output key file
	    log "writing monkeysphere authorized_keys file... "
	    touch "$msAuthorizedKeys"
	    if [ "$(ls "$cacheDir")" ] ; then
		log -n "adding gpg keys... "
		cat "$cacheDir"/* > "$msAuthorizedKeys"
		echo "done."
	    else
		log "no gpg keys to add."
	    fi
	    if [ "$USER_CONTROLLED_AUTHORIZED_KEYS" ] ; then
		userHome=$(getent passwd "$uname" | cut -d: -f6)
		userAuthorizedKeys=${USER_CONTROLLED_AUTHORIZED_KEYS/\%h/"$userHome"}
		if [ -s "$userAuthorizedKeys" ] ; then
		    log -n "adding user authorized_keys file... "
		    cat "$userAuthorizedKeys" >> "$msAuthorizedKeys"
		    echo "done."
		fi
	    fi
	    log "monkeysphere authorized_keys file generated:"
	    log "$msAuthorizedKeys"
	done
	;;

    'gen-key'|'g')
	gen_key
	;;

    'publish-key'|'p')
	publish_key
	;;

    'trust-key'|'t')
	if [ -z "$1" ] ; then
	    failure "you must specify at least one key to trust."
	fi
	trust_key "$@"
	;;

    'update-user-userid'|'u')
	uname="$1"
	shift
	if [ -z "$uname" ] ; then
	    failure "you must specify user."
	fi
	if [ -z "$1" ] ; then
	    failure "you must specify at least one userid."
	fi
	for userID ; do
	    AUTHORIZED_USER_IDS="$MS_HOME"/authorized_user_ids/"$uname"
	    if ! grep -q "^${userID}\$" "$AUTHORIZED_USER_IDS" ; then
		log "userid '$userID' not in authorized_user_ids file."
		continue
	    fi
	    log "processing user id: '$userID'"
	    process_user_id "$userID" "$userKeysCacheDir" > /dev/null
	done
	;;

    'help'|'h'|'?')
        usage
        ;;

    *)
        failure "Unknown command: '$COMMAND'
Type 'cereal-admin help' for usage."
        ;;
esac