#!/bin/sh
PROGNAME=`basename $0`

main()
{
    local SITEID

    if [ "X$1" = X ]; then
        cat /etc/motd
        exit 0
    elif [ "X$2" != X ]; then
        usage
    else
        SITEID="$1"
    fi

    case $SITEID in
        esoredcable|esoair|mythcable|mythair|standalone) : ;;
        *) usage ;;
    esac

    ##########################################################################
    #
    #  SHUTDOWN PHASE
    #
    ##########################################################################

    #  NFS mounts will hang if they remain when we restart networking in 
    #  such a way that the network is no longer accessible (e.g. only eth0
    #  up --> only dummy0 up.
    info "unmounting NFS filesystems ..."
    umount -a -t nfs
    #  AMD mount points show up as type 'nfs' but without the 'vers=3', and
    #  we are only concerned with *true* NFS mounts which will hang.
    ! mount | egrep ' nfs .*vers=' || error "failed to unmount all NFS mounts"

    info "shutting down services ..."
    ! pidof chronyd > /dev/null || /etc/init.d/chrony     stop
    /etc/init.d/am-utils   stop
    /etc/init.d/nis        stop
    #/etc/init.d/bind9      stop
    /etc/init.d/networking stop
    ifdown lo
   
    ##########################################################################
    #
    #  SWITCHOVER PHASE
    #
    ##########################################################################

    info "making configuration changes ..."
    switch_$SITEID
    
    ##########################################################################
    #
    #  STARTUP PHASE
    #
    ##########################################################################

    info "starting services ..."
    ifup lo
    /etc/init.d/networking start
    #/etc/init.d/bind9 start
    /etc/init.d/nis start
    /etc/init.d/am-utils start
    ! $RUN_CHRONYD || /etc/init.d/chrony start
}

usage()
{
    echo "Usage: $PROGNAME { esoredcable | esoair | mythcable | mythair | standalone }" >&2
    exit 1
}

switch_mythclient()
{
    local NIC
    NIC=$1

    nisserver graces.myth.net 
    autonics lo $NIC
    mythnetauthority false
    switchsym /pub amd.staging/graces-diska-pub
    switchsym /var/mail ../amd.staging/graces-diska-var-mail
    switchsym /usr/server ../amd.staging/graces-diska-usr-server
    firewall false
    RUN_CHRONYD=true
    switchmotd "$2"
}

switch_esoclient()
{
    local NIC NISSERVER DESC
    NIC=$1
    NISSERVER=$2
    DESC="$3"

    nisserver $NISSERVER
    autonics lo $NIC dummy0
    mythnetauthority true
    switchsym /pub amd.staging/leda-diska-pub
    switchsym /var/mail ../amd.staging/leda-diska-var-mail
    switchsym /usr/server ../amd.staging/leda-diska-usr-server
    firewall true
    RUN_CHRONYD=true
    switchmotd "$DESC"
}

switch_mythcable()
{
    switch_mythclient eth0 "Home LAN (cable)"
}

switch_mythair()
{
    switch_mythclient ath0 "Home LAN (wireless)"
}

switch_esoredcable()
{
    switch_esoclient eth0 leda.myth.net "ESO (red cable)"
}

switch_esoair()
{
    switch_esoclient ath0 leda.myth.net "ESO (wireless)"
}

switch_standalone()
{
    nisserver `hostname -f`
    autonics lo dummy0 
    mythnetauthority true
    switchsym /pub amd.staging/leda-diska-pub
    switchsym /var/mail ../amd.staging/leda-diska-var-mail
    firewall true
    RUN_CHRONYD=false
    switchmotd "Standalone"
}

nisserver()
{
    perl -pi -e "s/^(ypserver ).*/\$1$1/" /etc/yp.conf
}

autonics()
{
    perl -pi -e "s/^(auto ).*/\$1$*/" /etc/network/interfaces
}

mythnetauthority()
{
    local ISAUTHORITY

    ISAUTHORITY=$1

    cp /etc/bind/named.conf.local /tmp
    if $ISAUTHORITY; then
        sed '/^\/\/ zone/,/^\/\/ }/s/^\/\/ //' /tmp/named.conf.local > /etc/bind/named.conf.local
    else
        sed '/^zone/,/^}/s/^/\/\/ /' /tmp/named.conf.local > /etc/bind/named.conf.local
    fi
    rm -f /tmp/named.conf.local
}

switchmotd()
{
    local DESC
    [ "X$1" != X -a "X$2" = X ] || internal "switchmotd: usage error"

    perl -pi -e "s/(Current network config: ).*/\$1$1/" /etc/motd
}

switchsym()
{
    local LINK TARGET
    [ "X$2" != X -a "X$3" = X ] || internal "switchsym: usage error"
    LINK="$1"
    TARGET="$2"

    #  remove the link
    if [ -h $LINK ]; then
        rm -f $LINK
    elif [ -e $LINK ]; then
        error "$LINK: exists and is not symlink"
    fi
    
    #  recreate link
    ln -s $TARGET $LINK
}

firewall()
{
    local ENABLE
    [ "X$1" != X -a "X$2" = X ] || internal "firewall: usage error"
    ENABLE="$1"

    perl -pi -e "s/^(FIREWALL_FLAG=).*/\$1$ENABLE/" /etc/iptables.conf
}

error()
{
    echo "$PROGNAME: ERROR: $1" >&2
    exit 1
}

info()
{
    echo "$PROGNAME: INFO: $1" >&2
}

main "$@"