#!/bin/bash
#  $HeadURL$ $LastChangedRevision$
set -e
PROGNAME=$(basename $0)

#  Load support functions
. $(pcms-config PCMS_SHARE_PREFIX)/scripts/support.sh

main()
{
    #  Defaults for options
    VERBOSELEVEL=2
    OPT_FILE=			#  Can't set it to specific value because that is derived
    OPT_TOUCH=false

    #  Process options
    while [ $# -ge 1 ]; do
        case $1 in
            --file=*)        OPT_FILE=${1#*=} ;;
            --touch)         OPT_TOUCH=true ;;
            --debug=*)       VERBOSELEVEL=${1#*=} ;;
            -d)              VERBOSELEVEL=$2; shift ;;
            -v|--verbose)    VERBOSELEVEL=3 ;;
            --)              shift; break ;;
            -*)              error "main: $1: bad option" ;;
            *)               break ;;
        esac
        shift
    done

    #  Process arguments
    [ $# = 1 ] || usage
    eval set -- $(encode --decode "$1")
    [ $# -ge 2 ] || usage
    DEVICE="$1"
    METHOD="$2"
    shift 2

    #  Sanity checks and derivations
    [[ $DEVICE =~ ^((eth|br|wlan|dummy|eno)[0-6]|lo)$  ]] || error "$DEVICE: invalid device"
    [[ $METHOD =~ ^(loopback|static|dhcp|nm|manual|external)$  ]] || error "$METHOD: invalid method"

    method_$METHOD "$@"
}

method_loopback()
{
    [ $# -eq 0 ] || usage

    debug 10 "loopback: DEVICE=$DEVICE"
    ifdown --force $DEVICE 2> /dev/null || true
    sleep 2
    ifconfig $DEVICE down 2>/dev/null || true
    sleep 2
    echo -e "auto $DEVICE\niface $DEVICE inet loopback\n" > ${OPT_FILE:-/etc/network/interfaces.d/$DEVICE}
    ifup $DEVICE
}

method_static()
{
    [ $# -ge 3 ] || usage
    IPADDR=$1
    NETMASK=$2
    GATEWAY_FLAG=$3
    [[ $GATEWAY_FLAG =~ ^(true|false)$ ]] || error "$GATEWAY_FLAG: invalid gateway flag"
    if $GATEWAY_FLAG; then
        [ $# = 4 ] || usage
        GATEWAY_IPADDR=$4
    else
        [ $# = 3 ] || usage
    fi

    debug 10 "method_static: DEVICE=$DEVICE, METHOD=$METHOD, IPADDR=$IPADDR, NETMASK=$NETMASK, GATEWAY_FLAG=$GATEWAY_FLAG"
    ifdown --force $DEVICE 2> /dev/null || true
    sleep 2
    ifconfig $DEVICE down 2>/dev/null || true
    sleep 2
    if $GATEWAY_FLAG; then
        echo -e "auto $DEVICE\niface $DEVICE inet $METHOD\n    address $IPADDR\n    netmask $NETMASK\n    gateway $GATEWAY_IPADDR\n" > ${OPT_FILE:-/etc/network/interfaces.d/$DEVICE}
    else
        echo -e "auto $DEVICE\niface $DEVICE inet $METHOD\n    address $IPADDR\n    netmask $NETMASK\n" > ${OPT_FILE:-/etc/network/interfaces.d/$DEVICE}
    fi
}

method_manual()
{
    [ $# = 0 ] || usage
    ifdown --force $DEVICE 2> /dev/null || true
    sleep 2
    ifconfig $DEVICE down 2>/dev/null || true
    sleep 2
    echo -e "iface $DEVICE inet $METHOD\n" > ${OPT_FILE:-/etc/network/interfaces.d/$DEVICE}
}

method_external()
{
    [ $# = 0 ] || usage
    ifdown --force $DEVICE 2> /dev/null || true
    sleep 2
    ifconfig $DEVICE down 2>/dev/null || true
    sleep 2
    
    echo -e "#  $DEVICE defined in a different file (probably because it's complicated.\nsource /etc/network/interfaces.d/$DEVICE\n" > ${OPT_FILE:-/etc/network/interfaces.d/$DEVICE}
}

usage() { echo "Usage: $PROGNAME [ --file=<file> ] <device>@<method>[@<ipaddr>@<netmask>@<gateway-flag>[@<gateway-ipaddr]]" >&2; exit 1; }

main "$@"