#!/bin/bash

guess_localnet () {
  local found=0
  for net in $( ip add show | grep 'inet ' | awk '{print $2}' ); do
    [[ "$net" =~ ^10\. ]] && found=1 && break
    [[ "$net" =~ ^192\.168\. ]] && found=1 && break
    [[ "$net" =~ ^172\.(1[6-9]|2[0-9]|3[12])\. ]] && found=1 && break
  done
  [ $found -eq 1 ] && echo $net
}

guess_wanip () {
  for net in $( ip add show | grep 'inet ' | awk '{print $2}' ); do
    [[ "$net" =~ ^127\.0\.0\.1 ]] && continue
    [[ "$net" =~ ^10\. ]] && continue
    [[ "$net" =~ ^192\.168\. ]] && continue
    [[ "$net" =~ ^172\.(1[6-9]|2[0-9]|3[12])\. ]] && continue
    break
  done
  echo ${net%/*}
}

guess_start_ip () {
    local netip=$1
    # TODO: see below
    echo "${netip%.*}.100"
}

get_ip_by_count () {
    local startip=$1
    local count=$2
    # TODO: adds support for classless addresses
    # Now assums that local network is /24 network for simplicity
    local ipnet=${startip%.*}
    local iphost=${startip##*.}
    echo "$ipnet.$((iphost+count))"
}



gen_dhcpd_conf () {
    local startip=$1
    local vmcount=$2
    
    echo "group rainbow {"
    for i in $( seq 0 $vmcount ); do
        i2=$( printf '%02d\n' "$i" )
        echo -e "\thost rainbow$i { hardware ethernet 52:54:00:c1:0d:$i2; fixed-address $( get_ip_by_count $startip $i ); }"
        if [ -n "$create_statedir" ]; then
            mkdir -p "$MAC_STATE_DIR/52:54:00:c1:0d:$i2"
        fi
    done
    echo "}"
}

gen_iptables_config_rdp () {
    local startip=$1
    local startport=$2
    local vmcount=$3
    local wanip=$4

    for i in $( seq 0 $vmcount ); do
        i2=$( printf '%02d\n' "$i" )
        vmip=$( get_ip_by_count $startip $i )
        vmport=$(( startport + i ))
        echo -e "-A PREROUTING  -d $wanip -m tcp -p tcp --dport $vmport\t-j DNAT --to-destination $vmip:3389"
        if [ -n "$create_statedir" ]; then
            echo "$vmip" > "$MAC_STATE_DIR/52:54:00:c1:0d:$i2/ip"
            echo "$wanip:$vmport" > "$MAC_STATE_DIR/52:54:00:c1:0d:$i2/rdp"
        fi
    done
}

gen_iptables_config_ssh () {
    local startip=$1
    local startport=$2
    local vmcount=$3
    local wanip=$4

    for i in $( seq 0 $vmcount ); do
        i2=$( printf '%02d\n' "$i" )
        vmip=$( get_ip_by_count $startip $i )
        vmport=$(( startport + i ))
        echo -e "-A PREROUTING  -d $wanip -m tcp -p tcp --dport $vmport\t-j DNAT --to-destination $vmip:22"
        if [ -n "$create_statedir" ]; then
            echo "$wanip:$vmport" > "$MAC_STATE_DIR/52:54:00:c1:0d:$i2/ssh"
        fi
    done
}

# common environment
[ -f /etc/sysconfig/rainbow-nethelper ] && . /etc/sysconfig/rainbow-nethelper
export MAC_STATE_DIR=${MAC_STATE_DIR:-/var/spool/rainbow-nethelper}

# main input processing cycle
g_localnet=$( guess_localnet )
g_wanip=$( guess_wanip )
save_dhcpd=/tmp/rainbow-nethelper.dhpcd
save_iptables_rdp=/tmp/rainbow-nethelper.iptables-rdp
save_iptables_ssh=/tmp/rainbow-nethelper.iptables-ssh

echo "Welcome to Rainbow Networking Helper configuration wizard!"
echo -n "Enter WAN IP address [$g_wanip]: "
read wanip 
[ -z "$wanip" ] && wanip=$g_wanip

echo -n "Specify cluster LAN network address [$g_localnet]: "
read localnet
[ -z "$localnet" ] && localnet=$g_localnet

g_startip=$( guess_start_ip $localnet )
echo -n "Please define a start IP address for the Rainbow dynamic pool [$g_startip]: "
read startip
[ -z "$startip" ] && startip=$g_startip

echo -n "What will be the size of Rainbow dynamic pool (max number of VMs) [100]: "
read poolsize
[ -z "$poolsize" ] && poolsize=100
poolsize=$(( poolsize - 1 ))

echo -n "Please define a start port number to be used for RPD forwarding [33800]: "
read rdpsport
[ -z "$rdpsport" ] && rdpsport=33800

echo -n "Please define a start port number to be used for SSH forwarding [22200]: " 
read sshsport
[ -z "$sshsport" ] && sshsport=22200


echo -n "Would you like to create Rainbow Networking Helper statedir (any previous statedir content will be overwritten) [Y/n]: "
read statedir
if [ "$statedir" = "Y" -o -z "$statedir" ]; then
    rm -rf $MAC_STATE_DIR
    export create_statedir=1
else
cat <<END

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!                        WARNING !!!                         !!
!!  Without statedir creation in accordance to IPtables/DHCP  !!
!!  settings Rainbow Helper is missoperational!               !!
!!  Please make sure configs are consistent.                  !!
!!  Press 'Enter' key to continue.                            !!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

END
read
fi

echo "Add the following configuration for DHCP server (/etc/dhcp/dhcpd.conf):"
gen_dhcpd_conf $startip $poolsize | tee $save_dhcpd
echo "--- press 'Enter' key to continue ---"
read

echo "Add the following configuration to IPTables config (/etc/sysconfig/iptables) to forward RDP sessions:"
gen_iptables_config_rdp $startip $rdpsport $poolsize $wanip | tee $save_iptables_rdp
echo "--- press 'Enter' key to continue ---"
read

echo "Add the following configuration to IPTables config (/etc/sysconfig/iptables) to forward SSH sessions:"
gen_iptables_config_ssh $startip $sshsport $poolsize $wanip | tee $save_iptables_ssh

echo -e "\n\nRainbow Networking Helper configuration is now finished:"
if [ -n "$create_statedir" ]; then
    echo -e "\tStatedir has been created in at $MAC_STATE_DIR"
else
    echo -e "\tStatedir WAS NOT created. All configuration provided for information purposes only."
fi
echo -e "\tGenerated DHCP/IPTables configuration saved to:"
echo -e "\t\t$save_dhcpd"
echo -e "\t\t$save_iptables_rdp"
echo -e "\t\t$save_iptables_ssh"