#!/bin/bash

set -u

PUBLIC_PREFIX=20 # 20, 21, 22...

MCAST_PREFIX_BASE="235"
MCAST_COMMON_ADDR="$MCAST_PREFIX_BASE.0.0.1"
MCAST_BASE_PORT=4000

set +u
[ -z "$USER" ] && export USER=$(id -un)
set -u

error() {
	echo ERROR : "allocator : $@ !"
	exit 1
}

# Numéro de l'utilisteur sur la machine
# Utilisé par la redirection de port
computeLocalUser() {

	set +u
	[ -z "$USER" ] && export USER=$(id -un)
	set -u

	local u=$USER
	#[ $# = 2 ] && u=$2

	ps --no-headers --sort=start_time -eo user:14,lstart | gawk -v USER=$u -e '
	BEGIN {
		n=0	
	}
	
	/[^[:space:]]+ .*/ {

		user=$1
		#print $0 USER "===" user
			
		if(user == USER) {
			print n%32
			exit 0
		} 

		
		if ( ! ( user in users ) ) {
			#print "SET USER : user :" $0
			users[user]=n
			n=n+1
		}
	}
	'

}

# Calcule les paramètres d'un hôte
# $1 : hôte

computeDb() {
	local split host network user domain

	[ -d $VDN_PATH/allocators/db-$VDN_RESOURCES_ALLOCATOR ] && dir=$VDN_PATH/allocators/db-$VDN_RESOURCES_ALLOCATOR
	[ -d /etc/vdn/allocators/db-$VDN_RESOURCES_ALLOCATOR ] && dir=/etc/vdn/allocators/db-$VDN_RESOURCES_ALLOCATOR

	ALLOCATOR_DIR=$dir

	[ -z "$dir" ] && error "Allocators dir not found!"

	split="${1//./ }"

	set - $split

	set +u

	host=$1
	network=$2
	user=$3
	domain=$4


	[ -z "$domain" ] && domain=vdn
	[ $domain != vdn ] && error "computeDb : bad domain $domain"

	set +u
        [ -z "$user" -a -n "$GUEST_OWNER" ] && user=$GUEST_OWNER
        set -u

	[ -z "$user" ] && user=$USER


	[ -z "$network" ] && {
		[ -z "$NETWORK_DIR" ] && 
			error "computeDb : no network and NETWORK_DIR is empty !"
		network=$(basename $NETWORK_DIR)
	}

	[ -z "$host" ] && error "computeDb : host is empty !"

	#echo "computeDb : $VDN_NETWORKS_BASE_DIR/$network/$host.conf" >&2

	##[ ! -e $VDN_NETWORKS_BASE_DIR/$network/$host.conf ] && \
	##	error "computeDb : host $host not found in network $network!"

	grep -q $network:$host $dir/hosts || {
		error "host $host not found in network $network"
	}

	###

	set +u
	[ -z "$DB_CURRENT_USER" ] && DB_CURRENT_USER=""
	set -u

	[ "$user" != "$DB_CURRENT_USER" ] && {
		! cat $dir/users |  grep -q "^$user$"  && 
			error "computeDb : user $user not found"

		export DB_CURRENT_USER_NUM=$(cat $dir/users |  grep -n "^$user$" | cut -d ':' -f 1)
		export DB_CURRENT_USER=$user
		export DB_CURRENT_LOCAL_USER_NUM=$(computeLocalUser $user $host)

	}

	[ -z "$DB_CURRENT_LOCAL_USER_NUM" ] && $(computeLocalUser $user $host)

	set +u
        [ -z "$DB_CURRENT_NETWORK" ] && DB_CURRENT_NETWORK=""
        set -u


	[ "$network" != "$DB_CURRENT_NETWORK" ] && {
		#local netList=$(cd $VDN_NETWORKS_BASE_DIR; find . -maxdepth 1 -type d)
		local netList=$(cat $dir/networks)

		export DB_CURRENT_NETWORKS_LIST="$netList"

		DB_CURRENT_NETWORK_NUM=$(echo "$DB_CURRENT_NETWORKS_LIST" |  grep -n "^$network$" | cut -d ':' -f 1)

		[ -z "$DB_CURRENT_NETWORK_NUM" ] && 
			error "computeDb : DB_CURRENT_NETWORK_NUM empty (not in $VDN_NETWORKS_BASE_DIR ?)" 

		#local hostsList=$(cd $VDN_NETWORKS_BASE_DIR/$network; find . -maxdepth 1 -type f -name '*.conf' )
		local hostsList=$(cat $dir/hosts | grep "^$network:" | cut -d ':' -f 2 )
		export DB_CURRENT_HOSTS_LIST="$hostsList"
		DB_CURRENT_HOST_NUM=$(echo "$DB_CURRENT_HOSTS_LIST" |  grep -n "^$host$" | cut -d ':' -f 1)

		[ -z "$DB_CURRENT_HOST_NUM" ] && {
			error "computeDb : DB_CURRENT_HOST_NUM empty (not in $VDN_NETWORKS_BASE_DIR/$network/*.conf ?)"
		}
		DB_CURRENT_NETWORK=$network
		DB_CURRENT_HOST=$host
	}

	cat << EOF > /dev/null
	echo "
host:$host
network:$network
user:$user

hostNum:$DB_CURRENT_HOST_NUM
networkNum:$DB_CURRENT_NETWORK_NUM
userNum=$DB_CURRENT_USER_NUM
"
EOF
}

# $1		: host
# $2		: proto (tcp/udp)
# $3		: port à redirigé
# en sortie : affichage d'un port libre
computeRedir() {
	local base dst proto=$2

	computeDb $1

	base=$(( 5000+$DB_CURRENT_LOCAL_USER_NUM*1024 ))
	dst=$(( $base + $DB_CURRENT_HOST_NUM*32+($3%16) ))

	dst=$(findUnusedPort $proto $dst)
	echo $dst
}

# Affiche l'IP PUBLIC de la machine
# L'hôte (ex : tiny.demo.user.vdn)

computePublicIp() {
	computeDb $1

	grep -q "$DB_CURRENT_NETWORK:$DB_CURRENT_HOST" $ALLOCATOR_DIR/hosts.global || return

	#echo $NETWORKS | egrep -q 'NET_0|NET_G' || return
	#echo "keys: $DB_CURRENT_USER $DB_CURRENT_NETWORK $DB_CURRENT_HOST"
	#echo "keys: userNum networkNum hostNum : $DB_CURRENT_USER_NUM $DB_CURRENT_NETWORK_NUM $DB_CURRENT_HOST_NUM"

	# 20.X.Y.Z => 24 bits dispo
	# Une adresse IP_PUBLIC par machine
	# 13 bits de poids fort pour le numero de l'utilisateur (max 8192)
	# 6 bits pour le numéro réseau (max 64 réseaux)
	# 5 bits pour le numéro d'hôte (max 32 hôte par réseau)
	#
	# IP = -------- -------- ---------
    #      ^            ^^      ^^   ^
	#      +------------++------++---+
	#          user         net   host 

	local ip=$(( $DB_CURRENT_USER_NUM * 2**11 + $DB_CURRENT_NETWORK_NUM * 2**5 + $DB_CURRENT_HOST_NUM))


	ip1=$(( $ip/2**24 )) 
	ip2=$(( ($ip-$ip1*2**24) / 2**16 )) 
	ip3=$(( ($ip- $ip1*2**24 - $ip2*2**16) / 2**8 )) 
	ip4=$(( $ip % 256 ))

	echo "$(($PUBLIC_PREFIX+$2)).$ip2.$ip3.$ip4"

}

# $1 : 
# $2 : le numéro du lien souhaihé
computeMacAddr() {

	computeDb $1
	
	# xx:xx:xx:xx:xx:xx
    # 52 ----- -- -- -- 
    #                ^ -interface (8 bits, max 256 interface par hôte)
	#             ^-  host (8 bits, max 256 hôtes par réseau)
	#		   ^network (8 bits, max 256 réseaux)
	#	^user (16 bits, max 65536 utilisateurs)

	local uHigh=$(($DB_CURRENT_USER_NUM /256))
	local uLow=$(($DB_CURRENT_USER_NUM %256))

	printf "52:%02X:%02X:%02X:%02X:%02X\n" $uHigh $uLow $DB_CURRENT_NETWORK_NUM $DB_CURRENT_HOST_NUM $2 
}

# Affiche l'adresse IPv4 multicast du brin ethernet  n°$1
# $1 : l'hôte
# $2 : le numéro du lien souhaité

computeEthLink() {
	computeDb $1

	echo "=== computeEthLink:$2" >&2
	echo "DB_CURRENT_USER_NUM:$DB_CURRENT_USER_NUM" >&2
	echo "DB_CURRENT_NETWORK_NUM:$DB_CURRENT_NETWORK_NUM" >&2
	#echo "DB_CURRENT_HOST_NUM:$DB_CURRENT_HOST_NUM" >&2

	# idem que pour l'IP publique sauf :
	#   - préfixe de l'adresse mcast IPv4 
	#   - le numéro de brin remplace le numéro d'hôte.
	# (5bits = 32 brins max par réseau)
    # 230.X.Y.Z 

    # 13 bits de poids fort pour le numero de l'utilisateur (max 8192)
    # 6 bits pour le numéro réseau (max 64 réseaux)
    # 5 bits pour le numéro de brins (max 32 hôte par réseau)
    #
    # IP = -------- -------- ---------
    #      ^            ^^      ^^   ^
    #      +------------++----++---+
    #          user        net  link 


    local ip=$(( $DB_CURRENT_USER_NUM * 2**11 + $DB_CURRENT_NETWORK_NUM * 2**5))

	ip1=$(( $ip/2**24 ))
        ip2=$(( ($ip-$ip1*2**24) / 2**16 ))
        ip3=$(( ($ip- $ip1*2**24 - $ip2*2**16) / 2**8 ))
        ip4=$(( $ip % 256 ))
    echo "==> $MCAST_PREFIX_BASE.$ip2.$ip3.$ip4:$MCAST_BASE_PORT" >&2
    echo "$MCAST_PREFIX_BASE.$ip2.$ip3.$ip4:$MCAST_BASE_PORT"
}