#!/bin/sh

. /lib/functions.sh

DHCP_ACS_URL=""
DHCP_PROV_CODE=""
MIN_WAIT_INVL=""
INVL_MULTIPLIER=""

get_opt43() {
	# Check if option value is in encapsulated form
	local opt43="$1"
	local len="$2"

	[ "$len" -gt "2" ] || return

	first_byte=${opt43:0:2}
	first_byte=$(printf "%d\n" "0x$first_byte")

	if [ $len -ge 4 ] && [ $first_byte -ge 1 ] && [ $first_byte -le 4 ]; then
		# it is in encapsulated form
		# opt43 encapsulated vendor-specific option has data in below format
		#  Code   Len   Data item        Code   Len   Data item        Code
		# +-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+
		# |  T1 |  n  |  d1 |  d2 | ... |  T2 |  n  |  D1 |  D2 | ... | ... |
		# +-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+

		#hex-string 2 character=1 Byte
		# length in hex string will be twice of actual Byte length

		data="${opt43}"
		rem_len="${len}"
		# parsing of suboption of option 43
		while [ $rem_len -gt 0 ]; do
			# get the suboption id
			sub_opt_id=${data:0:2}
			sub_opt_id=$(printf "%d\n" "0x$sub_opt_id")

			# get the length of suboption
			sub_opt_len=${data:2:2}
			sub_opt_len=$(printf "%d\n" "0x$sub_opt_len")
			sub_opt_len=$(( sub_opt_len * 2 ))

			# get the value of sub option starting 4 means starting after length
			sub_opt_val=${data:4:${sub_opt_len}}

			# assign the value found in sub option
			case "${sub_opt_id}" in
				"1") DHCP_ACS_URL=$(echo -n $sub_opt_val | sed 's/\([0-9A-F]\{2\}\)/\\\\\\x\1/gI' | xargs printf && echo '')
				;;
				"2") DHCP_PROV_CODE=$(echo -n $sub_opt_val | sed 's/\([0-9A-F]\{2\}\)/\\\\\\x\1/gI' | xargs printf && echo '')
				;;
				"3") MIN_WAIT_INVL=$(echo -n $sub_opt_val | sed 's/\([0-9A-F]\{2\}\)/\\\\\\x\1/gI' | xargs printf && echo '')
				;;
				"4") INVL_MULTIPLIER=$(echo -n $sub_opt_val | sed 's/\([0-9A-F]\{2\}\)/\\\\\\x\1/gI' | xargs printf && echo '')
				;;
			esac

			# add 2 bytes for sub_opt id and sub_opt len field
			sub_opt_end=$(( sub_opt_len + 4 ))

			# fetch next sub option hex string
			data=${data:${sub_opt_end}:${len}}

			# update the remaining sub option hex string length
			rem_len=$((rem_len - sub_opt_end))
		done
	else
		DHCP_ACS_URL=$(echo -n $opt43 | sed 's/\([0-9A-F]\{2\}\)/\\\\\\x\1/gI' | xargs printf && echo '')
	fi
}

config_load cwmp
config_get_bool enable_cwmp cpe enable 1
config_get wan_intf cpe default_wan_interface "wan"
config_get dhcp_discovery acs dhcp_discovery "0"

discovery_enable=0
if [ "$dhcp_discovery" = "1" ] || [ "$dhcp_discovery" = "true" ] || [ "$dhcp_discovery" = "enable" ]; then
	discovery_enable=1
fi

if [ "$enable_cwmp" = "0" ] || [ "$discovery_enable" = "0" ]; then
	return 0
fi

if [ "${wan_intf}" == "${INTERFACE}" ]; then
	if [ -n "$opt43" ]; then
		len=$(printf "$opt43"|wc -c)
		get_opt43 "$opt43" "$len"
	fi

	if [ -z "$DHCP_ACS_URL" ]; then
		return 0
	fi

	sec=$(uci -q get cwmp.acs)
	if [ -z "${sec}" ]; then
		return 0
	fi

	uci -q set cwmp.acs.dhcp_url="$DHCP_ACS_URL"

	if [ -n "$MIN_WAIT_INVL" ]; then
		uci -q set cwmp.acs.dhcp_retry_min_wait_interval="$MIN_WAIT_INVL"
	fi

	if [ -n "$INVL_MULTIPLIER" ]; then
		uci -q set cwmp.acs.dhcp_retry_interval_multiplier="$INVL_MULTIPLIER"
	fi
	uci -q commit cwmp

	sec=$(uci -q get cwmp.cpe)
	if [ -z "${sec}" ]; then
		return 0
	fi

	if [ -n "$DHCP_PROV_CODE" ]; then
		uci -q set cwmp.cpe.dhcp_provisioning_code="$DHCP_PROV_CODE"
		uci -q commit cwmp
	fi
fi