#!/bin/sh /etc/rc.common
# Copyright (C) 2021 Tianling Shen <cnsztl@immortalwrt.org>

USE_PROCD=1
START=90

CONF="dnsproxy"
PROG="/usr/bin/dnsproxy"

is_enabled() {
	local enabled
	config_get enabled "$1" "$2" "0"
	if [ "$enabled" -eq "1" ]; then
		return 0
	else
		return 1
	fi
}

is_empty() {
	local empty
	config_get empty "$1" "$2" $3
	if [ -z "$empty" ]; then
		return 0
	else
		return 1
	fi
}

append_param() {
	procd_append_param command "$1" $2
}

append_param_arg() {
	local value
	config_get value "$1" "$2" $4
	[ -n "$value" ] && append_param "$3" "$value"
}

append_param_bool() {
	is_enabled "$1" "$2" && append_param "--${2//_/-}"
}

load_config_arg() {
	append_param_bool "$1" "all_servers"
	append_param_bool "$1" "fastest_addr"
	append_param_bool "$1" "http3"
	append_param_bool "$1" "insecure"
	append_param_bool "$1" "ipv6_disabled"
	append_param_bool "$1" "refuse_any"
	append_param_bool "$1" "verbose"
}

load_config_list() {
	if is_empty "global" "listen_addr"; then
		append_param "--listen" "127.0.0.1"
	else 
		config_list_foreach "global" "listen_addr" "append_param '--listen'"
	fi

	if is_empty "global" "listen_port"; then
		append_param "--port" "5353"
	else 
		config_list_foreach "global" "listen_port" "append_param '--port'"
	fi

	is_empty "bogus_nxdomain" "ip_addr" || config_list_foreach "bogus_nxdomain" "ip_addr" "append_param '--bogus-nxdomain'"

	for i in "bootstrap" "fallback" "upstream"; do
		is_empty "servers" "$i" || config_list_foreach "servers" "$i" "append_param '--$i'"
	done
}

load_config_param() {
	append_param_arg "global" "log_file" "--output"
	append_param_arg "global" "timeout" "--timeout"
	append_param_arg "global" "max_go_routines" "--max-go-routines"
	append_param_arg "global" "rate_limit" "--ratelimit"
	append_param_arg "global" "udp_buf_size" "--udp-buf-size"

	is_enabled "cache" "enabled" && {
		append_param "--cache"
		append_param_bool "cache" "cache_optimistic"
		append_param_arg "cache" "size" "--cache-size"
		append_param_arg "cache" "min_ttl" "--cache-min-ttl"
		append_param_arg "cache" "max_ttl" "--cache-max-ttl"
	}

	is_enabled "dns64" "enabled" && {
		append_param "--dns64"
		append_param_arg "dns64" "dns64_prefix" "--dns64-prefix"
	}

	is_enabled "edns" "enabled" && {
		append_param "--edns"
		append_param_arg "edns" "edns_addr" "--edns-addr"
	}
}

start_service() {
	config_load "$CONF"

	is_enabled "global" "enabled" || return 1

	procd_open_instance "$CONF"
	procd_set_param command "$PROG"

	load_config_arg "global"
	load_config_list
	load_config_param

	procd_set_param respawn
	procd_set_param stdout 1
	procd_set_param stderr 1
	procd_set_param user dnsproxy

	procd_close_instance
}

reload_service() {
	stop
	start
}

service_triggers() {
	procd_add_reload_trigger "$CONF"
}
