#!/bin/bash

printf "Better to run as root, because of permisions handeling.\n"

sleep 2

printf "Do you want to set up firewall rules by iptables? [Y/n]: \n"
read ansFirewallSetup



if [[ "$ansFirewallSetup" =~ ("N"|"n") ]]; then

	printf "+ Thanks, working on next bit\n"

else
	
	printf "Do you want to block non-LAN ssh connections? [Y/n/castom]: "
	read sshBlockRange


	if [[ $sshBlockRange =~ ("n"|"N") ]]; then
	
		printf "+ OK, working on next bit\n"
		ipList=""

	elif [[ $sshBlockRange =~ ("y"|"Y") || -z $sshBlockRange ]]; then
	
		#Pipes all informations about ip interfaces
		ipList=$(ip -o -4 a show scope global)

		#Founds data in pattern
		ipList=$(echo $ipList | grep -Eo "([0-9]*\.){3}[0-9]*/[0-9]*")

		#substitues space for coma
		ipList=$(echo $ipList | tr " " ",") 

		printf "+ Accepting SSH connections only on these ip's: $ipList\n"


	else
			printf "\nHope you know what you are doing, I am not checking these :]"
			
			printf "\nSubmit your IP range to acces SSH in format 192.168.1.1/24 
				\nYour IP range: "
			read ipList
			printf "\n+ Allowing SSH on this range: $ipList \n"
	fi
fi

sleep 2

# Just to be shure
printf "\n+ Starting to upgrade base system\n\n"

sudo apt update
sudo apt upgrade -y

# Installing depandencies
printf "\n+ Installing depandencies \n\n" 
sudo apt install openjdk-17-jre-headless screen p7zip-full iptables -y

# User and groupe managment
printf "\n+ Creating user minecraft and basic file structure"
groupadd minecraft

useradd --system --shell /usr/sbin/nologin --home /opt/minecraft -g minecraft minecraft

# File strukture and basic install
mkdir /opt/minecraft 

mv data/Forge-1.20.1.jar /opt/minecraft/

cd /opt/minecraft/

# Installing server
printf "+ Installing Forge 1.20.1 \n \n"

java -Xms512M -Xmx2048M -jar Forge-1.20.1.jar --installServer

cd -

cd data/
mv eula.txt server-icon.png server.properties run.sh user_jvm_args.txt /opt/minecraft/
cd ..

mkdir /opt/minecraft/mods

printf "\n+ Unpacking mods \n \n"

7z x Mods.zip -o/opt/minecraft/mods/

# Permision handeling 
printf "\n+ Permision handeling\n"
chown -R minecraft:minecraft /opt/minecraft

# SystemD service
printf "+ Preparign systemD service\n"
cp mc-forge.service /etc/systemd/system/

systemctl daemon-reload
systemctl start mc-forge.service
systemctl enable mc-forge


# integration of Maxopoly's instructions on firewall

if [[ "$ansFirewallSetup" =~ ("Y"|"y") || -z "$ansFirewallSetup" ]]; then
	
		printf "+ Executing firewall setup"

		iptables -P INPUT ACCEPT #Clears existing rules

		iptables -A INPUT -i lo -j ACCEPT #Allow loopback

		iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT #Allow continuing connections

		iptables -A INPUT -p tcp --dport 22 --source $ipList -j ACCEPT #Allow ssh from set network

		iptables -A INPUT -p tcp --dport 25565 -j ACCEPT #Allow MC port

		iptables -L ### Good place to paste a manual check to not lock yourself out 

		printf "\n Does it looks right? [Y/n]: "
			read ansFirewallOK

		if [[ "$ansFirewallOK" =~ ("Y"|"y") || -z "$ansFirewallOK" ]]; then	
		
			iptables -P INPUT DROP #Disallow everythink else

			iptables -P FORWARD DROP #Block all forwarding

			iptables -P OUTPUT ACCEPT #Allow all outgouing
		
		else
			
			printf "\nOK it is time for manual configuration"
			printf "\nAfter you are done ramamber to run 'apt install iptables-persistent' to save your config. System will automaticly remove your work after restart"

		fi

		apt install iptables-persistent -y

fi

printf "\n+ Done, thanks for your time. It is goode idea to chack if everythink is alright by running:"
printf "\nsystemctl status mc-forge"
printf "\nsu minecraft -s /bin/bash"
printf "\n+ it is good idea to have some fun with screen before trying to open minecraft conesole 'screen -r' while loged wia minecraft user"