#!/bin/sh

# Script to run on the mud host/server to authorize new players who will connect to the MUD on the host/server.
# It first prompts the user for a player name and an SSH key.
# It then checks if a user with that player name and SSH key already exists, and if so, exits.
# If the user and key combination do not already exist, it adds the key to the authorized_keys file and creates the corresponding user.

echo "This spell authorizes a new player to connect to this computer via their player key (SSH key). Run this on the MUD host computer."
echo "A new user account will be created on your system with limited permissions for the new player."
echo "MUD users are in the group \"mud\", and this group only has access to your shared rooms (folders) in the MUD."

echo "Enter player name:"
read playername

# Check if user already exists. Check now so they don't have to enter the SSH key over and over.
if id "$playername" >/dev/null 2>&1; then
    echo "Error: user $playername already exists. Please delete the existing user first and try again."
    exit 1
fi

echo "Enter SSH key:"
read sshkey

# Check if key already exists in authorized_keys file
if grep -q "$sshkey" ~/.ssh/authorized_keys; then
    echo "Error: key already exists in authorized_keys file. Please delete the existing key first and try again."
    exit 1
fi

# Create new system user
useradd "$playername"

# Create the directories on this path, if they don't exist
mkdir -p /home/$playername/.ssh

# Add key to authorized_keys file in their home directory, so they can log in as themselves
echo "$sshkey $playername@mud" >> /home/$playername/.ssh/authorized_keys