#!/bin/bash
set -e

port=22  # default SSH port
cache=".maccess-lastused"
journal=".maccess-journal"
user_host=""
user="default"
jump=""
lock_file="lock.mutex"

usage() {
    echo "Usage: $0 [-p PORT -J jump1,jump2] user@host"
    exit 1
}

# Parse command line options
while getopts ":p:J:u:" opt; do
    case $opt in
        p) 
            if ! [[ "$OPTARG" =~ ^[0-9]+$ ]] || [ "$OPTARG" -gt 65535 ]; then
                echo "Invalid port number: $OPTARG"
                exit 1
            fi
            port="$OPTARG"
            ;;
	    J)
            jump="-J $OPTARG"
            echo "ProxyJump: $jump"
            ;;
        u)
            user="$OPTARG"
            ;;
        \?)
            echo "Invalid option: -$OPTARG"
            usage
            ;;
        :)
            echo "Option -$OPTARG requires an argument"
            exit 1
            ;;
    esac
done
shift $((OPTIND -1))

if [ $# -ne 1 ]; then 
    echo "Using $cache"

    if [ -f "$cache" ]; then
        {
            read -r jump_cached
            read -r port_cached
            read -r user_host_cached
        } < "$cache"
        jump="$jump_cached"
        port="$port_cached"
        user_host="$user_host_cached"
    else
        echo "Error: Cache file $cache not found." >&2
        usage
    fi
else
    user_host="$1"   
    echo "$jump" > "$cache"
    echo "$port" >> "$cache"
    echo "$user_host" >> "$cache"   
fi


# Check if lock file exists on remote
if ssh $jump -p "$port" "$user_host" "test -e '$lock_file'"; then
    echo "Error: Lock file $lock_file exists on $user_host" >&2
    whoisusing=$(ssh $jump -p $port $user_host "cat $lock_file")
    echo "At the moment in use by $whoisusing" >&2
    echo "Session might be active. Exiting." >&2
    exit 1
fi

# Create lock file
ssh $jump -p "$port" "$user_host" "echo '$user' > '$lock_file'"
echo "Locked for user $user"
echo "[Start] [$(date +%Y-%m-%d-%H-%M-%S)] $user" >> $journal
cleanup() {
    echo "Removing lock file..."
    ssh $jump -p "$port" "$user_host" "rm -f '$lock_file'"
    echo "[End] [$(date +%Y-%m-%d-%H-%M-%S)] $user" >> $journal
}

# Register cleanup trap
trap cleanup EXIT INT TERM

# Start interactive session
echo "Starting SSH session (port $port). Lock file created."
ssh $jump -p "$port" "$user_host"