#!/bin/bash

MCUSER='minecraft'
MCGROUP='minecraft'

MCHOME="/home/$MCUSER"
MCNAME=$1
MCPATH="$MCHOME/$MCNAME"
MCLOG="$MCPATH/logs/latest.log"
BACKUPPATH="backup"
WORLD="world"

ME=`whoami`

as_user(){
    if [ "$ME" = "$MCUSER" ] ; then
        bash -c "$1"
    else
        su - $MCUSER -c "$1"
    fi
}

mc_screen(){
    mc_check
    echo "$(mc_pid).mc-$MCNAME"
}

mc_isup(){
    if pgrep -u $MCUSER -f $MCNAME > /dev/null ; then
        return 0
    else
        return 1
    fi
}

mc_check(){
    if ! mc_isup ; then
        echo "$MCNAME is not running."
        exit
    fi
}

mc_stuff(){
    as_user "screen -p 0 -S $(mc_screen) -X eval 'stuff \"$1\"\015'"
}

mc_saveon(){
    mc_check
    echo "$MCNAME is running... re-enabling saves"
    mc_stuff "save-on"
}

mc_saveoff(){
    mc_check
    echo "$MCNAME is running... suspending saves"
    mc_stuff "save-off"
    mc_stuff "save-all"
}

mc_list(){
    mc_check
    pre_log_len=`wc -l $MCLOG | awk '{print $1}'`
    mc_stuff "list"
    sleep .1
    tail -n $((`wc -l $MCLOG | awk '{print $1}'`-$pre_log_len)) $MCLOG
}


mc_pid(){
    mc_check
    echo `pgrep -u $MCUSER -f $MCNAME`
}

mc_status(){
    mc_check
    echo "$MCNAME is running."
}

mc_backup(){
    mc_isup && mc_saveoff
    mc_isup && mc_stuff "say SERVER BACKUP STARTING. Server going readonly..."

    NOW=`date "+%Y-%m-%d_%Hh%M"`
    BACKUP_FILE="$BACKUPPATH/${MCNAME}_${NOW}.tar"
    as_user "tar -C \"$MCPATH\" -cf \"$MCPATH/$BACKUP_FILE\" $WORLD"
    
    mc_isup && mc_saveon
    mc_isup && mc_stuff "say SERVER BACKUP ENDED. Server going read-write..."

    echo "Compressing backup..."
    as_user "gzip -f $MCPATH/$BACKUP_FILE"
    echo "Done."
}

case $2 in
    pid)
        mc_pid $1
        ;;
    status)
        mc_status
        ;;
    screen)
        mc_screen
        ;;
    list)
        mc_list
        ;;
    backup)
        mc_backup
        ;;
    *)
    echo "Usage: $0 instance {pid, status, list, backup}"
    exit 1
    ;;
esac

exit 0