#!/bin/sh

config_file="zsmc.conf"
if [ ! -f "$config_file" ]
then
  echo "Generating default config file"
  cat > "$config_file" << EOF
# zsmc config file
SCREEN_NAME=Minecraft
JAR_FILE=server.jar
JAVA_COMMAND=java
JAVA_ARGUMENTS=-Xmx2G
SERVER_ARGUMENTS=--nogui
BACKUP_PATH=backup
EOF
  exit 100
fi

# quit if screen isn't installed
which screen >/dev/null || { echo "screen not installed, screen is required for this script to work" >&2;  exit 1 ; }

# load config
. "$(pwd)/$config_file"

fname="$(basename "$0")"
usage() {
echo "$fname <argument>"
echo 'Manage minecraft servers
Backups do not work with bukkit and spigot

Arguments:
  start             : Start server in background with screen
  startLocal        : Start server on the current console
  console           : Bring up the screen instance of the server  (C^a then d to leave)
  eraseCache        : Upgrade world and clear cached data
  backup [file]     : Make a world backup. If no file is specifed the current date is used as name
  restore [file]    : Restore this world backup. If no file is specified, will take the latest file
  log [date...]     : Display entire log. No date means latest
  login [date...]   : Display login/logout log. No date means latest

--DATE FORMAT --
  l             for latest
  t             for today
  yyyy-mm-dd    for given day
  -<x>          for x days before today
'
}


# Functions

start_server ()
{
  if screen -ls | cut -sd'.' -f2 | awk '{print $1}' | grep -qw "$SCREEN_NAME" # abort if server running
  then
    echo "A screen under the name '$SCREEN_NAME' is already running" >&2
    return 1
  else
    screen -dmS "$SCREEN_NAME" $JAVA_COMMAND $JAVA_ARGUMENTS -jar "$JAR_FILE" $SERVER_ARGUMENTS
  fi
}

attach () {
  screen -r "$SCREEN_NAME"
}

stop_server () {
  screen -S "$SCREEN_NAME" -X stuff "^Mstop^M"
}

eraseCache ()
{
  if screen -ls | cut -sd'.' -f2 | awk '{print $1}' | grep -qw "$SCREEN_NAME" # abort if server running
  then
    echo "A screen under the name '$SCREEN_NAME' is already running" >&2
    return 1
  else
    screen -dmS "$SCREEN_NAME" $JAVA_COMMAND $JAVA_ARGUMENTS -jar "$JAR_FILE" $SERVER_ARGUMENTS --forceUpgrade --eraseCache && stop_server && attach
  fi
}

world_backup ()
{
  # no server.properties
  [ ! -f server.properties ] && echo "server.properties not found" >&2 && return 1
  # extract save name
  world="$(grep "level-name=" server.properties | cut -d '=' -f2-)"

  # create backup path
  [ ! -d "$BACKUP_PATH" ] && mkdir -p "$BACKUP_PATH"

  # get filename
  FILE="$1"
  echo "$1" | grep -q '.tar.gz$' || FILE="$FILE.tar.gz" # add .tar.gz extension if not present

  echo "Backing up world to $FILE"
  if [ -n "$(command -v pv)" ] # fancy progress bar
  then tar -cf - "$world" -P | pv -s "$(du -sb "$world" | awk '{print $1}')" | gzip > "$BACKUP_PATH/$FILE"
  else tar -cvzf "$BACKUP_PATH/$FILE" "$world"
  fi
}

world_restore () {
  tar -xvf "$BACKUP_PATH/$1"
}

show_log ()
{
  # no arg = latest
  [ -z "$1" ] && show_log l

  # latest
  if [ "$1" = "l" ] || [ "$1" = "latest" ]
  then
    cat logs/latest.log 2>/dev/null

  # latest + all current date
  elif [ "$1" = "t" ]  || [ "$1" = "today" ] ; then
    show_log l
    show_log "$(date -u "+%F")"

  # -X : translate to date
  elif [ "$(echo "$1" | cut -c1)" = "-" ] ; then
    show_log "$(date -u --date=@$((  $(date -u +%s) - $((86400 * $(echo "$1" | cut -c2-) ))  )) +%F)"

  # date format iterate files
  else
    LIST=$(find logs -maxdepth 1 -type f -name "$1*")
    for I in $LIST
    do
      gzip -dc "$I" 2>/dev/null || cat $I
    done

  fi
}


# Main process

case $1 in
  start)      start_server ;;
  startLocal) $JAVA_COMMAND $JAVA_ARGUMENTS -jar "$JAR_FILE" $SERVER_ARGUMENTS ;;
  console)    attach ;;
  stop)       stop_server ;;
  eraseCache) eraseCache ;;
  backup)
    shift 1
    if [ $# -gt 0 ]
    then world_backup "$1"
    else world_backup "$(date -u "+%F_%H%M%S")"
    fi
    ;;
  log)
    shift 1
    if [ $# -gt 0 ]
    then for N ; do show_log "$N" ; done
    else show_log l
    fi
    ;;
  login)
    shift 1
    if [ $# -gt 0 ]
    then for N ; do show_log "$N" | grep -E '] logged in with entity id | left the game' ; done
    else show_log l | grep -E '] logged in with entity id | left the game'
    fi
    ;;
  restore)
    shift 1
    if [ "$#" -gt 0 ]
    then world_restore "$1"
    else world_restore "$(ls -lt "$BACKUP_PATH" | head -n 2 | tail -n 1 | awk '{print $9}')"
    fi
    ;;
  *)
    usage
    exit 1
    ;;
esac