#!/bin/bash

set -euo pipefail

if [ "${DEBUG:-false}" == "true" ]; then
  set -x
fi

: "${RCON_HOST:=localhost}"
: "${RCON_PORT:=25575}"
: "${RCON_PASSWORD:=minecraft}"

export RCON_HOST
export RCON_PORT
export RCON_PASSWORD

###############
##  common   ##
## functions ##
###############

is_elem_in_array() {
  # $1 = element
  # All remaining arguments are array to search for the element in
  if [ "$#" -lt 2 ]; then
    log INTERNALERROR "Wrong number of arguments passed to is_elem_in_array function"
    return 2
  fi
  local element="${1}"
  shift
  local e
  for e; do
    if [ "${element}" == "${e}" ]; then
      return 0
    fi
  done
  return 1
}

log() {
  if [ "$#" -lt 1 ]; then
    log INTERNALERROR "Wrong number of arguments passed to log function"
    return 2
  fi
  local level="${1}"
  shift
  local valid_levels=(
    "INFO"
    "WARN"
    "ERROR"
    "INTERNALERROR"
  )
  if ! is_elem_in_array "${level}" "${valid_levels[@]}"; then
    log INTERNALERROR "Log level ${level} is not a valid level."
    return 2
  fi
  (
    # If any arguments are passed besides log level
    if [ "$#" -ge 1 ]; then
      # then use them as log message(s)
      <<<"${*}" cat -
    else
      # otherwise read log messages from standard input
      cat -
    fi
    if [ "${level}" == "INTERNALERROR" ]; then
      echo "Please report this: https://github.com/itzg/docker-mc-backup/issues"
    fi
  ) | awk -v level="${level}" '{ printf("%s %s %s\n", strftime("%FT%T%z"), level, $0); fflush(); }'
} >&2

retry() {
  if [ "$#" -lt 3 ]; then
    log INTERNALERROR "Wrong number of arguments passed to retry function"
    return 1
  fi

  # How many times should we retry?
  # Value smaller than zero means infinitely
  local retries="${1}"
  # Time to sleep between retries
  local interval="${2}"
  readonly retries interval
  shift 2

  if (( retries < 0 )); then
    local retries_msg="infinite"
  else
    local retries_msg="${retries}"
  fi

  local i=-1 # -1 since we will increment it before printing
  while (( retries >= ++i )) || [ "${retries_msg}" != "${retries}" ]; do
    # Send SIGINT after 5 minutes. If it doesn't shut down in 30 seconds, kill it.
    if output="$(timeout --signal=SIGINT --kill-after=30s 5m "${@}" 2>&1 | tr '\n' '\t')"; then
      log INFO "Command executed successfully ${*}"
      return 0
    else
      log ERROR "Unable to execute ${*} - try ${i}/${retries_msg}. Retrying in ${interval}"
      if [ -n "${output}" ]; then
        log ERROR "Failure reason: ${output}"
      fi
    fi
    # shellcheck disable=SC2086
    sleep ${interval}
  done
  return 2
}

is_function() {
  if [ "${#}" -ne 1 ]; then
    log INTERNALERROR "is_function expects 1 argument, received ${#}"
  fi
  name="${1}"
  [ "$(type -t "${name}")" == "function" ]
}

call_if_function_exists() {
  if [ "${#}" -lt 1 ]; then
    log INTERNALERROR "call_if_function_exists expects at least 1 argument, received ${#}"
    return 2
  fi
  function_name="${1}"
  if is_function "${function_name}"; then
    eval "${@}"
  else
    log INTERNALERROR "${function_name} is not a valid function!"
    return 2
  fi
}

##########
## main ##
##########


log INFO "waiting for rcon readiness..."
# 20 times, 10 second delay
retry 20 10s rcon-cli save-on


if retry 5 10s rcon-cli save-off; then
    # No matter what we were doing, from now on if the script crashes
    # or gets shut down, we want to make sure saving is on
    trap 'retry 5 5s rcon-cli save-on' EXIT

    retry 5 10s rcon-cli save-all
    retry 5 10s sync

    rcb backup

    retry 20 10s rcon-cli save-on
    # Remove our exit trap now
    trap EXIT
  else
    log ERROR "Unable to turn saving off. Is the server running?"
    exit 1
  fi

  if (( PRUNE_BACKUPS_DAYS > 0 )); then
    rcb cleanup
  fi