#!/bin/bash
#
# factorio_manager.sh
#
# Copyright (C) 2020, Branko Majic <branko@majic.rs>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#

# Treat unset variables as errors.
set -u

program="factorio_manager.sh"
version="0.1"

function synopsis() {
cat <<EOF
$program $version, helper tool for managing Factorio instances

Usage:
  $program [OPTIONS] launch INSTANCE
  $program [OPTIONS] info INSTANCE
  $program [OPTIONS] list

  $program [OPTIONS] create INSTANCE
  $program [OPTIONS] create-server INSTANCE
  $program [OPTIONS] copy SOURCE_INSTANCE DESTINATION_INSTANCE
  $program [OPTIONS] remove INSTANCE
  $program [OPTIONS] import INSTANCE SOURCE_DIRECTORY

  $program [OPTIONS] versions
  $program [OPTIONS] set-version INSTANCE

  $program [OPTIONS] list-backups INSTANCE
  $program [OPTIONS] backup INSTANCE [DESCRIPTION]
  $program [OPTIONS] restore INSTANCE BACKUP_NAME
  $program [OPTIONS] remove-backup INSTANCE BACKUP_NAME

  $program [OPTIONS] set-game-dir GAME_INSTALLATIONS_DIRECTORY
EOF
}

function short_usage() {
cat <<EOF
$(synopsis)

For more details see $program -h.
EOF
}

function usage() {
    cat <<EOF
$(synopsis)

$program is a helper tool for managing multiple Factorio
instances.

Each instance is designated a dedicated directory, which contains all
of its configuration files, saves games, and mods, and is kept
separate from all other instances.

A single Factorio version installation (base files) can be used by
multiple instances, but each instance is bound to a specific version
of Factorio.

Factorio Manager keeps instances in sub-directories under the
~/.factorio/ directory. Sub-directories are named after the
instances. The following instance names are reserved for special use
by the tool:

 - .game_installations (used for storing symlink towards directory
   containing Factorio installations)

Multiple commands are provided for managing Factorio instances, and
they all expect different positional parameters:


set-game-dir GAME_INSTALLATIONS_DIRECTORY

    Sets the passed-in directory path as the base directory where
    different versions of Factorio will be looked-up. Each
    sub-directory within this directory should be named after the
    version of Factorio it represents, and should be the base
    directory under which the Factorio installation files can be
    found.


versions

    Shows locally available Factorio versions.


list

    Lists available Factorio instances, and shows some basic
    information about them.


create INSTANCE

    Creates a new Factorio instance with the given name. Command will
    prompt the user to pick between locally available Factorio
    versions.


launch INSTANCE

    Launches an instance with the given name.

    NOTE:: When launching the instance for the first time, Factorio
    will report that its configuration file is invalid, and offer to
    fix it. The reason is that the manager creates a minimal
    configuration file when creating an instance, and Factorio does
    not like this. It should be safe to allow Factorio to fix the
    configuration file (this will populate it with the necessary
    commented-out options).


backup INSTANCE [DESCRIPTION]

    Creates backup of an instance. All backups will be stored as
    subdirectories under the .bak directory within the instance
    directory. An optional description can be passed-in to make it
    easier to distinguish between different backups. Hidden files
    (names starting with '.') will be omitted from the backup.


list-backups INSTANCE

    Lists available backups of an instance, including description (if any is set).


$program accepts the following options:

    -q
        Quiet mode. Output a message only if newer packages are available.
    -d
        Enable debug mode.
    -v
        Show script licensing information.
    -h
        Show usage help.


Please report bugs and send feature requests to <branko@majic.rs>.
EOF
}

function version() {
    cat <<EOF
$program, version $version

+-----------------------------------------------------------------------+
| Copyright (C) 2020, Branko Majic <branko@majic.rs>                    |
|                                                                       |
| This program is free software: you can redistribute it and/or modify  |
| it under the terms of the GNU General Public License as published by  |
| the Free Software Foundation, either version 3 of the License, or     |
| (at your option) any later version.                                   |
|                                                                       |
| This program is distributed in the hope that it will be useful,       |
| but WITHOUT ANY WARRANTY; without even the implied warranty of        |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         |
| GNU General Public License for more details.                          |
|                                                                       |
| You should have received a copy of the GNU General Public License     |
| along with this program.  If not, see <http://www.gnu.org/licenses/>. |
+-----------------------------------------------------------------------+

EOF
}

# Set-up colours for message printing if we're not piping and terminal is
# capable of outputting the colors.
_color_terminal=$(tput colors 2>&1)
if [[ -t 1 ]] && (( ${_color_terminal} > 0 )); then
    _text_black=$(tput setaf 0)
    _text_red=$(tput setaf 1)
    _text_green=$(tput setaf 2)
    _text_yellow=$(tput setaf 3)
    _text_blue=$(tput setaf 4)
    _text_purple=$(tput setaf 5)
    _text_cyan=$(tput setaf 6)
    _text_white=$(tput setaf 7)

    _text_bold=$(tput bold)
    _text_reset=$(tput sgr0)

    _bg_black=$(tput setab 0)
    _bg_red=$(tput setab 1)
    _bg_green=$(tput setab 2)
    _bg_yellow=$(tput setab 3)
    _bg_blue=$(tput setab 4)
    _bg_purple=$(tput setab 5)
    _bg_cyan=$(tput setab 6)
    _bg_white=$(tput setab 7)
else
    _text_black=""
    _text_red=""
    _text_green=""
    _text_yellow=""
    _text_blue=""
    _text_purple=""
    _text_cyan=""
    _text_white=""

    _text_bold=""
    _text_reset=""

    _bg_black=""
    _bg_red=""
    _bg_green=""
    _bg_yellow=""
    _bg_blue=""
    _bg_purple=""
    _bg_cyan=""
    _bg_white=""
fi

# Make the colors available via an associative array as well.
declare -A _text_colors=()

_text_colors[black]="${_text_black}"
_text_colors[blue]="${_text_blue}"
_text_colors[cyan]="${_text_cyan}"
_text_colors[green]="${_text_green}"
_text_colors[purple]="${_text_purple}"
_text_colors[red]="${_text_red}"
_text_colors[white]="${_text_white}"
_text_colors[yellow]="${_text_yellow}"

_text_colors[boldblack]="${_text_bold}${_text_black}"
_text_colors[boldblue]="${_text_bold}${_text_blue}"
_text_colors[boldcyan]="${_text_bold}${_text_cyan}"
_text_colors[boldgreen]="${_text_bold}${_text_green}"
_text_colors[boldpurple]="${_text_bold}${_text_purple}"
_text_colors[boldred]="${_text_bold}${_text_red}"
_text_colors[boldwhite]="${_text_bold}${_text_white}"
_text_colors[boldyellow]="${_text_bold}${_text_yellow}"

# Set-up functions for printing coloured messages.
function debug() {
    if [[ $debug != 0 ]]; then
        echo "${_text_bold}${_text_blue}[DEBUG]${_text_reset}" "$@"
    fi
}

function info() {
    echo "${_text_bold}${_text_white}[INFO] ${_text_reset}" "$@"
}

function success() {
    echo "${_text_bold}${_text_green}[OK]   ${_text_reset}" "$@"
}

function warning() {
    echo "${_text_bold}${_text_yellow}[WARN] ${_text_reset}" "$@"
}

function error() {
    echo "${_text_bold}${_text_red}[ERROR]${_text_reset}" "$@" >&2
}

#
# Prints text in requested color to standard output. Behaves as thin
# wrapper around the echo built-in.
#
# Two invocation variants with different arguments are
# supported. First argument is the one that will determine what the
# desired invocation is.
#
# Arguments (variant 1):
#
#   $1 (echo_options)
#     Additional options to pass-in to echo. Must be a single argument
#     with leading dash followed by echo's own options. E.g. "-ne".
#
#   $2 (color)
#     Text color to use. Supported values: black, blue, cyan, green,
#     purple, red, white, yellow.
#
#   $3 (text)
#     Text to output.
#
#
# Arguments (variant 2):
#
#   $1 (color)
#     Text color to use. Supported values: black, blue, cyan, green,
#     purple, red, white, yellow, boldblack, boldblue, boldcyan,
#     boldgreen, boldpurple, boldred, boldwhite, boldyellow.
#
#   $2 (text)
#     Text to output.
#
function colorecho() {
    local options="" color text
    local reset="$_text_reset"

    if [[ ${1-} =~ -.* ]]; then
        options="$1"
        shift
    fi

    color="$1"
    text="$2"

    if [[ -n $options ]]; then
        echo "$options" "${_text_colors[$color]}$text${reset}"
    else
        echo "${_text_colors[$color]}$text${reset}"
    fi
}

#
# Prints text in requested color to standard output using printf
# format string and arguments.. Behaves as thin wrapper around the
# printf built-in.
#
# Arguments:
#
#   $1 (color)
#     Text color to use. Supported values: black, blue, cyan, green,
#     purple, red, white, yellow.
#
#   $2 (format_string)
#     printf-compatible format string.
#
#   $3 .. $n
#      Replacement values for the the format string.
#
function colorprintf() {
    local reset="$_text_reset"

    local color="$1"
    local format="$2"
    shift 2

    printf "${_text_colors[$color]}${format}${reset}" "$@"
}

#
# Presents user with a warning, asks user for confirmation to
# continue, and terminates the script is confirmation is not provided
# with designated exit code.
#
# This function can be used to request confirmation for dangerous
# actions/operations (such as removal of large number of files etc).
#
# The user must type-in YES (with capital casing) to proceed.
#
# Arguments:
#
#   $1 (prompt_text)
#     Text to prompt the user with.
#
#   $2 (abort_text)
#     Text to show to user in case the operation was aborted by user.
#
#   $3 (exit_code)
#     Exit code when terminating the proram.
#
function critical_confirmation() {
    local prompt_text="$1"
    local abort_text="$2"
    local exit_code="$3"

    echo -n "${_text_bold}${_text_yellow}[WARN] ${_text_reset}" "${prompt_text} Type YES to confirm (default is no): "
    read confirm

    if [[ $confirm != "YES" ]]; then
        error "$abort_text"
        exit "$ERROR_GENERAL"
    fi
}

#
# Validates that the specified value conforms to designated setting.
#
# This is a small helper function used within read_server_settings
# function to validate the settings.
#
# Arguments:
#
#   $1 (name)
#     Name of the setting. Used to show erros to the user.
#
#   $2 (value)
#     Value to validate.
#
#   $3 (type)
#
#     Value type. Currently supports the following types:
#
#       - bool (boolean)
#       - int (integer/number)
#       - str (string, essentially anything can pass this validation)
#       - list (space-separated list of strings, essentially anything
#         can pass this validation)
#       - VAL_1|...|VAL_N (choice between different values)
#
#     When using the VAL_1|...|VAL_N variant, validation is slightly
#     relaxed for string values to allow both quoted and unquoted
#     variants. For example, if type was set to true|false|"admins",
#     then both 'admin' and '"admins"' will validate successfully
#     against the type.
#
# Returns:
#
#   0 if validation has passed, 1 if validation failed, and 2 if
#   passed-in type is not supported.
#
function validate_server_setting_value() {
    local name="$1"
    local value="$2"
    local type="$3"

    declare -a possible_values

    local i

    # Assume failure.
    local result=1

    if [[ $type == "bool" ]]; then
        [[ $value == true || $value == false ]] && result=0 || colorecho "red" "$name must be a boolean [true|false]."

    elif [[ $type == "int" ]]; then
        [[ $value =~ ^[[:digit:]]+$ ]] && result=0 || colorecho "red" "$name must be a number."

    elif [[ $type == "str" ]]; then
        result=0

    elif [[ $type == "list" ]]; then
        # This is free-form space-delimited list.
        result=0

    elif [[ $type =~ ^.+\|.+$ ]]; then
        readarray -d "|" -t possible_values < <(echo -n "$type")

        for i in "${possible_values[@]}"; do
            # Allow strings without quotes to be specified by the user.
            [[ $value == $i || \"$value\" == $i ]] && result=0
        done

        [[ $result == 0 ]] || colorecho red "$name must be one of listed values [$type]."
    else
        error "Unsupported type associated with '$name': $type"
        result=2
    fi

    return "$result"
}

#
# Prompts user to provide settings for a server instance.
#
# Function will go over a number of questions, providing a set of
# default values, and allowing the user to edit them in-place. Once
# all questions have been answered, user is presented with summary and
# ability to revisit the settings again.
#
# The function will transform the answers to be fully usable in the
# server configuration file, making sure the parameters are properly
# escaped for use in a JSON file.
#
# Defaults are mostly identical to the ones listed under Factorio's
# default "server-settings.json" with some exceptions to options that
# may be considered invasion of privacy:
#
#   - User verification is disabled. Otherwise the central
#     authentication server will always be aware of who is playing the
#     game at the moment.
#   - Game is specifically configured to be non-public.
#
# In addition to settings from the "server-settings.json"
# configuiration file, settings also cover the server port (specified
# in the "config.ini").
#
# Arguments:
#
#   $1 (server_name)
#     Default name to use for the server.
#
# Sets:
#
#   settings_value
#     Associative array storing settings and their values. Keys are
#     equivalent to setting names in the server configuration file.
#
function read_server_settings() {

    # Read arguments.
    local server_name="$1"

    # Local helper variables.
    local key="" value="" prompt="" confirmed="" item="" validation_passed possible_values i

    declare -A settings_prompt=()
    declare -A settings_description=()
    declare -A settings_type=()

    declare -a settings_order=()

    # Global variables set by the function.
    declare -g -A settings_value=()

    # Set-up listings of server settings. Each setting is described
    # with name, prompt, description, default value, and
    # type. Supported types are: bool, int, str, list (input treated
    # as space-delimited list).
    #
    # Maintain additional array with keys in order to maintain
    # order when displaying questions to users.
    key="name"
    settings_prompt["$key"]="Name"
    settings_description["$key"]="Name of the game as it will appear in the game listing"
    settings_value["$key"]="$server_name"
    settings_type["$key"]="str"
    settings_order+=("$key")

    key="description"
    settings_prompt["$key"]="Description"
    settings_description["$key"]="Description of the game that will appear in the listing"
    settings_value["$key"]=""
    settings_type["$key"]="str"
    settings_order+=("$key")

    key="tags"
    settings_prompt["$key"]="Tags"
    settings_description["$key"]="Tags for the game that will appear in the listing (space-separated)"
    settings_value["$key"]=""
    settings_type["$key"]="list"
    settings_order+=("$key")

    # Not part of "server-settings.json", but important to show and
    # prompt the user for.
    key="port"
    settings_prompt["$key"]="Port"
    settings_description["$key"]="Port on which the server should listen"
    settings_value["$key"]="34197"
    settings_type["$key"]="int"
    settings_order+=("$key")

    key="max_players"
    settings_prompt["$key"]="Maximum players"
    settings_description["$key"]="Maximum number of players allowed, admins can join even a full server. 0 means unlimited."
    settings_value["$key"]="0"
    settings_type["$key"]="int"
    settings_order+=("$key")

    key="public"
    settings_prompt["$key"]="Publicly available"
    settings_description["$key"]="Game will be published on the official Factorio matching server."
    settings_value["$key"]="false"
    settings_type["$key"]="bool"
    settings_order+=("$key")

    key="lan"
    settings_prompt["$key"]="Broadcast on LAN"
    settings_description["$key"]="Game will be broadcast on LAN."
    settings_value["$key"]="false"
    settings_type["$key"]="bool"
    settings_order+=("$key")

    key="username"
    settings_prompt["$key"]="Factorio login username"
    settings_description["$key"]="Your factorio.com login credentials. Required for games with visibility public."
    settings_value["$key"]=""
    settings_type["$key"]="str"
    settings_order+=("$key")

    key="password"
    settings_prompt["$key"]="Factorio login password"
    settings_description["$key"]="Your factorio.com login credentials. Required for games with visibility public."
    settings_value["$key"]=""
    settings_type["$key"]="str"
    settings_order+=("$key")

    key="token"
    settings_prompt["$key"]="Factorio authentication token"
    settings_description["$key"]="Authentication token. May be used instead of 'password' for factorio.com login credentials."
    settings_value["$key"]=""
    settings_type["$key"]="str"
    settings_order+=("$key")

    key="game_password"
    settings_prompt["$key"]="Server password"
    settings_description["$key"]="Server password used to authenticate users towards the server itself. Default value has been randomly generated using /dev/urandom."
    settings_value["$key"]=$(tr -dc 'A-Za-z0-9' < /dev/urandom | head -c 33)
    settings_type["$key"]="str"
    settings_order+=("$key")

    key="require_user_verification"
    settings_prompt["$key"]="Require user verification"
    settings_description["$key"]="When set to true, the server will only allow clients that have a valid Factorio.com account."
    settings_value["$key"]="false"
    settings_type["$key"]="bool"
    settings_order+=("$key")

    key="max_upload_in_kilobytes_per_second"
    settings_prompt["$key"]="Maxiumum upload in kilobytes per second"
    settings_description["$key"]="Limits the maximum upload speed from server towards the clients (for map transfers etc). 0 means unlimited."
    settings_value["$key"]="0"
    settings_type["$key"]="int"
    settings_order+=("$key")

    key="max_upload_slots"
    settings_prompt["$key"]="Maximum upload slots"
    settings_description["$key"]="Limits the number of simulataneous uploads from server towards clients. 0 means unlimited."
    settings_value["$key"]="5"
    settings_type["$key"]="int"
    settings_order+=("$key")

    key="minimum_latency_in_ticks"
    settings_prompt["$key"]="Minimum latency in ticks"
    settings_description["$key"]="Minimum tolerable latency in ticks for connecting clients. One tick is 16ms in default speed. 0 means no minimum."
    settings_value["$key"]="0"
    settings_type["$key"]="int"
    settings_order+=("$key")

    key="ignore_player_limit_for_returning_players"
    settings_prompt["$key"]="Ignore player limit for returning players"
    settings_description["$key"]="Players that played on this map already can join even when the max player limit was reached."
    settings_value["$key"]="false"
    settings_type["$key"]="bool"
    settings_order+=("$key")

    key="allow_commands"
    settings_prompt["$key"]="Allow commands"
    settings_description["$key"]="Allow execution of commands via Lua console."
    settings_value["$key"]="admins-only"
    settings_type["$key"]="true|false|\"admins-only\""
    settings_order+=("$key")

    key="autosave_interval"
    settings_prompt["$key"]="Autosave interval"
    settings_description["$key"]="Autosave interval in minutes."
    settings_value["$key"]="10"
    settings_type["$key"]="int"
    settings_order+=("$key")

    key="autosave_slots"
    settings_prompt["$key"]="Autosave slots"
    settings_description["$key"]="Number of autosave slots to use. Autosave slots are cycled through when the server autosaves."
    settings_value["$key"]="5"
    settings_type["$key"]="int"
    settings_order+=("$key")

    key="afk_autokick_interval"
    settings_prompt["$key"]="AFK auto-kick interval"
    settings_description["$key"]="How many minutes until someone is kicked when doing nothing, 0 for never."
    settings_value["$key"]="0"
    settings_type["$key"]="int"
    settings_order+=("$key")

    key="auto_pause"
    settings_prompt["$key"]="Auto-pause"
    settings_description["$key"]="Whether should the server be paused when no players are present."
    settings_value["$key"]="true"
    settings_type["$key"]="bool"
    settings_order+=("$key")

    key="only_admins_can_pause_the_game"
    settings_prompt["$key"]="Only admins can pause the game"
    settings_description["$key"]="Specify if only admins should be able to pause the game."
    settings_value["$key"]="true"
    settings_type["$key"]="bool"
    settings_order+=("$key")

    key="autosave_only_on_server"
    settings_prompt["$key"]="Autosave only on server"
    settings_description["$key"]="Whether autosaves should be saved only on server or also on all connected clients."
    settings_value["$key"]="true"
    settings_type["$key"]="bool"
    settings_order+=("$key")

    key="non_blocking_saving"
    settings_prompt["$key"]="[EXPERT] Non-blocking saving"
    settings_description["$key"]="Highly experimental feature, enable only at your own risk of losing your saves. On UNIX systems, server will fork itself to create an autosave. Autosaving on connected Windows clients will be disabled regardless of autosave_only_on_server option."
    settings_value["$key"]="false"
    settings_type["$key"]="bool"
    settings_order+=("$key")

    key="minimum_segment_size"
    settings_prompt["$key"]="[EXPERT] Minimum segment size"
    settings_description["$key"]="Long network messages are split into segments that are sent over multiple ticks. Their size depends on the number of peers currently connected. Increasing the segment size will increase upload bandwidth requirement for the server and download bandwidth requirement for clients. This setting only affects server outbound messages. Changing these settings can have a negative impact on connection stability for some clients."
    settings_value["$key"]="25"
    settings_type["$key"]="int"
    settings_order+=("$key")

    key="minimum_segment_size_peer_count"
    settings_prompt["$key"]="[EXPERT] Minimum segment size peer count"
    settings_description["$key"]="See description for minimum_segment_size"
    settings_value["$key"]="20"
    settings_type["$key"]="int"
    settings_order+=("$key")

    key="maximum_segment_size"
    settings_prompt["$key"]="[EXPERT] Maximum segment size"
    settings_description["$key"]="See description for minimum_segment_size"
    settings_value["$key"]="100"
    settings_type["$key"]="int"
    settings_order+=("$key")

    key="maximum_segment_size_peer_count"
    settings_prompt["$key"]="[EXPERT] Maxmium segment size peer count"
    settings_description["$key"]="See description for minimum_segment_size"
    settings_value["$key"]="10"
    settings_type["$key"]="int"
    settings_order+=("$key")

    # Loop until user has confirmed the settings.
    while [[ ${confirmed,,} != 'y' ]]; do
        confirmed=""

        # Display the settings.
        echo "Current settings:"
        echo
        for key in "${settings_order[@]}"; do
            colorecho -n "yellow" "${settings_prompt[$key]}: "
            echo "${settings_value[$key]}"
        done

        # Prompt user to confirm settings.
        while [[ ${confirmed,,} != 'y' && ${confirmed,,} != 'n' ]]; do
            echo
            colorecho -n "green" "Are you satisfied with current settings (y/n)? "
            read -n1 confirmed
            echo
        done

        # Allow user to provide changed values if not satisfied with
        # settings.
        if [[ ${confirmed,,} == 'n' ]]; then
            echo

            local total_questions="${#settings_order[@]}"
            local current_question=1

            for key in "${settings_order[@]}"; do

                # Prompt based on associated value type for the setting.
                if [[ ${settings_type[$key]} == "bool" ]]; then
                    prompt="${settings_prompt[$key]} [true|false]:"
                elif [[ ${settings_type[$key]} == "int" ]]; then
                    prompt="${settings_prompt[$key]} [number]:"
                elif [[ ${settings_type[$key]} == "str" ]]; then
                    prompt="${settings_prompt[$key]} [text]:"
                elif [[ ${settings_type[$key]} == "list" ]]; then
                    prompt="${settings_prompt[$key]} [space-delimited list]:"
                else
                    prompt="${settings_prompt[$key]} [${settings_type[$key]}]:"
                fi

                # Add some coloring to the prompt.
                prompt=$(colorprintf "green" "%02d/%02d ${prompt} " "$current_question" "$total_questions")

                # Show setting description.
                colorecho "white" "${settings_description[$key]}" | fold -s

                # Keep prompting user until a valid value is provided.
                validation_result=""
                until [[ $validation_result == 0 ]]; do

                    read -p "$prompt" -e -i "${settings_value[$key]}" value

                    validate_server_setting_value "${settings_prompt[$key]}" "$value" "${settings_type[$key]}"
                    validation_result="$?"
                    [[ $validation_result == 2 ]] && error "Internal error, type not set correctly for setting: $key." && exit "$ERROR_GENERAL"
                done

                settings_value[$key]="$value"

                echo
                let current_question++
            done
        fi
    done

    # Prepare values so they can be used within the JSON file.
    for key in "${settings_order[@]}"; do
        debug "Raw value for $key: ${settings_value[$key]}"

        if ! validate_server_setting_value "$key (${settings_prompt[$key]})" "${settings_value[$key]}" "${settings_type[$key]}"; then
            error "Failed to validate the settings value. This is most likely an internal bug in $program."
            exit "$ERROR_GENERAL"
        fi

        if [[ ${settings_type[$key]} == "str" ]]; then
            settings_value[$key]="\"${settings_value[$key]}\""

        # Used for selecting between multiple values.
        elif [[ ${settings_type[$key]} =~ ^.+\|.+$ ]]; then
            readarray -d "|" -t possible_values < <(echo -n "${settings_type[$key]}")

            for i in "${possible_values[@]}"; do
                # Convenience for allowing strings without quotes specified by the user.
                [[ \"${settings_value[$key]}\" == $i ]] && settings_value[$key]="\"${settings_value[$key]}\""
            done

        # List of strings.
        elif [[ ${settings_type[$key]} == "list" ]]; then
            value=""

            for item in ${settings_value[$key]}; do
                value="$value, \"$item\""
            done

            settings_value[$key]="[${value##, }]"
        fi
        debug "Processed value for $key: ${settings_value[$key]}"
    done
}

# Define error codes.
SUCCESS=0
ERROR_ARGUMENTS=1
ERROR_CONFIGURATION=2
ERROR_GENERAL=3

# Disable debug and quiet modes by default.
debug=0
quiet=0

# Set-up some default paths.
manager_directory="$HOME/.factorio"
game_installations_directory="$manager_directory/.game_installations"

# If no arguments were given, just show usage help.
if [[ -z ${1-} ]]; then
    short_usage
    exit "$SUCCESS"
fi

# Parse the arguments
while getopts "qdvh" opt; do
    case "$opt" in
	q) quiet=1;;
	d) debug=1;;
        v) version
           exit "$SUCCESS";;
        h) usage
           exit "$SUCCESS";;
        *) usage
           exit "$ERROR_ARGUMENTS";;
    esac
done
i=$OPTIND
shift $(($i-1))

# Make sure the manager home directory exists.
if [[ ! -e $manager_directory ]]; then
    info "Creating Factorio Manager home directory under: $manager_directory"
    mkdir -p "$manager_directory"
fi

command="$1"
shift

#==============#
# set-game-dir #
#==============#
if [[ $command == set-game-dir ]]; then

    # Read and verify additional positional arguments.
    game_installations_directory="${1-}"
    shift

    if [[ -z $game_installations_directory ]]; then
        error "Missing argument: GAME_INSTALLATIONS_DIRECTORY"
        exit "$ERROR_ARGUMENTS"
    fi

    if [[ ! -e $game_installations_directory ]]; then
        error "No such directory: $game_installations_directory"
        exit "$ERROR_GENERAL"
    fi

    # Set-up additional derived variables.
    symlink="$manager_directory/.game_installations"

    # Verify that at least one Factorio instance can be found.
    factorio_versions_found=0
    for candidate in "$game_installations_directory"/*; do
        if [[ -f $candidate/bin/x64/factorio ]]; then
            let factorio_versions_found++
        fi
    done

    if (( $factorio_versions_found == 0 )); then
        error "Could not locate any Factorio installations under: $game_installations_directory"

        exit "$ERROR_GENERAL"
    fi

    # Update the link
    if [[ -L $symlink ]]; then
        rm "$symlink"
    fi

    if ! ln -s "$game_installations_directory" "$symlink"; then
        error "Could not create symlink from $game_installations_directory to $symlink."

        exit "$ERROR_GENERAL"
    fi

#==========#
# versions #
#==========#
elif [[ $command == versions ]]; then

    # Make sure user has set directory with game installations - test
    # both symlink and target destination.
    if [[ ! -L $game_installations_directory ]]; then
        error "Game installations directory has not been properly set. Please run the set-game-dir command first."
        exit "$ERROR_CONFIGURATION"
    fi

    if [[ ! -d $game_installations_directory ]]; then
        error "Game installations directory has not been properly set. Please run the set-game-dir command first."
        exit "$ERROR_CONFIGURATION"
    fi

    echo "Locally available Factorio versions:"
    echo

    # Find all sub-directories that are Factorio installations.
    for candidate in "$game_installations_directory"/*; do
        if [[ -d $candidate && -e $candidate/bin/x64/factorio ]]; then
            echo "  - $(basename "$candidate")"
        fi
    done
    echo

#======#
# list #
#======#
elif [[ $command == list ]]; then
    echo "Available instances:"
    echo

    # Find all sub-directories that are valid instances.
    for candidate in "$manager_directory"/*; do
        if [[ -f $candidate/instance.conf ]]; then
            source "$candidate/instance.conf"
            echo "  - $(basename "$candidate") ($game_version)"
        fi
    done
    echo

#========#
# create #
#========#
elif [[ $command == create ]]; then
    # Make sure user has set directory with game installations - test
    # both symlink and target destination.
    if [[ ! -L $game_installations_directory ]]; then
        error "Game installations directory has not been properly set. Please run the set-game-dir command first."
        exit "$ERROR_CONFIGURATION"
    fi

    if [[ ! -d $game_installations_directory ]]; then
        error "Game installations directory has not been properly set. Please run the set-game-dir command first."
        exit "$ERROR_CONFIGURATION"
    fi

    # Read positional arguments.
    instance="${1-}"
    shift

    # Calculate derived variables.
    instance_directory="$manager_directory/$instance"
    instance_config="$instance_directory/instance.conf"
    game_config="$instance_directory/config.ini"

    # Verify arguments.
    if [[ -z $instance ]]; then
        error "Missing argument: INSTANCE"
        exit "$ERROR_ARGUMENTS"
    fi

    if [[ -e $instance_directory ]]; then
        error "Instance already exists."
        exit "$ERROR_ARGUMENTS"
    fi

    # Display list of available Factorio versions and let user pick one.
    echo "The following versions of Factorio are locally available:"
    echo

    for candidate in "$game_installations_directory"/*; do
        if [[ -f $candidate/bin/x64/factorio ]]; then
            echo "  - $(basename "$candidate")"
        fi
    done

    echo

    echo -n "Please specify what version you would like to use: "
    read game_version_selected

    # Validate user input.
    if [[ ! -f "$game_installations_directory/$game_version_selected/bin/x64/factorio" ]]; then
        error "Requested version not locally available: $game_version_selected"
        exit "$ERROR_ARGUMENTS"
    fi

    # Set-up the instance.
    mkdir "$instance_directory"
    mkdir "$instance_directory/mods"
    echo "{}" > "$instance_directory/mods/mod-list.json"

    cat <<EOF > "$instance_config"
game_version="$game_version_selected"
EOF

    # @TODO: If we could somehow obtain stock config.ini file without
    # having to first run Factorio, that would be great. As it is, the
    # user will presented with warning about corrupt config.ini when
    # running the instance for the first time.
    cat <<EOF > "$game_config"
[path]
read-data=__PATH__executable__/../../data
write-data=${instance_directory}

[general]
locale=

[other]
check-updates=false
enable-crash-log-uploading=false

[interface]

[controls]

[sound]

[map-view]

[debug]

[multiplayer-lobby]

[graphics]
EOF

    echo
    warning "Factorio Manager has created a minimal empty configuration file for Factorio under $game_config."
    warning "Since the generated configuration file is almost empty, Factorio will complain that the file seems corrupt."
    warning "Factorio will offer to fix the corrupted configuration file by filling-in the missing information during the first startup."
    warning "It should be safe to accept this. This warning will be shown by Factorio only the first time."
    echo
    echo "Please read the warning above, and press any key to continue."
    read

elif [[ $command == launch ]]; then

    # Read positional arguments.
    instance="${1-}"
    shift

    # Set-up derived variables.
    instance_directory="$manager_directory/$instance"
    instance_config="$instance_directory/instance.conf"
    game_config="$instance_directory/config.ini"
    server_config="$instance_directory/server-settings.json"

    # Verify arguments.
    if [[ -z $instance ]]; then
        error "Missing argument: INSTANCE"
        exit "$ERROR_ARGUMENTS"
    fi

    if [[ ! -f $instance_config ]]; then
        error "Missing instance configuration file: $instance_config"
        exit "$ERROR_GENERAL"
    fi

    if [[ ! -f $game_config ]]; then
        error "Missing game configuration file: $game_config"
        exit "$ERROR_GENERAL"
    fi

    # Update instance write directory prior to launching - this is a
    # failsafe in case it got changed by hand through some other means
    # (or maybe it was copied over from another instance).
    current_write_data=$(grep "^write-data=" "$game_config")
    expected_write_data="write-data=${instance_directory}"

    if [[ $current_write_data != $expected_write_data ]]; then
        warning "Incorrect path specified for write-data in game configuration file: $game_config"
        warning "Current configuration is: $current_write_data"
        warning "Configuration will be replaced with: $expected_write_data"
        sed -i -e "s#^write-data=.*#$expected_write_data#" "$game_config"
    fi

    # Read launcher configuration for the instance.
    source "$instance_config"

    if [[ -z $game_version ]]; then
        error "Missing game version information in $game_config."
        exit "$ERROR_CONFIGURATION"
    fi

    # Set-up paths for launching the game, and ensure they still exist
    # (versions can be removed by user).
    game_directory="${game_installations_directory}/${game_version}"
    factorio_bin="$game_directory/bin/x64/factorio"

    if [[ ! -e $factorio_bin ]]; then
        error "Could not locate Factorio binary under: $factorio_bin"
        error "Factorio $game_version installation may have been removed from game installations directory:"
        error "   $(readlink -f "$game_installations_directory")"
        exit "$ERROR_CONFIGURATION"
    fi

    # Launch instance
    if [[ -e $server_config ]]; then
        "$factorio_bin" --config "$game_config" --start-server "$instance_directory/saves/default.zip"
    else
        "$factorio_bin" --config "$game_config"
    fi

elif [[ $command == backup ]]; then
    # Read positional arguments.
    instance="${1-}"
    description="${2-}"
    shift 2

    # Use timestamp-based names for backups.
    timestamp=$(date +%Y-%m-%d_%H:%M:%S)

    # Set-up derived variables.
    instance_directory="$manager_directory/$instance"
    instance_config="$instance_directory/instance.conf"
    game_config="$instance_directory/config.ini"
    lock_file="$instance_directory/.lock"

    backup_directory="$instance_directory/.bak"
    backup_destination="$backup_directory/$timestamp"
    backup_description="$backup_destination/.description"

    # Verify positional arguments.
    if [[ -z $instance ]]; then
        error "Missing argument: INSTANCE"
        exit "$ERROR_ARGUMENTS"
    fi

    # Verify that we are trying to backup an actual instance.
    if [[ ! -f $instance_config ]]; then
        error "Missing instance configuration file: $instance_config"
        exit "$ERROR_GENERAL"
    fi

    if [[ ! -f $game_config ]]; then
        error "Missing game configuration file: $game_config"
        exit "$ERROR_GENERAL"
    fi

    # Make sure we do not overwrite the backup destination by mistake
    # - although highly unlikely unless user spams the backup command.
    if [[ -e $backup_destination ]]; then
        error "Backup already exists: $backup_destination"
    fi

    (

        # Obtain lock - Factorio uses the same mechanism, so we should
        # be able to detect the game is running in this way.
        flock --exclusive --nonblock 200
        if [[ $? != 0 ]]; then
            error "Could not lock instance directory via lock file $lock_file. Is Factorio instance still running?"
            exit "$ERROR_GENERAL"
        fi

        function remove_lock() {
            rm "$lock_file"
        }

        trap remove_lock EXIT

        # Backup the instance. Clean-up the backup destination in case of failure.
        mkdir -p "$backup_destination"
        if ! cp -a "$instance_directory"/* "$backup_destination"; then
            error "Could not create backup under: $backup_destination"
            rm -rf "$backup_destination"
            exit "$ERROR_GENERAL"
        fi

        # Store (optional) description.
        if [[ -n $description ]]; then
            echo "$description" > "$backup_description"
        fi

        success "Backup saved to: $backup_destination"

    ) 200>"$lock_file"

#==============#
# list-backups #
#==============#
elif [[ $command == list-backups ]]; then

    # Read positional arguments.
    instance="${1-}"
    shift

    # Set-up derived variables.
    instance_directory="$manager_directory/$instance"
    instance_config="$instance_directory/instance.conf"
    game_config="$instance_directory/config.ini"
    backup_directory="$instance_directory/.bak"

    # Verify positional arguments.
    if [[ -z $instance ]]; then
        error "Missing argument: INSTANCE"
        exit "$ERROR_ARGUMENTS"
    fi

    # Verify instance.
    if [[ ! -d $instance_directory ]]; then
        error "No such instance: $instance"
        exit "$ERROR_ARGUMENTS"
    fi

    if [[ ! -f $instance_config ]]; then
        error "Missing instance configuration file: $instance_config"
        exit "$ERROR_GENERAL"
    fi

    if [[ ! -f $game_config ]]; then
        error "Missing game configuration file: $game_config"
        exit "$ERROR_GENERAL"
    fi

    # Extended regular expression for matching YYYY-MM-DD-hh:mm:ss format.
    backup_destination_name_pattern="[[:digit:]]{4}-[[:digit:]]{2}-[[:digit:]]{2}_[[:digit:]]{2}:[[:digit:]]{2}:[[:digit:]]{2}"

    # Read current game version.
    source "$instance_config"
    current_game_version="$game_version"
    unset game_version

    # Detect and show available backups to the user.
    if [[ ! -d $backup_directory ]] || ! ls "$backup_directory" | grep -q -E "^$backup_destination_name_pattern\$"; then
        echo "No backups are available for instance $(colorecho -n green "$instance")."
    else
        echo "Available backups for instance $(colorecho -n green "$instance") (current version $(colorecho -n green "$current_game_version"))."
        echo

        for backup_destination in "$backup_directory"/*; do

            if [[ $backup_destination =~ $backup_destination_name_pattern ]]; then
                backup_date=$(basename "$backup_destination")

                # Read instance configuration for backup.
                source "$backup_destination/instance.conf"

                if [[ -f "$backup_destination/.description" ]]; then
                    backup_description=$(<"$backup_destination/.description")
                    echo "  - $backup_date - version $(colorecho -n green "$game_version") ($backup_description)"
                else
                    echo "  - $backup_date - version $(colorecho -n green "$game_version")"
                fi


            fi
        done

        echo

    fi

#=========#
# restore #
#=========#
elif [[ $command == restore ]]; then

    # Read positional arguments.
    instance="${1-}"
    backup_name="${2-}"
    shift 2

    # Set-up derived values.
    instance_directory="$manager_directory/$instance"
    restore_source="$instance_directory/.bak/$backup_name"
    backup_instance_config="$restore_source/instance.conf"
    backup_game_config="$restore_source/config.ini"
    lock_file="$instance_directory/.lock"

    # Verify positional arguments.
    if [[ -z $instance ]]; then
        error "Missing argument: INSTANCE"
        exit "$ERROR_ARGUMENTS"
    fi

    if [[ -z $backup_name ]]; then
        error "Missing argument: BACKUP_NAME"
        exit "$ERROR_ARGUMENTS"
    fi

    # Verify we are working with legitimate instance and backup.
    if [[ ! -d $instance_directory ]]; then
        error "No such instance: $instance"
        exit "$ERROR_ARGUMENTS"
    fi

    if [[ ! -d $restore_source ]]; then
        error "Specified backup not available under: $restore_source"
        exit "$ERROR_ARGUMENTS"
    fi

    if [[ ! -f $backup_instance_config ]]; then
        error "Invalid backup, missing instance configuration file: $backup_instance_config"
        exit "$ERROR_GENERAL"
    fi

    if [[ ! -f $backup_game_config ]]; then
        error "Invalid backup, missing game configuration file: $backup_game_config"
        exit "$ERROR_GENERAL"
    fi

    (
        # Obtain lock - Factorio uses the same mechanism, so we should
        # be able to detect the game is running in this way.
        flock --exclusive --nonblock 200
        if [[ $? != 0 ]]; then
            error "Could not lock instance directory via lock file $lock_file. Is Factorio instance still running?"
            exit "$ERROR_GENERAL"
        fi

        function remove_lock() {
            rm "$lock_file"
        }
        trap remove_lock EXIT

        # Set-up a list of files and directories that will get removed.
        shopt -s nullglob
        entries_to_remove=($instance_directory/*)
        shopt -u nullglob

        # Present user with extensive warning on consequences.
        echo
        warning "You are about to replace current instance's files, including (but not limited to):"
        warning
        warning "  - configuration files"
        warning "  - blueprints"
        warning "  - savegames"
        warning "  - achievements"
        warning "  - mods"
        warning
        warning "All instance files will be replaced by files from specified backup."

        # Display backup information.
        echo
        if [[ -f "$restore_source/.description" ]]; then
            backup_description=$(<"$restore_source/.description")
            backup_info="$backup_name ($backup_description)"
        else
            backup_info="$backup_name"
        fi
        echo "Restore instance $(colorecho -n green "$instance") from backup: $(colorecho -n green "$backup_info")"
        echo

        # Show user what files will be removed.
        if [[ ${#entries_to_remove[@]} == 0 ]]; then
            echo "Instance directory is currently empty. No files will be removed."
            echo
        else
            echo "Files and directories that will be removed:"
            echo
            for entry in "${entries_to_remove[@]}"; do
                echo "  - $entry"
            done
            echo
        fi

        # Request from user to confirm the operation.
        critical_confirmation "Are you sure you want to proceed?" \
                              "Aborted restore process, no changes have been made to instance files." \
                              "$ERROR_GENERAL"

        if [[ ${#entries_to_remove[@]} != 0 ]]; then
            if ! rm -rf "${entries_to_remove[@]}"; then
                error "Failed to remove existing instance files."
                exit "$ERROR_GENERAL"
            fi
        fi

        if ! cp -a "$restore_source"/* "$instance_directory"; then
            error "Failed to restore backup from: $restore_source"
            exit "$ERROR_GENERAL"
        fi

        success "Instance restored from backup."

    ) 200>"$lock_file"

#===============#
# remove-backup #
#===============#
elif [[ $command == remove-backup ]]; then

    # Read positional arguments.
    instance="${1-}"
    backup_name="${2-}"
    shift 2

    # Verify positional arguments.
    if [[ -z $instance ]]; then
        error "Missing argument: INSTANCE"
        exit "$ERROR_ARGUMENTS"
    fi

    if [[ -z $backup_name ]]; then
        error "Missing argument: BACKUP_NAME"
        exit "$ERROR_ARGUMENTS"
    fi

    # Set-up derived values.
    instance_directory="$manager_directory/$instance"
    removal_target="$instance_directory/.bak/$backup_name"
    backup_instance_config="$removal_target/instance.conf"
    backup_game_config="$removal_target/config.ini"
    lock_file="$instance_directory/.lock"

    # Verify we are working with legitimate instance and backup.
    if [[ ! -d $instance_directory ]]; then
        error "No such instance: $instance"
        exit "$ERROR_ARGUMENTS"
    fi

    if [[ ! -d $removal_target ]]; then
        error "Specified backup not available under: $removal_target"
        exit "$ERROR_ARGUMENTS"
    fi

    if [[ ! -f $backup_instance_config ]]; then
        error "Invalid backup, missing instance configuration file: $backup_instance_config"
        exit "$ERROR_GENERAL"
    fi

    if [[ ! -f $backup_game_config ]]; then
        error "Invalid backup, missing game configuration file: $backup_game_config"
        exit "$ERROR_GENERAL"
    fi

    # Present user with warning.
    echo
    if [[ -f "$removal_target/.description" ]]; then
        backup_description=$(<"$removal_target/.description")
        backup_info="$backup_name ($backup_description)"
    else
        backup_info="$backup_name"
    fi

    warning "You are about to remove an instance backup. All files belonging to specified backup will be removed."
    echo
    echo "Instance: $(colorecho -n green "$instance")"
    echo
    echo "Backup: $(colorecho -n green "$backup_info")"
    echo
    echo "Files and directories that will be removed:"
    echo
    echo " - $removal_target"
    echo

    # Request from user to confirm the operation.
    critical_confirmation "Are you sure you want to proceed?" \
                          "Aborted backup removal, no changes have been made to backup files." \
                          "$ERROR_GENERAL"

    if ! rm -rf "$removal_target"; then
        error "Failed to remove existing instance files."
        exit "$ERROR_GENERAL"
    fi

    success "Backup removed."

#=============#
# set-version #
#=============#
elif [[ $command == set-version ]]; then
    # Read positional arguments.
    instance="${1-}"
    shift

    # Verify positional arguments.
    if [[ -z $instance ]]; then
        error "Missing argument: INSTANCE"
        exit "$ERROR_ARGUMENTS"
    fi

    # Make sure user has set directory with game installations - test
    # both symlink and target destination.
    if [[ ! -L $game_installations_directory ]]; then
        error "Game installations directory has not been properly set. Please run the set-game-dir command first."
        exit "$ERROR_CONFIGURATION"
    fi

    if [[ ! -d $game_installations_directory ]]; then
        error "Game installations directory has not been properly set. Please run the set-game-dir command first."
        exit "$ERROR_CONFIGURATION"
    fi

    # Set-up derived variables.
    instance_directory="$manager_directory/$instance"
    instance_config="$instance_directory/instance.conf"
    game_config="$instance_directory/config.ini"

    # Verify we are working with legitimate instance.
    if [[ ! -f $instance_config ]]; then
        error "Missing instance configuration file: $instance_config"
        exit "$ERROR_GENERAL"
    fi

    if [[ ! -f $game_config ]]; then
        error "Missing game configuration file: $game_config"
        exit "$ERROR_GENERAL"
    fi

    # Load instance configuration.
    source "$instance_config"

    # Display list of available Factorio versions.
    echo
    echo "The following versions of Factorio are locally available:"
    echo

    for candidate in "$game_installations_directory"/*; do
        if [[ -f $candidate/bin/x64/factorio ]]; then
            candidate_version=$(basename "$candidate")
            if [[ $candidate_version == $game_version ]]; then
                echo "  - $candidate_version $(colorecho -n green "[current]")"
            else
                echo "  - $candidate_version"
            fi

        fi
    done
    echo

    # Display current version.
    echo "Current version used for instance $(colorecho -n green "$instance") is $(colorecho -n green "$game_version")."
    echo
    read -p "Please specify what version you would like to use (enter to keep current): " game_version_selected

    if [[ -z $game_version_selected ]]; then
        game_version_selected="$game_version"
    fi

    # Validate user input.
    if [[ ! -f "$game_installations_directory/$game_version_selected/bin/x64/factorio" ]]; then
        error "Requested version not locally available: $game_version_selected"
        exit "$ERROR_ARGUMENTS"
    fi

    # Change instance game version.
    if [[ $game_version_selected == $game_version ]]; then
        info "Current version has been kept."
    else
        sed -i -e "s/^game_version=.*/game_version=$game_version_selected/" "$instance_config"
        success "Version changed to: $(colorecho -n green "$game_version_selected")"
    fi

#======#
# info #
#======#
elif [[ $command == info ]]; then
    # Make sure user has set directory with game installations - test
    # both symlink and target destination.
    if [[ ! -L $game_installations_directory ]]; then
        error "Game installations directory has not been properly set. Please run the set-game-dir command first."
        exit "$ERROR_CONFIGURATION"
    fi

    if [[ ! -d $game_installations_directory ]]; then
        error "Game installations directory has not been properly set. Please run the set-game-dir command first."
        exit "$ERROR_CONFIGURATION"
    fi

    # Read positional arguments.
    instance="${1-}"
    shift

    # Verify positional arguments.
    if [[ -z $instance ]]; then
        error "Missing argument: INSTANCE"
        exit "$ERROR_ARGUMENTS"
    fi

    # Set-up derived variables.
    instance_directory="$manager_directory/$instance"
    instance_config="$instance_directory/instance.conf"
    game_config="$instance_directory/config.ini"

    # Verify we are working with legitimate instance.
    if [[ ! -f $instance_config ]]; then
        error "Missing instance configuration file: $instance_config"
        exit "$ERROR_GENERAL"
    fi

    if [[ ! -f $game_config ]]; then
        error "Missing game configuration file: $game_config"
        exit "$ERROR_GENERAL"
    fi

    # Load instance configuration.
    source "$instance_config"

    # Basic information.
    echo "Instance name: $(colorecho -n green "$instance")"

    if [[ -e "$game_installations_directory/$game_version" ]]; then
        echo "Game version: $(colorecho -n green "$game_version")"
    else
        echo "Game version: $(colorecho -n red "$game_version [not available locally]")"
    fi

    echo "Instance path: $(colorecho -n green "$instance_directory")"
    echo

    # Mod information.
    shopt -s nullglob
    mod_files=($instance_directory/mods/*.zip)
    mod_list="$instance_directory/mods/mod-list.json"
    shopt -u nullglob

    if [[ ${#mod_files[@]} == 0 ]]; then
        echo "Available mods: none"

    # Plain listing.
    elif ! hash jqs 2>/dev/null; then
        echo "Available mods:"
        echo

        # Determine if mod is enabled by default or not when added to
        # mods directory (and is not yet listed in the mod list file).
        if grep -i -q "^[[:blank:]]*enable-new-mods=false" "$game_config"; then
            enable_new_mods="false"
        else
            enable_new_mods="true"
        fi

        # Process every mod found.
        for mod_file in "${mod_files[@]}"; do

            if [[ -f $mod_file ]]; then
                # Extract basic information about mod from the filename.
                mod_basename=$(basename "$mod_file" .zip)
                mod_name="${mod_basename%_*}"
                mod_version="${mod_basename##*_}"

                # Determine if mod is enabled or not.

                if grep -A1 "\"name\": \"$mod_name\"" "$mod_list" | tail -n1 | grep -q '"enabled": false'; then
                    color="$_text_yellow"
                elif grep -A1 "\"name\": \"$mod_name\"" "$mod_list" | tail -n1 | grep -q '"enabled": true'; then
                    color=""
                elif [[ $enable_new_mods == "false" ]]; then
                    color="$_text_yellow"
                else
                    color=""
                fi

                # Show colored-information for the mod.
                printf "$color  - %-48s %8s $_text_reset\n" "$mod_name" "$mod_version"
            fi

        done

    # Fancy listing with detection for enabled mods using jq.
    elif hash jq 2>/dev/null; then
        echo "Available mods (enabled/${_text_yellow}disabled${_text_reset}):"
        echo

        # Determine if mod is enabled by default or not when added to
        # mods directory (and is not yet listed in the mod list file).
        if grep -i -q "^[[:blank:]]*enable-new-mods=false" "$game_config"; then
            enable_new_mods="false"
        else
            enable_new_mods="true"
        fi

        # Query string used in jq tool to determine if mod is enabled
        # or not. Take note that this string should remain
        # single-quoted, and that $ expansions are actually done
        # internally in jq itself. Query accepts two vars - mod_name
        # and enable_new_mods.
        jq_is_enabled_query='.mods | map(select(.name==$mod_name))[0] // {"name": "default", "enabled": $enable_new_mods} | .enabled'

        # Process every mod found.
        for mod_file in "${mod_files[@]}"; do

            if [[ -f $mod_file ]]; then

                # Extract basic information about mod from the filename.
                mod_basename=$(basename "$mod_file" .zip)
                mod_name="${mod_basename%_*}"
                mod_version="${mod_basename##*_}"

                # Determine if mod is enabled or not.
                if jq -e \
                      --arg "mod_name" "$mod_name" \
                      --argjson "enable_new_mods" "$enable_new_mods" \
                      "$jq_is_enabled_query" "$mod_list" > /dev/null; then
                    color=""
                else
                    color="$_text_yellow"
                fi

                # Show colored-information for the mod.
                printf "$color  - %-48s %8s $_text_reset\n" "$mod_name" "$mod_version"
            fi
        done
    fi
    echo

    # Call self for displaying list of backups. Better than duplicating code.
    "$program" list-backups "$instance" | sed -e "s/^Available backups for instance.*/Available backups:/"


#========#
# remove #
#========#
elif [[ $command == remove ]]; then

    # Read positional arguments.
    instance="${1-}"
    shift

    # Verify positional arguments.
    if [[ -z $instance ]]; then
        error "Missing argument: INSTANCE"
        exit "$ERROR_ARGUMENTS"
    fi

    # Set-up derived values.
    instance_directory="$manager_directory/$instance"
    instance_config="$instance_directory/instance.conf"
    lock_file="$instance_directory/.lock"

    # Verify we are working with legitimate instance and backup.
    if [[ ! -d $instance_directory ]]; then
        error "No such instance: $instance"
        exit "$ERROR_ARGUMENTS"
    fi

    if [[ ! -f $instance_config ]]; then
        error "Missing instance configuration file: $instance_config"
        exit "$ERROR_GENERAL"
    fi

    (
        # Obtain lock - Factorio uses the same mechanism, so we should
        # be able to detect the game is running in this way.
        flock --exclusive --nonblock 200
        if [[ $? != 0 ]]; then
            error "Could not lock instance directory via lock file $lock_file. Is Factorio instance still running?"
            exit "$ERROR_GENERAL"
        fi

        # Removing lock file will most likely fail if we manage to
        # remove the instance.
        function remove_lock() {
            rm -f "$lock_file"
        }
        trap remove_lock EXIT

        # Set-up a list of files and directories that will get removed.
        shopt -s nullglob dotglob
        entries_to_remove=($instance_directory/*)
        shopt -u nullglob dotglob

        # Present user with extensive warning on consequences.
        echo
        warning "You are about to remove all instance's files, including (but not limited to):"
        warning
        warning "  - configuration files"
        warning "  - blueprints"
        warning "  - savegames"
        warning "  - achievements"
        warning "  - mods"
        warning "  - backups"
        warning
        warning "All instance files will be removed."
        echo

        # Show user what files will be removed.
        if [[ ${#entries_to_remove[@]} == 0 ]]; then
            echo "Instance directory is currently empty. No files will be removed."
            echo
        else
            echo "Files and directories that will be removed:"
            echo
            echo "  - $instance_directory"
            for entry in "${entries_to_remove[@]}"; do
                echo "  - $entry"
            done
            echo
        fi

        # Display instance information.
        source "$instance_config"
        echo "Instance name:    $(colorecho -n green "$instance")"
        echo "Instance version: $(colorecho -n green "$game_version")"
        echo

        # Request from user to confirm the operation.
        critical_confirmation "Are you sure you want to proceed?" \
                              "Aborted instance removal, no changes have been made to instance files." \
                              "$ERROR_GENERAL"

        if [[ ${#entries_to_remove[@]} != 0 ]]; then
            if ! rm -rf "${entries_to_remove[@]}"; then
                error "Failed to remove instance files."
                exit "$ERROR_GENERAL"
            fi
        fi

        if ! rmdir "$instance_directory"; then
            error "Failed to remove instance files."
            exit "$ERROR_GENERAL"
        fi

        success "Instance removed."

    ) 200>"$lock_file"


#======#
# copy #
#======#
elif [[ $command == copy ]]; then

    # Make sure user has set directory with game installations - test
    # both symlink and target destination.
    if [[ ! -L $game_installations_directory ]]; then
        error "Game installations directory has not been properly set. Please run the set-game-dir command first."
        exit "$ERROR_CONFIGURATION"
    fi

    if [[ ! -d $game_installations_directory ]]; then
        error "Game installations directory has not been properly set. Please run the set-game-dir command first."
        exit "$ERROR_CONFIGURATION"
    fi

    # Read positional arguments.
    source_instance="${1-}"
    destination_instance="${2-}"
    shift 2

    # Verify positional arguments.
    if [[ -z $source_instance ]]; then
        error "Missing argument: SOURCE_INSTANCE"
        exit "$ERROR_ARGUMENTS"
    fi

    if [[ -z $destination_instance ]]; then
        error "Missing argument: DESTINATION_INSTANCE"
        exit "$ERROR_ARGUMENTS"
    fi

    # Calculate derived variables.
    source_instance_directory="$manager_directory/$source_instance"
    source_instance_config="$source_instance_directory/instance.conf"
    source_game_config="$source_instance_directory/config.ini"
    source_lock_file="$source_instance_directory/.lock"

    destination_instance_directory="$manager_directory/$destination_instance"
    destination_instance_config="$destination_instance_directory/instance.conf"

    # Verify we are working with legitimate source and destination.
    if [[ ! -d $source_instance_directory ]]; then
        error "No such instance: $source_instance"
        exit "$ERROR_ARGUMENTS"
    fi

    if [[ ! -f $source_instance_config ]]; then
        error "Missing instance configuration file: $source_instance_config"
        exit "$ERROR_GENERAL"
    fi

    if [[ ! -f $source_game_config ]]; then
        error "Missing game configuration file: $source_game_config"
        exit "$ERROR_GENERAL"
    fi

    if [[ -e $destination_instance_directory ]]; then
        error "Instance already exists."
        exit "$ERROR_ARGUMENTS"
    fi

    (
        # Obtain lock - Factorio uses the same mechanism, so we should
        # be able to detect the game is running in this way.
        flock --exclusive --nonblock 200
        if [[ $? != 0 ]]; then
            error "Could not lock instance directory via lock file $source_lock_file. Is Factorio instance still running?"
            exit "$ERROR_GENERAL"
        fi

        function remove_lock() {
            rm "$source_lock_file"
        }

        trap remove_lock EXIT

        # Load source instance configuration.
        source "$source_instance_config"

        # Display list of available Factorio versions.
        echo
        echo "If you wish to, you can now change version of Factorio used for destination instance, or keep the same version as for source instance."
        echo
        echo "The following versions of Factorio are locally available:"
        echo

        for candidate in "$game_installations_directory"/*; do
            if [[ -f $candidate/bin/x64/factorio ]]; then
                candidate_version=$(basename "$candidate")
                if [[ $candidate_version == $game_version ]]; then
                    echo "  - $candidate_version $(colorecho -n green "[current]")"
                else
                    echo "  - $candidate_version"
                fi
            fi
        done
        echo

        # Display current version.
        echo "Current version used for instance $(colorecho -n green "$source_instance") is $(colorecho -n green "$game_version")."
        echo
        read -p "Please specify what version you would like to use for new instance (press enter to keep the current version): " game_version_selected

        if [[ -z $game_version_selected ]]; then
            game_version_selected="$game_version"
        fi

        # Validate user input.
        if [[ ! -f "$game_installations_directory/$game_version_selected/bin/x64/factorio" ]]; then
            error "Requested version not locally available: $game_version_selected"
            exit "$ERROR_ARGUMENTS"
        fi

        # Check if user wants to copy backup files as well.
        copy_backups=""

        until [[ $copy_backups == "y" || $copy_backups == "n" ]]; do
            echo
            read -n1 -p "Would you like to copy backup files as well? (y/n)" copy_backups
            echo
            copy_backups="${copy_backups,,}"

            if [[ $copy_backups != "y" && $copy_backups != "n" ]]; then
                echo
                error "Please answer only with 'y' or 'n'."
            fi
        done

        # Set-up a list of files and directories to copy.
        entries_to_copy=($source_instance_directory/*)

        if [[ $copy_backups == "y" && -e "$source_instance_directory/.bak" ]]; then
             entries_to_copy+=("$source_instance_directory/.bak")
        fi

        # Create copy of source instance.
        mkdir "$destination_instance_directory"
        cp -a "${entries_to_copy[@]}" "$destination_instance_directory/"

        # Update write-data directory of destination instance,
        # including the backups.
        write_data="write-data=${destination_instance_directory}"
        find "$destination_instance_directory/" -type f -name config.ini -exec \
             sed -i -e "s#^write-data=.*#$write_data#" '{}' \;

        sed -i -e "s/^game_version=.*/game_version=$game_version_selected/" "$destination_instance_config"

        success "Created new instance $(colorecho -n green "$destination_instance") using version $(colorecho -n green "$game_version_selected") as copy of instance $(colorecho -n green "$source_instance")."

    ) 200>"$source_lock_file"

#========#
# import #
#========#
elif [[ $command == import ]]; then

    # Make sure user has set directory with game installations - test
    # both symlink and target destination.
    if [[ ! -L $game_installations_directory ]]; then
        error "Game installations directory has not been properly set. Please run the set-game-dir command first."
        exit "$ERROR_CONFIGURATION"
    fi

    if [[ ! -d $game_installations_directory ]]; then
        error "Game installations directory has not been properly set. Please run the set-game-dir command first."
        exit "$ERROR_CONFIGURATION"
    fi

    # Read positional arguments.
    instance="${1-}"
    source_directory="${2-}"
    shift 2

    # Verify positional arguments.
    if [[ -z $instance ]]; then
        error "Missing argument: INSTANCE"
        exit "$ERROR_ARGUMENTS"
    fi

    if [[ -z $source_directory ]]; then
        error "Missing argument: SOURCE_DIRECTORY"
        exit "$ERROR_ARGUMENTS"
    fi

    # Calculate derived variables.
    instance_directory="$manager_directory/$instance"
    instance_config="$instance_directory/instance.conf"
    game_config="$instance_directory/config.ini"

    source_config="$source_directory/config/config.ini"
    source_lock_file="$source_directory/.lock"

    # List of entries to import from the source directory.
    declare -A import_entries=()
    import_entries["achievements-modded.dat"]="contains achivement information for modded plays"
    import_entries["achievements.dat"]="contains achievement information for vanilla plays"
    import_entries["archive"]="contains desync reports"
    import_entries["blueprint-storage.dat"]="contains global (non-savegame specific) blueprints"
    import_entries["config/config.ini"]="contains game configuration, including things like shortcuts etc."
    import_entries["crop-cache.dat"]="purpose is not known"
    import_entries["factorio-current.log"]="contains logs from the currently running game"
    import_entries["factorio-previous.log"]="contains logs from the previously running game"
    import_entries["mods"]="contains mods and mod settings"
    import_entries["player-data.json"]="contains global information about the player, such as username, login token, chat history, etc."
    import_entries["saves"]="contains savegames"

    # Ensure we are working with valid directories.
    if [[ -e $instance_directory ]]; then
        error "Instance already exists."
        exit "$ERROR_ARGUMENTS"
    fi

    if [[ ! -f $source_directory/bin/x64/factorio ]]; then
        error "Could not locate Factorio binary in source directory under: $source_directory/bin/x64/factorio"
        error "Factorio Manager natively supports instance imports only when all game data (savegames etc) are stored within Factorio installation directory."
        exit "$ERROR_ARGUMENTS"
    fi

    # Display list of available Factorio versions and let user pick one.
    echo "Factorio version must  be selected manually for imported instances."
    echo
    echo "The following versions of Factorio are locally available:"
    echo

    for candidate in "$game_installations_directory"/*; do
        if [[ -f $candidate/bin/x64/factorio ]]; then
            echo "  - $(basename "$candidate")"
        fi
    done

    echo

    echo -n "Please specify what version you would like to use: "
    read game_version_selected

    # Validate user input.
    if [[ ! -f "$game_installations_directory/$game_version_selected/bin/x64/factorio" ]]; then
        error "Requested version not locally available: $game_version_selected"
        exit "$ERROR_ARGUMENTS"
    fi

    (

        # Obtain lock - Factorio uses the same mechanism, so we should
        # be able to detect the game is running in this way.
        flock --exclusive --nonblock 200
        if [[ $? != 0 ]]; then
            error "Could not lock instance directory via lock file $source_lock_file. Is Factorio instance still running?"
            exit "$ERROR_GENERAL"
        fi

        function remove_lock() {
            rm "$source_lock_file"
        }

        trap remove_lock EXIT

        # Create instance directory.
        mkdir "$instance_directory"

        # Sort the associative array keys.
        IFS=$'\n' import_entries_keys=($(sort <<<"${!import_entries[*]}"))
        unset IFS

        # Copy files and directories.
        echo
        declare -a missing_import_entries=()
        for source_entry in "${import_entries_keys[@]}"; do
            source_entry_path="$source_directory/$source_entry"
            if [[ -e $source_entry_path ]]; then
                info "Importing $(colorecho -n blue "$source_entry")..."

                if ! cp -a "$source_entry_path" "$instance_directory/"; then
                    error "Could not import $source_entry from $source_entry_path (see above for errors)."
                    exit "$ERROR_GENERAL"
                fi
            else
                missing_import_entries+=("$source_entry")
            fi

            # Copy the configuration file.
        done

        echo

        cat <<EOF > "$instance_config"
game_version="$game_version_selected"
EOF

        # Fix write-data in config.ini
        write_data="write-data=${instance_directory}"
        sed -i -e "s#^write-data=.*#$write_data#" "$game_config"

        if [[ ${#missing_import_entries[@]} != 0 ]]; then
            warning "A number of files or directories were missing from the specified source."
            warning "For some of the entries this is perfectly normal, but you should verify that no critical files have been missed by mistake before switching to using this instance."
            echo
            for missing_import_entry in "${missing_import_entries[@]}"; do
                echo "$(colorecho blue "$missing_import_entry"), ${import_entries[$missing_import_entry]}"
                echo
            done
            warning "Press any key to continue."
            read -n1
        fi

        success "Finished import of instance $(colorecho -n green "$instance")."

    ) 200>"$source_lock_file"


#===============#
# create-server #
#===============#
elif [[ $command == create-server ]]; then
    instance="${1-}"

    # Make sure user has set directory with game installations - test
    # both symlink and target destination.
    if [[ ! -L $game_installations_directory ]]; then
        error "Game installations directory has not been properly set. Please run the set-game-dir command first."
        exit "$ERROR_CONFIGURATION"
    fi

    if [[ ! -d $game_installations_directory ]]; then
        error "Game installations directory has not been properly set. Please run the set-game-dir command first."
        exit "$ERROR_CONFIGURATION"
    fi

    # Read positional arguments.
    instance="${1-}"
    shift

    # Calculate derived variables.
    instance_directory="$manager_directory/$instance"
    instance_config="$instance_directory/instance.conf"
    game_config="$instance_directory/config.ini"
    server_config="$instance_directory/server-settings.json"
    saves_directory="$instance_directory/saves"
    main_save="$saves_directory/default.zip"

    # Verify arguments.
    if [[ -z $instance ]]; then
        error "Missing argument: INSTANCE"
        exit "$ERROR_ARGUMENTS"
    fi

    if [[ -e $instance_directory ]]; then
        error "Instance already exists."
        exit "$ERROR_ARGUMENTS"
    fi

    # Display list of available Factorio versions and let user pick one.
    echo "The following versions of Factorio are locally available:"
    echo

    for candidate in "$game_installations_directory"/*; do
        if [[ -f $candidate/bin/x64/factorio ]]; then
            echo "  - $(basename "$candidate")"
        fi
    done

    echo

    echo -n "Please specify what version you would like to use: "
    read game_version_selected

    # Validate user input.
    if [[ ! -f "$game_installations_directory/$game_version_selected/bin/x64/factorio" ]]; then
        error "Requested version not locally available: $game_version_selected"
        exit "$ERROR_ARGUMENTS"
    fi

    # Grab server settings from user.
    echo "You will now be prompted to provide settings for the server, with some pre-filled settings."
    echo "Do not change settings marked with [EXPERT] unless you know what you are doing."
    echo
    read_server_settings "$instance"

    # Set-up the instance.
    mkdir "$instance_directory"
    mkdir "$instance_directory/mods"
    echo "{}" > "$instance_directory/mods/mod-list.json"

    cat <<EOF > "$instance_config"
game_version="$game_version_selected"
EOF
    cat <<EOF > "$game_config"
[path]
read-data=__PATH__executable__/../../data
write-data=${instance_directory}

[general]
locale=

[other]
check-updates=false
enable-crash-log-uploading=false
port=${settings_value[port]}


[interface]

[controls]

[sound]

[map-view]

[debug]

[multiplayer-lobby]

[graphics]
EOF

    echo
    cat <<EOF >> "$server_config"
{
  "name": ${settings_value[name]},
  "description": ${settings_value[description]},
  "tags": ${settings_value[tags]},
  "max_players": ${settings_value[max_players]},
  "visibility":
  {
    "public": ${settings_value[public]},
    "lan": ${settings_value[lan]}
  },

  "_comment_credentials": "Your factorio.com login credentials. Required for games with visibility public",
  "username": ${settings_value[username]},
  "password": ${settings_value[password]},

  "_comment_token": "Authentication token. May be used instead of 'password' above.",
  "token": ${settings_value[token]},

  "game_password": ${settings_value[game_password]},

  "_comment_require_user_verification": "When set to true, the server will only allow clients that have a valid Factorio.com account",
  "require_user_verification": ${settings_value[require_user_verification]},

  "_comment_max_upload_in_kilobytes_per_second" : "optional, default value is 0. 0 means unlimited.",
  "max_upload_in_kilobytes_per_second": ${settings_value[max_upload_in_kilobytes_per_second]},

  "_comment_max_upload_slots" : "optional, default value is 5. 0 means unlimited.",
  "max_upload_slots": ${settings_value[max_upload_slots]},

  "_comment_minimum_latency_in_ticks": "optional one tick is 16ms in default speed, default value is 0. 0 means no minimum.",
  "minimum_latency_in_ticks": ${settings_value[minimum_latency_in_ticks]},

  "_comment_ignore_player_limit_for_returning_players": "Players that played on this map already can join even when the max player limit was reached.",
  "ignore_player_limit_for_returning_players": ${settings_value[ignore_player_limit_for_returning_players]},

  "_comment_allow_commands": "possible values are, true, false and admins-only",
  "allow_commands": ${settings_value[allow_commands]},

  "_comment_autosave_interval": "Autosave interval in minutes",
  "autosave_interval": ${settings_value[autosave_interval]},

  "_comment_autosave_slots": "server autosave slots, it is cycled through when the server autosaves.",
  "autosave_slots": ${settings_value[autosave_slots]},

  "_comment_afk_autokick_interval": "How many minutes until someone is kicked when doing nothing, 0 for never.",
  "afk_autokick_interval": ${settings_value[afk_autokick_interval]},

  "_comment_auto_pause": "Whether should the server be paused when no players are present.",
  "auto_pause": ${settings_value[auto_pause]},

  "only_admins_can_pause_the_game": ${settings_value[only_admins_can_pause_the_game]},

  "_comment_autosave_only_on_server": "Whether autosaves should be saved only on server or also on all connected clients. Default is true.",
  "autosave_only_on_server": ${settings_value[autosave_only_on_server]},

  "_comment_non_blocking_saving": "Highly experimental feature, enable only at your own risk of losing your saves. On UNIX systems, server will fork itself to create an autosave. Autosaving on connected Windows clients will be disabled regardless of autosave_only_on_server option.",
  "non_blocking_saving": ${settings_value[non_blocking_saving]},

  "_comment_segment_sizes": "Long network messages are split into segments that are sent over multiple ticks. Their size depends on the number of peers currently connected. Increasing the segment size will increase upload bandwidth requirement for the server and download bandwidth requirement for clients. This setting only affects server outbound messages. Changing these settings can have a negative impact on connection stability for some clients.",
  "minimum_segment_size": ${settings_value[minimum_segment_size]},
  "minimum_segment_size_peer_count": ${settings_value[minimum_segment_size_peer_count]},
  "maximum_segment_size": ${settings_value[maximum_segment_size]},
  "maximum_segment_size_peer_count": ${settings_value[maximum_segment_size_peer_count]}
}
EOF

    # Generate main save/map.
    info "Generating default savegame/map."
    game_directory="${game_installations_directory}/${game_version_selected}"
    factorio_bin="$game_directory/bin/x64/factorio"

    if ! "$factorio_bin" --config "$game_config" --create "$saves_directory/default.zip"; then
        error "Failed to generate default savegame/map under: $saves_directory/default.zip"
        exit "$ERROR_GENERAL"
    fi

    success "Created new server instance $(colorecho -n green "$instance")"
else
    error "Invalid command: $command"

    exit "$ERROR_ARGUMENTS"
fi