#!/usr/bin/ruby

require "thor"
require "httparty"
require "logger"
require "fileutils"


class FactorioTools < Thor
  SOURCE_LINK = "https://www.factorio.com/get-download/latest/headless/linux64"
  TARGET_FILE = "factorio.tar.xz"
  BINARY_PATH = "/opt/factorio/bin/x64/factorio"

  class_option :quiet, type: :boolean, aliases: "-q"
  class_option :log, type: :string, aliases: "-l"


  class Factorio
    class << self

      def setup_logger(options = {})
        $logger = ::Logger.new(options[:log] ? options[:log] : STDOUT)
        $logger.level = options[:quiet] ? ::Logger::WARN : ::Logger::INFO
        $logger.datetime_format = "%Y-%m-%d %H:%M:%S"
        $logger.formatter = proc do |severity, datetime, program_name, message|
          "#{datetime.strftime($logger.datetime_format)} #{severity}: #{message}\n"
        end
        $logger
      end


      def get_installed_version(options = {})
        version_command = "#{BINARY_PATH} --version"
        if File.exist? BINARY_PATH
          version = `#{version_command}`[/Version: ([\d\.]+)/, 1]
          if version.empty?
            $logger.fatal "Could not parse version from command output: #{version_command}"
            exit
          end
          version
        else
          unless options[:silent]
            $logger.fatal "Could not find factorio binary at: #{BINARY_PATH}"
            exit
          end
        end
      rescue Exception => e
        $logger.fatal e.message
        exit
      end


      def get_target_time
        File.mtime(TARGET_FILE).to_time.to_i
      rescue
        0
      end


      def get_remote_info(version = "latest")
        source_link = SOURCE_LINK.gsub "latest", "#{version.downcase}"
        begin
          response = HTTParty.head SOURCE_LINK
          source_link = response.request.last_uri.to_s

          if response["last-modified"].nil? || response["last-modified"].empty?
            $logger.fatal "Could not find Last-Modified HTTP header: #{response}"
            exit
          end

          begin
            last_modified_at = DateTime.strptime(response["last-modified"], "%a, %d %b %Y %H:%M:%S %Z").to_time.to_i
          rescue Exception => e
            $logger.fatal "Could not parse version from Last-Modified HTTP header: #{response["last-modified"]}"
            $logger.fatal e.message
            exit
          end

          version = source_link[/factorio_headless_x64_([\d\.]+)\.tar/, 1]
          if version.empty?
            $logger.fatal "Could not parse version from URL: #{source_link}"
            exit
          end

          return OpenStruct.new(
            url:              source_link,
            last_modified_at: last_modified_at,
            version:          version,
          )
        rescue Exception => e
          $logger.fatal "Could not access remote URL: #{source_link}"
          $logger.fatal e.message
          exit
        end
      end


      def download_package(remote_info)
        $logger.info "Downloading package #{remote_info.url}"
        File.open(TARGET_FILE, "w") do |file|
          response = HTTParty.get(remote_info.url, stream_body: true) do |part|
            file.write part
          end
        end

        $logger.info "Updating package mtime"
        FileUtils.touch TARGET_FILE, mtime: remote_info.last_modified_at
      end


      def install_package
        $logger.info "Extracting package"
        `tar -Jxf #{TARGET_FILE}`

        $logger.info "Changing ownership to user 'factorio'"
        FileUtils.chown_R "factorio", "factorio", "./factorio"

        $logger.info "Restarting service"
        `systemctl restart factorio`
      end

    end
  end


  desc "version", "Detect the currently installed version of Factorio"
  def version
    Factorio.setup_logger options
    if version = Factorio.get_installed_version
      puts version
    end
  end


  desc "latest", "Detect the latest version of Factorio available"
  def latest
    Factorio.setup_logger options
    if remote_info = Factorio.get_remote_info
      puts remote_info.version
    end
  end


  desc "install [VERSION]", "Install Factorio version (default: latest)"
  option :force, type: :boolean
  def install(version = "latest")
    Factorio.setup_logger options
    if installed_version = Factorio.get_installed_version(silent: true)
      $logger.fatal "Factorio is already installed. Use 'upgrade' to install a different version."
      exit
    end
    remote_info = Factorio.get_remote_info version
    if options[:force] || Factorio.get_target_time != remote_info.last_modified_at
      Factorio.download_package remote_info
    end
    Factorio.install_package
  end


  desc "upgrade [VERSION]", "Upgrade to Factorio version (default: latest)"
  option :force, type: :boolean
  def upgrade(version = "latest")
    Factorio.setup_logger options
    remote_info = Factorio.get_remote_info version
    if options[:force] || remote_info.version != Factorio.get_installed_version(silent: true)
      if options[:force] || Factorio.get_target_time != remote_info.last_modified_at
        Factorio.download_package remote_info
      end
      Factorio.install_package
      $logger.info "Factorio #{remote_info.version} has been installed."
    else
      $logger.info "Factorio #{remote_info.version} is already up to date."
    end
  end


  desc "download [VERSION]", "Download Factorio package for version (default: latest)"
  option :force, type: :boolean
  def download(version = "latest")
    Factorio.setup_logger options
    remote_info = Factorio.get_remote_info version
    if options[:force] || Factorio.get_target_time != remote_info.last_modified_at
      Factorio.download_package remote_info
      $logger.info "#{TARGET_FILE} has been downloaded."
    else
      $logger.info "#{TARGET_FILE} is already present and up to date."
    end
  end


  desc "backup", "Backup current installation to the archives folder"
  def backup
    Factorio.setup_logger options
    backup_path = "archived/games"
    version = Factorio.get_installed_version
    FileUtils.mkdir_p backup_path
    FileUtils.cp_r "factorio", "#{backup_path}/factorio-#{version}", remove_destination: true
    $logger.info "Archived current Factorio installation to '#{backup_path}'"
  end

end


FactorioTools.start ARGV