#!/usr/bin/env ruby
require 'json'
require 'pathname'
require 'fileutils'
require 'open3'

LXC_PATH=Pathname.new("/data/containers")
BACKUP_LOCATIONS = %w{home srv etc usr/local}
CONFIG_PATH="/etc/lxc/container.json"
DUPLICITY_PATH= Pathname.new("/data/duplicity/")
BACKUP_PATH="file:///mnt/backup/duplicity"
FULL_BACKUP_COUNT=1

def load_config
  return JSON.load(File.open(CONFIG_PATH))
rescue SystemCallError => e
  abort "failed to open configuration '#{CONFIG_PATH}', #{e}"
rescue JSON::ParserError => e
  abort "failed to parse configuration '#{CONFIG_PATH}', #{e}"
end

def sh(cmd, env={}, *args)
  pretty_args = args.map {|arg| "'#{arg}'"}
  puts ([cmd] + pretty_args).join(" ")
  system(env, cmd, *args)
end

class Container
  def initialize(name, backup_paths, backup_scripts)
    @name = name
    @backup_paths = backup_paths
    @backup_scripts = backup_scripts
    @path = LXC_PATH.join(name, "rootfs")
  end
  def backup_paths
    paths = BACKUP_LOCATIONS
    if @backup_paths.is_a?(Array)
      paths += @backup_paths
    end
    paths.map do |relative_path|
      @path.join(relative_path)
    end
  end
  def run_backup_scripts
    if @backup_scripts.is_a?(Array)
      @backup_scripts.map do |script|
        backup_script(script)
      end
    else
      []
    end
  end

  private
  def backup_script(script)
    unless script.is_a?(Hash)
      abort("backup-scripts: Expected an Object, got #{script.class}")
    end
    command = script["command"]
    if command.nil?
      abort("command not set for backup-scripts for container '#{@name}'")
    end
    backupname = script["backupname"]
    if backupname.nil?
      abort("backupname not set for backup-scripts for container '#{@name}'")
    end
    backupname = DUPLICITY_PATH.join(backupname.gsub("/", ""))
    FileUtils.mkdir_p(backupname)
    puts "cd #{backupname}"
    Dir.chdir(backupname) do
      sh(command)
    end
    backupname
  end

  def empty_directory?(path)
    return false unless Dir.exists?(path)
    return Dir.entries(path).size <= 2 # - [".", ".."]
  end
end

Dir.chdir(DUPLICITY_PATH) do
  config = load_config
  backup_paths = BACKUP_LOCATIONS.map do |location|
    "/#{location}"
  end
  config["network"].each do |container, data|
  next if data["lxc"] == false
  container = Container.new(container, data["backup-paths"], data["backup-scripts"])
    backup_paths += container.backup_paths
    backup_paths += container.run_backup_scripts
  end
  gpg_args = ["--sign-key", "AF5834A6", "--encrypt-key", "AF5834A6", "--gpg-options", "--secret-keyring ./duplicity.sec --keyring ./duplicity.pub"]
  args = ["--archive-dir", "cache", "--log-file", "/var/log/duplicity.log"] + gpg_args
  backup_args = args + ["--verbosity", "notice",
       "--full-if-older-than", "30D",
       "--num-retries", "3",
       "--asynchronous-upload",
       "--volsize", "250",
       "--include-globbing-filelist", "/dev/stdin", "--exclude", "**",
       "/", BACKUP_PATH]
  env = { "PASSPHRASE" => File.read("pgp-passphrase") }
  sh("find", "cache", "-type", "f", "-name", "lockfile.lock", "-exec", "rm -f {} ;")
  sh("duplicity", env, "cleanup", "--force", BACKUP_PATH, *args)
  stdin, stdout, stderr = Open3.popen3(env, "duplicity", *backup_args)
  backup_paths.each do |path|
    stdin.puts(path)
    puts(path)
  end
  stdin.close
  puts stdout.read
  puts stderr.read
  sh("duplicity", env, "remove-older-than", "30D", "--force", BACKUP_PATH, *args)
  sh("duplicity", env, "remove-all-inc-of-but-n-full", FULL_BACKUP_COUNT.to_s, "--force", BACKUP_PATH, *args)
end