#!/usr/bin/ruby
# encoding: UTF-8
#
# Program to receive backups and run rsync in receive mode.  Must check that
# user as authorised by SSH is allowed to access particular directory.

$LOAD_PATH << '/usr/lib/byteback'

require 'trollop'
require 'byteback'
require 'byteback/restore'

include Byteback::Log

if ENV['SSH_ORIGINAL_COMMAND']
  ARGV.concat(ENV['SSH_ORIGINAL_COMMAND'].split(' '))
end

byteback_host = ENV['BYTEBACK_HOST']
fatal('BYTEBACK_HOST environment not set') unless byteback_host

byteback_root = ENV['HOME'] + '/' + ENV['BYTEBACK_HOST']
fatal("#{byteback_root} does not exist") unless File.directory?(byteback_root)

#
# Calling byteback-restore really needs rsync to restore the files.
#
if ARGV[0] == 'byteback-restore'
  #
  # Ignore the first arg
  #
  ARGV.shift

  args = ['rsync']
  snapshot = nil
  verbose = false
  all = false

  #
  # Mangle the arguments, and pull out any that are not-rsync compatible.
  #
  while (arg = ARGV.shift)
    case arg
    when '.'
      break
    when /^-([^-]*v[^-]*|-verbose)$/
      verbose = true
      args << arg
    when '--snapshot'
      snapshot = ARGV.shift
    when '--all'
      all = true
    else
      args << arg
    end
  end

  # Always exclude the current directory, because it can change the
  # ownership at the restorers end.
  args << '--exclude=.'

  #
  # Search for certain files
  # DANGER the args might be too long if lots of files are returned.
  #
  paths = Byteback::Restore.decode_args(ARGV)

  restore = Byteback::Restore.new(byteback_root)
  restore.snapshot = snapshot if snapshot
  restore.find(paths, all: all)

  Dir.chdir(byteback_host)

  args << '.'

  restore.results.each do |r|
    args << File.join('.', r.snapshot, r.path)
  end

  if restore.results.empty?
    STDERR.puts '** Sorry.  There were no files matching:'
    STDERR.puts '--> ' + paths.join("\n--> ")
    exit 1
  end

  STDERR.puts 'Restoring:'
  STDERR.puts restore.list
  STDERR.puts(args.join(' ')) if verbose

  exec(*args)

elsif ARGV[0] == 'rsync'
  ARGV[-1] = "#{byteback_root}/current"
  exec(*ARGV)

elsif ARGV[0] == 'byteback-snapshot'
  ARGV.concat(['--root', byteback_root.to_s])
  exec(*ARGV)

elsif ARGV[0] == 'restore'
  puts '** Your byteback package needs to be updated.  Please update and try again.'
  exit(1)

end

opts = Trollop.options do
  opt :ping, 'Check connection parameters and exit'
  opt :complete, 'Mark current backup as complete'
  opt :list, 'Show backed up files matching the given pattern'
  opt :all,  'Show all stored versions of a file'
  opt :snapshot, 'Show backed up files in a certain snapshot.', default: '*'
  opt :verbose, 'Print diagnostics'
end

#
# Make sure we don't get crazy option combinations.
#
n_modes = opts.keys.inject(0) do |s, m|
  [:ping, :complete, :list].include?(m) ? s += 1 : s
end

error('Please only choose one mode') unless n_modes == 1

if opts[:complete]
  system('byteback-snapshot', '--root', byteback_root)

elsif opts[:list]
  args = Byteback::Restore.decode_args(ARGV[1..-1])

  restore = Byteback::Restore.new(byteback_root)
  restore.snapshot = opts[:snapshot]
  restore.find(args, all: opts[:all], verbose: opts[:verbose])

  if restore.results.empty?
    puts '** Sorry.  There were no files matching:'
    puts '--> ' + args.join("\n--> ")
  else
    puts restore.list
  end

  exit(0)

elsif opts[:ping]
  exit 0

else
  STDERR.print "byteback-receive failed\n"
  exit 9

end