#!/usr/bin/ruby -wKU
#
# mailshears, to prune unused mail directories.
#
# Mail accounts for virtual hosts are stored in SQL, and managed by
# Postfixadmin. However, the physical directories are handled by
# Postfix/Dovecot and are left untouched by Postfixadmin. This is good
# for security, but comes at a cost: Postfixadmin can't remove a
# user's mail directory when his or her account is deleted.
#
# This program compares the list of filesystem accounts with the ones
# in the database. It outputs any accounts that exist in the
# filesystem, but not the database.
#

# We need Pathname to get the real filesystem path
# of this script (and not, for example, the path of
# a symlink which points to it.
require 'pathname'

# This bit of magic adds the parent directory (the
# project root) to the list of ruby load paths.
# Thus, our require statements will work regardless of
# how or from where the script was run.
executable = Pathname.new(__FILE__).realpath.to_s
$: << File.dirname(executable) + '/../'

# Load our config file.
require 'bin/configuration'

# And the necessary classes.
require 'src/errors.rb'
require 'src/exit_codes.rb'
require 'src/dovecot_mailstore'
require 'src/postfixadmin_db'

dms = DovecotMailstore.new(Configuration::MAIL_ROOT)

pgadb = PostfixadminDb.new(Configuration::DBHOST,
                           Configuration::DBPORT,
                           Configuration::DBOPTS,
                           Configuration::DBTTY,
                           Configuration::DBNAME,
                           Configuration::DBUSER,
                           Configuration::DBPASS)

begin
  # Get the list of accounts according to the filesystem.
  fs_accts = dms.get_accounts_from_filesystem()
rescue StandardError => e
  puts "There was an error retrieving accounts from the filesystem: #{e.to_s}"
  Kernel.exit(ExitCodes::FILESYSTEM_ERROR)
end

begin
  # ...and according to the Postfixadmin database.
  db_accts = pgadb.get_accounts_from_db()
rescue DatabaseError => e
  puts "There was an error connecting to the database: #{e.to_s}"
  Kernel.exit(ExitCodes::DATABASE_ERROR)
end


# Figure out which addresses are in the filesystem, but not in the
# database.
difference = [fs_accts - db_accts]

# Don't output any unnecessary junk. Cron might mail it to someone.
if difference.size > 0

  # The header that we output before the list of accounts.
  # Just the path of this script, and the current time.
  header = "#{$0}, "
  
  current_time = Time.now()
  if current_time.respond_to?(:iso8601)
    # Somehow this method is missing on some machines.
    header += current_time.iso8601.to_s
  else
    # Fall back to whatever this looks like.
    header += current_time.to_s
  end
  
  puts header
  puts '-' * header.size # Underline the header.
  puts difference
  puts ""
end