require 'pg'

require 'common/postfixadmin_plugin'
require 'rm/rm_plugin'


# Handle the removal of users and domains from the Postfixadmin database.
#
class PostfixadminRm

  include PostfixadminPlugin
  include RmPlugin


  # Remove *user* from the Postfixadmin database. This should remove
  # him from _every_ table in which he is referenced. Unfortunately,
  # Postfixadmin does not use foreign keys or ON DELETE CASCADE
  # triggers so we need to delete the associated child table records
  # ourselves.
  #
  # @param user [User] the user to remove.
  #
  def remove_user(user)
    raise NonexistentUserError.new(user.to_s()) if not user_exists(user)

    # Remove aliases FROM our user to some other address.
    sql_queries = ['DELETE FROM alias WHERE address = $1;']

    # Also delete aliases that point SOLELY TO our user.
    sql_queries << "DELETE FROM alias WHERE goto = $1;"

    # But aliases don't need to point to a single user! If our user
    # was part of a multi-recipient alias, we want to remove our user
    # from the alias and leave the other recipients.
    #
    # We want to delete the comma that precedes/follows the address,
    # too.  Since the address to be replaced can appear at either the
    # beginning or the end of the list (as well as in the middle), we
    # have to try to fix both cases: comma before, and comma after.
    comma_before = "CONCAT(',', $1)"
    comma_after  = "CONCAT($1, ',')"
    sql_queries << "UPDATE alias SET goto=REPLACE(goto, #{comma_before}, '');"
    sql_queries << "UPDATE alias SET goto=REPLACE(goto, #{comma_after}, '');"

    sql_queries << 'DELETE FROM mailbox WHERE username = $1;'
    sql_queries << 'DELETE FROM quota WHERE username = $1;'
    sql_queries << 'DELETE FROM quota2 WHERE username = $1;'
    sql_queries << 'DELETE FROM vacation WHERE email = $1;'

    # Should be handled by a trigger, according to PostfixAdmin code.
    sql_queries << 'DELETE FROM vacation_notification WHERE on_vacation = $1;'

    connection = PG::Connection.new(@db_hash)

    begin
      sql_queries.each do |sql_query|
        varchar = 1043 # from pg_type.h
        params = [{:value => user.to_s(), :type => varchar}]
        connection.sync_exec_params(sql_query, params)
      end
    ensure
      # Make sure the connection gets closed even if a query explodes.
      connection.close()
    end
  end


  # Remove *domain* from the Postfixadmin database. This should remove
  # the domain from _every_ table in which it is referenced. It should
  # also remove every user that belongs to the doomed domain
  # Postfixadmin has some experimental support for triggers, but they
  # don't do a very good job of cleaning up. Therefore we remove all
  # users in the domain manually before removing the domain itself.
  #
  # Log entries (from the "log" table) are not removed since they may
  # still contain valuable information (although they won't mention
  # this removal).
  #
  # @param domain [Domain] the domain to remove.
  #
  def remove_domain(domain)
    raise NonexistentDomainError.new(domain.to_s()) if not domain_exists(domain)

    # First remove all users belonging to the domain. This will handle
    # alias updates and all the sensitive crap we need to do when
    # removing a user.
    users = list_domains_users([domain])
    users.each { |u| remove_user(u) }

    # The domain_admins table contains one record per domain
    # (repeating the user as necessary), so this really is sufficient.
    sql_queries = ['DELETE FROM domain_admins WHERE domain = $1;']

    # Some of the following queries should be redundant now that we've
    # removed all users in the domain.
    sql_queries << 'DELETE FROM alias WHERE domain = $1;'
    sql_queries << 'DELETE FROM mailbox WHERE domain = $1;'
    sql_queries << 'DELETE FROM alias_domain WHERE alias_domain = $1;'
    sql_queries << 'DELETE FROM vacation WHERE domain = $1;'
    sql_queries << 'DELETE FROM domain WHERE domain = $1;'

    connection = PG::Connection.new(@db_hash)

    begin
      sql_queries.each do |sql_query|
        connection.sync_exec_params(sql_query, [domain.to_s()])
      end
    ensure
      # Make sure the connection gets closed even if a query explodes.
      connection.close()
    end
  end

end