require 'pg'

require 'common/agendav_plugin'
require 'mv/mv_plugin'


# Handle moving (renaming) Agendav users in its database. Agendav has
# no concept of domains.
#
class AgendavMv

  include AgendavPlugin
  include MvPlugin

  # Move the user *src* to *dst* within the Agendav database. This
  # should "rename" him in _every_ table where he is referenced.
  #
  # This can fail if *dst* already exists before the move. It should
  # also be an error if the destination domain doesn't exist. But
  # Agendav doesn't know about domains, so we let that slide.
  #
  # If the source user doesn't exist, we do our best. AgenDAV has a
  # "shares" table that isn't keyed on the username, but rather the
  # principal URL. And its "prefs" table doesn't contain entries for
  # users who have default preferences. As a result, we may need to
  # perform some find/replaces in the "shares" table even if no
  # corresponding user exists in the "prefs" table (which is how we
  # tell if a user exists in AgenDAV). Thus it's not a fatal error if
  # the *src* user doesn't exist.
  #
  # @param src [User] the source user to be moved.
  #
  # @param dst [User] the destination user being moved to.
  #
  def mv_user(src, dst)
    raise UserAlreadyExistsError.new(dst.to_s()) if user_exists(dst)

    connection = PG::Connection.new(@db_hash)
    begin
      # The "prefs" table uses the normal username as a key...
      # This should be harmless if the source user does not exist.
      sql_query0 = 'UPDATE prefs SET username = $1 WHERE username = $2;'
      connection.sync_exec_params(sql_query0, [dst.to_s(), src.to_s()])

      # But the "shares" table uses encoded principal URLs. For the
      # "shares" table, we need to do a find/replace on the username
      # with its "@" symbol translated to a "%40".
      encoded_src = src.to_s()['@'] = '%40'
      encoded_dst = dst.to_s()['@'] = '%40'

      # Unlike in the "rm" plugin, we do modify the "calendar" field
      # here. That's because in the usual legitimate use case, the
      # calendar URL will change when a user moves. This will ALSO
      # affect people who name their calendars something like
      # "user%40example.com", but screw those people.
      sql_queries = ['UPDATE shares SET owner=REPLACE(owner, $2, $1);']
      sql_queries << 'UPDATE shares SET calendar=REPLACE(calendar, $2, $1);'
      sql_queries << 'UPDATE shares SET "with"=REPLACE("with", $2, $1);'

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

end