# frozen_string_literal: true

module Unified
  module SupportOperations
    def run_command(op)
      database = entities.get(:database, op.use!('object'))

      use_arguments(op) do |args|
        args.use!('commandName')

        cmd = args.use!('command')

        opts = {}
        if (session = args.use('session'))
          opts[:session] = entities.get(:session, session)
        end
        if (read_preference = args.use('readPreference'))
          opts[:read] = ::Utils.snakeize_hash(read_preference)
        end
        if (timeout_ms = args.use('timeoutMS'))
          opts[:timeout_ms] = timeout_ms
        end

        database.command(cmd, **opts)
      end
    end

    def run_cursor_command(op)
      build_command_cursor(op).to_a
    end

    def create_command_cursor(op)
      cursor = build_command_cursor(op)
      if (name = op.use('saveResultAsEntity'))
        entities.set(:cursor, name, cursor)
      end
      cursor
    end

    def build_command_cursor(op)
      database = entities.get(:database, op.use!('object'))

      use_arguments(op) do |args|
        args.use!('commandName')
        cmd = args.use!('command')

        session = args.use('session')
        read_preference = args.use('readPreference')

        opts = extract_options(args, 'batchSize', 'maxTimeMS', 'comment',
                               'timeoutMS', 'cursorType', 'timeoutMode')
        symbolize_options!(opts, :cursor_type, :timeout_mode)

        opts[:session] = entities.get(:session, session) if session
        opts[:read] = ::Utils.snakeize_hash(read_preference) if read_preference

        database.cursor_command(cmd, **opts)
      end
    end

    def fail_point(op)
      consume_test_runner(op)
      use_arguments(op) do |args|
        client = entities.get(:client, args.use!('client'))
        client.command(fp = args.use('failPoint'))

        # Use the client's actual primary address rather than the cached
        # ClusterConfig value, which can become stale after a replSetStepDown.
        primary_server = client.cluster.servers.find(&:primary?)
        address = primary_server&.address || ClusterConfig.instance.primary_address

        $disable_fail_points ||= []
        $disable_fail_points << [ fp, address ]
      end
    end

    def targeted_fail_point(op)
      consume_test_runner(op)
      use_arguments(op) do |args|
        session = args.use!('session')
        session = entities.get(:session, session)
        unless session.pinned_server
          raise ArgumentError, 'Targeted fail point requires session to be pinned to a server'
        end

        client = ClusterTools.instance.direct_client(session.pinned_server.address,
                                                     database: 'admin')
        client.command(fp = args.use!('failPoint'))
        args.clear

        $disable_fail_points ||= []
        $disable_fail_points << [
          fp,
          session.pinned_server.address,
        ]
      end
    end

    def end_session(op)
      session = entities.get(:session, op.use!('object'))
      session.end_session
    end

    def get_snapshot_time(op)
      session = entities.get(:session, op.use!('object'))
      session.snapshot_timestamp
    end

    def assert_session_dirty(op)
      consume_test_runner(op)
      use_arguments(op) do |args|
        session = entities.get(:session, args.use!('session'))
        session.dirty? || raise(Error::ResultMismatch, 'expected session to be dirty')
      end
    end

    def assert_session_not_dirty(op)
      consume_test_runner(op)
      use_arguments(op) do |args|
        session = entities.get(:session, args.use!('session'))
        session.dirty? && raise(Error::ResultMismatch, 'expected session to be not dirty')
      end
    end

    def assert_same_lsid_on_last_two_commands(op, expected: true)
      consume_test_runner(op)
      use_arguments(op) do |args|
        client = entities.get(:client, args.use!('client'))
        subscriber = @subscribers.fetch(client)
        unless subscriber.started_events.length >= 2
          raise Error::ResultMismatch, "Must have at least 2 events, have #{subscriber.started_events.length}"
        end

        lsids = subscriber.started_events[-2..-1].map do |cmd|
          cmd.command.fetch('lsid')
        end
        if expected
          unless lsids.first == lsids.last
            raise Error::ResultMismatch, 'lsids differ but they were expected to be the same'
          end
        elsif lsids.first == lsids.last
          raise Error::ResultMismatch, 'lsids are the same but they were expected to be different'
        end
      end
    end

    def assert_different_lsid_on_last_two_commands(op)
      assert_same_lsid_on_last_two_commands(op, expected: false)
    end

    def start_transaction(op)
      $klil_transactions = true
      session = entities.get(:session, op.use!('object'))
      assert_no_arguments(op)
      session.start_transaction
    end

    def assert_session_transaction_state(op)
      consume_test_runner(op)
      use_arguments(op) do |args|
        session = entities.get(:session, args.use!('session'))
        state = args.use!('state')
        unless session.send("#{state}_transaction?")
          raise Error::ResultMismatch, "Expected session to have state #{state}"
        end
      end
    end

    def commit_transaction(op)
      session = entities.get(:session, op.use!('object'))
      opts = {}
      use_arguments(op) do |args|
        opts[:timeout_ms] = args.use('timeoutMS')
      end
      session.commit_transaction(opts.compact)
    end

    def abort_transaction(op)
      session = entities.get(:session, op.use!('object'))
      opts = {}
      use_arguments(op) do |args|
        opts[:timeout_ms] = args.use('timeoutMS')
      end
      session.abort_transaction(opts.compact)
    end

    def with_transaction(op)
      $kill_transactions = true
      session = entities.get(:session, op.use!('object'))
      use_arguments(op) do |args|
        ops = args.use!('callback')

        if args.empty?
          opts = {}
        else
          opts = ::Utils.underscore_hash(args)
          if (value = opts[:read_concern]&.[](:level))
            opts[:read_concern][:level] = value.to_sym
          end
          args.clear
        end

        # Preserve a deep copy of the raw ops so that on each retry of
        # the withTransaction block we get fresh UsingHash objects whose
        # keys have not been consumed by the previous attempt.
        ops_raw = deep_to_plain(ops)

        session.with_transaction(**opts) do
          execute_operations(ops_raw.map { |o| UsingHash[deep_wrap(o)] }, propagate_errors: true)
        end
      end
    end

    private

    def deep_to_plain(value)
      case value
      when Hash
        value.each_with_object({}) { |(k, v), h| h[k] = deep_to_plain(v) }
      when Array
        value.map { |v| deep_to_plain(v) }
      else
        value
      end
    end

    def deep_wrap(value)
      case value
      when Hash
        UsingHash[value.transform_values { |v| deep_wrap(v) }]
      when Array
        value.map { |v| deep_wrap(v) }
      else
        value
      end
    end

    public

    def assert_session_pinned(op, state = true)
      consume_test_runner(op)
      use_arguments(op) do |args|
        session = entities.get(:session, args.use!('session'))

        if state
          raise Error::ResultMismatch, 'Expected session to be pinned but it is not' unless session.pinned_server
        elsif session.pinned_server
          raise Error::ResultMismatch, 'Expected session to be not pinned but it is'
        end
      end
    end

    def assert_session_unpinned(op)
      assert_session_pinned(op, false)
    end

    def _loop(op)
      consume_test_runner(op)
      use_arguments(op) do |args|
        ops = args.use!('operations')

        if (store_errors = args.use('storeErrorsAsEntity'))
          entities.set(:error_list, store_errors, [])
        end

        if (store_failures = args.use('storeFailuresAsEntity'))
          entities.set(:failure_list, store_failures, [])
        end

        store_iterations = args.use('storeIterationsAsEntity')
        iterations = 0
        store_successes = args.use('storeSuccessesAsEntity')
        successes = 0

        loop do
          break if stop?

          begin
            ops.map(&:dup).each do |op|
              execute_operation(op)
              successes += 1
            end
          rescue Unified::Error::ResultMismatch => e
            if store_failures
              warn "Failure: #{e.class}: #{e}"
              entities.get(:failure_list, store_failures) << {
                error: "#{e.class}: #{e}",
                time: Time.now.to_f,
              }
            elsif store_errors
              warn "Failure: #{e.class}: #{e} (reporting as error)"
              entities.get(:error_list, store_errors) << {
                error: "#{e.class}: #{e}",
                time: Time.now.to_f,
              }
            else
              raise
            end
          rescue Interrupt
            raise
          rescue StandardError => e
            if store_failures
              warn "Error: #{e.class}: #{e} (reporting as failure)"
              entities.get(:failure_list, store_failures) << {
                error: "#{e.class}: #{e}",
                time: Time.now.to_f,
              }
            elsif store_errors
              warn "Error: #{e.class}: #{e}"
              entities.get(:error_list, store_errors) << {
                error: "#{e.class}: #{e}",
                time: Time.now.to_f,
              }
            else
              raise
            end
          end
          iterations += 1
        end

        entities.set(:iteration_count, store_iterations, iterations) if store_iterations
        entities.set(:success_count, store_successes, successes) if store_successes
      end
    end

    def assert_event_count(op)
      consume_test_runner(op)
      use_arguments(op) do |args|
        client = entities.get(:client, args.use!('client'))
        subscriber = @subscribers.fetch(client)
        event = args.use!('event')
        assert_eq(event.keys.length, 1, "Expected event must have one key: #{event}")
        count = args.use!('count')

        events = select_events(subscriber, event)
        if %w[serverDescriptionChangedEvent poolClearedEvent].include?(event.keys.first)
          # We publish SDAM events from both regular and push monitors.
          # This means sometimes there are two ServerMarkedUnknownEvent
          # events published for the same server transition.
          # Allow actual event count to be at least the expected event count
          # in case there are multiple transitions in a single test.
          assert_gte(events.length, count,
                     "Expected event #{event} to occur #{count} times but received it #{events.length} times.")
        else
          assert_eq(events.length, count,
                    "Expected event #{event} to occur #{count} times but received it #{events.length} times.")
        end
      end
    end

    SDAM_SERVER_TYPE_MAP = {
      'Standalone' => :standalone,
      'RSPrimary' => :primary,
      'RSSecondary' => :secondary,
      'RSArbiter' => :arbiter,
      'Mongos' => :sharded,
      'Unknown' => :unknown,
      'PossiblePrimary' => :unknown,
      'RSGhost' => :ghost,
      'RSOther' => :other,
      'LoadBalancer' => :load_balancer,
    }.freeze

    def select_events(subscriber, event)
      expected_name, opts = event.first
      expected_name = expected_name.sub(/Event$/, '').sub(/^(.)/) { ::Regexp.last_match(1).upcase }
      subscriber.wanted_events.select do |wevent|
        next unless wevent.class.name.sub(/.*::/, '') == expected_name

        spec = UsingHash[opts]
        result = true
        if (new_desc = spec.use('newDescription')) && (type = new_desc.use('type'))
          expected_type = SDAM_SERVER_TYPE_MAP[type] || type.downcase.to_sym
          result &&= wevent.new_description.server_type == expected_type
        end
        if (command_name = spec.use('commandName'))
          result &&= wevent.respond_to?(:command_name) && wevent.command_name == command_name
        end
        raise NotImplementedError, "Unhandled keys: #{spec}" unless spec.empty?

        result
      end
    end

    def assert_number_connections_checked_out(op)
      consume_test_runner(op)
      use_arguments(op) do |args|
        client = entities.get(:client, args.use!('client'))
        connections = args.use!('connections')
        actual_c = client.cluster.servers.map(&:pool_internal).compact.sum do |p|
          p.instance_variable_get(:@checked_out_connections).length
        end
        assert_eq(actual_c, connections,
                  "Expected client #{client} to have #{connections} checked out connections but there are #{actual_c}.")
      end
    end

    private

    # @param [ UsingHash ] args the arguments to extract options from
    # @param [ Array<String | Hash> ] keys an array of strings and Hashes,
    #   where Hashes represent a mapping from the MDB key to the correspoding
    #   Ruby key. For Strings, the Ruby key is assumed to be a simple conversion
    #   of the MDB key, from camel-case to snake-case.
    # @param [ true | false ] allow_extra whether or not extra keys are allowed
    #   to exist in the args hash, beyond those listed.
    def extract_options(args, *keys, allow_extra: false)
      {}.tap do |opts|
        keys.each do |key|
          Array(key).each do |mdb_key, ruby_key|
            value = args.use(mdb_key)
            opts[ruby_key || mdb_name_to_ruby(mdb_key)] = value unless value.nil?
          end
        end

        raise NotImplementedError, "unhandled keys: #{args}" if !allow_extra && !args.empty?
      end
    end

    def symbolize_options!(opts, *keys)
      keys.each do |key|
        opts[key] = mdb_name_to_ruby(opts[key]) if opts[key]
      end
    end

    def mdb_name_to_ruby(name)
      name.to_s.gsub(/([a-z])([A-Z])/) { "#{::Regexp.last_match(1)}_#{::Regexp.last_match(2)}" }.downcase.to_sym
    end

    def assert_no_arguments(op)
      return unless op.key?('arguments')

      raise NotimplementedError, 'Arguments are not allowed'
    end

    def consume_test_runner(op)
      v = op.use!('object')
      return if v == 'testRunner'

      raise NotImplementedError, 'Expected object to be testRunner'
    end

    def decode_hex_bytes(value)
      value.scan(/../).map { |hex| hex.to_i(16).chr }.join
    end
  end
end
