require "test_helper"

using BinaryString

class FlowControlTest < Minitest::Test
  def test_flow_control_window_update_server
    open_server_connection { |con|
      before_ws = con.recv_remaining_window
      con.window_update(500)

      last = sent_frames.last
      assert_equal(:window_update, last.type)
      assert_equal(0, last.stream_id)
      assert_equal(500, last.payload.uint32)
      assert_equal(before_ws + 500, con.recv_remaining_window)
    }
  end

  def test_flow_control_window_update_stream
    open_new_stream { |stream|
      before_ws = stream.recv_remaining_window
      stream.window_update(500)

      last = sent_frames.last
      assert_equal(:window_update, last.type)
      assert_equal(stream.id, last.stream_id)
      assert_equal(500, last.payload.uint32)
      assert_equal(before_ws + 500, stream.recv_remaining_window)
    }
  end

  def test_flow_control_window_update_zero
    open_new_stream { |stream|
      assert_stream_error(:protocol_error) {
        stream.receive_frame Frame::WindowUpdate.new(stream.id, 0)
      }
    }
  end

  def test_flow_control_window_update_frame_size
    open_new_stream { |stream|
      assert_connection_error(:frame_size_error) {
        stream.receive_frame Frame.craft(type: :window_update,
                                         stream_id: stream.id,
                                         payload: "".push_uint16(0))
      }
    }
  end

  def test_flow_control_dont_send_data_exceeding_send_window
    open_new_stream { |stream|
      con = stream.connection
      con << Frame::Settings.new(initial_window_size: 4 * 2 + 1).assemble
      # only extend stream window size
      con << Frame::WindowUpdate.new(stream.id, 100).assemble
      10.times { |i|
        stream.send Frame::Data.new(stream.id, "".push_uint32(i))
      }

      last = sent_frames.last
      assert_equal(1, last.payload.uint32)
    }
  end

  def test_flow_control_dont_send_data_upto_updated_send_window
    open_new_stream { |stream|
      con = stream.connection
      con << Frame::Settings.new(initial_window_size: 4 * 2 + 1).assemble
      10.times { |i|
        stream.send Frame::Data.new(stream.id, "".push_uint32(i))
      }
      # only extend stream window size
      con << Frame::WindowUpdate.new(stream.id, 100).assemble
      # and extend connection window size
      con << Frame::WindowUpdate.new(0, 4 * 2 + 1).assemble

      last = sent_frames.last
      assert_equal(3, last.payload.uint32)
    }
  end

  def test_flow_control_update_send_initial_window_size
    open_new_stream { |stream|
      con = stream.connection
      con << Frame::Settings.new(initial_window_size: 4 * 2 + 1).assemble
      10.times { |i|
        stream.send Frame::Data.new(stream.id, "".push_uint32(i))
      }
      # only extend stream window size
      con << Frame::WindowUpdate.new(stream.id, 100).assemble
      # and update initial window size
      con << Frame::Settings.new(initial_window_size: 4 * 4 + 1).assemble

      last = sent_frames.reverse.find { |f| f.type == :data }
      assert_equal(3, last.payload.uint32)
    }
  end

  def test_flow_control_recv_window_exceeded
    prepare = ->(&blk) {
      open_new_stream { |stream|
        con = stream.connection
        con.settings(initial_window_size: 24)
        blk.call(con, stream)
      }
    }

    prepare.call { |con, stream|
      con.window_update(500) # extend only connection
      con << Frame::Headers.new(stream.id, "", end_headers: true).assemble
      assert_stream_error(:flow_control_error) {
        con << Frame::Data.new(stream.id, "\x00" * 30, end_stream: true).assemble
      }
    }

    prepare.call { |con, stream|
      stream.window_update(500) # extend only stream
      con << Frame::Headers.new(stream.id, "", end_headers: true).assemble
      assert_connection_error(:flow_control_error) {
        con << Frame::Data.new(stream.id, "\x00" * 30, end_stream: true).assemble
      }
    }
  end

  def test_flow_control_update_recv_initial_window_size
    open_new_stream { |stream|
      con = stream.connection
      con.settings(initial_window_size: 24)
      stream.window_update(1)
      con << Frame::Headers.new(stream.id, "", end_headers: true).assemble
      con << Frame::Data.new(stream.id, "\x00" * 20, end_stream: true).assemble
      assert_equal(4, con.recv_remaining_window)
      assert_equal(5, stream.recv_remaining_window)
      con.settings(initial_window_size: 60)
      assert_equal(40, con.recv_remaining_window)
      assert_equal(41, stream.recv_remaining_window)
    }
  end
end