package handler

import (
	"bytes"
	"encoding/xml"
	"testing"
	"time"

	"github.com/stretchr/testify/require"
)

func TestPeriodicWriter(t *testing.T) {
	const dur = 100 * time.Millisecond
	const whitespaces = 8
	expected := []byte(xml.Header)
	for i := 0; i < whitespaces; i++ {
		expected = append(expected, []byte(" ")...)
	}

	t.Run("writes data", func(t *testing.T) {
		buf := bytes.NewBuffer(nil)
		stop := periodicXMLWriter(buf, dur)

		// N number of whitespaces + half durations to guarantee at least N writes in buffer
		time.Sleep(whitespaces*dur + dur/2)
		require.True(t, stop())
		require.Equal(t, expected, buf.Bytes())

		t.Run("no additional data after stop", func(t *testing.T) {
			time.Sleep(2 * dur)
			require.Equal(t, expected, buf.Bytes())
		})
	})

	t.Run("does not write data", func(t *testing.T) {
		buf := bytes.NewBuffer(nil)
		stop := periodicXMLWriter(buf, dur)
		time.Sleep(dur / 2)
		require.False(t, stop())
		require.Empty(t, buf.Bytes())

		t.Run("disabled", func(t *testing.T) {
			stop = periodicXMLWriter(buf, 0)
			require.False(t, stop())
			require.Empty(t, buf.Bytes())
		})
	})
}